L THAM KIN - United Heckathorn Superfund Siteunitedheckathornsuperfundsite.com/uhwp/wp-content/uploads/2016/09/... · L THAM KIN s LLP January 26, ... LATHAM KINS modeling based on

L THAM KIN s LLP

January 26, 2015

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Taly Jolish, Assistant Regional Counsel U.S. EPA, Region 9 75 Hawthorne Street (ORC-3) San Francisco, CA 94105

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File No. 011427-0030

Re: United Heckathorn: Preliminary Technical Analysis Related to FFS and Remedy Selection

Dear Taly:

In October 2014, the United States Environmental Protection Agency ("EPA") met with Montrose Chemical Corporation of California ("Montrose") to discuss developments at the United Heckathorn Site (the "Site"). Among other topics, Montrose raised initial concerns with recent EPA studies, including but not limited to the Tier 1 and 2 Sediment Transport Studies, the DDT Fate and Transport Study, the Source Identification Study, and the Fish Tissue Sampling and Analysis study. Neither Montrose nor EPA had technical representatives on hand for the meeting, and any discussions involving the EPA studies were of a preliminary nature.

Following the October meeting, Montrose authorized Exponent Consulting to conduct a more rigorous initial review of the EPA studies to date. Attached please find a memorandum from Exponent highlighting preliminary key concerns and questions related to the sufficiency of the EPA Studies and the preparation ofthe Focus Feasibility Study ("FFS"). The Exponent team that prepared the memo includes Dr. Torn Ginn, Dr. Rick Bodishbaugh, Dr. Susan Paulsen, and Dr. Pravi Shrestha. Each brings considerable multidisciplinary expertise, and their respective CV s are attached. In addition, Dr. Ginn has extensive Site knowledge given his history, having consulted for Montrose in connection with United Heckathorn for more than a decade.

Montrose appreciates EPA's willingness to discuss the status of activities at the Site, and to allow Montrose to participate in a dialogue as remedial alternatives take shape. Montrose respectfully requests that EPA review and address the concerns, questions, and data requests made in the attached memorandum in connection with, and prior to, issuing the FFS. Following their preliminary analysis, Exponent has determined that it would be premature for EPA to weigh remedial alternatives at this juncture based on the EPA studies. For example, the source

January 26, 2015 Page 2

LATHAM KINS

modeling based on 34 days of dry weather sampling is insufficient to determine loading from upland sources, stormwater, sediment redistribution, etc., that occur almost exclusively during wet weather flow, which was not considered by EPA's consultants. Further, there are significant sources that have not been adequately addressed. EPA may need to conduct additional analyses to address limitations in the EPA studies prior to finalizing any remedial alternative analyses in the FFS.

Please do not hesitate to contact me if you have any questions.

Kelly E. Richardson of LATHAM & WATKINS LLP

SD\1549192.2

1406103.000 - 4899

TO: Joe Kelly, President, Montrose Chemical Corporation of California

FROM: Rick Bodishbaugh, Susan Paulsen, Pravi Shrestha, Alex Revchuk and Tom Ginn

DATE: January 23, 2015

PROJECT: 1406103.000 0101

SUBJECT: Preliminary Technical Analysis Related to Parr-Richmond FFS and Remedy Selection

Exponent has reviewed several key documents that describe studies conducted by the U.S. Environmental Protection Agency (EPA) since the 2011 third 5-year review at the United Heckathorn Superfund site, in addition to certain historical documents. Based on this review, and as discussed in greater detail in this memorandum, we have several key concerns and questions related to the preparation of the upcoming focused feasibility study (FFS). A number of unanswered or inadequately answered questions remain concerning fundamental issues at the site, including the performance history of the original remedy, significance of ongoing sources, and fate and transport of sediment contaminants. Because of these significant uncertainties, it would be premature for EPA to make a decision regarding a future remedy at this time. Additional analyses should be performed prior to finalizing any recommendations that may be made in the upcoming FFS.

Our key concerns are summarized below, followed by corresponding detailed discussions on each of the topics of concern.

Outline of Key Concerns and Questions Related to the Upcoming FFS

1. We recommend a comprehensive evaluation of the dredging/sand layer placement remedy conducted in 1996–1997, as well as data from published studies conducted in the years immediately following the remedy implementation1 to identify why post-remedy pollutant concentrations that initially met remedial goals subsequently rose to levels that exceeded the sediment and bioaccumulation objectives. This evaluation should include a more comprehensive consideration of possible ongoing sources than that completed to date (see discussion below), as well as the effects of storm events and sediment resuspension/redistribution due to maintenance dredging and other human activities in the area. A thorough understanding of the factors or conditions that led to current conditions is essential to incorporate “lessons learned” from the prior remedial efforts and to avoid issuing a potentially incomplete FFS. We also recommend that EPA consider a range of

1 For example, see Anderson et al. 2000 and Weston et al. 2002

E X T E R N A L M E M O R A N D U M

Preliminary Technical Analysis Related to Parr-Richmond FFS January 23, 2015

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remedial alternatives, including (but not limited to) use of activated carbon and localized hot spot treatment, and evaluate the costs and benefits of each option.

2. Certain key conclusions and assumptions in the source identification study are unsupported by the report. We recommend that additional information be provided so that we can evaluate the existing study, including but not limited to: data for organic carbon, metals, and organic compounds in sediments, soils, and water samples collected from marine and upland areas of the site and storm drains; data and calculations of sources and losses; and information from site surveys. In addition, we recommend that an analysis be done to evaluate storm drains, laterals, and other potential stormwater sources; to evaluate and demonstrate the efficacy of the upland cap remedy; to evaluate the importance of subtidal outfalls and other sources; to evaluate historical events for their influence on sediment redistribution (e.g., storm events and navigation maintenance dredging of Santa Fe Channel by the City of Richmond in the late 1990s); and to evaluate embankment soils and unremediated sediments as potential ongoing sources.

3. The recently released sediment transport study, conducted on behalf of EPA by Sea Engineering, was conducted to characterize conditions over a short time period during the dry season, even though pollutant and sediment transport is typically greatest during the wet season and during major storm events. Thus, the sediment transport study did not analyze conditions that are most important for sediment transport and resuspension, and failed to account for possible important ongoing sources and sediment transport mechanisms. In addition, Exponent recommends requesting additional information related to the transport and mass balance models developed by Sea Engineering, including: the initial and boundary conditions; the parameterization of important processes influencing hydrodynamics and sediment transport; calibration, validation, and sensitivity and/or uncertainty analyses; hindcast and forecast simulations (if conducted); and use of the model in source identification study components. Without analyzing this additional information, Exponent is unable to determine the validity and reliability of the models for use in remedy selection or in predictions of remedy performance.

4. An evaluation of additional contaminants present at the site (e.g., metals and organic compounds commonly present in stormwater, contaminants from shipping and other waterfront industrial processes) should be conducted to supplement the source identification study and to determine if other contaminants are impacting beneficial uses and should also be considered in the FFS. While the 1994 Record of Decision (ROD) and subsequent review reports focused primarily on DDT and dieldrin, elevated post-remedial concentrations of PAHs, PCBs, and chlordane in Lauritzen Channel sediments have been documented. Without incorporating additional contaminants into a planned remedy, if and as appropriate, the likelihood increases that beneficial uses will not be protected by future remedial actions.

5. Risk estimates for human and wildlife receptors from pesticides in sediments have not been updated since the ROD, and have not been reviewed adequately in light of the 2008 fish tissue study. We recommend that a spatial and temporal analysis of measured DDT and dieldrin, as well as other contaminant concentrations, in sediments and fish tissue be


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performed to assess current risk drivers. In addition to the studies used to support the original remedial investigation, a number of sediment and bioaccumulation studies have been conducted in Lauritzen Channel over the years that would permit an assessment of sediment and biota concentration trends over time (e.g., Anderson et al. 2000, Weston et al. 2002, CH2M Hill 2008). While DDT sediment and fish tissue concentrations have consistently been much higher than dieldrin, acceptable risk thresholds for dieldrin can be much lower, particularly for human health. Any evaluation of the need for additional remedial action should consider relative residual risk levels of DDT and dieldrin, as well as other contaminants in Lauritzen Channel.

6. Exponent recommends requesting data and information to support a more thorough review of the conclusions reached in the various EPA study reports, including additional pollutant concentration data and detailed information describing the hydrodynamic and sediment modeling studies (see a more complete list provided in Section 6 of this memorandum). Based on this review, Exponent may recommend additional data collection and analyses, to supplement the studies performed to date and to inform remedy selection.

1. Remedy Evaluation

The available information indicates that the target surface sediment DDT concentrations achieved in the remedy implemented in 1996–1997 have not been maintained, but the reason(s) for this change is unclear. For example, was the original remedy specification inadequate or inappropriate, or have site conditions changed due to undocumented factors? Furthermore, has re-contamination occurred, due to ongoing sources, or is a combination of these factors taking place? In any case, proceeding with specification and implementation of additional remediation would be unwise without fully understanding the relative importance of all possible reasons for the apparent increase in sediment pesticide concentrations, since the remedial action was completed and the Certificate of Completion was issued in 1997. Additional analysis is needed of the pollutant concentrations in the sediments over time, and of the relative magnitude of various pollutant sources, including both those that may have contributed to the increase in pesticide concentrations since the implementation of the prior remedy and those that may threaten the integrity of potential future remedies. In short, it is important to understand the reasons for lack of long-term effectiveness of the past remedy, which included dredging and placement of a thin sand layer, and the possible role of recontamination from uncontrolled sources before proceeding with an additional remedy. If such analyses are not conducted, it is possible that future remedial design and implementation may simply result in a repeat of past failures.

The 1996–1997 dredging event was followed by confirmatory sampling (the average DDT concentration in 18 post-dredge samples was found to be below the remedial target of 590 µg/kg [CH2M Hill 2014, p. 8-1]), and then by the addition of a thin sand layer. Subsequent sampling events conducted in 1999 and after did not find the sand layer to be intact and found concentrations of DDT in sediments that were higher than those found in post-dredging confirmatory sampling. The reasons for this finding are unclear. Possible explanations include physical processes (e.g., erosion and resuspension of sediments outside the area dredged during 1996-1997) and/or inputs of contaminants from other sources that were not addressed by the


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prior remedy (e.g., stormwater, upland areas, sediment redistribution due to other area dredging operations). Potential problems with the long term performance of the Lauritzen Channel remedy were documented by multiple dredging effectiveness studies conducted in the late 1990s. In a study conducted shortly after implementation of the remedy, a group of researchers from the University of California and the California Department of Fish and Game concluded that “The degree of contamination and toxicity at this site after extensive remediation of contaminated sediments is problematic, and it suggests that future remediation projects that rely on similar methodologies should incorporate greater consideration of possible sources for postremediation contamination to better achieve the project goals.” (Anderson et al. 2000, p. 886). Recent conclusions reached by EPA and its consultants about the effectiveness of the past remedy appear to be largely unsubstantiated and may be unwarranted. We have not been able to review the calculations by EPA and its consultants that were used to estimate the DDT mass resident in the sediments of the Lauritzen Canal (i.e., to calculate the values shown in Table 5 at p. 11 and in Figure 4 at p. 13 of the Fate and Transport study), because the details of the data used in the calculations and the calculation method do not appear to be included in the materials we have reviewed to date. We suspect that significant “error bars” should be shown along with these point estimates; if error bars are shown, it is not clear whether or not the apparent upward trend in DDT mass over time will be justified or statistically significant.

Similarly, various additional sources (e.g., deposition from Bay, other sources, groundwater) and losses (e.g., vessel resuspension, diffusion losses) are assumed to be small relative to the mass of pollutant in the sediments at the site, but the data used to support these assumptions and the calculation method are not provided. This is inconsistent with the conclusion of the EPA 2014 DDT Fate and Transport Study that DDT mass in sediments has been increasing over time, likely due to ongoing sources (Sea Engineering 2014). Many aspects of EPA’s analysis of ongoing sources are unclear. For example, “other sources” include pipes and outfalls, which as noted above, were not sampled or considered fully during wet weather conditions, and it appears that sampling would not be conducted unless or until storm-drain cleanout is completed. Thus, it is unclear whether the source calculations in the report assume that a cleanout has been completed, or if the calculation represents this source in its current condition (i.e., without cleanouts or routine maintenance). Further analysis of events that occurred immediately following remediation is necessary to understand and account for the apparent post-remedial increase in DDT concentrations in channel sediment. Rain events, which would cause stormwater flows through and over uncapped areas, open pipes and laterals, could have led to significant transport of contaminated sediments. Further, the impact of other upland pesticide formulators and manufacturers (e.g., Calspray) are not addressed. Again, it is unclear whether the reported fluctuations in sediment DDT mass balances over time are due to an uncharacterized, ongoing source, or to variability in model inputs and assumptions. To evaluate the past remedy and why concentrations achieved at that time have not been maintained, a thorough evaluation of available data is needed. In addition, we encourage EPA


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to evaluate a range of remedial alternatives, including activated carbon, and localized hotspot treatment, to develop careful and complete cost estimates and cost-benefit analyses for all remedial alternatives. If ongoing source control is needed, activated carbon should be considered in addition to simple removal alternatives.

2. Source Identification and Control

The adequacy of source control prior to and since the original remedy has been repeatedly questioned over the years in published reports. Anderson et al. (2000) made the following observations regarding source control: “….postremediation contamination may have come either from an upland source or from one where the timing or conditions under which metabolic alteration of DDT differed from those of the preremediation sediments. Identifying the sources of postremediation contamination was beyond the scope of this study but should be addressed at this site before similar remediation plans are implemented” (Anderson et al. 2000, p. 885) and “Such [source] identification should also be included in any future investigations at this site to minimize inputs and to prevent further habitat contamination” (ibid.).

There appear to be five major potential sources of contaminants in receiving-water sediments, each of which is discussed briefly below.

Redistribution of in-channel sediments. As detailed above, EPA’s measurements and modeling and source analyses evaluated conditions during a 1-month period in the dry season. In addition to the limitations of the model, the decision to model conditions only during a dry period limits the utility of the modeling on which the remedy will be based. It will be important to characterize the fate of in-channel sediments that may be resuspended by vessel movements, wind and waves, and other factors, before a future remedy is selected. Historical events should also be considered for their influence on sediment redistribution, including storm events and the navigation maintenance dredging of Santa Fe Channel by the City of Richmond in the late 1990s (noted by Anderson et al. [2000]).

Stormwater, including storm drains and laterals. A narrative of a 2001 site inspection included in the first 5-year review report states that “Lauritzen Channel has numerous outfall pipes, including interceptor outfalls and City of Richmond outfalls” (USEPA 2001, p. 15). Conditions within these storm drain systems have not been well characterized, and thus, it is unknown whether stormwater has been or may continue to be a significant source of sediment and contaminants to the receiving water. It appears that sediment was not sampled in storm drains until 2007 (CH2M Hill 2011, Attachment 1, Table 1). Because conditions have been dry in recent years, pipes and outfalls “have not been inspected or sampled during wet weather conditions” (CH2M Hill 2011, p. 3-3). According to annual reports, “…occasional minor sedimentation [is] observed within the storm drains” (CH2M Hill 2011, p. 6-2), indicating transport of soils. In 2008, sampled sediments within storm drains had detected concentrations “up to 52 mg/kg” of DDT (CH2M Hill 2011, p. 6-6), which were attributed to historical operations and lack of cleaning. Reports indicate that “to date [March 2014], the municipal storm drains have not been cleaned out; therefore, the


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stormwater sampling will not be conducted and the cleaning of the storm drain system will be included in the evaluation of remedial alternatives in the FFS” (CH2M Hill 2014, p. 2-2). Although it is important to understand the role of the storm drain system as a potential ongoing source, it appears that EPA may not wish to characterize this source prior to remediation of the storm drains themselves. As noted in CH2M Hill (2014), “Stormwater discharges from the municipal storm drain at the head of the Lauritzen Channel were to be sampled as part of this source identification study after the residual sediments in the storm drain system had been removed. However, these sediments have not yet been removed, so the potential for the municipal storm drain system to act as an ongoing DDT transport pathway in the future cannot be evaluated. If the residual sediments are removed prior to completion of the FFS, then stormwater sampling may be performed, to verify whether or not discharges from the municipal storm drain system are an ongoing source of contamination to the Lauritzen Channel. Otherwise, development of the remedial alternatives should address this potential ongoing source” (CH2M Hill 2014, p. 6-1).

The reports we have reviewed to date indicate that important information is missing. For example, the reports indicate that, “Storm drain sediment sampling was also performed by EPA’s START contractor in 2012 to support a potential emergency removal action. Due to cost implications, the removal action was placed on hold and the sampling report was not finalized; therefore, the data are not included in this evaluation” (CH2M Hill 2014, p. 6-2). The reports also indicate that “…the structural integrity, invert elevations, and hydraulic connections could not be determined for all drains because of the large amount of residual sediment in the system” (CH2M Hill 2014, p. 6-1), and the reports describe cracks in piping and water infiltration (CH2M Hill 2014, p. 6-3). Further, none of the reports have addressed the potential effect of post-remedial storm events, which may have led to episodic inflows of sediment from the storm drain systems and other piping and laterals. It would be prudent to review information related to these issues before proceeding with remedy selection, to avoid selection of an inappropriate or premature additional remedy before the recontamination potential is fully understood.

As detailed within this memorandum, the remedy conducted in 1996–1997 appears to have failed to maintain remedial goals; recent reports acknowledge that concentration “bounce back” occurred in several interceptors over the years, indicating the importance of characterizing source mechanisms prior to dredging (CH2M Hill 2014, p. 6-3). Understanding whether this failure was the result of additional pollutant sources from stormwater runoff is important to planning additional remedial measures.

Upland areas. The third 5-year review report concludes that “[t]he remedy implemented at the upland areas of the United Heckathorn Superfund Site is protective of human health and the environment, due to capping of contaminated soils which has eliminated human health exposure pathways and prevented erosion. Routine inspection and monitoring assures the protectiveness of the upland remedy at the Site…” (CH2M Hill 2011, p. viii). The document also concludes that the remedy implemented at the marine areas of the Site “is not protective because DDT concentrations in sediment, water and biota remain a potential exposure risk…” (CH2M Hill 2011, p. viii). Conclusions regarding the upland areas appear to be based on annual reports that document the implementation of the operations and maintenance plan, and that found that “the


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upland cap is determined to be uncompromised and functioning as intended” (CH2M Hill 2011, p. 6-1). However, it does not appear that runoff over the capped upland areas was sampled, or that pollutant concentrations have been measured in “occasional minor sedimentation observed within the storm drains” (CH2M Hill 2011, p. 6-2). Moreover, based on photographs included in the third 5-year review report that show visible cracks in the upland cap, the integrity of the cap seems unclear (see USEPA 2011, p. 20-21). Without additional documentation and data, it appears to be premature to conclude that the upland area is not contributing sediment and pollutant loads to the marine areas, or that drains associated with upland areas that were not sealed until after the 1997 remedy did contribute to recontamination of sediments. The possibility of contribution from upland area runoff to post-remedial DDT sediment concentrations was raised by Anderson et al. (2000), who noted that post-remedial sediment DDT to DDD concentration ratios were intermediate between ratios measured in pre-remedial sediments and upland soils. The authors concluded that “This suggests that post-remediation contamination may have come either from an upland source or from one where the timing or conditions under which metabolic alteration of DDT differed from those of the pre-remediation sediments” (Anderson et al. 2000, p. 885). Subtidal or obscured areas. As noted by CH2M Hill, “… other pipes and conveyances that are not visible may exist (i.e., features that terminate behind rip rap or sheetpile, or are subtidal). Any of the identified or unidentified pipes and conveyances could have and may still act as preferential pathways for the transport of DDT from the upland area to the Lauritzen Channel, particularly adjacent to the former plant site and former train scale area where highly contaminated soils and groundwater still exist” (CH2M Hill 2014, p. 9-1). Clearly, it would be prudent to characterize these potential sources and understand their importance as an ongoing source of sediment and contaminants to the receiving waters, before proceeding with remedy selection.

Embankment soils and/or other unremediated sediments. Site surveys have noted areas of erosion (“erosion hotspots”) and seeps in the past. In addition, the existence of “preferential pathways” for contaminant migration has been suspected (CH2M Hill 2014, p. 3-2), but it is unclear whether such pathways have been characterized. As with other potential sources, the magnitude of these sources has not been well characterized, and it is not clear whether these sources have been addressed. For example, “Evidence of soil erosion was observed during the site surveys performed in 2012. Erosion under the sheet pile wall, observed as approximately 1‐ to 2‐foot voids, was noted at the north end of the eastern bank of the channel. These features were noted between bent ‐37 and the head of the channel. Sink holes and exposed cap material were also observed on the Levin property in the vicinity of bent ‐24 and T‐8.5” (CH2M Hill 2014, p. 3-3). It appears that an embankment soil erosion hotspot near bent +3 to bent -3 was not addressed during work in 1990–1993, or during 2002–2004 (CH2M Hill 2014, p. 3-2). Although a seep at T-8.5, “an ongoing source of DDT contamination to the channel” (CH2M Hill 2014, p. 3-2), was sealed in 2003, it is not clear whether the seal was effective or if it is routinely inspected and maintained, nor can it be determined whether other similar seeps exist or have been sealed, or whether significant amounts of pesticides were released before it was sealed. Finally, “… historical embankment soil and sediment data indicate that erosion of contaminated embankment soils on the northern and eastern sides of the channel is an ongoing


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source of contamination to the Lauritzen Channel. However, the magnitude of the source is difficult to quantify because most of the embankment is lined with sheetpile, rip rap, and/or concrete, with only localized areas of exposed soil subject to erosion.” (CH2M Hill 2014, p. 3-5).

Shoreline and under-pier sediments have also been identified as a potential ongoing source (Weston et al. 2002). These areas were not addressed by the original remedy due to engineering feasibility issues (CH2M Hill 2011). Redistribution of sediment contaminants from shoreline and under-pier areas cannot be ruled out as an important ongoing source and should be considered in future work.

The potential sources described above, along with any additional potential sources that may be identified as supplemental data and information are collected and reviewed, should be fully evaluated and characterized prior to remedy selection. Source identification and control will be essential to the success of any future planned remedy.

3. Sediment Transport Study

The Tier 1 and Tier 2 Sediment Transport Studies appear to be incomplete or inadequate in many respects, and hence do not provide the information needed to support planned remedial alternative evaluations and remedial action(s) at the United Heckathorn Superfund Site.

Dry Season Evaluation is Insufficient. The Tier 1 and Tier 2 sediment transport study reports describe the hydrodynamic and sediment transport modeling effort that was conducted to characterize flow and sediment conditions at the United Heckathorn Superfund Site. However, the modeling appears to have been flawed in important respects, and information to assess the adequacy and validity of the model is lacking. The primary flaw is that the simulation period in the hydrodynamic and sediment transport models was limited to a 34-day dry-season period from June 4 to July 9, 2013. However, sediment resuspension is typically greatest during storm events, when wind and wave conditions transfer the greatest amount of energy to the sediment bed. Sediment loads from land surfaces to receiving waters are also greatest during storm events. The numerical model simulations, therefore, are incomplete, because the simulations do not capture the important processes that occur during wet-weather conditions, and do not attempt to quantify or estimate sediment loadings to the model domain that occur during episodic flow events. In addition, the monitoring period is clearly not justified, given the conclusion that “[t]he total daily averaged sediment flux over the 34-day mooring deployment period was near zero kg/s at both locations. The near zero sediment flux was observed during a one-month dry period. Overall net accumulation in San Francisco Bay typically occurs during the wet fall and winter periods” (Sea Engineering 2014, p.17). The failure to simulate the wet periods that are most important to the spatial and temporal distribution of sediment and contaminants means that the models are not a reliable basis for selecting a remedy (or remedies) that must perform during both dry and wet conditions.

Important Transport Process Phenomena Were Not Considered. The Tier 1 and Tier 2 sediment transport study reports do not describe the hydrodynamic and sediment transport processes used in the respective models, and hence are incomplete from the perspective of


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understanding the model documentation and the model review process. The reports describe the use of the Environmental Fluid Dynamics Code (EFDC), which includes various constitutive equations and formulations that can be selected by the user. Processes that influence cohesive sediment transport include advection, dispersion, aggregation (flocculation), settling, consolidation, and resuspension. The reports do not identify the processes and formulations that were implemented in the model. For example, the two sediment size classes simulated (10 μm and 51 μm) fall into the cohesive class range, given the relatively high fraction of mud in most of the surface samples. Consequently, the settling velocities of these sediments are susceptible to aggregation (flocculation) in the water column; flocculation will result in settling velocities that are likely to differ from those calculated using the Cheng (1997) formulation. Furthermore, it is not clear how the model resuspends the two sediment size classes from the sediment bed, and how these sediment size classes are tracked in the sediment bed and in the water column. Finally, it appears that anthropogenic activities, such as scour from vessel movement, dredging activities, and outfall discharges, were not included in the model, possibly leading to a failure to identify all important transport mechanisms responsible for elevated sediment DDT concentrations.

Initial and Boundary Conditions Are Inadequately Described. Accurately modeling hydrodynamics and sediment transport requires appropriate initial conditions (which are used to describe the “starting point” of the model runs) and boundary conditions (which are used to characterize conditions at model boundaries). Both are inadequately described, and may have been inadequately specified. For dynamic simulations, initial conditions need to be set up for all dependent variables. For the hydrodynamic model, these variables include salinity, temperature, and velocity in all seven sigma layers for all grid cells in the model domain. For the sediment transport model, initial conditions include the fractions of the two sediment classes simulated, the dry density, and sediment erodibility (erosion rate function and critical shear stress) with depth within the sediment bed for all grid cells in the model domain. Suspended sediment concentrations also need to be specified for all seven sigma layers in all grid cells in the model domain. As described in Sea Engineering (2014, 24-28), a Sedflume analysis was conducted for 10 cores in the Lauritzen Channel. Results showed that the erosion rates were highly variable. Because of the limited number of samples and their variable erodibility, it appears that the Sedflume tests could not be used to set up the initial bed sediment conditions in the Lauritzen Channel. The relevance of the Sedflume tests, therefore, is limited to assessment of site-specific erosion, and the tests do not provide the required spatial discretization (horizontally and vertically) for use in the sediment transport model. If data are limited for setting up the initial conditions, then the effectiveness of the model, in its current state, is likewise limited for supporting sediment management plans.

It also appears that the boundary conditions to the hydrodynamic and sediment transport models neglected important components. The hydrodynamic model was forced by only two boundary conditions—namely: (i) the water levels at the Richmond Inner Harbor Tidal Station, which were applied to the southern boundary of the model domain; and (ii) wind data from the National Oceanic and Atmospheric Administration (NOAA) Station at Richmond, which were applied uniformly over the entire model domain. Hydrodynamic boundary conditions that were not incorporated in the model include: (i) meteorological boundary conditions other than wind


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speed and direction, (ii) freshwater flows from all outfalls, (iii) non-point surface runoff, and (iv) groundwater flows. Similarly, boundary conditions to the sediment transport model that were not incorporated into the model include sediment loading at all outfall locations, from non-point sources, and at the tidal boundary; the sediment loading would also need to specify the concentration of each of the two sediment size classes simulated. Absent specification of relevant boundary conditions, the hydrodynamic and sediment transport processes cannot be simulated realistically. The models, in their current state, appear therefore to be unreliable for supporting sediment management plans.

Calibration and Validation of Models Was Inadequate. Typically, a model is calibrated by adjusting model parameters so that modeled and measured data match for a given time period. Models are then validated by simulating an additional time period using the model parameters from the calibration, and comparing the model output to measured data. Finally, sensitivity/uncertainty analyses are typically provided to evaluate the sensitivity of the model to changes in key model parameters. Here, however, calibration was limited, and validation was not performed. It appears also that sensitivity/uncertainty analyses of model input parameters were not performed.

The hydrodynamic and sediment transport models were not adequately calibrated or validated to past or monitored conditions and hence cannot be expected to serve as a viable tool for predicting future conditions. For the hydrodynamic model, it appears that only water level (stage) was used to compare model predictions to measured data; validations of model output for other hydrodynamic parameters were not presented. Specifically, it appears that model-data comparisons of water levels were carried out at only one of two Acoustic Doppler Current Profiler (ADCP) locations (i.e., at the mouth of Lauritzen Channel), which is minimal at best. Model-data comparisons of velocity were not depicted graphically; instead, the report states that “the low signal-to-noise velocities in the system did not facilitate direct model comparison” (Sea Engineering 2014, 57) and alludes to modeled tidal velocities being consistent with analytical solutions of tidal velocities based on the tidal prism. Model-data comparisons of salinities and temperature were also not performed. The study reports did not describe what hydrodynamic model parameters were used to calibrate the model, but instead states, “The water levels described above were used as the primary calibration and validation metrics” (Sea Engineering 2014, 57). Although calibration parameters for hydrodynamic models typically include the bottom roughness and the mixing coefficient, the report does not substantiate the conclusion that “[o]verall, the model was insensitive to adjustments in background eddy viscosities and bottom roughness, typical of similar systems, giving confidence in the model for the applications below” (Sea Engineering 2014, p.57).

Similarly, it appears that the sediment transport model was not calibrated or validated. Model-data comparisons of the spatial and temporal distribution of suspended solids would have provided insight on model performance. Calibration parameters that are relevant to the sediment transport model include sediment size class modeled, distribution of grain sizes in the model domain, settling velocities, and erodibility characteristics such as erosion rates and critical shear stress for erosion, and dry density. The inadequacy of the calibration and validation effort severely limits the reliability and usefulness of the model, and calls into


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question the validity of any future remedy selection based in any significant way on the findings of this model.

Sensitivity Analyses of Models Was Not Performed. A sensitivity/uncertainty analyses requires that each calibration parameter (e.g., initial conditions, upstream and downstream boundary conditions, bottom roughness, mixing coefficients, and sediment size and erodibility characteristics) be perturbed above and below their optimized values to evaluate model response to hydrodynamic circulation patterns and sediment concentrations in the water column and sediment bed. Absent a thorough sensitivity/uncertainty analysis, the model cannot be used reliably as a predictive tool.

In conclusion, it appears that model performance was not evaluated with sufficient rigor so as to develop confidence in the model. Hindcasting and mass balance analyses could have been conducted to provide additional confidence in the modeling tools. In addition to the inadequacy of the model calibration and validation efforts and the lack of sensitivity/uncertainty analysis, there was no attempt to perform hindcast simulations to assess the reliability of the model using known or estimated inputs from the past, to see how well the model reproduces known conditions. A hindcast simulation for the period from completion of remediation to current conditions could have provided confidence in the model, and (as discussed in greater detail below) might have provided important insight into the performance of the prior remedy. Finally, the modeling study did not perform a diagnostic analysis for sediment mass balance for the simulation period, to show that sediment mass is conserved in accordance with the equation, Input – Output = Storage. The lack of a hindcast simulation and mass balance diagnostic analysis undermines the credibility of the models.

Modeling Results Were Insufficient to Support Conceptual Site Model Development. The model output appears to have been used to support the Conceptual Site Model (CSM). However, the CSM was based primarily on flawed modeling results and limited field studies conducted during the approximately 1-month dry-season period. As a result, the CSM is incomplete and unreliable in explaining sediment and associated contaminant transport and distribution in the Lauritzen Channel. For example, ADCP measurements and modeling results from the dry-season period were used to show that the Lauritzen Channel is a low-energy environment and a sediment sink in the absence of ship traffic. Again, limited ADCP data were used to show that maximum tidally induced bed shear stresses were only slightly above the critical shear stresses measured in the Sedflume analysis, to support the assertion that “tidal currents do not play a significant role in mobilizing sediment in the Lauritzen Channel” (Sea Engineering 2014, p.67).

As part of the CSM, the Tier II report presents a conceptual sediment budget. Key sediment loading sources to the system include the tidally driven inflows from San Francisco Bay and upland sources. As reported, the 34-day averaged sediment flux calculated from the ADCP data showed a net tidally driven transfer of zero. A net tidally driven transfer of zero appears to contradict the assertion in the report that, “The bay provides a constant delivery of silt and clay to the margins, including harbors” (Sea Engineering 2014, p.70). Consequently, tidally driven sediment loading was not quantified in the report, which instead states, “Had the ADCPs been deployed during winter months, increased flux from the bay may have been more apparent” (Sea Engineering 2014, p.70). Because sediment delivery from upland sources was not


12

quantified due to the lack of data, the report estimates sediment delivery using the U.S. Department of Agriculture method, which gives a gross estimate of sediment loading based on average rainfall and watershed area. Given that high flow events resulting from high-intensity rainfall produce the most sediment loading to a system, it is unrealistic to rely on gross methods to compute sediment delivery from a watershed.

The CSM and sediment budget are, at best, conceptual in nature and do not provide insight into which sediment transport processes are most important, or how these sediment processes influence the potential spatial and temporal distribution of sediment and contaminants within the study area. The available data, which indicate significant increases in both sediment and DDT mass (Sea Engineering 2014, Table 5), are difficult to reconcile with this CSM. Because they are conceptual and do not characterize conditions during the all-important wet season and for episodic events, they should not be used in remedy selection or in predictions of remedy performance.

4. Other Contaminants at the Site

Given the long history of industrial development and activity at the Site, it is likely that concentrations of other constituents in addition to DDT have been measured in sediment samples, soil samples, and water samples collected from the marine and upland areas of the site over time. For example, concentrations of metals (e.g., arsenic, cadmium, copper, lead, zinc) and other organic contaminants (e.g., polycyclic aromatic hydrocarbons [PAHs], polychlorinated biphenyls [PCBs]) are commonly measured in environmental samples, as part of remedial actions, discharge permitting, property transactions, and routine monitoring. Elevated post-remedial concentrations of PAHs, PCBs, and chlordane in Lauritzen Channel sediments have been documented, and post-remedial concentrations were as high or higher than pre-remedial concentrations (Anderson et al. 2000). The source of these contaminants remains uncharacterized, but Anderson et al. noted that industrial activities in the channel area including shipping operations and a “variety of land-based businesses, including manufacturing, recycling, and construction,” all of which are potential sources (ibid.). While these constituents are not currently the target of planned remedial activities, several of the maximum concentrations reported in sediments exceed generic chemistry benchmarks commonly used for human health and ecological risk screening purposes (e.g., NOAA ER-Ls). While not necessarily indicative of unacceptable risk or the need for action, screening benchmark exceedances may indicate the need for further evaluation. In addition, concentrations of all anthropogenic constituents, together with concentrations of DDT and dieldrin, can be used in many circumstances to establish source “fingerprints.” For example, concentrations of metals may be higher in stormwater than in embankment sediments, and the presence (or absence) of those metals in receiving-water sediments can be used to characterize the source of those sediments and the contaminants found on those sediments. Without a site-specific risk assessment, it is unclear whether these elevated metal and organic sediment contaminants currently represent a potential impairment of beneficial uses in Lauritzen Channel, independent of pesticide contamination.

Information on other constituents present can also contribute significantly to the understanding of pollutant fate and transport at a site. For example, concentrations of metals in sediment cores collected from the Palos Verdes Shelf were critical to understanding that DDT was biodegrading


13

at that site—peak concentrations of metals in cores from that site remained relatively steady in cores collected over long periods of time, while concentrations of DDT in the same cores decreased over time, indicating that sediment mixing was not responsible for declining concentrations of DDT (see, e.g., Paulsen et al. 1999). If available, concentrations of additional constituents should be obtained and reviewed in order to supplement the source identification work completed to date, and to put together as complete a picture as possible of the various sources of contaminants to the receiving waters at the site.

Finally, Exponent suggests that data collected to date should be examined to assess if other constituents are impairing beneficial uses. Although other constituents are not currently driving decisions regarding potential future remedies, based on our experience with TMDLs throughout the state, it is possible that additional constituents may need to be addressed. In addition to the likelihood that storm water discharges and surface runoff from industrial facilities in the area have contributed to sediment contamination (see discussion above), the Lauritzen Channel and surrounding waterways have a long history of commercial shipping terminal use. Sediment contamination scenarios commonly associated with shipping operations include petroleum hydrocarbons from fueling and treated wood piers, as well as copper and organotin loadings from the attrition of antifouling hull paints. Studies conducted in active harbors have concluded that leachate from copper-based hull coatings can be the primary dissolved copper loading source (Bloom 1995, US Navy 1998). Incorporating additional constituents into a planned remedy now, if and as appropriate, would maximize the likelihood that beneficial uses will be protected by future remedial actions and protect against the failure of future remedies due to elevated levels of non-pesticide sediment contaminants.

5. Fish and Mussel Tissue Data

The relevant exposure pathway for both human and ecological receptors, and therefore the driver for any additional remediation of sediments, is via uptake into the aquatic food web. The risk analyses used to support the ROD are now 20 years old, and they have not been updated to reflect the most recent fish and mussel tissue data reported in the 2008 fish-tissue study. Any analysis of the need for additional remediation should include a full assessment of complete exposure pathways for all sediment contaminants. At a minimum, the relative risk of exposure to DDT and dieldrin, as well as other contaminants of concern, should be assessed for human and wildlife receptors using current data. The spatial distribution of both pesticides should also be assessed using the most current data. It is our recommendation that exposure and risk assumptions be critically re-evaluated, given the age of the original risk analysis and data.

The post-remedial bioaccumulation monitoring record provides evidence of a change in conditions at the site during the decade following implementation of the remedy, leading to higher DDT levels in tissue, and possibly indicating the influence of ongoing sources. An early study (Weston et al. 2002) evaluated a rapid increase in the bioaccumulation of pesticides by mussels in and around Lauritzen Channel in 1998, the year immediately following remediation. The authors concluded that this was the result of recontamination by suspended sediments and material from undredged areas: “After completion of dredging, the canal bottom was quickly covered by a veneer of sediments that were as contaminated as the sediments present prior to dredging. Direct exposure of the biota to the redeposited surficial layer of contaminated


14

sediments and indirect exposure via trophic transfer of ΣDDT [sum of DDT and primary metabolites] led to pesticide body burdens that were as great or greater than body burdens before dredging” (Weston et al. 2002, p. 2223). The authors also suggested that “If the contaminated material had been capped in place, post-remediation ΣDDT levels in canal biota may have been lower than the levels we observed after dredging” (ibid.). The first 5-year review report characterized this initial post-remediation increase in pesticide bioaccumulation levels as a transient phenomenon, with decreasing mussel tissue concentrations noted in 1999-2001 monitoring data, even though the remedial objectives for DDT and dieldrin concentrations in water and sediment had not been met at that time (USEPA 2001). The second 5-year review report, which included biological monitoring data through 2003, documented a general decline in DDT levels in mussel and fish tissue, with sediment and water remedial objectives being met in some but not most areas (USEPA 2006). The third 5-year review report added biological data from 2007 and 2009, which show an increase in mussel tissue DDT residues, back to pre-remedial levels (USEPA 2011). Taken as a whole, the bioaccumulation data record suggests a change in conditions between 2003 and 2007, leading to a reversal of the decrease in biological uptake of DDT attributed by EPA to the remediation at the time of the second five year review. The reasons for this are unclear, but should be thoroughly assessed prior to attempting any additional remedial action.

6. Data Request

As detailed throughout these comments, Exponent recommends that additional data and information be obtained to support a more thorough review of sediment transport, pollutant sources, and remedy selection. Specifically, the following information should be requested from EPA for review:

• Available chemical data, including data for organic carbon, metals, and organic compounds, for sediment samples, soil samples, and water samples collected from the marine and upland areas of the site and from storm drains or other areas; electronic format (e.g., Excel or Access) for data is preferred

• Data and calculations of the DDT mass estimated to be resident in the sediments of the Lauritzen Canal (i.e., to calculate values shown in Table 5 at p. 11 and in Figure 4 of p. 13 of the Fate and Transport Study, CH2M Hill 2014)

• Data and calculations of the sources and losses of DDT, as discussed in Section 4 of the Fate and Transport Study (CH2M Hill 2014, p. 13 et seq.)

• Data describing DDT, dieldrin, and other elevated contaminant concentrations in marine sediments and fish and mussel tissue; electronic format (e.g., Excel or Access) for data is preferred

• Information related to the hydrodynamic and sediment transport modeling, including:


15

− Documentation of the Environmental Fluid Dynamics Code (EFDC) with respect to hydrodynamic and sediment transport models

− Model grid information, including grid resolution and bathymetric conditions

− Initial conditions used to set up each model, including freshwater inflows, water levels, temperature and salinity conditions, sediment bed characteristics such as grain size distribution, settling velocities, erodibility characteristics of the bed sediments, and suspended sediment concentrations for both sediment size classes

− Boundary conditions not described in the reports, including meteorology boundary conditions other than wind speed and direction; freshwater flow rates from all outfalls; non-point surface runoff; groundwater flow rates; and sediment loading at the tidal boundary and at outfall locations for both sediment size classes simulated in the model

− Process descriptions and formulations used within the Environmental Fluid Dynamics Code (EFDC) model of the receiving waters, including formulations used to simulate cohesive sediment transport, advection, dispersion, aggregation (flocculation), settling, consolidation, and resuspension

− Description of how the two sediment size classes in the sediment bed were modeled, and how sediment size classes are tracked in the sediment bed and water column

− Modeled and measured water level, velocity, temperature, salinity, and suspended sediment concentrations for which model results are available

− Description of the calibration process used for the hydrodynamic model and the calibrated values of model parameters, including (but not limited to) the values used for bottom roughness, the mixing coefficient, particle settling velocities, critical shear stress for erosion, and sediment dry density

− Hindcast and forecast simulation results, if available

• Data from storm drain sediment sampling performed by EPA’s START contractor in 2012 (referenced in CH2M Hill 2014 p. 6-2), including maps of known storm drains, details about remediation and volume of material removed, and chemistry data.

• Identification or quantification of “preferential pathways,” as referenced in CH2M Hill 2014 (p. 3-2)


16

• Description of the sealing process used at the seep at T-8.5, including maintenance

• Additional information on areas of soil erosion observed during site surveys performed in 2012.

References

Anderson B.S., Hunt J.W., Phillips B.M., Stoelting M., Becker J., Fairey R., Puckett H.M., Stephenson M., Tjeerdema R., Martin M. 2000. Ecotoxicologic change at a remediated Superfund site in San Francisco, California, USA. Environmental Toxicology and Chemistry 19:879–887. Bloom, M.S. 1995. A quantitative assessment of copper loading to San Diego Bay, CA. Thesis submitted in partial fulfillment for the degree Master of Public Health, San Diego State University, San Diego, CA. 158 pp.

CH2M Hill. 2011. Third five-year review report for United Heckathorn Superfund Site, Richmond, California. September.

CH2M Hill. 2014. Source identification study report, United Heckathorn Superfund Site. March.

CH2M Hill. 2014. United Heckathorn Superfund Site: Tier 2 Sediment Transport Study. February.

Cheng, N. 1997. Simplified settling velocity formula for sediment particles. J. Hydraul. Eng. 123(2):149–152.

Paulsen, S.C., E.J. List, and P.H. Santschi. 1999. Modeling variability in 210Pb and sediment fluxes near the Whites Point outfalls, Palos Verdes shelf, California. Environ. Sci. Technol. 33:3077–3085.

Sea Engineering. 2014. United Heckathorn Superfund Site, Richmond, California, DDT Fate and Transport Study. May.

U.S. Environmental Protection Agency (USEPA). 2001. First Five-Year Review Report for United Heckathorn Superfund Site. Town of Richmond, Contra Costa County, California. Prepared by USEPA Region IX, San Francisco, CA. September 2001.

U.S. Environmental Protection Agency (USEPA). 2006. Second Five-Year Review Report for United Heckathorn Superfund Site. Richmond, California. Prepared for contract No. 68-W-98-225/WA NO. 214-FRFE-09R3. USEPA Region IX, San Francisco, CA. September 2006.


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U.S. Environmental Protection Agency (USEPA). 2011. Third Five-Year Review Report for United Heckathorn Superfund Site. Richmond, California. Prepared for contract No. EP-S9-08-04/WA NO. 214-FRFE-09R3. USEPA Region IX, San Francisco, CA. September 2011.

US Navy. 1998. Copper Loading to U.S. Navy Harbors. Norfolk, VA; Pearl Harbor, HI; and San Diego, CA. H. D. Johnson J. G. Grovhoug. Technical Document 3052. 79 pp. December 1998. Weston, D. P., Jarman, W. M., Cabana, G., Bacon, C. E. and Jacobson, L. A. (2002), An evaluation of the success of dredging as remediation at a DDT-contaminated site in San Francisco Bay, California, USA. Environmental Toxicology and Chemistry, 21: 2216–2224

879

Environmental Toxicology and Chemistry, Vol. 19, No. 4, pp. 879–887, 2000q 2000 SETAC

Printed in the USA0730-7268/00 $9.00 1 .00

ECOTOXICOLOGIC CHANGE AT A REMEDIATED SUPERFUND SITE IN SANFRANCISCO, CALIFORNIA, USA

BRIAN S. ANDERSON,*† JOHN W. HUNT,† BRYN M. PHILLIPS,† MATT STOELTING,‡ JONATHON BECKER,‡RUSSELL FAIREY,§ H. MAX PUCKETT,zz MARK STEPHENSON,# RONALD S. TJEERDEMA,† and MICHAEL MARTIN#

†Department of Environmental Toxicology, University of California, Davis, California 95616, USA‡Institute of Marine Sciences, University of California, Santa Cruz, California 95064, USA

§San Jose State University Foundation, Moss Landing Marine Laboratories, P.O. Box 747, Moss Landing, California 95039, USAzzCalifornia Department of Fish and Game, Marine Pollution Studies Laboratory, 34500 Coast Route 1, Monterey, California 93940, USA

#California Department of Fish and Game, 20 Lower Ragsdale Drive, Suite 100, Monterey, California 93940–5729, USA

(Received 26 April 1999; Accepted 26 July 1999)

Abstract—Lauritzen Channel is an industrial waterway adjacent to the former United Heckathorn facility in the inner RichmondHarbor area of San Francisco Bay, California, USA. Marine sediments at this Superfund site were dredged from late 1996 throughearly 1997 to remove the primary chemicals of concern: DDT, and dieldrin. This study assessed the Lauritzen Channel marineenvironment immediately before and approximately one year after the dredging of sediments. The study included chemical analysisof sediments, tissue concentrations of transplanted mussels, toxicity testing of sediment samples, and characterization of benthiccommunity structure. Results indicated that sediment toxicity to bivalve larvae (Mytilus galloprovincialis) decreased in postre-mediation samples, but that toxicity to the amphipod Eohaustorius estuarius increased significantly. Assessment of benthos at thissite suggested a transitional benthic community structure. In addition, postremediation sediments remained contaminated by a varietyof organic chemical compounds, including DDT, dieldrin, chlordane, polycyclic aromatic hydrocarbons, and polychlorinated bi-phenyls. Tissue concentrations of DDT and dieldrin in mussels (M. galloprovincialis) were lower than those in preremediationsamples, indicating that although sediment concentrations of organochlorine pesticides remained high, concentrations of thesechemicals in the water column were reduced after dredging. This study demonstrates that the components of the site assessmentwere useful in determining effectiveness of the remediation activities.

Keywords—Marine superfund Sediment remediation DDT Toxicity

INTRODUCTION

Lauritzen Channel is an industrial waterway adjacent to theformer United Heckathorn facility in the inner Richmond Har-bor area of San Francisco Bay, California, USA. Various cor-porations operated pesticide-processing facilities in the uplandarea adjacent to this site from approximately 1945 to 1966.These activities resulted in soil and sediment contaminationby chlorinated pesticides, primarily DDT and dieldrin, and thearea was designated by the U.S. Environmental ProtectionAgency (U.S. EPA) as a Superfund site in 1990. Several ac-tions were taken to clean the most contaminated areas of thesite, including removal of contaminated soil from the uplandareas and an embankment adjacent to the marine habitat.

The U.S. EPA completed an ecologic risk assessment forthe marine environment at the site in 1992 that included mea-sures of sediment chemistry and toxicity, bioaccumulation, andbenthic community structure [1]. Results of this study con-firmed that dieldrin and DDT were the primary chemicals ofconcern, and that concentrations of these compounds weresufficient to account for low amphipod survival in the sedimenttoxicity tests, degraded benthic community structure, and sig-nificant bioaccumulation of DDT in the resident and trans-planted biota [1,2]. As part of the remediation activities in themarine habitat, approximately 100,000 metric tons of contam-

* To whom correspondence may be addressed([email protected]). The current address of B.S. Anderson isMarine Pollution Studies Laboratory, 34500 Coast Route 1—GraniteCanyon, Monterey, CA 93940, USA.

inated sediment were removed from Lauritzen Channel. In thisprocess, the channel was dredged to remove all sediment abovethe relatively uncontaminated, older bay mud [3] and thencapped with 15 to 46 cm of clean sand. These activities werecompleted in April 1997.

The present study was sponsored by the California De-partment of Fish and Game to assess the marine environmentimmediately before and approximately one year after thedredging of Lauritzen Channel. The study components in-cluded chemical analysis of sediments, tissue concentrationsof transplanted mussels, toxicity testing of sediment samples,and characterization of benthic community structure.

Remediation of the United Heckathorn Superfund site pro-vided an opportunity to use standard ecotoxicologic tools toevaluate the restoration of a pesticide-contaminated marinehabitat. The objectives of this study were twofold: to assesswhether remediation activities reduced concentrations of thechemicals of concern in the marine environment to levels thatprevent risk of injury to marine biota, and to evaluate theeffectiveness of the various monitoring components to describeecotoxicologic change because of dredging and capping at thesite. The results are intended to provide guidance for futureprojects involving remediation of contaminated marine sedi-ments.

METHODS

Station locations and study dates

For comparative purposes, stations were selected on thebasis of those sampled during the ecologic risk assessment

880 Environ. Toxicol. Chem. 19, 2000 B.S. Anderson et al.

Fig. 1. Location of sediment sampling stations in Lauritzen Channel.Global Imaging System (GIS) coordinates (GIS lattitude/GIS longi-tude) by station: station 1, 37.92261667/122.36701667; station 2,37.92246667/122.36701667; station 3, 37.92178333/122.36703333;station 4, 37.92030000/122.36846667.

study described by Lee et al. [1] and Swartz et al. [2]. Stationsdesignated as Lauritzen Channel 1 to 4 were sampled beforeand after remediation of channel sediments (Fig. 1). LauritzenChannel 1 was identified in previous studies as the most con-taminated station. Lee et al. [1] found that contamination de-creased along a gradient leading out of the Channel towardLauritzen Channel 4, which was located at the confluence ofthe Lauritzen and the Santa Fe Channels (Fig. 1). Note thatGlobal Imaging System coordinates were not available forstations 1 to 4 reported in Lee et al. [1]; therefore, the locationsfor these stations in the present study are based on best ap-proximations from the site maps of the previous study. Stations1 to 4 in the present study are identified by Global ImagingSystem coordinates (Fig. 1). Samples for preremediation tox-icity tests were collected during July 1996, and preremediationmussel bioaccumulation analyses were conducted from Augustthrough September 1996. Channel dredging began in late Sep-tember 1996 and was completed in April 1997. Samples forpostremediation toxicity tests and bulk-phase chemistry werecollected during March 1998. Postremediation bioaccumula-tion in mussels was conducted for 125 days, ending in Sep-tember 1997.

Sampling procedures

Homogenized sediments. Sediment sampling required col-lection of homogenized sediment for solid-phase chemistryand amphipod toxicity tests and of intact (i.e., unhomogenized)sediment cores for sediment-water interface toxicity tests. Sed-iments were collected using a Young-modified, Kynary-coated(Elf Atochem, Paris, France), Van Veen grab sampler accord-ing to the procedures described by Fairey et al. [4]. Surficialsediments (top 5 cm) were collected from half of each grabsample using a Teflont scoop; intact cores were taken fromthe second half of each grab (described later). Multiple grabswere deployed at each station to obtain enough sediment ho-mogenate and intact sediment cores for chemical and physicalanalyses and for toxicity testing. Except for the intact cores,sediment samples were composited into 6-L polycarbonatetubs and covered with a Teflon sheet. The tubs were thenpurged with nitrogen gas, sealed, and placed in an ice chestfor transport to the laboratory, where the sediments were thor-oughly rehomogenized using a polycarbonate rod and ali-

quotted for solid-phase toxicity testing and chemistry as de-scribed by Fairey et al. [4].

Intact sediment cores. Intact sediment cores were collectedfor toxicity testing from the second half of each grab sampleby pressing polycarbonate core tubes 5 cm into the sediment,sealing the bottom of the cores for removal from the sampler,and then removing the cores. Cores were quickly sealed withpolyethylene caps, dried and tightly sealed with Parafilmt toprevent leakage, and then stored upright on ice for transport.Core integrity was confirmed by the presence of a shallowlayer of overlying water atop the sediment.

Benthics. Benthic community structure was characterized inthe sediment samples collected at each station after remedia-tion had been completed. The methods used followed thosedescribed in Anderson et al. [5]. Cores for characterizing ben-thic community structure were collected from the Van Veengrab sampler at the same time that sediment samples werecollected for chemistry and toxicity. The coring device was apolycarbonate cylinder with a diameter of 10 cm that enclosedan area of 0.0071 m2 and sampled to an average depth of 10cm. One sample was collected at each station, sieved througha 0.5-mm screen, fixed with formalin, and then transferred toisopropyl alcohol 3 d later. All samples were sorted, and in-faunal organisms were identified to species (whenever possi-ble) or to the next lowest taxonomic group.

Toxicity testing procedures. Sediment samples were heldat 48C until required for testing. All solid-phase sediment testswere initiated within 14 d of the sample collection date. Solid-phase sediment toxicity was assessed using the 10-d amphipodsurvival protocol for Eohaustorius estuarius [6]. Test con-tainers were 1-L glass beakers containing 2 cm of sedimentand filled to the 700-ml line with seawater adjusted to 20‰using distilled water. Five laboratory replicates of each sample,including a negative sediment control consisting of five lab-oratory replicates of home sediment from the amphipod col-lection site, Yaquina Bay, Oregon, USA, were tested. After 10d, the sediments were sieved through a 0.5-mm screen (AquaticEco-Systems, Apopka, FL, USA) to recover the test animals,and the number of survivors was recorded for each replicate.Overlying water-quality parameters, including ammonia, dis-solved oxygen, pH, and salinity, were measured in one rep-licate test container from each sample. Interstitial sulfide andammonia were also examined. Measurements were taken atthe beginning and at the end of all tests. Positive control ref-erence tests were conducted concurrently with each sedimenttest using cadmium chloride as a reference toxicant.

Sediment-water interface exposures were conducted ac-cording to the methods described by Anderson et al. [7]. Intactsediment cores were returned to the laboratory and preparedfor testing by adding 300 ml of 28‰ overlying water. Thecores were then allowed to equilibrate overnight with slowaeration. Before test initiation, 25-mm mesh screen tubes wereinserted into each sediment core and positioned 1 cm abovethe sediment.

Sediment toxicity was assessed using embryo-larval de-velopment of the mussel Mytilus galloprovincialis [8]. Ap-proximately 200 mussel embryos were pipetted into the screentubes and exposed for 48 h. Tests were terminated by removingthe screen tube and then rinsing larvae into vials to be fixedwith 5% formalin. All resulting larvae were counted in eachtest container at the end of the exposure to determine thepercentage of embryos that developed into live, normal larvae.Five laboratory replicates of each sample were tested, with an

Ecotoxicologic change at a Superfund site Environ. Toxicol. Chem. 19, 2000 881

Fig. 2. Survival of amphipods in sediments and development of bi-valve embryos exposed at the sediment-water interface in both pre-and postremediation samples from Lauritzen Channel.

additional sacrificial replicate for water quality (i.e., overlyingwater dissolved oxygen, pH, salinity, and ammonia). A neg-ative sediment control consisting of five laboratory replicatesof Yaquina Bay home sediment was included as well. Positivecontrol reference tests were conducted concurrently using cad-mium chloride as a reference toxicant.

Chemical analyses

Because bulk-phase chemical concentrations at this site hadbeen well characterized in several previous studies, includingthe extensive ecologic risk assessment completed by the U.S.EPA [1], we did not measure bulk-phase chemistry beforeremediation. Instead, the analyses conducted by U.S. EPA andreported in Swartz et al. [2] were used for comparison withpostremediation analyses conducted as part of the currentstudy. Trace organic compounds were measured in sedimenthomogenates collected during the postremediation samplingdescribed earlier. Samples were analyzed for 24 polychlori-nated biphenyl (PCB) congeners, 36 pesticides, and 24 poly-cyclic aromatic hydrocarbons (PAHs) using modifications ofthe methods described by Sloan et al. [9]. Sediment extractswere divided into two portions: one for chlorinated hydrocar-bon analysis, and the other for PAH analysis. The chlorinatedhydrocarbon portion was separated into two fractions on asilica/alumina column and then concentrated for analysis usinga Hewlett-Packard (Palo Alto, CA, USA) 5890 Series II cap-illary gas chromatograph with an electron-capture detector.The PAH portion was eluted through a silica/alumina columnwith methylene chloride and then concentrated for analysisusing gas chromatography/mass spectrometry in single ionmonitoring mode. Standard quality-assurance procedures, in-cluding measurement of standard reference materials as wellas quantification of surrogate recoveries and matrix spikes,were followed during all analyses; all chemical analyses metprescribed quality assurance guidelines.

Percent total organic carbon was determined using a Con-trol Equipment Model 240-A elemental analyzer [10]. Samplegrain size was determined using procedures described by Folk[11], incorporating both wet and dry sieve techniques, and wasreported as percent fines.

Bioaccumulation

Preremediation. Bags of mussels (M. californianus) weredeployed at all four sampling locations approximately 1 yearbefore dredging. Bags were suspended from pier pilings belowthe low tide level. Mussels remained in the field for 23 d (July17–August 9, 1996), after which they were retrieved and takento the California Department of Fish and Game Mussel Watchfacility in Moss Landing, California, and stored frozen. Mus-sels were prepared and dissected under positive-pressure,clean-room conditions [12], and concentrations of selectedtrace organic compounds were analyzed according to the meth-ods described by Sloan et al. [9].

Postremediation. Postremediation monitoring of bioaccu-mulation in deployed mussels was conducted by Battelle Ma-rine Sciences Pacific Northwest Laboratory (Sequim, WA,USA) for U.S. EPA Region IX. Methods were comparable tothose described earlier, except that mussels were deployed fora longer time period and were placed at two of the four prere-mediation monitoring stations (station 2 and 4). Postremedia-tion mussels remained in the field for 125 d (September 3,1997, to January 6, 1998). Methods of analysis followed thosedescribed by the U.S. EPA [13].

RESULTS

Sediment toxicity

Amphipod survivals in preremediation sediment samplesfrom Lauritzen Channel were comparable to those reported bySwartz et al. [2] for stations 1 through 4. Survival rates of E.estuarius were 58%, 54%, 70%, and 87%, respectively, atstations 1 through 4 (Fig. 2). Development of bivalves (M.galloprovincialis) exposed to preremediation sediments at thesediment-water interface was also inhibited at all four stations,with the lowest developmental rate (54%) occurring at station1 and rates of 64%, 68%, and 58% occurring at stations 2, 3,and 4, respectively (Fig. 2).

Survival of amphipods was considerably lower in postre-mediation sediments, particularly at stations 1, 2, and 3. Postre-mediation amphipod survival rates were 6%, 16%, 14%, and74% at stations 1 through 4, respectively (Fig. 2). Whereasamphipod survival declined, development of bivalve embryosexposed at the sediment-water interface improved in postre-mediation sediments. No significant toxicity to bivalve de-velopment was detected in any samples one year after the sitewas dredged and capped (Fig. 2).

Sediment infauna

Sediment samples collected from all stations one year afterremediation contained relatively few species and individualsand, for the most part, were dominated by polychaetes andoligochaetes (Table 1). No amphipods were present in anysample, and only one crustacean species was counted at eachof two of the stations (Cumacea, Nippoleucon hinumensis).The number of species identified ranged from five to seven,but the number of polychaete species ranged from two to four(e.g., Tharyx parvus, Eteone lighti, Dorvillea articulata, Cap-itella spp.). In addition, all samples had at least one oligochaete


Table 1. Summary of benthic community structure at LauritzenChannel stations 1–4 after remediation of channel sediments

Station1

(n)

Station2

(n)

Station3

(n)

Station4

(n)

Total individuals 77 124 205 36Total species 6 5 6 7Crustacean individuals 0 2 0 6Crustacean species 0 1 0 1Mollusk individuals 2 3 5 3Mollusk species 1 1 2 1Polychaete individuals 31 6 14 12Polychaete species 4 2 3 4Oligochaete individuals 44 113 186 15

Table 2. Sediment SDDT and dieldrin concentrations beforea and after site remediation of the Lauritzen Channel

Chemical

Station 1

Before After

Station 2

Before After

Station 3

Before After

Station 4

Before After

SDDT (mg/kg dry wt) 77,700.00 21,361.80 47,800.00 27,883.00 26,000.00 15,555.00 2,740.00 840.20SDDT (mg/g OC)b 3,500.00 2,637.26 2,710.00 1,366.81 1,520.00 691.33 189.00 53.18Dieldrin (mg/kg dry wt) 748.00 371.00 528.00 619.00 442.00 196.00 35.70 25.80Dieldrin (mg/g OC) 35.20 45.80 28.70 30.34 25.80 8.71 2.46 1.63Fines (%) 92.30 23.50 85.20 91.59 85.90 94.45 89.50 92.58OC (%) 2.38 0.81 1.78 2.09 1.73 2.25 1.46 1.58

a [2].b OC 5 organic carbon.

species. Stations 2 and 3 had relatively greater numbers ofindividuals because of high densities of oligochaetes, but notrends in either the number of species or individuals could bediscerned among the four stations sampled.

Sediment chemistry

Bulk-phase analyses of postremediation sediment samplesindicated that the site remains relatively contaminated by pes-ticides. Concentrations of the primary chemicals of concernidentified at this site declined at all four stations, but SDDTand dieldrin concentrations remained relatively high (Table 2).This is particularly true when concentrations of these pesti-cides are expressed on an organic carbon (OC)–normalizedbasis. The concentration of OC-normalized SDDT remainedparticularly high at stations 1 and 2, which were the two mostcontaminated preremediation stations (Table 2). Postremedia-tion concentrations of OC-normalized SDDT were 75%, 50%,45%, and 28% of the preremediation concentrations at stations1 through 4, respectively. Concentrations of OC-normalizeddieldrin actually increased at stations 1 and 2. Concentrationof OC decreased threefold in sediments from station 1 afterremediation but increased in sediments from all other stations(Table 2). The relative proportion of DDT metabolites changedin postremediation sediments relative to those measured inpreremediation sediments. In the postremediation sediments,60% of the total was 49,4-DDT, whereas 22% was 49,4-dich-lorodiphenyldichloroethane (DDD).

In addition to these pesticides, concentrations of PAH com-pounds were elevated in postremediation samples from all sta-tions (Table 3). Total bulk-phase concentrations of low- andhigh-molecular-weight PAHs exceeded the effects range me-dian (ERM) sediment-quality guideline values of Long et al.[14] at all stations. Concentrations of PAHs were particularlyhigh at stations 2 and 3; in fact, the concentration of low-

molecular-weight PAHs at station 3 exceeded the ERM valueby as much as 14-fold. The concentrations of total PAHs alsoexceeded the ERM value at stations 2 and 3. Concentrationsof PCBs were higher in postremediation than in preremediationsediments as well. For example, the bulk-sediment concentra-tions of Arochlorst 1248, 1254, and 1260 (all from Monsanto,St. Louis, MO, USA) were 1400, 690, and 370 ng/g (dry wt),respectively, in the postremediation sediment sample from sta-tion 2. Bulk-phase concentrations of Aroclors 1254 and 1260were 118 and 60 ng/g in preremediation sediment from station2 [1].

Bivalve tissue chemistry

Concentrations of selected pesticides were elevated incaged mussels (M. galloprovincialis) deployed for 23 d at thefour stations before the remediation of channel sediments (Ta-ble 4). Concentrations of total chlordane, SDDT, and dieldrinwere greater at the stations with the most contaminated sed-iments (stations 1 and 2). Concentrations of SDDT and dieldrinin mussels deployed for 125 d at stations 2 and 4 were mea-sured by the U.S. EPA as part of a postremediation monitoringprogram. Analysis of SDDT and dieldrin in postremediationmussel tissues indicated declines in SDDT and dieldrin atstation 2 but increases at station 4. The SDDT declined by77% in postremediation mussel tissue at station 2 and was12% greater at station 4 during postremediation monitoring.Postremediation mussels that were compared to preremedia-tion mussels from station 4, however, apparently were placedbetween preremediation stations 3 and 4, which could haveresulted in elevated pesticide concentrations among these an-imals relative to those in the preremediation animals.

DISCUSSION

The results of this study indicate that despite removal ofapproximately 100,000 metric tons of contaminated sedimentsand capping with clean San Francisco Bay sand, the sedimentsof Lauritzen Channel remain toxic to infaunal amphipods andare still polluted with organic chemicals. Toxicity of LauritzenChannel sediments to the free-burrowing amphipod E. es-tuarius increased at all stations after remediation of channelsediments, particularly at stations 1 to 3, where the mean am-phipod survival rate is now 12% (Fig. 2). Relative to sedimentstested with amphipods from other U.S. coastal sites [2], thesethree stations are now among the most toxic of those measurednationwide.

Toxicity to amphipods increased after remediation of chan-nel sediments, but toxicity to bivalve embryos exposed at thesediment-water interface declined. No significant toxicity wasdetected using bivalve development at any station after dredg-


Table 3. Concentrations (mg chemical/g organic carbon [OC]) of selected low-molecular-weight (LMW)and high-molecular-weight (HMW) polycyclic aromatic hydrocarbon (PAH) compounds in Lauritzen

Channel sediments before and after remediation

Compound

Lauritzen Channel stations

1After

1Beforea

2After

3After

4After

Acenapthylene 2.96 8.20 5.29 11.38 0.58Acenapthene 71.60 1.70 166.67 306.22 25.82Anthracene 71.11 19.00 126.96 184.89 28.73Benzo(a)anthracene 120.62 25.00 203.43 276.89 41.33Benzo(a)pyrene 125.93 72.00 177.94 230.22 40.06Benzo(b)fluoranthrene 180.25 97.00 270.10 376.44 55.06Benzo(k)fluoranthrene 61.85 51.00 92.65 254.67 19.43Benzo(ghi)perylene 53.46 NR 66.18 71.11 21.90Benzo(e)pyrene 87.78 NR 120.59 157.33 28.99Biphenyl 11.72 NR 26.96 50.22 4.04Chrysene 132.10 NR 196.08 288.44 50.70Fluoranthrene 337.04 41.00 612.75 991.11 139.24Fluorene 65.93 4.00 127.45 209.33 23.16Naphthalene 39.51 8.60 58.33 83.11 8.23Phenanthrene 222.22 16.00 504.90 840.00 96.20Perylene 29.88 NR 42.55 50.67 11.39Pyrene 250.62 69.00 416.67 622.22 108.86Total OC (%) 0.81 2.38 2.04 2.25 1.58LMW PAH (mg/kg dry wt) 4,664.90b NRc 24,366.00b 44,734.00b 3,367.60b

LMW PAH (mg/g OC) 575.91 1,194.41 1,988.18 213.14HMW PAH (mg/kg dry wt) 11,828.00b NR 46,994.00b 77,356.00b 8,613.00HMW PAH (mg/g OC) 1,460.25 2,303.63 3,438.04 545.13Total PAH (mg/kg dry wt) 16,492.90 NR 71,360.00b 122,090.00b 11,980.60Total PAH (mg/g OC) 2,036.16 3,498.04 5,426.22 758.27

a [2].b Exceeds the effects range median value.c NR 5 not reported.

Table 4. Concentrations (ng/g dry wt) of select organic compounds in mussel tissues (Mytiluscalifornianus)a

Station

Before

Total PCBscTotal

chlordanes SDDT Dieldrin

Afterb

SDDT Dieldrin

1 522.70 161.00 14,310.00 572.00 NA NA2 376.80 179.90 15,427.00 569.00 3,502.00 279.003 266.90 52.30 4,853.00 224.00 NA NA4 151.50 26.68 1,283.00 90.60 1,448.00 165.00

a Before remediation, mussels were deployed for 23 d, from July 17–August 9, 1996. After remediation,mussels were deployed for 125 d, from September 3, 1997, to January 6, 1998.

b [29].c PCBs 5 polychlorinated biphenyls.

ing and capping. Differences in response between these twotoxicity test protocols likely results from variable sensitivityto contaminants present in postremediation sediments and var-iable routes of exposure. Eohaustorius estuarius likely is ex-posed to sediment contaminants via dermal uptake from porewater and consumption of particle-bound contaminants [15].When exposed at the sediment-water interface, however, M.galloprovincialis embryos presumably are exposed to dis-solved chemicals fluxed from the sediment into the overlyingwater [7]. To our knowledge, no published studies have com-pared the relative sensitivity of these protocols, though pre-vious research using spiked water samples and contaminatedfield samples have indicated that these protocols have variablesensitivity to contaminants. Results of dose-response studieshave demonstrated that embryo-larval development tests areparticularly sensitive to metal toxicity but may be less sensitive

to some organic compounds [16,17]. Even so, E. estuarius isrelatively sensitive to SDDT and dieldrin [2] and to PAHcompounds [18,19]. Both protocols have shown variable sen-sitivity to contaminated sediments from San Francisco Bay[20,21].

Analysis of benthic community structure in postremediationsediments indicates that this site has not recovered to whatwould be considered reference conditions for Central San Fran-cisco Bay sediments [21]. During postremediation sampling,the infaunal communities at these stations were dominated bypolychaetes and oligochaetes. Benthic community structure inSan Francisco Bay is notoriously difficult to characterize [21],but the postremediation sediment infaunal communities inLauritzen Channel were classified as being transitional by thebenthic ecologists who analyzed the samples. This classifi-cation indicates a site with a benthic assemblage somewhere


between degraded and undegraded conditions and is based onthe presence of negative indicator species (e.g., worms) andthe absence of positive indicator species (e.g., mollusca, crus-tacea; P. Slattery, personal communication). Polychaete speciesin these samples included those that have previously beencategorized as being contaminant tolerant (e.g., Eteone sp.,Capitella sp., Dorvillea sp.) [21]. Sampling for benthic com-munity structure consisted of only one replicate sample at eachstation; therefore, these data may underestimate species abun-dance at the site. Regardless of this limitation, only one crus-tacean species each was found in samples from stations 2 and4 (Family Cumacea; data not shown), and no amphipod specieswere found in samples from any station. Swartz et al. [2] alsofound that sediments from Lauritzen Channel had few crus-tacean species and suggested that the amphipod species presentin greatest numbers among preremediation samples (Grandi-dierella japonica) was one that may be capable of adaptingto polluted conditions.

Interpretation of benthic community data at this site is con-founded by several factors unrelated to chemical contamina-tion. Because this site was completely dredged one year beforethe benthic sampling, the lack of a well-defined benthic com-munity structure may have resulted from disturbance of thesite and lack of adequate recovery time. In addition to thedredging of Lauritzen Channel as part of the remediation pro-ject reported here, the adjacent Santa Fe Channel had recentlybeen dredged by the City of Richmond as part of a navigationalmaintenance project conducted before the postremediationsampling (A. Lincoff, personal communication). This probablydisrupted adjacent infaunal communities that could haveserved as a recruitment source for Lauritzen Channel. Sedi-ments at this site also continue to be disturbed by prop scourfrom tug boats and other shipping vessels. The combined in-fluence of chemical contamination and disruption of benthosbecause of dredging and boat activities cannot be separated.Therefore, benthic community information may be less valu-able than other ecotoxicologic indicators for assessing changeat this site.

This study was not designed to investigate causes of tox-icity, but results of previous studies associating bulk-phasechemical concentrations and impacts on amphipod survivalmay be applied to these results. Results of previous investi-gations regarding the toxicity of DDT, PAH compounds, anddieldrin indicate that concentrations of these chemicals in post-remediation Lauritzen Channel sediments are sufficient to ac-count for the observed amphipod mortality, particularly whenthese chemicals are considered as mixtures. Swartz et al. [2]reported that the threshold for 10-d sediment toxicity to am-phipods was approximately 300 mg SDDT/g OC, and that theE. estuarius 10-d LC50 for SDDT in Lauritzen Channel sed-iment was 2,500 mg SDDT/g OC. The postremediation con-centration of OC-normalized SDDT at station 1 (2,637.26 mgSDDT/g OC; Table 2) exceeded the 10-d LC50 for E. es-tuarius, and concentrations of SDDT/g OC were well abovethe threshold effect concentration for this species at stations2 and 3. In addition to DDT, dieldrin concentrations in postre-mediation sediments remained at elevated concentrations andmay have been partially responsible for amphipod mortality.Dieldrin concentrations in channel sediments were well belowthe amphipod 10-d LC50 (;1,955 mg dieldrin/g OC) [2] andprobably contributed only incremental toxicity to E. estuarius(Table 2).

Concentrations of PAH compounds were considerably

higher in postremediation sediments than those reported bySwartz et al. [2] (Table 3) for preremediation sediments. Inaddition, concentrations of low-molecular-weight, high-mo-lecular-weight, and total PAH compounds were well above theERM sediment quality guidelines values reported by Long etal. [14]. The ERMs are the bulk-phase PAH concentrationsabove which toxicity to amphipods is considered to be prob-able. When applied to the SPAH model described by Swartzet al. [18], the summed toxic units (STU) of the 13 PAHcompounds for which this model applies were not sufficientto explain the observed toxicity in postremediation sediments(S 5 acenapthylene, acenapthene, anthracene, ben-zo[a]anthracene, benzo[a]pyrene, benzo[b]fluoranthrene, ben-zo[k]fluoranthrene, chrysene, fluoranthrene, fluorene, napthy-lene, phenanthrene, pyrene). The STUs for the 13 PAH com-pounds in sediments collected from all four stations were al-ways less than 0.20 (data not shown).

Swartz [19] recently proposed consensus sediment-qualityguidelines for PAH mixtures using these 13 PAH compounds.These guidelines were based on the mean of the existing sed-iment-quality guidelines previously published for total PAHmixtures. The OC-normalized consensus guidelines proposedby Swartz [19] are separated into a threshold effect concen-tration (290 mg SPAH/g OC) below which no toxicity fromPAHs is to be expected, a median effect concentration (1,800mg SPAH/g OC) above which amphipod toxicity may occur,and an extreme effects concentration (10,000 mg SPAH/g OC)above which effects are expected. The sum of the 13 OC-normalized PAH compounds used by Swartz [19] were1,853.3, 3,241.8, 5,096.9, and 692 mg SPAH/g OC in sedi-ments at stations 1 through 4, respectively. Total PAH con-centrations at stations 1 to 3 exceeded the median effect con-centration, and the SPAH exceeded the threshold effect con-centration at station 4. The median effect concentration is con-sidered to be a median effect value at which an approximately50% probability of toxicity exists in samples where PAH con-tamination is the dominant ecotoxicologic factor [19]. We didnot consider metals as a source of toxicity in this study, becausemetals measured in previous studies were not present at suf-ficient concentrations to be considered toxic [2].

Concentrations of selected pesticides as measured in thetissues of bagged mussels deployed before and after the siteremediation showed a decline in SDDT and dieldrin at station2 and an increase in these compounds at station 4. Comparisonscan only be made for these two stations, however, becausepostremediation monitoring at the site did not include all fourstations (Table 4). The increase in SDDT and dieldrin at station4 may result from the exposure time for the postremediationmussel bioaccumulation monitoring (123 d) being almost four-fold as long as for those deployed before the site remediation(23 d). Preremediation mussels were removed early becauseof the initiation of channel dredging. In addition, postreme-diation mussels apparently were deployed on the east side ofthe channel and somewhat farther north of station 4 than thepreremediation mussels. Because the concentrations of SDDTand dieldrin increased northward up the channel, this may haveinfluenced bioaccumulation in the postremediation musselsfrom station 4.

These data indicate that bioaccumulatable concentrationsof the two primary chemicals of concern declined at the mostcontaminated station (station 1). Bioaccumulation of SDDTand dieldrin was one of the principal ecologic concerns iden-tified in the ecologic risk assessment conducted at this site by


Lee et al. [1]. Bioaccumulation using field-deployed musselswas included as the sole biologic component in U.S. EPApostremediation monitoring in Lauritzen Channel, becausethese data could be compared with a relatively large prere-mediation database extending over several years [3]. Thesedata were intended to complement water column chemicalmeasurements included in postremediation monitoring. Sedi-ment toxicity testing data in this study augment such watercolumn bioaccumulation data by providing information re-garding the toxicologic effects of sediment contaminants. Theadditional ecotoxicologic measurements were included in thepresent study because, in addition to human health and eco-logic concerns regarding elevated tissue concentrations ofDDT and dieldrin to water column organisms, the CaliforniaDepartment of Fish and Game was interested in determiningwhether the remediation practices removed chemicals thatthreatened sediment biota. Risk to sediment biota could onlybe assessed with appropriate toxicity tests and sediment chem-ical measurements.

Why postremediation sediments in Lauritzen Channel wereso heavily contaminated is unclear. As discussed earlier, ap-proximately 100,000 metric tons of contaminated sedimentswere dredged from this site. Extensive premeditation chemicalcharacterization of the site showed that most chemical con-tamination was associated with the younger bay mud, and itwas assumed that most of the chemical contamination wouldbe removed after dredging to a depth of approximately 15 cmbelow the older bay mud horizon [3]. Possible sources of post-remediation contamination may be separated into two cate-gories: residual contamination, or new contamination. Resid-ual contamination results from incomplete removal and mighthave occurred where dredging or capping was not effective,particularly at locations in the channel where the clamshelldredge could not operate. New contamination could occur viaterrestrial surface runoff, storm water pipes or other dischargestructures, the dredge material dewatering process, recontam-ination from the adjacent marine environment, and recontam-ination from polluted groundwater. All these sources were con-sidered in the remediation feasibility study [3] and addressed(to varying degrees) in the final remediation workplan [22].The source of PAHs in postremediation sediments is unknown,but industrial activities in the channel area include shippingoperations and a variety of land-based businesses, includingmanufacturing, recycling, and construction. All are possiblesources of PAHs. White et al. [23] reported relatively highconcentrations of both low- and high-molecular-weight PAHsin composite (sample depth, 30.5 cm) samples collected fromLauritzen Channel sediments, particularly those collected nearstation 3 in the present study.

Lauritzen Channel was capped with 15 to 46 cm of cleansand after dredging was completed in 1997, but postremedia-tion grain-size distributions indicate that stations 2, 3, and 4were dominated by fine-grained sediments (Table 2). Becausechemicals are associated with finer-grained sediments, this maypartially account for the continued contamination in the chan-nel. The sand layer was relatively shallow, because it wasintended to provide habitat for benthic fish species rather thanto serve as a cap to prevent mobilization of chemicals in deeperlayers. Finer sediments have settled into the channel, but thesource of this sediment is unknown. Possibilities include re-suspended material from the dredging in Santa Fe Channel,slumping of sediments from the undredged margins of Laur-

itzen Channel, and material deposited from the dredging ves-sels that are stored in the channel.

Approximately 60% of the SDDT in postremediation sed-iments was 49,4-DDT; the remainder was dominated by 49,4-DDD (22%). These ratios differed considerably from thosereported by Lee et al. [1] for preremediation sediments fromLauritzen Channel. Those authors found a greater proportionof 49,4-DDD (50%) relative to 49,4-DDT (37%). Upland sam-ples adjacent to the marine habitat had 80% 49,4-DDT, 13%29,4-DDT, and 6% 49,4-DDD [1], which is similar to technicalformulations of DDT [24]. The relative proportions of thedifferent DDT metabolites in postremediation sediments there-fore fall between those of preremediation sediments and thoseof the upland samples as reported by Lee et al. [1]. This sug-gests that postremediation contamination may have come ei-ther from an upland source or from one where the timing orconditions under which metabolic alteration of DDT differedfrom those of the preremediation sediments. Identifying thesources of postremediation contamination was beyond thescope of this study but should be addressed at this site beforesimilar remediation plans are implemented. Chlordane andPAH concentrations were considerably higher in postremedia-tion sediments relative to those concentrations as described byLee et al. [1], but identification of the source (or sources) ofthese compounds in postremediation sediments was, again,beyond the scope of this study. Such identification should alsobe included in any future investigations at this site to minimizeinputs and to prevent further habitat contamination.

To our knowledge, relatively few studies regarding the ef-fects from remediation of organochlorine-contaminated sedi-ments on ecotoxicologic endpoints have been reported. Bergenet al. [25] described the distribution of PCBs after New Bed-ford Harbor (NBH) sediments were dredged to remove themost contaminated hotspot. Approximately 7,600 m3 of PCB-contaminated sediments from NBH were removed via suctiondredging and disposed off-site. Congener measurements ofPCB distributions were combined with statistical and graphicanalyses to show that harborwide concentrations of total PCBcongeners decreased in NBH sediments by more than fourorders of magnitude in surficial sediments. Postremediationmonitoring of NBH included toxicity tests with the amphipodAmpelisca abdita, characterization of benthic communitystructure, and bioaccumulation in mussel tissue. Postremedia-tion monitoring conducted two years after the PCB hotspot inupper NBH was removed indicated that whereas no apparentchange in benthic community structure had occurred, sedimenttoxicity had increased in the upper and lower harbors. Ap-parently, this resulted from resuspension of PCB-contaminatedsediments during the dredging process ([26]; W. Nelson, per-sonal communication). Bremle and Larson [27] measured con-centrations of PCBs in water and fish tissue both upstream anddownstream from Lake Jarnsjan in southern Sweden after con-taminated lake sediments were removed via suction dredging;concentrations of PCBs decreased by greater than 70% and50%, respectively, in water and fish after removal of lakesediments. Removal of PCB-contaminated sediments was lesssuccessful, however, after dredging of the Shiawassee River,Michigan, USA. Rice and White [28] used caged fish and clamsto show that postremediation concentrations of PCBs were notsignificantly less in river waters, because a considerableamount of PCBs remained in river sediments 6 months afterremediation.


CONCLUSIONS

The United Heckathorn Superfund site in Richmond, Cal-ifornia, is one of a few marine habitats to date where sedimentcontamination by chlorinated pesticides has been consideredto pose sufficient ecologic and human health risk to warrantremediation through dredging and off-site disposal. This studydemonstrates the utility of including multiple ecotoxicologicmeasures in a weight-of-evidence approach for assessing theeffectiveness of dredging as a remediation alternative. All mea-sures employed in this study were useful for assessing change,but interpretation of the benthic community data was con-founded because of sediment disturbance from shipping anddredging activities both at this site and in the adjacent area.Because the remediation activities were designed largely tominimize exposure of DDT and dieldrin to higher-trophic-levelorganisms, postremediation monitoring at this site emphasizedwater column concentrations of these chemicals and their bio-accumulation in mussel tissues because of ecologic and humanhealth concerns [13]. These measures demonstrated that dredg-ing reduced concentrations of DDT and dieldrin in LauritzenChannel water and in the surrounding system [29]. Analysisof bulk-phase chemistry and toxicity indicated continued sed-iment contamination and toxicity at this site and demonstratedthe applicability of these measurements for assessing ecotox-icologic change in this compartment of the system. These toolsare relatively simple and provide no mechanistic information[30], but the combination of toxicity tests, analytic chemistry,and bioaccumulation measurements was sufficient to assessthe effectiveness of remediation activities at this site. Con-centrations of chlorinated pesticides have declined in mussels;however, insufficient data exist to determine whether the re-sidual sediment contamination in Lauritzen Channel is af-fecting the larger system. Further analyses of these chemicalsin the tissues of local fish populations, particularly in speciesthat prey extensively on benthic fauna, would help to answerthis question. The degree of contamination and toxicity at thissite after extensive remediation of contaminated sediments isproblematic, and it suggests that future remediation projectsthat rely on similar methodologies should incorporate greaterconsideration of possible sources for postremediation contam-ination to better achieve the project goals.

Acknowledgement—Support for this work was provided by the Cal-ifornia Department of Fish and Game. The authors thank Nancy Kohnfor helpful discussions concerning the results and conclusions of thisstudy and for providing postremediation mussel bioaccumulation data.The manuscript was improved through review comments provided byAndy Lincoff and two anonymous reviewers.

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THIS PAPER IS CITED AS Cheng, N. S. (1997). "A simplified settling velocity formula for sediment particle." Journal of Hydraulic Engineering, ASCE, 123(2), 149-152.

A SIMPLIFIED SETTLING VELOCITY FORMULA FOR SEDIMENT PARTICLE By Nian-Sheng Cheng1

ABSTRACT: A new and simplified formula for predicting the settling velocity of natural sediment particles is developed. The formula proposes an explicit relationship between the particle Reynolds number and a dimensionless particle parameter. It is applicable to a wide range of Reynolds numbers from the Stokes flow to the turbulent regime. The proposed formula has the highest degree of prediction accuracy when compared with other published formulas. It also agrees well with the widely used diagrams and tables proposed by the U. S. Inter-Agency Committee (1957). INTRODUCTION A pre-requisite to certain quantitative analysis in sediment transport is a knowledge of the settling velocity of sediment particles. Many attempts have been made for its prediction but most of the relevant researches apply only to spherical particles. Basically, there are two types of prediction methods for settling velocity of either spherical or non-spherical particles. One is the analytical solution of Stokes which is applicable only for particle Reynolds number, Re = wd/v ≤ 1, where w = settling velocity of a particle, d = particle diameter and v = kinematic viscosity. The other includes tabulated data and diagrams consisting of families of curves based on the experimental data, e.g. Schiller and Naumann (1933) and U. S. Inter-Agency Committee (1957). They are suited to a wide range of Reynolds numbers but inconvenient to use in practice. The objective of this note is to derive a simple expression for the determination of the settling velocity of natural sediment particles over a wide range Re. _____________________________________________________________________________ 1School of Civil and Structural Engrg., Nanyang Technological University, Nanyang Avenue, Singapore, 639798 Key words: settling velocity, sediment particle, drag coefficient, Reynolds number

2

DRAG COEFFICIENT FOR SETTLING OF INDIVIDUAL PARTICLE In 1851, Stokes obtained the solution for the drag resistance of flow past a sphere by expressing the simplified Navier-Stokes equation together with the continuity equation in polar co-ordinates. Using his solution, the following expression for the settling velocity of spherical particles can be derived as,

w gd=

118

2Δν

(1)

where, Δ = (ρS - ρ)/ρ, ρ = density of fluid, ρS = density of particles, g = gravitational acceleration. Unfortunately, (1) is only valid for Re ≤ 1. Generally, by equating the effective weight force to the Newtonian expression of drag resistance, i.e.

( )ρ ρ π π ρS Dg d C d w

− =6 4 2

3 22

(2)

the drag coefficient CD can be expressed as

CD = 43 2

Δgdw

(3)

By substituting the Stokes’ solution in (1) into (3), CD may be related to the Reynolds number:

CD = ARe

(4)

where A = a constant, which is dependent on the shape factor of the particle. For Stokes’ solution, A = 24 for spherical particles. The effect of particle shape on the drag coefficient varies, being small at low Re and more appreciable at high Re (Schulz, et al., 1954). Usually the shape factor of sediment particle is less than unity and for natural sand particles, the shape factor is about 0.7. Table 1 shows the value of A to be about 32 based on the work of various investigators. Under the condition of high Reynolds numbers, say, 103 ~ 105, the drag coefficient of spheres has an average value of about 0.4. For natural sediment particles, CD lies between 1.0 ~ 1.2 as shown in Table 1. As the Stokes-type equation is restricted to Re ≤ 1, efforts have been made to develop a method for extending (4) to a much wider range of Reynolds numbers. Some quasi-theoretical formulas or empirical correlations for evaluating the settling velocity of individual particle can be found in the literature, e.g., Oseen (1927), Sha (1956), Zanke (1977) and Raudkivi (1990). In the light of all these studies, the following relation between CD and Re is assumed for natural sediment particles:

C AD = [(

Re]) + B

1n

1n n (5)

where A and B are constants, and n = an exponent. Eq. (5) automatically satisfies the two extreme conditions at low and high Reynolds numbers, that is, CD is inversely proportional to Re at low Reynolds numbers and becomes a constant at high Reynolds numbers. According to Table 1, A can be taken as 32, as most researchers did, and B = 1, being the lowest limit of the drag coefficient for sediment particles. As the relationship between CD and Re at the extreme Reynolds numbers is unaffected appreciably by n in (5), the latter may be estimated by fitting (5) with the experimental data in the intermediate Reynolds number range, i.e., 1 < Re < 1000. Based on the experimental data of Concharov (1962: see Ibad-zade, 1992), Zegzhda (1934), Arkhangel’skii (1935) and Sarkisyan (1958) for quartz sand particles, the average n-value was found to be 1.5. Therefore, with the foregoing values proposed for A and B, (5) can be rewritten as

CD = +[(Re

]32 1) 1

1.5 1.5 (6)

3

Eq. (6) is a general relationship between the drag coefficient and particle Reynolds number for natural sediment particles. Using a dimensionless particle parameter d* defined as

d g d* ( )=Δν 2

13 (7)

together with (3), we have

C dD =

43

3

2*

Re (8)

Substituting (8) into (6) yields

wd dν

= + −( . )*.25 1 2 52 1 5 (9)

Eq. (9) can be used to evaluate the settling velocity of natural sand particles explicitly. COMPARISON WITH PREVIOUS STUDIES There are numerous settling velocity formulas developed by different investigators for spherical and non-spherical particles. The settling velocity formulas for sediment particles used for comparison in this note are as follows: 1. Sha (1954)

w gd=

124

2Δν

for d < 0.01 cm (10a)

w gd= 114. Δ for d > 0.2 cm (10b)

(log Re . ) (log . )*

*dd+ + − =3790 5777 392 2 for d = 0.01 ~ 0.2 cm (10c)

2. Concharov (1962: see Ibad-zade, 1992)

w gd=

124

2Δν

for d < 0.015 cm (11a)

w gd= 1068. Δ for d > 0.15 cm (11b)

w d T= + −67 6 0 52

261. . ( )Δ Δ for d = 0.015 ~ 0.15 cm (11c)

In (11c), the temperature T is in oC, d in cm and w in cm/s. 3. Zhang (1989)

wd

gdd

= + −( . ) . .13 95 109 13 952ν νΔ (12)

4. Van Rijn (1989)

w gd=

118

2Δν

for d < 0.01 cm (13a)

w gd= 11. Δ for d > 0.1 cm (13b)

wd

d= + −10 1 0 01 13ν ( . )* (Zanke, 1977) for d = 0.01 ~ 0.1 cm (13c)

5. Zhu and Cheng (1993)

wd dν

α α α αα α

=− + + +

+24 576 18 3 6

9 18

3 6 3 2 3

3 2

cos cos ( cos . sin )cos . sin

* (14)

where α = 0 for d* ≤ 1 and α = π/(2+2.5(log d*)-3) for d* > 1. To test the accuracy of (9) and the others from (10) to (14), three data sets for sand particles were used. The first is the relations and table in Raudkivi (1990), on the average

4

settling velocity of quartz sand particles in water at 20oC. Table 2 shows the 13 sets data points which are computed using the method outlined in Raudkivi (1990). The second is the experimental data of Zegzhda (1934), Arkhangel’skii (1935) and Sarkisyan (1958), which were compiled in the order of decreasing particle diameter by Zhu and Cheng (1993), as shown in Table 3. The last is the tabulated data given by the U. S. Inter-Agency Committee (1957) (also see: Raudkivi, 1990) for settling velocity of natural sediment particles with a shape factor of 0.7, and specific gravity ranging from 2.0 to 4.3. The basic parameter used for the determination of accuracy of a formula is the average value of the relative error defined as

error calculated givengiven

=−| | ×100 (15)

Table 2 presents the comparison of the calculated settling velocity using (9) together with those using the other five methods, with the average values reproduced from Raudkivi (1990). It can be seen that (9) has the smallest relative error when compared with the other formulas. The comparison given in Table 3 is between the various computed results and the experimental data of Zegzhda (1934), Arkhangel’skii (1935) and Sarkisyan (1958). It shows that the average relative error of (9) is 6.1%, which is very close to the 5.8% achieved by Zhu and Cheng’s (1993) formula and the degree of accuracy is better than all the other formulas. The present formula is also simpler to use than that proposed earlier by Zhu and Cheng (1993). Fig. 1 displays the relationship of Re and d* derived from (9) and it can be seen that the computed data also agree very well with the tabulated ones given by the U. S. Inter-Agency Committee (1957). CONCLUSIONS An explicit and simple formula was developed for evaluating the settling velocity of individual natural sediment particles. The formula is applicable to the different regimes ranging from the Stokes flow to the high Reynolds number. Comparison with published experimental data shows that the proposed formula has a high degree of prediction accuracy. ACKNOWLEDGEMENTS The author is thankful to Dr. Siow-Yong Lim and Dr. Yee-Meng Chiew, School of Civil and Structural Engineering, Nanyang Technological University, and the anonymous referees for their reviews and useful comments. APPENDIX I. REFERENCES 1. Arkhangel’skii, B. V. (1935). “Experimental study of accuracy of hydraulic coarseness scale

of particles.” Izv. NIIG, No. 15, Moscow (in Russian). 2. Ibad-zade, Y. A. (1992). “Movement of sediment in open channels.” Translated by Ghosh,

S. P. Russian Translations Series, Vol. 49. A. A. Balkema/Rotterdam. 3. Oseen, C. W. (1927). “Neuere Methoden und Ergebnisse in der Hydrodynamik.”

Akademische Verlagsgesellschaft, Leipzig. 4. Raudkivi, A. J. (1990). “Loose boundary hydraulics.” 3rd edition, Pergamon Press. 5. Sarkisyan, A. A. (1958). “Deposition of sediment in a turbulent stream.” Izd. AN SSSR,

Moscow (in Russian). 6. Schiller, L., and Naumann, A. (1933). “ Uber die grundlegenden Berechnungen bei der

Schwekraftaubereitung.” Zeitschrift des Vereines Deutscher Ingenieure, 77(12), 318-320. 7. Schulz, S. F., Wilde, R. H., and Albertson, M. L. (1954). “Influence of shape on the fall

velocity of sedimentary particles.” M. R. D. Sediment Series, No. 5, Missouri River Div., U. S. Corps of Engrs.

8. Sha, Y. Q. (1956). “Basic principles of sediment transport.” Journal of Sediment Research. 1(2): 1-54. (in Chinese).

9. U. S. Inter-Agency Committee (1957). “Some fundamentals of particle size analysis. A

5

study of methods used in measurement and analysis of sediment loads in streams.” Sub-committee on Sedimentation, U. S. Inter-Agency Committee on Water Resources, Report No. 12, St. Anthony Falls Hydr. Lab., Minneapolis, Minn.

10. Van Rijn, L. C. (1989). “Handbook: Sediment transport by currents and waves.” Report H461, Delft Hydraulics, Netherlands.

11. Zanke, U. (1977). “Berechnung der Sinkgeschwindigkeiten von Sedimenten.” Mitt. Des Franzius-Instituts fur Wasserbau, Heft 46, Seite 243, Technical University, Hannover, Deutshland.

12. Zegzhda, A. P. (1934). “Settlement of sand gravel particles in still water.” Izv. NIIG, No.12 Moscow (in Russian).

13. Zhang, R. J. (1989). “Sediment dynamics in rivers.” Water Resources Press. (in Chinese). 14. Zhu, L. J., and Cheng, N. S. (1993). “Settlement of sediment particles.” Research Report,

Dept. of River and Harbour Engrg., Nanjing Hydr. Res. Institute, China. (in Chinese). APPENDIX II. NOTATIONS The following symbols are used in this paper: A,B = constants; CD = drag coefficient; d = diameter of a particle; d* = dimensionless particle parameter; g = gravitational acceleration; n = exponent; Re = wd/ν = particle Reynolds number; T = temperature; w = settling velocity of a particle; α = parameter; Δ = (ρS - ρ)/ρ; ν = kinematic viscosity of fluid; ρ = density of fluid; and ρS = density of sediment particles.

6

0.1

1

10

100

1000

10000

1 10 100 1000

d *

Re

U. S. Inter-Agency Committee (1957)

Eq. (9)

Fig. 1 Comparison between (9) and the U. S. Inter-Agency Committee Data, 1957

7

Table 1 Drag Coefficient of Sediment Particles at Extreme

Reynolds Numbers

Author CD (low Re) CD (high Re) Sha (1956) 32/Re 1.0 Concharov (1962) 32/Re 1.2 Zhang (1989) 34/Re 1.2 Van Rijn (1989) 24/Re 1.1 Raudkivi (1990) 32/Re 1.2 Zhu and Cheng (1993) 32/Re 1.2

10/14

Thomas C. Ginn, Ph.D. Principal Professional Profile Dr. Thomas Ginn is a Principal Scientist in Exponent’s EcoSciences practice. Dr. Ginn specializes in natural resource damage assessment (NRDA) and ecological risk assessment (ERA). He has conducted studies of the effects of inorganic and organic chemicals on aquatic and terrestrial organisms at sites nationwide. Dr. Ginn has specialized expertise in assessing the fate, exposure, and effects of substances such as PCBs, PAHs, dioxins, arsenic, cadmium, copper, lead, and mercury. He has provided scientific consultation regarding the design field and laboratory studies ecfor ERAs and NRDAs and he has provided technical support during negotiations with state and federal agencies. Dr. Ginn has provided support to industrial clients for NRDAs in Alaska, Arizona, California, Idaho, Indiana, Missouri, Montana, Massachusetts, Michigan, Minnesota, New Jersey, New York, Ohio, Oklahoma, South Carolina, Tennessee, Texas, Washington, and West Virginia. In these projects, he has worked closely with legal counsel during scientific assessments and settlement negotiations with state, federal, and tribal trustees. Dr. Ginn has performed detailed technical assessments of injuries to terrestrial and aquatic resources, including vegetation, benthic macroinvertebrates, fishes, birds, and mammals, and has also developed innovative and cost-effective restoration alternatives. He has provided deposition and trial testimony concerning injury to aquatic and terrestrial resources. Dr. Ginn has evaluated remedial alternative at contaminated sediment sites and has conducted state-of-the-art studies of the sources and distribution of trace metals. He has also developed site-specific sediment quality values based on the empirical relationships of chemical concentrations to biological effects. Dr. Ginn has authored many publications in the area of applied ecology. He has given numerous presentations and CLE seminars on risk assessment and natural resource damage assessment. Since 1983, he has co-authored the annual literature review of marine pollution studies published by the Research Journal of the Water Environment Federation. Dr. Ginn has served as an expert witness concerning the effects of waste discharges and chemicals in sediments on aquatic organisms. He has also served on scientific advisory committees concerning management of contaminated sediments for Puget Sound, San Francisco Bay, and New York/New Jersey Harbor. Dr. Ginn testified to the U.S. House of Representatives, Commerce Committee, concerning the natural resource damage provision of Superfund reauthorization. Academic Credentials and Professional Honors Ph.D., Biology, New York University, 1977 M.S., Biological Sciences, Oregon State University, 1971 B.S., Fisheries Science, Oregon State University, 1968

Thomas C. Ginn, Ph.D. Page 2 10/14

Licenses and Certifications Certified Fisheries Professional, American Fisheries Society, Certificate No. 2844 Publications Mearns AJ, Reish DJ, Oshida PS, Ginn T, Rempel-Hester MA, Arthur C, Rutherford N. Effects of pollution on marine organisms. Water Environ Res 2014; 86(10):1869–1954. Mearns AJ, Reish DJ, Oshida PS, Ginn T, Rempel-Hester MA, Arthur C, Rutherford N. Effects of pollution on marine organisms. Water Environ Res 2013; 85(10):1828–1933. Boehm PD, Ginn TC. The science of natural resource damage assessments. Environmental Claims Journal 2013; 25(3):185–225. Mearns AJ, Reish DJ, Oshida PS, Ginn T, Rempel-Hester MA, Arthur C. Effects of pollution on marine organisms. Water Environ Res 2012; 84(10):1737–1823. Mearns AJ, Reish DJ, Oshida PS, Ginn T, Rempel-Hester MA. Effects of pollution on marine organisms. Water Environ Res 2011; 83(10):1789–1852. Mearns AJ, Reish DJ, Oshida PS, Buchman M, Ginn T, Donnelly R. Effects of pollution on marine organisms. Water Environ Res 2009; 81(10):2070–2125. Gala W, Lipton J, Cernera P, Ginn TC, Haddad R, Henning MH, Jahn K, Landis WG, Mancini E, Nicoll J, Peters V, Peterson J. Ecological Risk Assessment (ERA) and Natural Resource Damage Assessment (NRDA): Synthesis of assessment procedures. Integrated Environ Assess Manage 2009; 5(4):515–522. Mearns AJ, Reish DJ, Oshida PS, Buchman M, Ginn T, Donnelly R. Effects of pollution on marine organisms. Water Environ Res 2008; 80(10):1918–1979. Becker DS, Ginn TC. Critical evaluation of the sediment effect concentrations for polychlorinated biphenyls. Integrated Environ Assess Manage 2008; 4(2):156–170. Mearns AJ, Reish DJ, Oshida PS, Buchman M, Ginn TC, Donnelly R. Effects of pollution on marine organisms. Water Environ Res 2007; 79(10):2102–2160. Becker DS, Long ER, Proctor DM, Ginn TC. Evaluation of potential toxicity and bioavailability of chromium in sediments associated with Chromite ore processing residue. Environ Toxicol Chem 2006; 25(10):2576–2583. Mearns AJ, Reish DJ, Oshida PS, Buchman M, Ginn TC. Effects of pollution on marine organisms. Water Environ Res 2006; 78(10):20332086.


Sampson JR, Sexton JE, Ginn TC, Pastorok RA, Spielman A, Young DR, Taganov I. Content of metals and some organic contaminants in environmental media of Lake Baikal. Proc Russ Geogr Soc 2006; 1:5258 (in Russian). Nielsen D, Ginn T, Ziccardi L, Boehm P. Study: Proposed offshore gulf LNG terminals will have minor effects on fish populations. Oil Gas J 2006; 104(28), July 28. Reish DJ, Oshida PS, Mearns AJ, Ginn TC, Buchman M. Effects of pollution on marine organisms. Water Environ Res 2005; 77(7):27332919. Dunford RW, Ginn TC, Desvousges WH. The use of habitat equivalency analysis in natural resource damage assessments. Ecol Econ 2004; 48(1):49–70. Reish DJ, Oshida PS, Mearns AJ, Ginn TC, Buchman M. Effects of pollution on marine organisms. Water Environ Res 2004; 76(7):2443. Reish DJ, Oshida PS, Mearns AJ, Ginn TC, Buchman M. Effects of pollution on marine organisms. Water Environ Res 2003; 75, 63 pp. Reish DJ, Oshida PS, Mearns AJ, Ginn TC, Buchman M. Effects of pollution on marine organisms. Water Environ Res 2002; 74, 78 pp. Reish DJ, Oshida PS, Mearns AJ, Ginn TC, Buchman M. Effects of pollution on marine organisms. Water Environ Res 2001; 73, 77 pp. Reish DJ, Oshida PS, Mearns AJ, Ginn TC, Buchman M. Effects of pollution on marine organisms. Water Environ Res 2000; 72, 59 pp. Reish DJ, Oshida PS, Mearns AJ, Ginn TC, Buchman M. Effects of pollution on marine organisms. Water Environ Res 1999; 71(5):11001115. Reish DJ, Oshida PS, Mearns AJ, Ginn TC, Buchman M. Effects of pollution on saltwater organisms. Water Environ Res 1998; 70(4):931949. Reish DJ, Oshida PS, Mearns AJ, Ginn TC, Godwin-Saad EM, Buchman M. Effects of pollution on saltwater organisms. Water Environ Res 1997; 69(4):877892. Reish DJ, Oshida PS, Mearns AJ, Ginn TC. Effects of pollution on saltwater organisms. Water Environ Res 1996; 68(4):784796. Becker DS, Ginn TC. Effects of storage time on toxicity of sediments from Puget Sound, Washington. Environ Toxicol Chem 1995; 14(5):829–835. La Tier AJ, Mulligan PI, Pastorok RA, Ginn TC. Bioaccumulation of trace elements and reproductive effects in deer mice (Peromyscus maniculatus). Proceedings, 12th Annual National


Meeting of the American Society for Surface Mining and Reclamation, Gillette, WY, pp. 3–14, 1995. Pastorok RA, La Tier AJ, Butcher MK, Ginn TC. Mining-related trace elements in riparian food webs of the Upper Clark Fork River Basin. Proceedings, 12th Annual National Meeting of the American Society for Surface Mining and Reclamation, Gillette, WY, pp. 31–51, 1995. Pastorok RA, Butcher MK, Ginn TC. Thresholds for potential effects of mining-related trace elements on riparian plant communities. Proceedings, 12th Annual National Meeting of the American Society for Surface Mining and Reclamation, Gillette, WY, pp. 15–30, 1995. Reish DJ, Oshida PS, Mearns AJ, Ginn TC. Effects of pollution on saltwater organisms. Water Environ Res 1995; 67(4):718731. Reish DJ, Oshida PS, Mearns AJ, Ginn TC. Effects of pollution on saltwater organisms. Water Environ Res 1994; 66(4):623635. Reish DJ, Oshida PS, Mearns AJ, Ginn TC. Effects of pollution on saltwater organisms. Res J Water Pollut Control Fed 1993; 65(4):573585. Reish DJ, Oshida PS, Mearns AJ, Ginn TC. Effects of pollution on saltwater organisms. Res J Water Pollut Control Fed 1992; 64(4):599610. Ginn TC, Pastorok RA. Assessment and management of contaminated sediments in Puget Sound. In: Sediment Toxicity Assessment. Burton GA (ed), Lewis Publishers, Inc., Boca Raton, FL, 1992. Johns DM, Pastorok RA, Ginn TC. A sublethal sediment toxicity test using juvenile Neanthes sp. (Polychaeta: Nereidae). In: Aquatic Toxicology and Risk Assessment: Fourteenth Volume. Mays MA, Barron MG (eds), ASTM STP 1124, American Society for Testing and Materials, Philadelphia, PA, pp. 280–283, 1992. Reish DJ, Oshida PS, Mearns AJ, Ginn TC. Fate and effects of pollutants: Effects on saltwater organisms. Res J Water Pollut Control Fed 1992; 62(4):577–593. Reish DJ, Oshida PS, Mearns AJ, Ginn TC. Effects on saltwater organisms. Res J Water Pollut Control Fed 1991; 63(4):696709. Reish DJ, Oshida PS, Mearns AJ, Ginn TC. Effects on saltwater organisms. Res J Water Pollut Control Fed 1990; 62(4):577593. Becker DS, Bilyard GR, Ginn TC. Comparisons between sediment bioassays and alterations of benthic macroinvertebrate assemblages at a marine Superfund site: Commencement Bay, Washington. Environ Toxicol Chem 1990; 9(5):669–685.


Reish DJ, Oshida PS, Mearns AJ, Ginn TC. Effects on saltwater organisms. J Water Pollut Control Fed 1989; 61(6):10421054. Ginn TC. Assessment of contaminated sediments in Commencement Bay (Puget Sound, Washington). In: Contaminated Marine Sediments—Assessment and Remediation. National Academy Press, Washington, DC, pp. 425–439, 1989. Barrick RC, Beller H, Becker DS, Ginn TC. Use of the apparent effects threshold approach (AET) in classifying contaminated sediments. In: Contaminated Marine Sediments—Assessment and Remediation. National Academy Press, Washington, DC, pp. 64–77, 1989. Reish DJ, Oshida PS, Mearns AJ, Ginn TC. Effects on saltwater organisms. J Water Pollut Control Fed 1988; 60(6):10651077. Ginn TC, Barrick RC. Bioaccumulation of toxic substances in Puget Sound organisms. In: Oceanic Processes in Marine Pollution, Volume 5. Wolfe DA and O’Connor TP (eds). Robert E. Krieger Pub. Co, Malabar, FL, pp. 157–168, 1988. Barrick RC, Pastorok R, Beller H, Ginn T. Use of sediment quality values to assess sediment contamination and potential remedial actions in Puget Sound. Proceedings, 1st Annual Meeting on Puget Sound Research, Volume 2. Puget Sound Water Quality Authority, Seattle, WA, pp. 667–675, 1988. Becker DS, Ginn TC, Bilyard GR. Field validation of sediment bioassays at a marine Superfund site: Commencement Bay, Washington. In: Superfund ‘88, Proceedings, 9th National Conference, Hazardous Materials Control Research Institute, Silver Spring, MD, pp. 323–328, 1988. Jacobs LA, Barrick R, Ginn T. Application of a mathematical model (SEDCAM) to evaluate the effects of source control or sediment coordination in Commencement Bay. Proceedings, 1st Annual Meeting on Puget Sound Research, Puget Sound Water Quality Authority, Seattle, WA, pp. 677–684, 1988. Reish DJ, Oshida PS, Mearns AJ, Ginn TC. Effects on saltwater organisms. J Water Pollut Control Fed 1987; 59(6):572586. Becker DS, Ginn TC, Landolt ML. Powell DB. Hepatic lesions in English sole (Parophrys vetulus) from Commencement Bay, Washington (USA). Mar Env Res 1987; 23:153173. Reish DJ, Oshida PS, Mearns AJ, Ginn TC. Effects on saltwater organisms. J Water Pollut Control Fed 1986; 58(6):671680. Williams LG, Chapman PM, Ginn TC. A comparative evaluation of marine sediment toxicity using bacterial luminescence, oyster embryo and amphipod sediment bioassays. Mar Env Res 1986; 19:225–249.


Reish DJ, Oshida PS, Mearns AJ, Ginn TC, Carr RS, Wilkes FG, Butowski N. Effects on saltwater organisms. J Water Pollut Control Fed 1985; 57(6):699712. Reish DJ, Oshida PS, Wilkes FG, Mearns AJ, Ginn TC, Carr RS. Effects on saltwater organisms. J Water Pollut Control Fed 1984; 56(6):759774. Reish DJ, Geesey GG, Wilkes FG, Oshida PS, Mearns AJ, Rossi SS, Ginn TC. Marine and estuarine pollution. J Water Pollut Control Fed 1983; 55(6):767787. Reish DJ, Geesey GG, Wilkes FG, Oshida PS, Mearns AJ, Rossi SS, Ginn TC. Marine and estuarine pollution. J Water Pollut Control Fed 1982; 54(6):786812. Poje GV, O’Connor JM, Ginn TC. Physical simulation of power plant condenser tube passage. Water Res 1982; 16(6):921–928. Reish DJ, Geesey GG, Oshida PS, Wilkes FG, Mearns AJ, Rossi SS, Ginn TC. Marine and estuarine pollution. J Water Pollut Control Fed 1981; 53(6):925949. Grieb TM, Porcella DB, Ginn TC, Lorenzen MW. Classification and analysis of cooling impoundments: an assessment methodology using fish standing crop data. Proceedings, Symposium on Surface Water Impoundments. American Society of Civil Engineering, Washington, DC, pp. 482494, 1981. Pastorok RA, Lorenzen MW, Ginn TC. Aeration/circulation as a control of algal production. Proceedings, Workshop on Algal Management and Control. Technical Report E-817. U.S. Army Corps of Engineers, Waterways Experiment Station, Vicksburg, MS, pp. 57–97, 1981. Pastorok RA, Ginn TC, Lorenzen MW. Evaluation of aeration/circulation as a lake restoration technique. Ecological Research Series, EPA-600/3-81/014. U.S. Environmental Protection Agency, Corvallis, OR, 1981. Pastorok RA, Ginn TC, Lorenzen MW. Review of aeration/circulation for lake management. In: Restoration of Lakes and Inland Waters. EPA-440/5-81/010. U.S. Environmental Protection Agency, Washington, DC, pp. 124–133, 1980. Ginn TC, O’Connor JM. Response of the estuarine amphipod Gammarus daiberi to chlorinated power plant effluent. Estuarine Coastal Mar Sci 1978; 6(5):459–469. Haven KF, Ginn TC. A mathematical model of the interactions of an aquatic ecosystem and a thermal power station cooling system. Proceedings, 4th National Workshop on Entrainment and Impingement. Jensen LD (ed). E.A. Communications, Melville, NY, pp. 321–344, 1978. Poje GV, Ginn TC, O’Connor JM. Responses of ichthyoplankton to stresses simulating passage through a power plant condenser tube. In: Energy and Environmental Stress in Aquatic Systems. J.H. Thorp and J.W. Gibbons (eds.). U.S. Department of Energy, Technical Information Center, Washington, DC, pp. 794–808, 1978.


Ginn TC, Waller WT, Lauer GL. Survival and reproduction of Gammarus spp. (Amphipoda) following short-term exposure to elevated temperature. Chesapeake Sci 1976; 17(1):8–14. Ginn TC, Waller WT, Lauer GL. The effects of power plant condenser cooling water entrainment on the amphipod, Gammarus sp. Water Res 1974; 8(11):937–945. Ginn TC, Bond CE. Occurrence of the cutfin poacher, Xeneretmus leiops, on the continental shelf off the Columbia River mouth. Copeia 1973; 4:814–815. Selected Project Experience Natural Resource Damage Assessments Silvertip Pipeline Oil Spill (Yellowstone River, Montana). Consulting expert participating in assessment of available information on aquatic and riparian resources, including fishes, benthic macroinvertebrates, and birds. Participation in negotiations with state and federal trustees. St. Croix Alumina Site. (U.S. Virgin Islands). Expert witness concerning alleged injuries to terrestrial resources from upland disposal of bauxite ore processing wastes for the case: Commissioner of the Department of Planning and Natural Resources, Alicia V. Barnes, et al. v. Virgin Islands Alumina Company et al. District Court of the Virgin Islands, Division of St. Croix, Civil Case No. 2005-0062. Tar Creek Superfund Site (Oklahoma). Expert witness concerning alleged injuries to terrestrial plant communities resulting from mining wastes for the case: The Quapaw Tribe of Oklahoma et al. v. Blue Tee Corp, et al. United States District Court, Northern District of Oklahoma, Case No. 03-CV-0846-CVE-PJC. Illinois River and Lake Tenkiller (Oklahoma). Assessment of the status of benthic macroinvertebrates and fishes in the aquatic environment and relationships of biotic characteristics to habitat factors and potential effects of poultry operations. Bayway and Bayonne Refineries (New Jersey). Evaluation of marine, wetland, and terrestrial communities at the refinery sites. Expert witness in the case and testified at trial (July 2014): New Jersey Department of Environmental Protection and Administrator, New Jersey Spill Compensation Fund v. Exxon Mobil Corporation, Superior Court of New Jersey, Law Division/Union County. Tittabawassee and Saginaw River/Bay (Michigan). Assessment of potential injuries to aquatic and terrestrial resources caused by releases of dioxins/furans and other substances. Negotiations with state, tribal, and federal trustees. Pine Bend Refinery (Minnesota). Key issues involve injuries to groundwater, surface water, and wetland resources resulting from releases of petroleum products. Negotiations with state and federal trustees.


FAG Bearing site (Missouri). The claim focused on potential injuries to groundwater resources and federally-listed aquatic species resulting from releases of trichloroethene. Negotiation with trustees and successful settlement. Ohio River (Ohio and West Virginia). Claim related to alleged releases of carbamate-metal complexes from a manganese smelter at Marrietta. Key issues involve the causes of mortalities in populations of freshwater mussels and fishes and restoration alternatives for important species. Negotiations with state and federal trustees and deposition. Ashtabula River/Harbor site (Ohio). Key issues include potential effects of PCBs and PAH on fishes and invertebrates in the harbor ecosystem. White River (Indiana). Alleged injuries included a major fish kill associated with releases of carbamate-metal complexes from an industrial facility. Participant in technical negotiations with state and federal trustees. Koppers site in Charleston Harbor (South Carolina). Assessment of PAH and metals in the estuarine environment and development of restoration alternatives. Negotiations with state and federal trustees. Coeur d’Alene River (Idaho). Provided expert testimony concerning potential injuries caused by metals at deposition and trial (U.S. v. Asarco et al). Saginaw River/Bay (Michigan). Key issues involve bioaccumulation and effects of PCBs in fishes, aquatic birds, and terrestrial wildlife. Participated in settlement negotiations with state and federal trustees. Three industrial sites on the St. Lawrence River (New York). Negotiations with federal, state, and tribal trustees on injuries related to PCBs and PAH and identification of restoration alternatives. Duwamish River (Washington). Claim related to releases of PCBs in the estuarine environment and potential injuries to fish, benthic, and bird resources. Participated in settlement negotiations with state, federal, and tribal trustees. Clark Fork Basin Superfund complex (Montana). Served as technical lead for PRP negotiations with the trustee and developed supporting scientific reports. Provided testimony at trial in areas of water quality, sediments, and ecosystem-level effects of metals for terrestrial environments. SMC Cambridge site (Ohio). Technical review and response to a natural resource damage claim associated with metals injuries to wetland resources. Participated in settlement negotiations with state and federal trustees. Pools Prairie Superfund site (Missouri). Key issues include groundwater injuries and potential effects on a federally listed species.


Koppers site in Texarkana (Texas). Assessment of aquatic injuries and developed restoration settlement package for client. Leader of technical negotiations with state and federal trustees. SMC Newfield site (New Jersey). Conducted technical review and response to a natural resource damage claim for groundwater resources at the. Participated in settlement negotiations with the state trustee. Ecological Risk Assessments Board of County Commissioners of the County of Kay, Oklahoma v. Freeport-McMoRan Copper and Gold Inc., et al. United States District Court for the Western District of Oklahoma Case No. CJ-2012-74. Expert witness for assessing effects of smelter materials containing arsenic, cadmium, lead, and zinc on aquatic and terrestrial organisms, including benthic macroinvertebrates, plants, birds, and mammals. NASSCO Shipyard (California). Expert and mediation support to resolve sediment remediation issues in response to a cleanup and abatement order. Issues involved the amount of dredging and other remediation required to reduce aquatic and human health risks at the site and the scope of post-remedial monitoring. San Diego Bay Shipyard sites (California). Studies of sediment contamination and ecological risks of metals (e.g., copper, zinc, and butyltins) and organic substances (PAH and PCBs) at two major shipyards. Site-specific studies included sediment triad assessment and sampling of resident biota for bioaccumulation and histopathology analyses. Hudson River (New York). Studies and agency presentations to support ecological risk assessment for the upper Hudson River. Technical leader for studies of the effects of PCBs on fishes, invertebrates, mammals, and birds of the upper Hudson River. National Zinc site (Oklahoma). Participated in agency negotiations on RI/FS implementation. Assessed effects of metals on aquatic and terrestrial biota. Lake Apopka (Florida). Ecotoxicological investigation of large-scale avian mortality at restored wetland habitats near the lake. The specific objective is to determine whether organochlorine pesticides or some other environmental factor was the causal agent of the mortalities. Shelter Island Boatyard (California). Principal investigator for field and laboratory studies and an assessment of sediment cleanup levels for copper, mercury, and butyltin near a commercial marine maintenance operation in San Diego Bay, California. PCB sites in Southeast. Principal-in-charge for ecological risk assessments conducted at several natural gas pipeline compressor stations located throughout the southeastern U.S. Led technical negotiations with EPA concerning the scope and interpretation of studies assessing risk of PCBs to aquatic and terrestrial biota.


Clark Fork River (Montana). Managed integrated ecological risk assessment studies at the Clark Fork River, Montana, Superfund site. Assessed the bioavailability and effects of metals in aquatic and terrestrial food chains. Chikaskia River (Oklahoma). Managed field and laboratory studies of the effects of cadmium and the development of site-specific water quality criteria using the water effect ratio approach. Campbell Shipyard (California). Directed an investigation of sediment chemical levels, biological effects, and human health risks at a major shipyard facility in San Diego Bay, California. Commencement Bay Superfund Site (Washington). Managed RI/FS that included extensive field sampling of sediments and biota, assessing effects of toxic substances, assessing health risks, and identifying pollutant sources. Puget Sound Estuary Program (Washington). Managed a multiyear, comprehensive field and laboratory investigation of the effects of chemicals in various sub-areas of Puget Sound. The study included numerous projects involving field and laboratory analyses, assessment of pollutant sources, assessments of human health and ecological risks, and development of sampling and analytical protocols. Sewage Discharges (Alaska). Managed field and laboratory studies of benthic macroinvertebrates, bioaccumulation, and water quality at three sewage outfalls in southeastern Alaska. Bering Sea (Alaska). Conducted study design, statistical analysis, and interpretation of results for a field study investigating the effects of commercial harvesting operations on surf clams and other invertebrates. Poplar River (Montana). Managed a risk assessment for water quality, air quality, and socioeconomic impacts of a coal-fired power plant in the Poplar River basin in Montana. Managed an EIS for river flow apportionment alternatives and atmospheric emissions from the plant. Klamath Lake (Oregon). Managed a project to evaluate water quality effects on fish populations in the Klamath River basin and to develop a modeling approach to assess the effects of flow apportionment alternatives on water quality and fish habitat. Puget Sound (Washington). Project manager for an assessment of potential biological effects caused by the release of dichloromethane from an industrial facility. Prepared expert report for use in litigation.


Regulatory Programs Project manager for technical support activities for EPA’s Office of Marine and Estuarine Protection. Supervised data management, development of technical guidance, estuarine program support, monitoring program design, bioaccumulation analyses, and quality assurance reviews. Served as one member of the five-member Technical Review Panel for the Long-Term Management Strategy for San Francisco Bay. The panel provided critical outside technical review of the program’s conceptual approach, scientific rigor, and technical findings. Specifically assigned to sediment toxicology aspects. Manager for a comprehensive review by EPA of sediment toxicity test methods and development of a resource document that is used to select appropriate test methods for use in NPDES monitoring programs at industrial facilities. Served as a member of a six-member Biological Resource Assessment Group for New York Harbor. Specifically assigned as an expert in chemical contaminants in sediments and bioaccumulation. For EPA multi-year project, served as chief biologist for technical evaluation of Clean Water Act Section 301(h) applications for permit modifications at marine sewage discharge sites throughout the United States. Provided technical support to the Oklahoma Water Resources Board for the development of site-specific water quality criteria for metals. For the Army Corps of Engineers, served as principal-in-charge for Puget Sound Dredged Disposal Analysis Phase I and II baseline biological surveys at dredged material disposal sites in Puget Sound, Washington. Served on the Technical Advisory Committee for the Puget Sound Estuary Program. The committee provided technical review and program guidance to the various sponsoring agencies. Other Water Quality Studies Served as principal investigator and expert witness for an assessment of benthic biological effects and sediment chemical levels near the Pt. Loma, California, sewage discharge. Assessment of the effects of offshore LNG terminals in the Gulf of Mexico on fish populations. Evaluated effects of fish egg and larvae entrainment of key species in proposed facilities at various locations. Conducted a comprehensive assessment of bioaccumulation of inorganic and organic substances in marine organisms in the Southern California Bight.


Directed a comprehensive review and evaluation of the biological impacts of oil spill cleanup operations on marine ecosystems. Conducted an evaluation of the role of soil and water bioassays for assessing biological effects of hazardous waste sites. Principal investigator to evaluate the biological impacts of ocean disposal of manganese nodule processing wastes. Managed a project to evaluate available cause and effect data and models to predict water quality and biological impacts for Puget Sound, Washington. Developed the biological components of an ecosystem model to evaluate effects of multiple power plant discharges on a single water body. Managed statistical analyses of benthic infauna data collected near the Waterflood Causeway in the Beaufort Sea. Project co-manager and principal investigator for a review and analysis of biological impact data for all currently operating coastal power plants in the United States. Principal scientist to evaluate responses of benthic invertebrates and fishes to lake aeration and circulation projects. Principal scientist for a comprehensive limnological evaluation of the Lafayette Reservoir in California. Evaluated the responses of benthic invertebrates and fishes to lake aeration and circulation programs and developed recommendations for applicable lake restoration techniques. Principal investigator in analyzing water quality conditions at a hypereutrophic lake and conducting public workshops on alternative restoration measures. Developed a method of predicting biological responses of new cooling lakes based on a deterministic ecosystem model and empirical fish production models. Conducted field and laboratory investigations of the effects of power plant entrainment on macroinvertebrates in the Hudson River estuary. Determined relationship of entrainment effects to populations in the lower estuary. Managed laboratory bioassay studies evaluating the combined effects of temperature, chlorine, and physical stress on estuarine ichthyoplankton and zooplankton.


Professional Affiliations

Society of Environmental Toxicology and Chemistry American Chemical Society American Institute of Fishery Research Biologists

Depositions Commissioner of the Department of Planning and Natural Resources, Alicia V. Barnes, et al. v. Virgin Islands Alumina Company et al. District Court of the Virgin Islands, Division of St. Croix, Civil Case No. 2005-0062, deposition 2012. The Quapaw Tribe of Oklahoma et al. v. Blue Tee Corp, et al., United States District Court, Northern District of Oklahoma, Case No. 03-CV-0846-CVE-PJC, deposition 2010. Moraine Properties, LLC v. Ethyl Corporation, United States District Court, Southern District of Ohio, Civil Action No. 3:07-cv-00229, deposition 2010. State of Oklahoma et al. v. Tyson Foods, Inc, et al., United States District Court for the Northern District of Oklahoma, Civil Action Number 4:05-CV-00329-TCK-SAJ, deposition 2009. New Jersey Department of Environmental Protection and Administrator, New Jersey Spill Compensation Fund v. Exxon Mobil Corporation, Superior Court of New Jersey, Law Division/Union County, DOCKET NO. L-3026-04, deposition 2008. United States of America, The State of West Virginia, and The State of Ohio v. Elkem Metals Co. L.P., Ferro Invest III Inc., Ferro Invest II Inc., and Eramet Marietta Inc, United States District Court, Southern District of Ohio, Eastern Division, Case No. 2:03 CV 528, deposition 2005. United States of America v. Asarco Incorporated et al., United States District Court for the District of Idaho, Case No. CV-96-0122-N-EVL, deposition, 2000. State of Montana v. Atlantic Richfield Company, United States District Court for the District of Montana, Case No. CV-83-317-HLN-PGH, deposition, 1996. Aluminum Company of America and Northwest Alloys, Inc. v. Accident and Casualty Insurance Company, et al, Superior Court of the State of Washington, King County, Case No. 92-2-28065-5, depositions 1995, 1996. Asarco v. American Home Insurance Company, et al., Superior Court of the State of Washington, King County, Case No. 90-2-23560-2, deposition 1993. U.S. v. City of San Diego, United States District Court, Southern District of California, Case No. 88-1101-B, depositions 1991, 1993.


Trials and Hearings New Jersey Department of Environmental Protection and Administrator, New Jersey Spill Compensation Fund v. Exxon Mobil Corporation, Superior Court of New Jersey, Law Division/Union County, DOCKET NO. L-3026-04, testimony at trial 2014. California Regional Water Quality Control Board – San Diego Region. Testimony at public hearing for consideration of Resolution No. R9-2011-0072, certification pursuant to the California Environmental Quality Act, of the Final Environmental Impact Report, for the San Diego Bay Shipyard Remediation Project, November 14, 2011. United States of America v. Asarco Incorporated et al., United States District Court for the District of Idaho, Case No. CV-96-0122-N-EVL, testimony at trial, 2001. State of Montana v. Atlantic Richfield Company, United States District Court for the District of Montana, Case No. CV-83-317-HLN-PGH, testimony at trial 1997 (aquatic and terrestrial phases of the trial). U.S. v. City of San Diego, United States District Court, Southern District of California, Case No. 88-1101-B, deposition, testimony at trial 1991, testimony at motion hearing 1994.

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D. Frederick Bodishbaugh, Ph.D. Managing Ecotoxicologist Professional Profile Dr. Rick Bodishbaugh is a Managing Ecotoxicologist in Exponent’s EcoSciences practice. He has 19 years of diverse experience in aquatic toxicology research, chemical and site assessment, ecological risk assessment (ERA) in aquatic and terrestrial systems, and natural resource damage assessment (NRDA). His specific areas of technical expertise include fish and wildlife toxicity assessment, resource/habitat equivalency analysis (REA/HEA), bioavailability of chemical contaminants in aquatic and terrestrial ecosystems, and chemical structure-activity relationships. Dr. Bodishbaugh’s graduate research focused on the aquatic toxicology of synthetic surfactant and other organic pollutants. Originally trained as a chemical engineer, he also has 4 years of experience as a geophysical and geochemical engineer in the international offshore oil and gas industry, and is trained and experienced in geophysical surveying and reservoir geology. Dr. Bodishbaugh also has formal training in marine biochemistry, molecular biology, and bioremediation principles. Dr. Bodishbaugh is experienced in evaluating the effects of contaminated soil, groundwater, surface water, and sediments on ecological receptors. He has conducted assessments of chemical risk at dozens of sites for energy, petrochemical, pulp and paper, manufacturing, and mining industry clients. He is intimately familiar with federal, regional, and various state guidance and standards or practice for ERA under common regulatory frameworks, and has extensive face-to-face negotiation experience with federal and state regulatory agency technical staff across the U.S. He is also experienced in evaluating and interpreting field bioaccumulation and laboratory toxicity bioassay data for use in assessing ecological risk. He is well versed in the environmental toxicology and assessment of metals and persistent organic pollutants, especially PCBs and PAHs. Dr. Bodishbaugh is experienced in providing technical support in a litigation context. He has extensive NRDA experience, and has helped clients develop defensive and settlement strategies for NRDA claims by federal, state, and tribal trustees at sites in Alaska, California, Indiana, Missouri, New Jersey, New York, Texas, and Washington. He is an expert in the application of REA and HEA, including applications for assessment of groundwater injury. He has worked closely with client legal teams to assess and critically evaluate the technical merits and costs of natural resource liability and settlement options, and has represented industry clients in both formal and informal trustee negotiations to arrive at rational injury assessments and cost effective, restoration-based compensation options. He has provided deposition testimony on NRD liability for east and west coast clients, and has contributed to numerous expert reports for NRD cases.

D. Frederick Bodishbaugh, Ph.D. Page 2 06/08

Academic Credentials and Professional Honors Ph.D., Aquatic Toxicology, Duke University, 1995 B.S., Chemical Engineering, University of Tulsa (cum laude), 1985 Publications Pastorok RA, Noftsker C, Iannuzzi TJ, Ludwig DF, Barrick RC, Ruby MV, Bodishbaugh DF. Natural remediation of polynuclear aromatic hydrocarbons and other petroleum hydrocarbons. In: Natural Remediation of Environmental Contaminants: Its Role in Ecological Risk Assessment and Management. Swindoll M, Stahl Jr RG, Ells SJ (eds), SETAC General Publications Series, Society of Environmental Toxicology and Chemistry, SETAC Press, Pensacola, FL, pp. 159–198, 2000. Bodishbaugh DF. Acute toxicity mechanisms and quantitative structure-activity relationships of alkylphenol polyethoxylate surfactants in fish. Dissertation. Duke University, Durham, NC, 1995. Bonaventura C, Bonaventura J, Bodishbaugh DF. Environmental bioremediation: Approaches and processes. In: Ecotoxicity and Human Health: A Biological Approach to Environmental Remediation. Bloom AD and de Serres FJ (eds) CRC Press, Boca Raton, FL, 1995. Bonaventura C, Bonaventura J, Bodishbaugh DF. Environmental bioremediation: Applications and new horizons. In: Ecotoxicity and Human Health: A Biological Approach to Environmental Remediation. Bloom AD and de Serres FJ (eds) CRC Press, Boca Raton, FL, 1995. Selected Presentations Ginn T, Bodishbaugh DF. Key issues for use of habitat equivalency analysis in scaling compensatory restoration projects. Presentation at SETAC Annual Meeting, Portland, OR, November 2004. Bodishbaugh DF, Moore ML, Godtfredsen KL. Congener composition of environmental PCB mixtures: An empirical analysis. Presentation at SETAC Annual Meeting, Austin, TX, November 2003. Bodishbaugh DF. Toxicity endpoint extrapolation for characterization of ecological risk: Which method is right? Invited presentation at SETAC Annual Meeting, San Francisco, CA, November 1997. Bodishbaugh DF. Toxicity assessment for calculation of ecological risk: The deterministic vs. probabilistic approaches to endpoint extrapolation. Presentation at SETAC Annual Meeting, Washington, DC, November 1996.


Bodishbaugh DF. In vitro studies of acute toxicity mechanisms and structure-activity relationships of nonionic surfactants in fish. Presentation at SETAC Annual Meeting, Denver, CO, November 1994. Project Experience Natural Resource Damage Assessment Performed injury assessments and developed restoration alternatives for more than a dozen NRDA sites, involving PCBs, mining wastes, pulp mill effluent, chemical plant discharges and other hazardous releases. Habitats assessed include freshwater rivers and lakes, estuaries, and marine systems, as well as terrestrial habitats. Familiar with NOAA, DOI, and various state trustee guidance and standard NRDA methods. Experienced in emerging NRDA issues, such as evaluation of groundwater resource damages, resource scaling in sensitive habitats, allocation at complex industrial sites, and allegations involving wood waste. Developed client-customizable HEA computational tools for real-time evaluation of injury and restoration alternatives. Provided technical support and strategy in preparation for and during legal negotiations between industry clients and trustees on NRD settlements. Developed and provided scientific rationale for cost-effective HEA-based restoration alternatives to avoid an expensive and arbitrary cash settlement. Presented and defended NRDA alternatives and technical justifications to trustees during face-to-face settlement negotiations. Ecological Risk Assessment Conducted or supervised ERAs for numerous industrial facilities where a combination of organic and inorganic contaminants were risk drivers. Sites have included pipelines, foundries, refineries, petrochemical plants, wood preservative sites, manufactured gas plant sites, shooting ranges, pulp mills, landfills, shipyards, mining sites, research facilities, and munitions plants. State-of-the-art approaches for ecological screening assessments, receptor exposure modeling, toxicity assessment, and chemical hazard characterization were integrated to form rational, science-based site assessments. Conducted extensive bioavailability and bioaccumulation assessments for organic and inorganic contaminants in aquatic systems to provide higher tiers of assessment at complex sites where conventional bulk sediment assessment failed to produce feasible remedial alternatives. Successfully implemented habitat assessment and bioavailability analysis as tools to focus the scope of ecological risk assessments and make site assessment manageable. Conducted ERAs of PCB contamination for numerous industrial clients. Contamination scenarios evaluated include direct product discharges and indirect transport of product to soil, groundwater, and surface water, including sensitive habitats. Industrial sites evaluated include pipeline facilities, heavy manufacturing facilities, and landfills. Developed site-specific food


web modeling approaches to the assessment of risk from PCBs, and negotiated technical approaches to assessment with state and federal regulatory agencies. Reviewed and critiqued recent research developments and helped design original research into environmental toxicity of PCBs. Developed, supported, and negotiated site-specific approaches to the assessment of metals toxicity at mining sites where natural mineralization and physical disturbance make bulk concentration a poor indicator of exposure and risk from site activities. Litigation Support Testified in deposition on general and site-specific NRDA issues on liability insurance case for a pulp and paper industry client in Alaska. Testified in deposition on potential groundwater injuries at an industrial facility in New Jersey. Authored and contributed to expert reports on NRDA issues submitted to state and federal courts on several NRD cases across the country. Reviewed literature and served as an expert technical consultant for client legal teams, and authored affidavits on aquatic toxicity and biodegradation issues in support of active litigation concerning client product liability. Conducted ERA and NRDA training for client legal staff. Aquatic Toxicology Research and Consulting Designed and conducted aquatic toxicity investigations using a variety of in vivo and in vitro techniques and test species, including studies on the toxicity mechanisms and structure-activity relationships of surfactant chemicals, detergents, and oil spill dispersants to fish. Provided oversight for client-supported independent research used to establish the value of potential restoration projects. Participated in the design of chronic dietary exposure studies to assess risk of endangered salmon species to PCBs and PAHs in estuarine sediments. Served as technical consultant on potential endocrine disruptor effects of chemicals and client operations. Conducted training for client technical staff. Professional Affiliations

• American Chemical Society • Society of Environmental Toxicology and Chemistry

01/15

Susan C. Paulsen, Ph.D., P.E. Principal Scientist & Practice Director Professional Profile Dr. Susan Paulsen is a Principal Scientist and the Director of Exponent’s Environmental and Earth Sciences practice. Dr. Paulsen has 24 years of experience with projects involving hydrodynamics, aquatic chemistry, and the environmental fate of a range of constituents. She has provided expert testimony on matters involving the Clean Water Act and state water quality regulations, and she also provides scientific and strategic consultation on matters involving Superfund (CERCLA) and Natural Resources Damages (NRD). She has expertise designing and implementing field and modeling studies of dilution and analyzing the fate and transport of organic and inorganic pollutants, including DDT, PCBs, PAHs, copper, lead, and selenium, in surface and groundwater and in sediments. Dr. Paulsen has designed and implemented field studies in reservoir, river, estuarine, and ocean environments using dye and elemental tracers to evaluate the impact of pollutant releases and treated wastewater, thermal, and agricultural discharges on receiving waters and drinking-water intakes. Dr. Paulsen has designed and managed modeling studies to evaluate transport and mixing, including the siting and design of diffusers, and has evaluated water quality impacts of stormwater runoff, irrigation, wastewater and industrial process water treatment facilities, and desalination brines. Dr. Paulsen has extensive knowledge of California water supply issues, including expertise in California’s Bay-Delta estuary, the development of alternative water supplies, and integration of groundwater basins into supply and storage projects. Dr. Paulsen has designed studies using one-dimensional hydrodynamic models (including DSM2 and DYRESM), three-dimensional CFD modeling, longitudinal dispersion modeling, and Monte Carlo analysis. Dr. Paulsen has participated in multi-disciplinary studies of the fate and transport of organic and inorganic pollutants, including DDT, PCBs, PAHs, copper, lead, selenium, and indicator bacteria in surface waters, groundwaters, and/or sediments. She has worked on matters involving both CERCLA and NRDA, including several involving the fate and transport of legacy pollutants, and she has evaluated the impacts of oil-field operations on drinking-water aquifers. Dr. Paulsen has broad expertise with water quality regulation through the Clean Water Act and state regulations in California, Washington, Hawaii, and other states, and has worked on temperature compliance models, NPDES permitting, permit compliance and appeals, third-party citizens’ suits, and TMDL development. She has evaluated the importance of background and natural sources on stormwater and receiving-water quality and the development of numeric limits for storm flows and process-water discharges. Dr. Paulsen is the author of multiple reports describing the history and development of water quality regulations and has provided testimony on regulatory issues, water quality, and water rights.

Susan C. Paulsen, Ph.D., P.E. Page 2 01/15

Academic Credentials and Professional Honors Ph.D., Environmental Engineering Science, California Institute of Technology, 1997 M.S., Civil Engineering, California Institute of Technology, 1993 B.S., Civil Engineering, Stanford University (with honors), 1991 Licenses and Certifications Registered Professional Civil Engineer, California, #66554 Languages Italian (Conversational) German (Conversational) Selected Publications and Presentations California Council for Environmental and Economic Balance (CCEEB); authored by Paulsen SC. A Clear Path to Cleaner Water: Implementing the vision of the State Water Board for improving performance and outcomes at the State Water Boards. CCEEB: San Francisco, CA. 2013. Available at www.cceeb.org. South Orange Coastal Ocean Desalination (SOCOD) Project; authored by Expert Panel Member Paulsen SC. Expert Panel Report: Offshore Hydrogeology/Water Quality Investigation Scoping, Utilization of Slant Beach Intake Wells for Feedwater Supply. Municipal Water District of Orange County (MWDOC): Fountain Valley, CA. 2012. Available at http://www.mwdoc.com/filesgallery/FINAL_Expert_Panel_Rept_10_9_2012.pdf. Paulsen SC, Goteti G, Kelly BK, Yoon VK. Automated flow-weighted composite sampling of stormwater runoff in Ventura County, CA. Proceedings, Water Environment Federation 2011.12 (2011): 4186-4203. Also published as automated flow-weighted composite sampling of stormwater runoff. Water Environment Laboratory Solutions 2012; 19(2):1–6. Paulsen SC, List EJ, Kavanagh KB, Mead AM, Seyfried R, Nebozuk S. Dynamic modeling and field verification studies to determine water quality and effluent limits downstream of a POTW discharge to the Sacramento River, California. Proceedings, Water Environment Federation 2007; 12:5695–5721. Paulsen SC, List EJ. Potential background constituent levels in storm water at Boeing’s Santa Susana Field Laboratory. Report to Expert Panel convened by The Boeing Company and Regional Water Quality Control Board, Los Angeles Region, 2007. Available at http://www.boeing.com/assets/pdf/aboutus/environment/santa_susana/water_quality/tech_reports/2007_background/2007_background_report.pdf.


Paulsen SC, List EJ, Santschi PH. Modeling variability in 210Pb and sediment fluxes near the Whites Point Outfalls, Palos Verdes Shelf, California. Environmental Science & Technology 1999; 33:3077–3085. Paulsen SC, List EJ, Santschi PH. Comment on “In situ measurements of chlorinated hydrocarbons off the Palos Verd es Peninsula, California.” Environmental Science & Technology 1999; 33:3927–3928. Paulsen SC, List EJ. A study of transport and mixing in natural waters using ICP-MS: Water-particle interactions. Water, Air, and Soil Pollution 1997; 99:149–156. Paulsen SC, List EJ. Tracing discharges in ocean environments using a rare earth tracer. Presented at the 27th IAHR Congress, San Francisco, CA, August 1997. Prior Experience

Various positions including President, Flow Science Incorporated, Pasadena, California, 1997–2014

Consultant to Flow Science Incorporated, Pasadena, California, 1994–1997 Staff Engineer, Dames & Moore, Civil Design Group, San Francisco, California, 1990-

1992 Graduate Research and Teaching Assistant, Hydrologic Transport Processes and Fluid

Mechanics, California Institute of Technology, Pasadena, California, 1993–1997 Research Engineer, Fraunhofer Institute for Atmospheric Environmental Research,

Garmisch-Partenkirchen, Germany (West), 1989 Instructor, Technical Communications Program (joint Business School/School of

Engineering program), Stanford University, Stanford, CA, 1989–1990 Professional Affiliations

American Society of Civil Engineers—ASCE Member, National Ground Water Association


Depositions (last 4 years) City of Cerritos, et al., v. Water Replenishment District of Southern California, Case No. BS128136, in the Superior Court of the State of California, County of Los Angeles. November 24, 2014. The Boeing Company et al. v. State of Washington, Department of Ecology, Appeal of the 2010 Industrial Stormwater General Permit, Pollution Control Hearings Board, State of Washington. Case No. 09-140. 2011. Puget Soundkeeper Alliance v. BNSF Railway Co., Case No. C09-1087-JCC, in the United States District Court, Western District of Washington at Seattle. 2011. Trials and Hearings (last 4 years) The Boeing Company et al. v. State of Washington, Department of Ecology, Appeal of the 2010 Industrial Stormwater General Permit, Pollution Control Hearings Board, State of Washington. Case No. 09-140. 2011.

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Parmeshwar L. Shrestha, Ph.D., P.E., D.WRE, D.CE Senior Managing Engineer Professional Profile Dr. Parmeshwar L. Shrestha (Pravi) is a Senior Managing Engineer in Exponent’s Civil Engineering practice. Dr. Shrestha has over 25 years of experience in the field of water resources and environmental engineering. His expertise in hydrology and hydraulics include a large number of studies for delineating flood hazards including simulation of flooding in alluvial fans, and mitigation of onsite and offsite flood waters. In addition, he has considerable experience in the planning, design, construction, and maintenance of irrigation and drainage channels and hydraulic structures. His experience in the area of hydrodynamic and sediment transport include the development and application of finite element (RMA series of models) and finite difference models (ECOMSED, EFDC) for hydrodynamic and sediment transport modeling (both cohesive and noncohesive) and inherent physico-chemical processes in surface water systems. Specific experience includes development and application of numerical models for Sam Rayburn Lake (Texas), San Francisco Bay, San Diego Bay, Clear Lake (California), New York and New Jersey Harbors, Housatonic River (Massachusetts), Lavaca Bay (Texas), Green Bay (Wisconsin), Tannery Bay (Michigan), Lake Waban (Massachusetts), and the Arafura Sea (Indonesia) for purposes of water quality assessment and mitigation of potential adverse effects. Dr. Shrestha has also conducted workshops and hands-on training on the use of hydrodynamic and sediment transport models for Sandia National Laboratory (NM), The Research Center on Flood and Drought Disaster Reduction (PRC), and Stevens Institute of Technology (NJ). His teaching experience includes courses in hydraulics and open channel flow at Virginia Tech and courses on sediment and pollutant transport at the Hong Kong University of Science and Technology. Dr. Shrestha is currently serving as an Associate Editor for the ASCE Journal of Hydrologic Engineering and serves on the Editorial Board of the Journal of Coastal Research of the Coastal Research and Education Foundation. He was involved in the Water Environment Federation Watershed and Wet Weather Technical Bulletin Advisory Board. He served on the ASCE Task Committee on Contaminated Sediments and on the ASCE Task Committee on Fluid Mud. He is currently serving on the ASCE Standards Committee KSTAT (Fitting of Hydraulic Conductivity with Statistical Spatial Estimation), the ASCE Surface Water Hydrology Technical Committee, and the COPRI Navigation Engineering Task Committee. Dr. Shrestha served as a member of the organizing committee for InterCoh 2003. He is also a member of the advisory committee for the biennial conference on Estuarine and Coastal Modeling. Academic Credentials and Professional Honors Ph.D., Water Resources Engineering, University of California, Davis, 1991 M.S., Water Resources Engineering, University of California, Davis, 1985 B.S., Civil Engineering, Jadavpur University (First class honors), 1979

Parmeshwar L. Shrestha, Ph.D., P.E., D.WRE, D.CE Page 2 06/14

Faculty of the Year Award, Department of Civil Engineering, Virginia Tech, 1994 Dean’s List for Outstanding Instructor, Virginia Tech, 1993, 1994 Nominated for Engineering Sporn Award in Teaching Excellence, Virginia Tech, 1994 Fulbright-Hays Scholar, M.S. Program, University of California, Davis, 1983–1986 Colombo Plan Scholar, Bachelor program, Jadavpur University, 1974–1979 Licenses and Certifications Registered Professional Engineer (Civil), California, #67971 Registered Professional Engineer (Civil), Arizona, #51083 Registered Professional Engineer (Civil), Virginia, #026710 Hong Kong Institution of Engineers, #MO0267236 Diplomate, Water Resources Engineer, #00278 Diplomate, Coastal Engineer, #65 Publications Shrestha PL, Su SH, James SC, Shaller PJ, Doroudian M, Firstenberg CE, Thompson CT. Conceptual site model for Newark Bay—Hydrodynamics and sediment transport. Journal of Marine Science and Engineering 2014; 2(1):123–139. Shaller PJ, Shrestha PL, Doroudian M, Sykora D, Hamilton D. Numerical modeling of the 2005 La Conchita landslide, Ventura County, California. In: Flood hazard identification and mitigation in semi- and arid environments. French RH and Miller JJ (eds), World Scientific Publishing Co., Inc., Hackensack, NJ, September 2012. French RH, Fuller JE, Shaller PJ, Shrestha PL. Needs and benefits of co-operation. In: Flood hazard identification and mitigation in semi- and arid environments. French RH and Miller JJ (eds), World Scientific Publishing Co., Inc., Hackensack, NJ, September 2012. Shaller PJ, Shrestha PL, Doroudian M, Sykora D, Hamilton D. The 2005 La Conchita landslide, California: Part 1 – Geology. In: 5th International Conference on Debris-Flow Hazards Mitigation: Mechanics, Prediction and Assessment, Padua, Italy, June 14-17, 2011. Italian Journal of Engineering Geology and Environment, Genevois R, Hamilton D, and Prestininzi A (eds), GeneCasa Editrice Università La Sapienza, Rome, Italy, 2011; 745–750. Shrestha PL, Shaller PJ, Doroudian M, Sykora D, Hamilton D. The 2005 La Conchita landslide, California: Part 2 – Modeling. In: 5th International Conference on Debris-Flow Hazards Mitigation: Mechanics, Prediction and Assessment, Padua, Italy, June 14-17, 2011. Italian Journal of Engineering Geology and Environment, Genevois R, Hamilton D, and Prestininzi A (eds), GeneCasa Editrice Università La Sapienza, Rome, Italy, 2011; 751–758. Loaiciga HA, et al. Standard guideline for geostatistical estimation and block-averaging of homogeneous and isotropic saturated hydraulic conductivity. ASCE/EWRI Standard 54-2010, ASCE Press, Reston, VA, 2010.


Loaiciga HA, et al. Standard guideline for fitting saturated hydraulic conductivity using probability functions. ASCE/EWRI Standard 50-08, ASCE Press, Reston, VA, 2008. Loaiciga HA, et al. Standard guideline for estimating the effective saturated hydraulic conductivity. ASCE/EWRI Standard 51-08, ASCE Press, Reston, VA, 2008. McAnally WH, Friedrichs C, Hamilton D, Hayter E, Shrestha P, Rodriguez H, Sheremet A, Teeter A. Management of fluid mud in estuaries, bays, and lakes. I: Present state of understanding on character and behavior. ASCE Journal of Hydraulic Engineering 2007; 133(1):922. McAnally WH, Teeter A, Schoellhamer D, Friedrichs C, Hamilton D, Hayter E, Shrestha P, Rodriguez H, Sheremet A, Kirby R. Management of fluid mud in estuaries, bays, and lakes. II: Measurement, Modeling, and Management. ASCE Journal of Hydraulic Engineering 2007; 133(1):2338. James S, Shrestha P, Roberts J. Modeling noncohesive sediment transport using multiple sediment size classes. Journal of Coastal Research 2006; 22(5):11251132. Shrestha P, Blumberg A. Cohesive sediment transport. pp. 327330. In: Encyclopedia of Coastal Science. Schwartz M (ed), Springer, The Netherlands, 2005. Roig LC, Shrestha P, Ramireddygari SR. Mixing and transport. Water Environment Research 2000; 72(5):1–50. Roig LC, Shrestha P. Mixing and transport. Water Environment Research 1999; 71(5):931948. Govindaraju RS, Ramireddygari SR, Shrestha P, Roig LC. Continuum bed model for estuarial sediments based on nonlinear consolidation theory. ASCE Journal of Hydraulic Engineering 1999; 125(3):300304. Shrestha P, Orlob GT, King IP. Comparison of 1-D and 2-D models for simulation of hydrodynamics and water quality in shallow bays. Journal of Environmental Science and Health 1997; A32(4):979999. Shrestha P. An integrated model suite for sediment and pollutant transport in shallow lakes. Advanced Engineering Software 1996; 27:201212. Shrestha P. Aggregation of cohesive sediments induced by internal shear rates with application to sedimentation. Environment International 1996; 22(6):717727. Shrestha P, Orlob GT. Multiphase distribution of cohesive sediments and heavy metals in estuarine systems. ASCE Journal of Environmental Engineering 1996; 122(8):730–740.


Govindaraju RS, Shrestha P, Orlob GT. Comparison of single mechanism and multi mechanism-based approaches for kinetics of sediment removal. Environmental Technology 1994; 15:11011120. Shrestha P, DeVries JJ. Design of inverted siphons—Program documentation. Advanced Engineering Software 1992; 31992(14):205212. Shrestha P, DeVries JJ. Interactive computer-aided design of inverted siphons. ASCE Journal of Irrigation and Drainage 1991; 2(117):233254. Shrestha P, Arulanandan K. Erosion rate of dispersive and non-dispersive clays. Discussion, Journal of Geotechical Engineering 1988; 114(5):22433; ASCE Journal of Geologic Engineering 1989; 18241826. Proceedings and Presentations Bailey JR, Shrestha PL, Dawson C, Head S. Analysis of maximum probable storm surge at the South Texas Project site. Proceedings, World Environmental and Water Resources Congress 2014: Water without Borders, Environmental Water Resources Institute of the American Society of Civil Engineers, Portland, OR, pp. 1412–1421, 2014. Shrestha PL, James SC, Shaller PJ, Doroudian M, Peraza DB, Morgan TA. Estimating the storm surge recurrence interval for Hurricane Sandy. Proceedings, World Environmental and Water Resources Congress 2014: Water without Borders, Environmental Water Resources Institute of the American Society of Civil Engineers, Portland, OR, pp. 1906–1915, 2014. James SC, Roberts JD, Shrestha PL. Simulating flow changes due to current energy capture: SNL-EFDC model verification. Proceedings, World Environmental and Water Resources Congress 2014: Water without Borders, Environmental and Water Resources Institute of the American Society of Civil Engineers, Portland, OR, pp. 816–825, 2014. Shaller PJ, Wren J, Shrestha PL, Sama M, Doroudian M. An evaluation of post-wildfire mitigation measures on flood hazard potential in Southern California. Poster, World Environmental and Water Resources Congress 2014: Water without Borders, Environmental Water Resources Institute of the American Society of Civil Engineers, Portland, OR, 2014. Shrestha PL, Su SH, James SC, Shaller PJ, Doroudian M, Firstenberg CE, Thompson CT. Conceptual site model for Newark Bay – hydrodynamics and sediment transport. Presented at the 13th International Conference on Estuarine and Coastal Modeling, San Diego, CA, November 4–6, 2013. Shaller PJ, Cydzik K, Sama M, Wren J, Shrestha P. The Station Fire revisited, projected versus realized flood impacts 2009–2013. Presented at 2013 Floodplain Management Conference, Anaheim, CA, September 4, 2013.


Shaller PJ, Cydzik K, Sama M, Wren J, Shrestha, P. The Station Fire revisited, projected versus realized flood impacts 2009–2013. Presented at 2013 Wildland Fire Litigation Conference, Monterey, CA, April 21, 2013. Shrestha PL, Lenaburg RT, Scheffner NW, Rezakhani M, Hamilton D, Cydzik K. Storm surge study of the Hawaiian Islands using the EST method. Proceedings, World Environmental and Water Resources Congress, Palm Springs, CA, May 22–26, 2011. Cydzik K, Hamilton D, Stennar H, Cattarossi A, Shrestha PL. Reconnaissance following the May 12, 2008 M7.9 Wenchuan Earthquake, Sichuan, China. Poster, World Environmental and Water Resources Congress, Palm Springs, CA, May 22–26, 2011. Shaller PJ, Cydzik K, Wren J, Hamilton D, Shrestha, PL. A case study of the fire-flood sequence in Southern California. Presentation, Wildland Fire Litigation Conference, San Diego, CA, April 15–17, 2011. Shaller PJ, Shrestha PL, Hamilton D, Jordan N, Doroudian M, Rezakhani M. Assessment of alluvial fan flooding hazards and proposed mitigation, Thousand Palms, California. Presentation, Floodplain Management Association Annual Conference, Henderson, NV, November 2–5, 2010. Shaller PJ, Shrestha PL, Doroudian M, Rezakhani M. Assessment of flood hazard, Travertine Point Area, Southeastern California. Presentation, Floodplain Management Association Annual Conference, Henderson, NV, November 2–5, 2010. Shaller PJ, Shrestha PL, Doroudian M, Hamilton D, Sykora D. The January 10, 2005 La Conchita landslide. Poster, GSA Cordilleran Section and Pacific Section AAPF with Western Regional SPE, Anaheim, CA, May 27–29, 2010. Cydzik K, Hamilton D, Stenner H, Cattarossi A, Shrestha PL. Natural hazard public policy implications of the May 12, 2008 M7.9 Wenchuan Earthquake, Sichuan, China. Poster, American Geophysical Union 2009 Fall Meeting, San Francisco, CA, December 14–18, 2009. Cydzik K, Shrestha PL, Hamilton D, Rezakhani M, Scheffner NW, Lenaburg RT. Numerical modeling to support floodplain mapping in coastal areas. Poster, American Geophysical Union 2009 Fall Meeting, San Francisco, CA, December 14–18, 2009. Shrestha PL, Hamilton DL, Cydzik K, Wardak S, Jordan N, Shaller PJ, Doroudian M. Flood hazard analysis and mitigation. Proceedings, International Conference on Water, Environment, Energy and Society (WEES-2009), pp. 699–706, New Delhi, India, January 12–16, 2009. Murillo B, Wardak S, Hamilton DL, Shrestha PL, Cydzik K, Doroudian M. Sedimentation analysis for existing and proposed development conditions. Proceedings, International Conference on Water, Environment, Energy and Society (WEES-2009), pp. 1636–1641, New Delhi, India, January 12–16, 2009.


Lenaburg RT, Scheffner NW, Shrestha PL, Cydzik K, Rezakhani M, Hamilton DL. EST-based tropical storm flood mapping of the Hawaiian Islands. Proceedings, An International Perspective on Environmental and Water Resources, Bangkok, Thailand, January 5–7, 2009. Shrestha PL, Hamilton D, Jordan N, Lyle JE, Doroudian M, Shaller PJ, Wardak S, Cydzik K, Medellin J. Inland flood hazard analysis and mitigation. Poster, ASCE-EWRI World Environmental & Water Resources Conference, Honolulu, HI, May 1216, 2008. Wardak S, Murillo B, Hamilton D, Shrestha PL, Doroudian M, Cydzik K, Medellin J, Shaller PJ. Sedimentation analysis in an open channel network for existing and proposed development conditions. Poster, ASCE-EWRI World Environmental & Water Resources Conference, Honolulu, HI, May 1216, 2008. Gangai JW, Lenaburg R, Batten B, Drei-Horgan E, Scheffner N, Hamilton D, Rezakhani M, Shrestha P. Hurricane flood insurance study for the Hawaiian Islands. Proceedings, ASCE-COPRI Solutions to Coastal Disasters Conference, Oahu, HI, April 1316, 2008. Shrestha P, Hamilton D, Lyle J, Doroudian M, Shaller P. Analysis of flood hazards for a residential development. Proceedings, ASCE World Environmental and Water Congress, Tampa, FL, May 1519, 2007. Shrestha P, Bigham G, Hamilton D, Doroudian M. A three-dimensional model for Lake Sam Rayburn, Texas. Proceedings, ASCE International Perspective on Environmental and Water Resources, New Delhi, India, December 1820, 2006. Cattarossi A, Mastrocola P, Hamilton D, Shrestha P. Hydrological potential for the restoration of the Mesopotamian marshlands. Proceedings, ASCE International Perspective on Environmental and Water Resources, New Delhi, India, December 1820, 2006. Futornick K, Shrestha P, Sykora D, Hamilton D. Post-Katrina strategies to manage consequences of levee failure. Presentation, A&WMA 99th Annual Conference and Exhibition, New Orleans, LA, June 2023, 2006. Hamilton D, Shrestha P, Lyle J, Doroudian M, Shaller P. Flood hazard analysis and protection plan for a residential development. Proceedings, ASCE World Environmental and Water Resources Congress, Omaha, NE, May 2125, 2006. Shaller P, Hamilton D, Shrestha P, Lyle J, Doroudian M. Investigation of flood and debris flow recurrence—Andreas Canyon, San Jacinto Range, Southern California. Proceedings, ASCE World Environmental and Water Resources Congress, Omaha, NE, May 2125, 2006. Shaller P, Hamilton D, Lyle J, Mathieson E, Shrestha P. The fire-flood-erosion sequence in California—A recipe for disaster. Proceedings, ASCE World Environmental and Water Resources Congress, Omaha, NE, May 21–25, 2006.


Jones C, James S, Roberts J, Shrestha P. Continuous treatment of cohesive and non-cohesive sediment dynamics in a 3-dimensional model of meandering flow. Presentation, 9th Estuarine and Coastal Modeling (ECM9), Charleston, NC, October 31November 2, 2005. Shrestha P, Roberts J, James S, Gailani J. Quantifying resuspension of fine-grained bottom sediments. Presentation, InterCoh2005, Saga University, Saga, Japan, September 2023, 2005. Shaller P, Hamilton D, Doroudian M, Shrestha P, Lyle J, Cattarossi A. Investigation of flood hazards on alluvial floodplains. Proceedings, ASCE World Water and Environmental Resources Congress, Anchorage, AK, May 16–19, 2005. James S, Shrestha P, Roberts J. Noncohesive sediment transport modeling with multiple class sizes. Proceedings, ASCE World Water and Environmental Resources Congress, Anchorage, AK, May 16–19, 2005. Shrestha P, Hamilton D, Jordan N, Doroudian M, Hong S, Proctor D. Impact of sewage line spills on pathogen levels in recreational waters. Proceedings, ASCE World Water and Environmental Resources Congress, Anchorage, AK, May 16–19, 2005. Hamilton D, Shaller P, Shrestha P, Lyle J, Doroudian M. Investigating flood hazards on alluvial floodplains. Presentation, Alluvial Fan Flood Hazard Management Symposium, Phoenix, AZ, April 2022, 2005. Shaller P, Hamilton D, Lyle J, Medley E, Mathieson E, Shrestha P. Fire-flood-erosion sequence: Analysis and mitigation. Presentation, Arid Regions 10th Biennial Conference, Restoration and Management of Arid Watercourses, Mesa, AZ, November 16–19, 2004. Hamilton D, Shaller P, Lyle J, Doroudian M, Shrestha P. Multi-disciplinary approach to distinguishing flood hazards on alluvial floodplains. Presentation, Arid Regions 10th Biennial Conference, Restoration and Management of Arid Watercourses, Mesa, AZ, November 16–19, 2004. Shaller P, Hamilton D, Doroudian M, Shrestha P, Lyle J, Cattarossi A. Interpretation of tectonic, fluvial, and eolian landforms in the Upper Coachella Valley, California, using aerial photography, DEM, and LiDAR technology. Poster, Geological Society of America, Annual Meeting, Denver, CO, November 7–10, 2004. Shrestha P. Sediment transport modeling. Invited Presentation, California Department of Water Resources, July 19, 2004. Hamilton D, Cattarossi A, Polo P, Shrestha P, Nielson D. Restoration of the Mesopotamian marshlands. Presentation, Society of Wetland Scientists, 25th Anniversary Meeting, Seattle, WA, July 1823, 2004. Cattarossi A, Hamilton D, Shrestha P, Polo P. Macro- and micro-scale circulation modeling in the Mesopotamian marshlands of southern Iraq. Proceedings, Arid Lands Symposium, ASCE-


EWRI World Water and Environmental Resources Congress, Salt Lake City, UT, June 27–July 1, 2004. James SC, Roberts J, Shrestha P, Jepson R, Gailani J. Quantifying sediment resuspension in surface water systems. Presentation, ASCE-EWRI, World Water and Environmental Resources Congress, Salt Lake City, UT, June 27–July 1, 2004. Shrestha P. Solving practical environmental problems using high technology tools: Hydrodynamics and sediment transport. Invited Presentation, University of California, Los Angeles, CA, April 27, 2004. Hamilton D, Cattarossi A, Shrestha P. The Eden Again Project: Restoration of the Mesopotamian marshlands. Keynote presentation, National Society of Consulting Soil Scientists 17th Annual Meeting, San Diego, CA, February 5–7, 2004. Hamilton D, Cattarossi A, Shrestha P. Numerical modeling of flows in the Iraqi marshlands. Presentation, Headwaters to Oceans (H2O) Conference, Long Beach, CA, October 23–25, 2003. Shrestha P, Blumberg A, Kaluarachchi D, Li H, Laguette H. Modeling the stability and transport of bed sediments in a shallow lake. Presentation, InterCoh 2003, VIMS, VA, October 1–4, 2003. Shrestha P, Blumberg A, Kaluarachchi D, Li H, Laguette H. Modeling the stability and transport of bed sediments in a shallow lake. Proceedings, Special Session on Contaminated Sediments, ASCE-EWRI Conference, Philadelphia, PA, June 2226, 2003. Farley K, Shrestha P, Blumberg AF, Damiani D, Miller R, Wands J. The use of sediment transport models in contaminant evaluations. Invited Presentation, NOPP-CSTM Workshop, Williamsburg, VA, September 29–October 2, 2002. Shrestha P. Simulation of sediment transport in Lavaca Bay. Video Presentation, NOPP-CSTM Workshop, Williamsburg, VA, September 29–October 2, 2002. Shrestha P, Blumberg AF, Kaluarachchi D, Li H, Laguette H. Modeling sediment stability in a shallow lake. Poster, NOPP-CSTM Workshop, Williamsburg, VA, September 29–October 2, 2002. Shrestha P. Hydrodynamics and sediment transport modeling. Invited Presentation, Sandia National Laboratory, Albuquerque, NM, May 8, 2002. Shrestha P, Blumberg AF. ECOMSED: Some history and its future. Presentation, 2002 Ocean Services Meeting, Session 0S21, ASLO/AGU, Honolulu, HI, February 11–15, 2002. Shrestha P, Paquin PR, Blumberg AF, Migliorini MC. Modeling contaminated sediments in a shallow bay. Proceedings, ASCE-EWRI Conference, Orlando, FL, May 20–24, 2001.


Shrestha P, Kaluarachchi DI, Anid PJ, Blumberg AF, DiToro DM. Cohesive sediment re-suspension: Experimentation and analysis. Proceedings, ASCE-EWRI Conference, Orlando, FL, May 20–24, 2001. Shrestha P, Blumberg AF Ramireddygari SR. ECOMSED: A 3-D time-dependent hydrodynamic and sediment transport model. Invited Presentation, National Community Sediment Transport Model Workshop, Woods Hole, MA, June 21–23, 2000. Shrestha P, Blumberg AF, Ramireddygari SR. Sediment transport studies as a precursor to modeling contaminant fate and transport. Invited Presentation, Institute of Engineering, Pulchowk Campus, Katmandu, Nepal, July 17, 2000. Shrestha P, Blumberg AF, DiToro DM, Hellweger F. A three-dimensional model for cohesive sediment transport in shallow bays. Invited Paper, ASCE Joint Conference on Water Resources Engineering and Water Resources Planning and Management, Minneapolis, MN, July 30August 2, 2000. Shrestha P, Paquin PR, Blumberg AF, Migliorini MC. Evaluating the stability of contaminated sediments in a shallow bay. Platform Presentation, SETAC 21st Annual Meeting, Nashville, TN, November 12–16, 2000. Shrestha P, Blumberg AF, DiToro DM, Fitzpatrick JJ, Hellweger FL, Khan LA. Sediment transport modeling in Green Bay: A precursor to addressing PCB fate and transport. Presentation, SETAC 20th Annual Meeting, Philadelphia, PA, November 14–18, 1999. Shrestha P, Khan LA, Blumberg AF, Schwab DJ. The importance of sediment transport modeling for assessing the fate of toxic chemicals in aquatic systems. Presentation, 6th International Conference on Estuarine and Coastal Modeling, New Orleans, LA, November 2–5, 1999. Shrestha P. Physico-chemical processes for transport and redistribution of contaminated sediments. Invited Presentation, EPRI Workshop. Newark, NJ, September 14, 1999. Shrestha P, Ziegler K, Blumberg AF. Hurricane-induced sediment transport in a shallow barrier island/bay system. Presentation, 5th International Conference on Estuarine and Coastal Modeling, Alexandria, VA, October 22–24, 1997. Govindaraju RS, Shrestha PL, Roig LC. A continuum theory for evolution of soft sediment beds with application to sediment dynamics. Proceedings, XVII IAHR Congress, Environmental and Coastal Hydraulics: Protecting the Aquatic Habitat, Vol. 2, Holly FM, Alsuffar A (eds), pp. 1262–1267, San Francisco, CA, August 10–15, 1997. Kumar A, Shrestha P. Verification of resistance criteria for alluvial streams. Proceedings, Rivertech ‘96, International Water Resources Association, pp. 67–74, Chicago, IL, September 2226, 1996.


Shrestha P. Sediment and mercury pollution in shallow lakes. Proceedings, ASCE North American Water and Environment Congress, Anaheim, CA, June 23–28, 1996. Shrestha P. An improved model for deposition of cohesive sediments. Proceedings, Australasian Fluid Mechanics Conference, pp. 711–714, Sydney, Australia, December 1015, 1995. Shrestha P. Modeling water quality in San Diego Bay. Proceedings, ASCE First International Conference on Water Resources Engineering, pp. 209–213, San Antonio, TX, August 14–18, 1995. Shrestha P, Govindaraju RS, Orlob GT. Modeling kinetics of sediment removal in water columns. Proceedings, ASCE National Conference on Hydraulic Engineering, pp. 1065–1069, Buffalo, NY, 1994. Shrestha P. Hydrodynamics of San Diego Bay. Proceedings, ASCE National Conference on Hydraulic Engineering, pp. 140–144, Buffalo, NY, August 15, 1994. Shrestha P, Saviz CM, Orlob GT, King IP, Sobey RJ, Ford RG. San Francisco Bay and Delta oil spill fate studies—Part I: Hydrodynamic simulation. Proceedings, ASCE National Conference on Hydraulic Engineering, pp. 635–640, San Francisco, CA, July 25–30, 1993. Ford RG, Sobey RJ, Shrestha P, Saviz CM, Orlob GT, King IP. San Francisco Bay and Delta oil spill fate studies—Part II: Oil spill simulation. Proceedings, ASCE National Conference on Hydraulic Engineering, pp. 641–646, San Francisco, CA, July 25–30, 1993. Shrestha P, Orlob GT. Modeling the fate and transport of toxic heavy metals in South San Francisco Bay. Proceedings, ASCE National Conference on Hydraulic Engineering, pp. 647–652, San Francisco, CA, July 25–30, 1993. Shrestha P, DeVries JJ, Krone RB. Hydrodynamic modeling for channel barrier design. Proceedings, ASCE National Conference on Hydraulic Engineering, pp. 1079–1084, San Francisco, CA, July 25–30, 1993. King IP, Shrestha P, Orlob GT. Wind induced circulation and contaminant transport in shallow lakes. Proceedings, ASCE National Conference on Hydraulic Engineering, pp. 1440–1445, San Francisco, CA, July 25–30, 1993. Bale A, Shrestha P, Orlob GT. A CASS for evaluation of mercury contamination in Clear Lake, California. Proceedings, 20th Anniversary Conference, ASCE Water Resources Planning and Management Division Conference, pp. 292–295, Seattle, WA, 1993. Shrestha P, Bale A, Orlob GT. Multiphase distribution of cohesive sediments and associated heavy metals in surface waters. Presentation, 5th Annual Research Symposium, UC Toxic Substances Research and Teaching Program, University of California, San Francisco, CA, October 19, 1991.


Workshops Conducted Shrestha P. POM/ECOMSED workshop. Lecture on sediment transport modeling at Stevens Institute of Technology, Hoboken, NJ, June 11, 2003. Shrestha P. ECOMSED training: Grid generation, hydrodynamics, sediment transport, simulation and analysis. Four-day workshop for The Research Center on Flood and Drought Disaster Reduction, Ministry of Water Resources, Beijing, PRC, December 2–5, 2002. Shrestha P, Li H, Ahsan Q, Kim N. ECOMSED workshop. Three-day workshop for Sandia National Laboratory participants, HydroQual, May 14–16, 2002. Prior Experience Senior Project Manager, HydroQual, Inc., 2001–2003 Project Manager, HydroQual, Inc., 2000–2001 Project Engineer, HydroQual, Inc., 1997–2000 Visiting Assistant Professor, Hong Kong University of Science & Technology, 1994–1996 Visiting Assistant Professor, Virginia Tech., 1993–1994 Post-doctoral Research Associate, University of California, Davis, 1992 Assistant Engineer and Engineer’s Representative, Department of Irrigation and Drainage, Nepal, 1980–1983 Academic Appointments

Visiting Assistant Professor, Hong Kong University of Science & Technology, 1994–1996

Visiting Assistant Professor, Virginia Tech., 1993–1994 Editorships and Editorial Boards

Associate Editor, ASCE–Journal of Hydrologic Engineering Editorial Board, CERF–Journal of Coastal Research

Professional Committees

Advisory Board, Estuarine and Coastal Modeling Conference Advisory Board, WEF Watershed and Wet Weather Technical Bulletin ASCE Standards Committee KSTAT ASCE Surface Water Hydrology Technical Committee ASCE Task Committee for Fluid Mud ASCE Task Committee on Contaminated Sediments COPRI Task Committee Navigation Engineering Organizing Committee, InterCoh, 2003


Professional Affiliations

Academy of Coastal Ocean Port & Navigation Engineers—ACOPNE American Academy of Water Resources Engineers—AAWRE American Geophysical Union American Society of Civil Engineers Association of State Floodplain Managers Coastal Education and Research Foundation Floodplain Management Association Water Environment Federation

Documents

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