APPENDIX K USACE PRELIMINARY ECOLOGICAL RISK … · vides a preliminary assessment of sediment quality by comparing bulk sediment chemistry results to sediment quality guidelines

APPENDIX K USACE PRELIMINARY

ECOLOGICAL RISK SCREENING REPORT

Final Report

Preliminary Ecological RiskScreening of Arlington and Garrows

Bend Channels and Adjacent AreaSediments

Prepared for

U.S. Army Corps of EngineersMobile District

Prepared by

August 2003

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Contents

Section Page

1. Introduction ........................................................................................................................ 1-1

2. Screening Method and Criteria....................................................................................... 2-12.1 Screening Criteria .................................................................................................. 2-12.2 Bioaccumulative Chemicals ................................................................................. 2-52.3 Toxicity Testing...................................................................................................... 2-62.4 Cleanup Target Levels .......................................................................................... 2-6

3. Results of Bulk Chemistry Screening............................................................................ 3-13.1 Metals ...................................................................................................................... 3-13.2 Organics .................................................................................................................. 3-93.3 Dioxins..................................................................................................................... 3-93.4 PAHs........................................................................................................................ 3-93.5 PCBs....................................................................................................................... 3-163.6 Chlorinated Pesticides......................................................................................... 3-16

4. Results of Bioaccumulation Studies .............................................................................. 4-1

5. Results of Toxicity Testing .............................................................................................. 5-1

6. Supplemental Sampling Results .................................................................................... 6-16.1 Introduction............................................................................................................ 6-16.2 Preliminary Risk Evaluation ................................................................................ 6-1

6.2.1 Metals ......................................................................................................... 6-36.2.2 Dioxins........................................................................................................ 6-36.2.3 Total PAH .................................................................................................. 6-36.2.4 DDT............................................................................................................. 6-3

6.3 Bioaccumulation .................................................................................................... 6-36.4 Discussion ............................................................................................................... 6-5

7. Conclusions......................................................................................................................... 7-1

8. References ........................................................................................................................... 8-1

CONTENTS, CONTINUED

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Tables Page

2-1 Ecological Screening Criteria ............................................................................................ 2-2

3-1 Identification of Chemicals Exceeding Ecological Screening Criteria......................... 3-23-2 Summary of Selected Chemicals by Depth Interval ...................................................... 3-43-3 Summary of Selected Chemicals by Sampling Station .................................................. 3-5

4-1 TBP for Selected Bioaccumulative COPCs Detected in Sediment ............................... 4-2

6-1 Estimation of Hazard Quotients ....................................................................................... 6-26-2 Tissue Sample Analytical Results ..................................................................................... 6-5

7-1 Vertical Profile of Selected Contaminants Exceeding the Screening Value................ 7-2

Figures

3-1 Lead Concentrations by Station........................................................................................ 3-73-2 Vertical Distribution of Lead Concentrations................................................................. 3-83-3 Mercury Concentrations by Station ............................................................................... 3-103-4 Vertical Distribution of Mercury .................................................................................... 3-113-5 Dioxin TEQ Concentrations by Station.......................................................................... 3-123-6 Vertical Distribution of Dioxin TEQ Concentrations................................................... 3-133-7 PAH Concentrations by Station...................................................................................... 3-143-8 Vertical Distribution of PAH Concentrations............................................................... 3-15

4-1 Theoretical Bioaccumulation Potential for Dioxins/Furans......................................... 4-34-2 Theoretical Bioaccumulation Potential for Total PAH .................................................. 4-44-3 Theoretical Bioaccumulation Potential for Total PCB ................................................... 4-54-4 Theoretical Bioaccumulation Potential for DDD............................................................ 4-64-5 Theoretical Bioaccumulation Potential for DDE ............................................................ 4-74-6 Theoretical Bioaccumulation Potential for DDT ............................................................ 4-8

6-1 Four Areas of Concern ....................................................................................................... 6-4

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Acronyms and Abbreviations

ADCNR Alabama Department of Conservation and Natural ResourcesADECA Alabama Department of Economic and Community AffairsADEM Alabama Department of Environmental ManagementBSAF Biota-sediment accumulation factorBGS Below ground surfaceCAA Clean Air ActCAD Confined Aquatic DisposalCCMPs comprehensive conservation and management plansCDF Confined Disposal FacilityCEQ Council on Environmental QualityCF Concentration Factorcfs cubic feet per secondCOPCs chemicals of potential concernCWA Clean Water ActCZARA Coastal Zone Act Reauthorization Amendments of 1990CZMA Coastal Zone Management ActCZPA Coastal Zone Protection Act of 1996DDD Dichlorodiphenyl DichloroEthaneDDE Dichlorodiphenyl DichloroEthyeneDDT Dichlorodiphenyl TrichloroEthaneDO Dissolved oxygenEEZ Exclusive Economic ZoneESA Endangered Species Act of 1973EIS Environmental Impact StatementEFH essential fish habitatERL Effects Range – LowERM Effects Range – MedianESVs ecological screening valuesFDA U.S. Food and Drug AdministrationFDEP Florida Department of Environmental ProtectionFEMA Federal Emergency Management AgencyFMCs Fishery Management CouncilsFMPs Fishery Management Plansfps feet per secondft footFWPCA Federal Water Pollution Control ActGMFMC Gulf of Mexico Fishery Management CouncilHpCDD Heptachlorodibenzo-p-dioxinHpCDF HeptachlorodibenzofuranHxCDD Hexachlorodibenzo-p-dioxinHQ Hazard QuotientHxCDF Hexachlorodibenzofuran

ACRONYMS AND ABBREVIATIONS, CONTINUED

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ITM Inland Testing ManualLBC Level Bottom CappingMAA Mobile Airport AuthorityMAWSS Mobile Area Water and Sewer SystemMFCMA Magnuson Fishery Conservation and Management Actug/kg Micrograms/kilogram; parts per billionmg/kg Milligrams per kilogram; parts per millionmg/L Milligrams per literml MilliliterMLLW Mean lower low watermm MillimeterMMPA Marine Mammal Protection Act of 1972MMS Minerals Management Servicemph miles per hourMPRSA Marine Protection, Research, and Sanctuaries Act of 1972msl mean sea levelNA Not applicableN/A Not availableND Non-detectNEP National Estuary ProgramNEPA National Environmental Policy Act of 1969ng/kg Nanograms per kilogram; parts per trillionNHPA National Historic Preservation Act of 1966NMFS National Marine Fisheries ServiceNMSA National Marine Sanctuaries ActNOAA National Oceanic and Atmospheric AdministrationNOx Nitrous oxidesNPDES National Pollutant Discharge Elimination SystemNRCS Natural Resources Conservation ServiceNRHP National Register of Historic PlacesNSR Noise Sensitive ReceptorNST National Status and TrendsNTUs Nephelometric turbidity unitsOCDD Octachlorodibenzo-p-dioxinOCDF OctachlorodibenzofuranOCRM Office of Ocean and Coastal Resource ManagementPAHs Polynuclear aromatic hydrocarbonsPCBs Polychlorinated biphenylsPeCCD Pentachlorodibenzo-p-dioxinPeCDF PentachlorodibenzofuranPEL Probable effects levelsPM10 Particulate matter (10 micron)ppm Parts per millionppt Parts per thousandROI region of influenceRCRA Resource Conservation and Recovery ActSAV Submerged aquatic vegetation

ACRONYMS AND ABBREVIATIONS, CONTINUED

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SHPO State Historic Preservation OfficerSIP State Implementation PlanSL standard lengthSOx sulfur oxidesSQGs sediment quality guidelinesSVOCs Semivolatile organic compoundsTBP Theoretical Bioaccumulation PotentialsTCDD Tetra Chlorodibenzo-p-DioxinTCDF TetrachlorodibenzofuranTEF toxicity equivalent factorTEL Threshold effects levelsTEQ Toxicity equivalent quotientTEU Twenty-foot equivalent unitsTKN total Kjeldahl nitrogenTOC Total organic carbonTSDF Treatment, Storage, and Disposal FacilityUSACE United States Army Corps of EngineersUSEPA U.S. Environmental Protection AgencyUSFWS U.S. Fish and Wildlife ServiceVOCs Volatile organic compoundsWES Waterways Experiment Station

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1. Introduction

The purpose of this report is to support the United States Army Corps of Engineers(USACE) in the analysis of alternatives for the Environmental Impact Statement (EIS) for thesediment contamination project in the Arlington and Garrows Bend Channels and adjacentarea, Mobile Bay, Alabama. This document provides an evaluation of detected chemicals inthe study area with regard to potential effects on aquatic organisms. The report also pro-vides a preliminary assessment of sediment quality by comparing bulk sediment chemistryresults to sediment quality guidelines (SQGs). This document is intended to help guide theanalysis of alternatives process and should not be considered a decision basis or ecologicalrisk assessment report.


2. Screening Method and Criteria

This report provides a framework to review the results from two investigations conductedin the Arlington and Garrows Bend Channel area (USACE, 2000 and 2002). These studieswere directed by the USACE, Mobile District and prepared by EA Engineering, Science, andTechnology, Inc. A variety of analytical procedures were performed on the sedimentsamples collected during the two sampling events conducted in the study area. Duringthese investigations vibracore samples were collected at 33 locations. Vibracore samplesfrom 30 locations were divided into 3-foot sample intervals (0- to 3, 3- to 6, 6- to 9, and 9- to12 feet) and were submitted for chemical analysis. Samples from three locations were usedby the USACE for biomarker analysis. In certain instances there was insufficient samplerecovery to analyze all depth intervals. Laboratory procedures included bulk chemistrytests for chemical constituents, toxicity testing with elutriate samples, and bioaccumulationstudies.

2.1 Screening CriteriaBulk sediment analytical results can be compared to a variety of Ecological Screening Values(ESVs). The sediment quality values adopted for this evaluation are typically based onbenthic macroinvertebrate receptor endpoints. These screening values should not beconsidered protective of higher trophic level receptors such as fish, birds, and mammals.Food chain and bioaccumulation pathways for exposure to higher organisms were beyondthe scope of this evaluation. It is acknowledged that higher trophic levels could be exposedto contaminants directly or through food chain and bioaccumulation effects based on thebiological communities present in the study area.

Analytical results were compared to available SQGs designated as ESVs for sediment.These values are not intended to be applied as regulatory criteria or remediation targets.The primary ESVs were obtained following U.S. Environmental Protection Agency (USEPA)Region 4’s recommended source hierarchy and included

• USEPA Region 4 screening values• USEPA Ecotox thresholds• Oak Ridge National Laboratory reports• Canadian sediment quality guidelines• Dutch sediment quality standards

USEPA Region 4 ESVs are derived from the chemical effects databases available through theFlorida Department of Environmental Protection (FDEP), National Oceanic andAtmospheric Administration (NOAA), and other sources.

Another source of ESVs that was reviewed included the SQGs developed by NOAA as partof the National Status and Trends (NST) Program. These guidelines define the EffectsRange – Low (ERL) and Effects Range – Median (ERM) values. ERM/ERL values are

2.0 SCREENING METHOD AND CRITERIA


informal (non-regulatory) guidelines for use in interpreting chemical data from sedimentanalyses.

Threshold effects levels (TEL) and probable effects levels (PEL) are two widely acceptedcriteria that have been applied to contaminated sediments in Florida and elsewhere in theSoutheast. TELs represent contaminant concentrations below which adverse biologicaleffects rarely occur. PEL values represent contaminant concentrations above which adverseeffects may be expected to occur. Contaminant concentrations that fall between the PEL andTEL represent concentrations at which adverse biological effects occasionally occur.Screening values and sources are presented in Table 2-1.

TABLE 2-1Ecological Screening CriteriaEvaluation of Arlington and Garrows Bend Channels and Adjacent Area Sediments

Chemical

ESVa

(USEPARegion 4)

AlternateESV ERLb ERMb TELc PELc

Pesticides (µg/kg)

4,4'-DDD 3.3 1.2 7.8

4,4'-DDE 3.3 2.2 27 2.1 374

4,4'-DDT 3.3 1.2 4.8

ALDRIN 2.5 1

CHLORDANE 1.7 2.3 4.8

DELTA-BHC

DIELDRIN 3.3 2.9 2 0.72 4.3

ENDOSULFAN I 3 5

ENDOSULFAN II 14 5

ENDOSULFAN SULFATE

ENDRIN 3.3

ENDRIN ALDEHYDE

HEPTACHLOR

HEPTACHLOR EPOXIDE 0.6 6

MIREX

Dioxin / Furans (ng/kg)

TEQ 2.5 7 21.6 3

Metals (mg/kg)

ALUMINUM

ANTIMONY 12

ARSENIC 7.2 8.2 70 7.2 42




Chemical

ESVa

(USEPARegion 4)


BERYLLIUM

CADMIUM 1.0 1.2 9.6 0.68 4.2

CHROMIUM 52 141 2 81 370 52 160

COBALT 20 1

COPPER 19 94 2 34 270 19 108

IRON

LEAD 30 94 2 47 218 30 112

MANGANESE

MERCURY 0.13 0.48 2 0.15 0.71 0.13 0.70

NICKEL 16 47 2 21 52 16 43

SELENIUM

SILVER 2.0 1.0 3.7 0.73 1.8

THALLIUM

TIN

ZINC 124 245 2 150 410 124 271

PAHs (µg/kg)

ACENAPHTHENE 330 16 500 6.7 89

ACENAPHTHYLENE 330 44 640 5.9 128

ANTHRACENE 330 85 1,100 47 245

BENZO(A)ANTHRACENE 330 261 1,600 75 693

BENZO(A)PYRENE 330 430 1,600 88 763

BENZO(B)FLUORANTHENE

BENZO(K)FLUORANTHENE

BENZO(GHI)PERYLENE

CHRYSENE 330 384 2,800 108 846

DIBENZO(A,H)ANTHRACENE 330 63 260 6.2 135

FLUORANTHENE 330 600 5,100 113 1,494

FLUORENE 330 19 540 21 144

INDENO(1,2,3-CD)PYRENE

1-METHYLNAPHTHALENE




Chemical

ESVa

(USEPARegion 4)


2-METHYLNAPHTHALENE 330 70 670 20 201

NAPHTHALENE 330 160 2,100 35 391

PHENANTHRENE 330 240 1,500 87 544

PYRENE 330 665 2,600 153 1,398

TOTAL PAHs 1,684 44,792 4 4,022 44,792 1,684 16,770

PCBs (µg/kg)

TOTAL PCBs 33 468 2 23 180 22 189Alt ESV Alternate ecological screening valueUSEPA U.S. Environmental Protection AgencyERL Effects range-lowERM Effects range-medianESV Ecological screening valuemg/kg milligrams per kilogram; parts per millionng/kg nanograms per kilograms parts per trillionPAH polynuclear aromatic hydrocarbonsPCBs polychlorinated biphenylsPEL Probable effects levelTEL Threshold effects levelµg/kg micrograms/kilograms; parts per billiona USEPA. November 1995. In: Supplemental Guidance to RAGS: Region 4 Bulletins - Ecological RiskAssessment. Bulletin No. 2. Http://www.epa.gov/region4/wastepgs/oftecser/otsguid.htmb NOAA. June 1999. Sediment Quality Guidelines Developed for the National Trends and Status Programc MacDonald, DD. 1994. Approach to the Assessment of Sediment Quality in Florida Coastal Waters. Volume I –Development and Evaluation of the Sediment Quality Assessment Guidelines. Report prepared for FloridaDepartment of Environmental Protection, Tallahassee, Florida.

Alternate ESV Source:1 Intervention values and target values (MHSPE 1994)2 Logistic model point estimate T50 concentrations (Field et al. 2002)3 Probable effects level (PEL) (CCME 1999, updated 2001)4 Effects range median (Long and Morgan 1990, Long et al. 1995)5 USEPA Sediment Quality Benchmark (USEPA 1996)6 Threshold Effects Level (TEL) (CCME 1995)7 Adopted from USEPA, 1993.

In most cases, the TEL and USEPA Region 4 ESV are the same value. Alternate ESVspresented in Table 2-1 were used in cases where no USEPA ESV was available. Additionally,in this evaluation the alternate ESV for dioxins/furans was used to screen sedimentconcentrations. This value was chosen over the USEPA Region 4 ESV of 2.5 ng/kg. TheUSEPA Region 4 value is based on a value protective of mammalian wildlife. The alternate



ESV is a PEL value for aquatic life. Given the site conditions and expected receptors, the useof an aquatic receptor is considered a conservative and reasonable choice. However, it isacknowledged that more conservative choices are available.

Regardless of the source, representative ESVs provide conservative values suitable for apreliminary screen of site contaminant levels to determine whether the site represents animpaired habitat. Sediment ESVs are derived from a variety of sources and methods. Thus,it is important to consider a range of criteria to evaluate sediment quality and to weigh thefrequency, magnitude, and pattern of exceedances. In essence, the use of a weight-of-evidence approach is emphasized in evaluating sediment quality.

As an initial step, all analytical results from both investigations were compared to the ESVspresented in Table 2-1. The criteria used in this approach are conservative values. Thisapproach is consistent with the ecological risk assessment practice for this region.

The second step was to focus on those chemicals that consistently exceeded the ESVs at thehighest number of locations; in many instances, the concentrations exceeded the ESV bymore than an order of magnitude. This approach was used to help focus the evaluation oncontaminants that may drive the analysis of alternatives and future evaluations. The verticaland horizontal extent and distribution of the chemicals in this category were reviewed toidentify areas of concern. Chemicals not in this category were eliminated from furtherdiscussion.

2.2 Bioaccumulative ChemicalsLaboratory tests were performed by exposing Nereis viren (sand worm) and Macoma nasuta(blunt nose clam) to the sediments for a period of 28 days under controlled conditions. Thepurpose was to evaluate the survival of the test organisms and the bioaccumulation ofcontaminants in the test organisms.

In addition to laboratory studies, the theoretical bioaccumulation potential of exposure tocontaminated sediments can be calculated. Many compounds bioaccumulate in organismsthat come into contact with them in the environment either through direct contact or byconsumption of the chemical. Those compounds identified in the screening process wereevaluated for bioaccumulation potential in benthic macroinvertebrates. TheoreticalBioaccumulation Potentials (TBPs) were calculated according to the methods described inthe Inland Testing Manual (ITM) (1998) and presented in the sediment quality characteri-zation report for adjacent areas (USACE, 2002). The TBP was calculated as:

TBP = BSAF*(Csediment/TOC)*Lipid content

TBP: expressed in same units as Csediment

Csediment: Concentration of chemical in sediment. Concentrations in the 0- to3-ft interval were used

BSAF: Biota-sediment accumulation factor, assumed to be 4 (Ankley et al.,1992)

TOC: Total organic carbon (%)



Lipid content: estimated whole body lipid content of receptor, assumed to be2% (USACE, 1998)

This screening model is used to identify chemicals that may bioaccumulate in receptortissues at unacceptable levels. The model is based on the concentration in sediment, theTOC in sediment, the receptor lipid content, and the BSAF. There are significant limitationsand uncertainty associated with the TBP model, particularly with PAHs, and results shouldbe used only as a tool to guide and focus subsequent evaluation of potentiallybioaccumulative contaminants. TBPs were calculated only for nonpolar organic chemicals,including pesticides, PAH, PCB, and dioxins/furans.

2.3 Toxicity TestingAcute water column and whole sediment toxicity tests were conducted to evaluate theeffects that the chemicals would have on test organisms. The test organisms includedArbacia punctulata (purple sea urchin), Mysidopsis bahia (opossum shrimp), and Cyprinodonvariegatus (sheepshead minnow). The acute water column test was used to evaluate thepotential effects resulting from chemicals leaching out of the sediments during dredgingand disposal. The whole sediment test was used to evaluate the potential effects of directexposure to the chemical-laden sediments on test organisms.

2.4 Cleanup Target LevelsThis screening level assessment is based upon ESVs and is not designed or intended tosupport the development or identification of cleanup target levels for contaminants in thestudy area. Also, the ESVs are not intended as pass-fail cleanup criteria or remediationtargets. A formal risk assessment approach is recommended, including an ecological riskassessment and/or human health risk assessment to develop remediation target levels.However, for preliminary planning purposes, the ESVs or alternate ESVs may be used asconservative cleanup target levels.


3. Results of Bulk Chemistry Screening

3.1 MetalsSeven metals had detected concentrations exceeding the ESV screening process identifiedabove (Table 3-1). With the exception of lead and mercury, none of the metals detected inthese investigations exceeded 10 times the ESVs (Detected Concentration/ESV < 10). Inaddition, all metals except lead and mercury were below the alternate ESV or ERL/ERM.

Lead was detected at concentrations exceeding the ESV in 18 of 49 samples and exceededthe ESV by up to a factor of 12. The highest concentrations were detected at Stations AG02-17 (220 mg/kg) and AG02-18 (363 mg/kg). Mean and maximum concentrations werehighest in the 0- to 3-ft sampling interval and declined with depth (Table 3-2). The spatialdistribution of lead does not demonstrate a discernible pattern other than the elevatedconcentrations at Stations AG02-17 and AG02-18 (Table 3-3, Figures 3-1 and 3-2). Across allstations, mean concentrations were below the ESVs in the sediment intervals below the 0- to3-ft depth, but maximum concentrations exceeded criteria in each sampled interval. Thedistribution of lead suggests that an area of elevated lead concentrations exists near StationsAG02-17 and AG02-18.

Mercury was detected at concentrations exceeding the ESV in 16 of 49 samples andexceeded it by up to a factor of 19 (Table 3-1). The highest detected concentration wasrecorded at Station AG02-17 (2.5 mg/kg). The spatial distribution of mercury does notfollow an identifiable pattern but was fairly ubiquitous, with 15 of 17 stations having at leastone sediment interval exceeding the ESV (Table 3-3, Figures 3-3 and 3-4). The three highestconcentrations were recorded from the 0– to 3-ft interval at Stations AG02-17, AG02-18, andAG02-19 (Table 3-2). Average concentrations for each depth interval exceeded the ESV,with the exception of the 9- to12-ft interval. Maximum concentrations exceeded the criteriain all depth intervals. The distribution of mercury suggests that elevated levels may bedistributed throughout the study area, with higher concentrations localized around theinner-channel stations (AG02-AG02-17, AG02 -18, and AG02 -19).

3.0 RESULTS OF BULK CHEMISTRY SCREENING


TABLE 3-1Identification of Chemicals Exceeding Ecological Screening CriteriaEvaluation of Arlington and Garrows Bend Channels and Adjacent Area Sediments

N Exceedances Maximum ESV Alt ESV ERL ERM

FrequencyAboveCriteria

PreliminaryHQ

ExceedsAlternateCriteria

Metals (mg/kg)Arsenic 49 6 10 7.2 N/A 8.2 70 12% 1.4 FALSECadmium 49 2 1.5 1.0 N/A 1.2 9.6 4% 1.5 FALSECopper 49 17 74 19 94 34 270 35% 4.0 FALSELead 49 18 363 30 94 47 218 37% 12 TRUEMercury 49 16 2.5 0.13 0.48 0.15 0.71 33% 19 TRUENickel 49 1 17 16 47 21 52 2% 1.1 FALSEZinc 49 10 397 124 245 150 410 20% 3.2 FALSEPesticides (µg/kg)DDD 33 2 4.3 3.3 N/A N/A N/A 6% 1.3 NADDE 33 11 9.8 3.3 N/A 2.2 27 33% 3.0 FALSEDDT 33 2 10 3.3 N/A N/A N/A 6% 3.0 NASum Total DDTs 33 11 20 N/A N/A 1.6 46 33% NA NAbeta-HCH 33 2 5.0 1.0 N/A N/A N/A 6% 5.0 NAHeptachlor Epoxide 33 1 1.3 0.60 N/A N/A N/A 3% 2.2 NADioxin/Furan (ng/kg)TEQ 41 17 1738 N/A 22 N/A N/A 45% 80.5 NAPolychlorinated Biphenyl (PCB)(µg/kg)Total PCB 49 8 275 33 468 23 180 16% 8.3 FALSEPolynuclear AromaticHydrocarbons (PAH) (µg/kg)Acenaphthene 49 15 100,000 330 N/A N/A N/A 31% 303 NAAcenaphthylene 49 6 3,800 330 N/A N/A N/A 12% 12 NAAnthracene 49 12 100,000 330 N/A N/A N/A 24% 303 NABenzo(a)anthracene 49 22 92,000 330 N/A N/A N/A 45% 279 NABenzo(a)pyrene 49 23 51,000 330 N/A N/A N/A 47% 155 NA



TABLE 3-1Identification of Chemicals Exceeding Ecological Screening CriteriaEvaluation of Arlington and Garrows Bend Channels and Adjacent Area Sediments

N Exceedances Maximum ESV Alt ESV ERL ERM

FrequencyAboveCriteria

PreliminaryHQ

ExceedsAlternateCriteria

Benzo(b)fluoranthene 49 NA 17,000 N/A N/A N/A N/A NA NA NABenzo(g,h,i)perylene 49 NA 15,000 N/A N/A N/A N/A NA NA NAChrysene 49 23 92,000 330 N/A N/A N/A 47% 279 NADibenz(a,h)anthracene 49 13 11,000 330 N/A N/A N/A 27% 33 NAFluoranthene 49 25 320,000 330 N/A N/A N/A 51% 970 NAFluorene 49 11 110,000 330 N/A N/A N/A 22% 333 NAIndeno(1,2,3)perylene 49 NA 3,400 N/A N/A N/A N/A NA NA NA1-Methylnaphthalene 49 NA 58,000 N/A N/A N/A N/A NA NA NA2-Methylnaphthalene 49 6 72,000 330 N/A N/A N/A 12% 218 NANaphthalene 49 5 9,900 330 N/A N/A N/A 10% 30 NAPhenanthrene 49 14 370,000 330 N/A N/A N/A 29% 1,121 NAPyrene 49 26 210,000 330 N/A N/A N/A 53% 636 NATotal PAH 49 27 1.64E+06 1,684 44,792 4,022 44,792 55% 975 TRUEAlt ESV Alternate ecological screening valueERL NOAA Sediment Quality Guideline (SQG) Effects Range-LowERM NOAA Sediment Quality Guideline (SQG) Effects Range-MedianESV Ecological screening valueHQ Hazard quotientµg/kg microgram per kilogrammg/kg milligram per kilogramng/kg nanogram per kilogramN Number of samplesNA Not applicableN/A Not availablePAH Polynuclear aromatic hydrocarbonPCB Polychlorinated biphenyl



TABLE 3-2Summary of Selected Chemicals by Depth IntervalEvaluation of Arlington and Garrows Bend Channels and Adjacent Area Sediments

Chemical Depth Interval (ft) N Minimum Maximum MeanAdjusted

Maximum*Adjusted

Mean*

Lead 0 - 3 17 8.1 363 62

3 - 6 12 2.2 82 28

6 - 9 10 1.7 44 19

9 - 12 10 1.1 32 11.1

Mercury 0 - 3 17 0.020 2.5 0.68

3 - 6 12 0.02 0.68 0.27

6 - 9 10 0.02 0.83 0.22

9 - 12 10 0.010 0.40 0.10

TEQ 0 - 3 13 14 1,738 413

3 - 6 10 6.8 389 85

6 - 9 9 6.6 338 82

9 - 12 9 6.3 61 14.2

Total PAH 0 - 3 17 290 282,335 54,685 282,335 54,685

3 - 6 12 55 1.64E+06 155,723 188,300 20,629

6 - 9 10 6.8 1.02E+06 111,405 74,528 10,431

9 - 12 10 6.8 83,774 9,112 83,774 9,112

Lead – mg/kgMercury – mg/kgTEQ (toxicity equivalent quotient) – ng/kgTotal PAH (polynuclear aromatic hydrocarbons) – µg/kg

* Two highest detections removed:

1.2E+6 -- AG02-17-361.0E+6 -- AG02-19-69



TABLE 3-3Summary of Selected Chemicals by Sampling StationEvaluation of Arlington and Garrows Bend Channels and Adjacent Area Sediments

Chemical Station N Minimum Maximum Mean

Lead AG02-08 1 24 24 24(mg/kg) AG02-09 4 2.7 9.5 5.9

AG02-10 4 16 32 26AG02-11 4 3.7 13 7.3

AG02-12 4 4.7 36 18

AG02-13 4 1.6 25 9.6

AG02-14 1 57 57 57

AG02-15 4 4.8 31 17

AG02-16 4 1.1 8.1 3.3

AG02-17 2 82 220 151

AG02-18 1 363 363 363

AG02-19 4 32 59 48

AG02-20 4 15 58 37

MH/AC 99-9 1 26.1 26.1 26.1

MH/AC 99-10 1 32 32 32

WES-BM-11 2 4.0 16 10

WES-BM-13 4 23 64 43

Total PAH AG02-08 1 3,688 3,688 3,688(µg/kg) AG02-09 4 6.8 864 233

AG02-10 4 1,282 9,520 6,030

AG02-11 4 78 10,297 2,745

AG02-12 4 98 67,413 18,226

AG02-13 4 10 3,327 920

AG02-14 1 36,250 36,250 36,250

AG02-15 4 764 137,576 37,183

AG02-16 4 24 2,608 705

AG02-17 2 178,665 1.64E+06 910,213

AG02-18 1 282,335 282,335 282,335

AG02-19 4 45,123 1.02E+06 334,343

AG02-20 4 1,978 146,660 42,067

MH/AC 99-9 1 645 645 645

MH/AC 99-10 1 919 919 919

WES-BM-11 2 272 290 281

WES-BM-13 4 3,105 74,528 22,216



TABLE 3-3Summary of Selected Chemicals by Sampling StationEvaluation of Arlington and Garrows Bend Channels and Adjacent Area Sediments

Chemical Station N Minimum Maximum Mean

Mercury AG02-08 1 0.38 0.38 0.38(mg/kg) AG02-09 3 0.020 0.060 0.037

AG02-10 4 0.15 0.83 0.44

AG02-11 4 0.030 0.35 0.12

AG02-12 4 0.030 0.62 0.25

AG02-13 4 0.010 0.26 0.085

AG02-14 1 0.43 0.43 0.43

AG02-15 4 0.020 0.82 0.26

AG02-16 1 0.020 0.020 0.020

AG02-17 2 0.16 2.5 1.3

AG02-18 1 1.0 1.0 1.0

AG02-19 4 0.22 1.7 0.75

AG02-20 4 0.11 0.43 0.30

MH/AC 99-9 1 0.83 0.83 0.83

MH/AC 99-10 1 0.64 0.64 0.64

WES-BM-11 2 0.070 0.20 0.14

WES-BM-13 4 0.38 1.1 0.60

TEQ AG02-08 1 134 134 134(ng/kg) AG02-09 4 6.3 17 9.3

AG02-10 4 13 316 176

AG02-11 4 7.9 149 46

AG02-12 4 7.8 1,738 463

AG02-13 4 6.5 101 33

AG02-14 1 390 390 390

AG02-15 4 8.1 535 141

AG02-16 4 6.4 14 8.5

AG02-17 2 35 1,290 662

AG02-18 1 345 345 345

AG02-19 4 61 472 315

AG02-20 4 10 373 109

MH/AC 99-10 1 65 65 65µg/kg microgram per kilogrammg/kg milligram per kilogramng/kg nanogram per kilogramTEQ toxicity equivalent quotientPAH polynuclear aromatic hydrocarbonWES Waterways Experiment Station



FIGURE 3-1Lead Concentrations by Station

0

50

100

150

200

250

300

350

400

AG02-20

AG02-19

AG02-17

AG02-18

WES-BM-13

AG02-16

AG02-15

AG02-14

AG02-13

WES-BM-11

AG02-12

AG02-10

AG02-11

MH/AC 99-10

AG02-9

AG02-8

MH/AC 99-9

Station

Con

cent

ratio

n (m

g/kg

)

MAXMEANESV/TELPEL



FIGURE 3-2Vertical Distribution of Lead Concentrations

Figure 3-2 Vertical Distribution of Lead Concentrations

AG02-8

AG02-9

AG02-10

AG02-11

AG02-12

AG02-13

AG02-14

AG02-15

AG02-16

AG02-17

AG02-18

AG02-19

AG02-20

AC 99-10

AC 99-11

AC 99-13

AC 99-9

Con

cent

ratio

n (m

g/kg

)

0

10

20

30

40

50

60

70

80

90

100

110

200

300

400

0-3 FT 3-6 FT 6-9 FT 9-12 FT PEL = 112 mg/kgESV/TEL = 30.2 mg/kg



3.2 OrganicsSeveral organic chemicals exceeded the Region 4 ESV. With the exception of dioxins(reported as TEQ) and PAHs (reported as total PAH), no detected organic chemicalsexceeded the ESV by a factor of 10. However, several organic chemicals did exceed thealternate ESV and are included in the discussion below.

3.3 DioxinsDioxin and furan concentrations were screened using the TEF methodology to calculate thetotal dioxin/furan TEQ value. TEQs exceeded the ESV in 17 of 41 samples. The highestdetected concentration exceeded the ESV by up to a factor of 80, with a maximum detectedTEQ concentration of 1,738 ng/kg at AG02-12 (Table 3-1). Detected concentrations weredistributed throughout the study area. Twelve of 14 stations had dioxin concentrationsexceeding the ESV in at least one sample interval (Table 3-2, Figures 3-5 and 3-6). The 0- to3-ft sampling interval had the highest maximum (1,738 ng/kg) and mean (386 ng/kg) TEQconcentrations (Table 3-2). Deeper intervals demonstrated declining concentrations withdepth. Only the 9- to 12-ft interval had concentrations that did not exceed the ESV.Elevated dioxin concentrations appear to be distributed throughout the study area, with tworegions of potentially elevated concentrations: one centered near Stations AG02-12, AG02-14, and AG02-15 and the other centered near Stations AG02-17, AG02-18, AG02-19, andAG02-20.

3.4 PAHsTotal PAH concentrations exceeded the ESV in 27 of 49 samples. The highest detectedconcentration exceeded the ESV by almost three orders of magnitude, with a maximumdetected concentration of 1,641,760 µg/kg at Station AG02-17 (Table 3-1). Concentrationswere generally higher at the inner-channel stations (AG02-17, AG02-18, AG02-19, andAG02-20) and tend to decrease towards the turning basin (Table 3-3, Figures 3-7 and 3-8).High concentrations of PAHs are also evident at stations AG02-12, AG02-14, and AG02-15.Concentrations appear to be elevated above criteria throughout the study area with 13 of 17stations having at least one detection above criteria. In the turning basin only one station,AG02-07, had total PAH concentrations (2,309 µg/kg) above criteria (1,684 µg/kg).Vertically, maximum and mean concentrations were higher in the 3- to 6- and 6- to 9-ftinterval than in the surface (0- to 3-ft) interval (Table 3-3). However, if the two highestconcentrations (1,641,760 and 1,020,175 µg/kg) are excluded, vertical concentrations declinewith depth (Table 3-2). Total PAH concentrations in the study area are significantlyelevated above the ESVs and alternate ESV in some areas. Generally, concentrations nearthe inner-channel stations are highest and, with the two exceptions noted above, associatedwith the 0– to 3-ft sampling interval.



FIGURE 3-3Mercury Concentrations by Station

0

0.5

1

1.5

2

2.5

3

AG02-20

AG02-19

AG02-17

AG02-18

WES-BM-13

AG02-16

AG02-15

AG02-14

AG02-13

WES-BM-11

AG02-12

AG02-10

AG02-11

MH/AC 99-10

AG02-9

AG02-8

MH/AC 99-9

Station

Con

cent

ratio

n (m

g/kg

)

MAXMEANESV/TELPEL



FIGURE 3-4Vertical Distribution of Mercury

Figure 3-4Vertical D istribution of M ercury

AG02-8AG02-9AG02-1

0AG02-1

1AG02-1

2AG02-1

3AG02-1

4AG02-1

5AG02-1

6AG02-1

7AG02-1

8AG02-1

9AG02-2

0AC 99-1

0AC 99-1

1AC 99-1

3AC 99-9

Con

cent

ratio

n (m

g/kg

)

0 .00

0.05

0.10

0.15

0.20

0.501.001.502.002.503.00

0-3 FT 3-6 FT 6-9 FT 9-12 FT P E L = 0 .7 m g/kgE S V /TE L = 0 .13 m g/kg



FIGURE 3-5Dioxin TEQ Concentrations by Station

0

200

400

600

800

1000

1200

1400

1600

1800

2000

AG02-20

AG02-19

AG02-18

AG02-17

AG02-16

AG02-15

AG02-13

AG02-14

AG02-12

AG02-10

AG02-11

MH/AC 99-10

Station

Con

cent

ratio

n (n

g/kg

)

MAXMEANESV/TEL



FIGURE 3-6Vertical Distribution of Dioxin TEQ Concentrations

AG02-8

AG02-9

AG02-10

AG02-11

AG02-12

AG02-13AG02

-14AG02-15AG02

-16AG02-1

7AG02

-18AG02

-19AG02

-20AC 99

-10AC 99

-11AC 99-13

AC 99-9

Con

cent

ratio

n (n

g/kg

) as

TEQ

0

5

10

15

20

25

400

800

1200

1600

2000

0-3 FT 3-6 FT 6-9 FT 9-12 FT PEL=21.6 ng/kg

Figure 3-6Vertical Distribution of Dioxin TEQ Concentrations



FIGURE 3-7PAH Concentrations by Station

0.0E+00

2.0E+05

4.0E+05

6.0E+05

8.0E+05

1.0E+06

1.2E+06

1.4E+06

1.6E+06

1.8E+06

AG02-20

AG02-19

AG02-17

AG02-18

WES-BM-13

AG02-16

AG02-15

AG02-14

AG02-13

WES-BM-11

AG02-12

AG02-10

AG02-11

MH/AC 99-10

AG02-9

AG02-8

MH/AC 99-9

Station

Con

cent

ratio

n (u

g/kg

)

MAXMEANESV/TELPEL



FIGURE 3-8Vertical Distribution of PAH Concentrations

Figure 3-8Vertical Distribution of PAH Concentrations

AG02-8AG02-9AG02-10AG02

-11AG02-1

2AG02-13AG02-14AG02

-15AG02-1

6AG02-17AG02-18AG02-19AG02-2

0AC 99-10AC 99

-11AC 99-1

3AC 99-9

Con

cent

ratio

n (u

g/kg

)

0

2500

5000

7500

10000

12500

15000

17500

20000

500000100000015000002000000

0-3 FT 3-6 FT 6-9 FT 9-12 FT PEL=16,770 ug/kgESV/TEL=1,684 ug/kg



3.5 PCBsTotal PCB concentrations were detected above the ESV in 8 of 49 samples. The maximumdetected concentration of 275 µg/kg exceeded the ESV of 33 µg/kg but was below thealternate ESV of 468 µg/kg (Table 3-1). Concentrations exceeding the ESV were mostfrequently associated with samples at Stations AG02-17, -18, and –19. The distribution ofPCBs is limited, with detections above the ESV recorded at only 5 of 21 stations. PCBs areprimarily restricted to the inner-channel stations. The limited distribution and lowconcentrations suggest that PCBs are not likely to be a significant contributor to any impactassociated with contaminants in the study area sediments.

3.6 Chlorinated PesticidesThe primary pesticides detected above criteria in the study area were DDD, DDE, and DDT.Beta-HCH was detected in two samples above criteria, while heptachlor epoxide wasdetected once (Table 3-1). Both chemicals were detected at concentrations less than 10 timesthe ESV. DDT and metabolites were detected at 11 of 33 stations above the ESV. DDE wasthe primary form detected above criteria. Concentrations did not exceed the ESV by a factorof 10 in any sample, and maximum detected concentrations of total DDT and metaboliteswere below the ERM of 46 µg/kg. Concentrations are distributed throughout the study areaand do not demonstrate any particular pattern or association with other chemicals. Thelimited distribution and low concentrations suggest that chlorinated pesticides are not likelyto contribute to any significant impact associated with contaminants in the study areasediments.


4. Results of Bioaccumulation Studies

Results of the 28-day bioaccumulation study indicate that the sediments are highly toxic tothe clam but not to the polychaete worm. Survival ranged from 85 to 99 percent for theworm, and survival in the test sediments was comparable to survival in the referencesediment. However, the clam exhibited significant mortality (83 percent) from exposure tosediments collected at the upper end of the project area (AC99-13). Stations in this area(AG02-17, AG02-18, AG02-19, AG02-20, and MH/AC99-13) have been identified as havingsome of the highest contaminant concentrations and highest frequency of exceedances of theRegion 4 ESV values and other SQGs.

Chemicals selected for TBP calculations included: total PAHs, total PCBs, dioxins/furans (asTEQ), DDE, DDT, and DDD. Results are presented in Table 4-1 and Figures 4-1 through– 4-6. There are no readily available screening concentrations for bioaccumulative chemicals inbenthic tissues, so concentrations were compared to TBP calculations for reference sedimentconcentrations presented in the Evaluation of Dredged Material, Arlington-Garrows BendChannel, Mobile Bay, Alabama. Final Report (USACE, 2000). There may be significantbioaccumulative potential in study area sediments relative to reference area TBP for benthicmacroinvertebrates. Total PAH, total PCB, and pesticides (DDD, DDE, DDT) exceededreference area TBPs. PAH and PCB TBPs exceeded reference area values in 100 percent ofthe samples evaluated. Pesticide values exceeded reference concentrations in 45 to82 percent of the samples evaluated. Dioxin/furan analysis was not performed with thereference sediment.

4.0 RESULTS OF BIOACCUMULATION STUDIES


TABLE 4-1TBP for Selected Bioaccumulative COPCs Detected in SedimentEvaluation of Arlington and Garrows Bend Channels and Adjacent Area Sediments

Sediment Concentration TBP

Sample ID

DepthInterval(feet) TOC BSAFa

Lipidb

(%)TEQ

(ng/kg)

TotalPAH

(µg/kg)

TotalPCB

(µg/kg)DDD

(µg/kg)DDE

(µg/kg)DDT

(µg/kg)TEQ

(ng/kg)

TotalPAH

(µg/kg)

TotalPCB

(µg/kg)DDD

(µg/kg)DDE

(µg/kg)DDT

(µg/kg)AG02-08-03 0 - 3 2% 4 2% 134 3,688 21 1.0 4.6 0.48 717 19,669 115 5.3 25 2.6AG02-09-03 0 - 3 1% 4 2% 17 864 2.7 0.52 0.18 110 5,713 18 3.4 1.2AG02-10-03 0 - 3 3% 4 2% 116 5,623 23 0.90 0.82 286 13,883 57 2.2 2.0AG02-11-03 0 - 3 11% 4 2% 149 10,297 23 2.2 4.5 9.9 109 7,557 17 1.6 3.3 7.3AG02-12-03 0 - 3 11% 4 2% 1,738 67,413 131 1.3 2.8 1.8 1,219 47,307 92 0.91 2.0 1.3AG02-13-03 0 - 3 4% 4 2% 101 3,327 5.5 1.3 0.76 217 7,116 12 2.8 1.6AG02-14-03 0 - 3 4% 4 2% 390 36,250 57 4.3 4.9 0.98 805 74,935 118 8.9 10 2.0AG02-15-03 0 - 3 4% 4 2% 535 137,576 25 2.1 8.1 10 1,144 294,281 54 4.5 17 21AG02-16-03 0 - 3 0% 4 2% 14 2,608 27 0.65 319 58,772 600 15AG02-17-03 0 - 3 7% 4 2% 1,290 178,665 236 1.6 3.4 0.49 1,419 196,605 260 1.8 3.7 0.54AG02-18-03 0 - 3 4% 4 2% 345 282,335 275 25 51 11 658 539,064 526 48 97 21AG02-19-03 0 - 3 7% 4 2% 472 45,123 116 9.0 22 3.9 516 49,382 127 9.8 24 4.3AG02-20-03 0 - 3 5% 4 2% 373 146,660 61 8.7 40 7.5 604 237,506 99 14 65 12MH/AC 99-9 0 - 3 5% 4 2% 645 4.4 3.9 9.8 0 1,131 7.8 6.8 17MH/AC 99-10 0 - 3 7% 4 2% 65 919 7.8 6.0 71 1,004 8.5 6.6WES-BM-11-1-1 0 - 3 3% 4 2% 290 2.0 0.61 0 716 4.9 1.5WES-BM-13-1-1 0 - 3 6% 4 2% 7,366 16 0.82 3.9 0 9,354 20 1.0 5.0a Taken from Ankley, et al. 1992. Bioaccumulation of PCB from sediments by oligochaetes and fish. Can. J. Fish. Aquat. Sci. 49:2080-2085. (Cited byUSEPA/USACE, 1998)b USEPA/USACE. 1998. Evaluation of dredged material proposed for discharge in waters of the U.S. - Inland Testing Manual (ITM). USEPA-823-B-98-004COPCs chemicals of potential concernBSAF Biota-sediment accumulation factorDDD Dichlorodiphenyl DichloroEthaneDDE Dichlorodiphenyl DichloroEthyeneDDT Dichlorodiphenyl Trichloroethaneµg/kg microgram per kilogrammg/kg milligram per kilogramng/kg nanogram per kilogramTEQ toxicity equivalent quotientPAH polynuclear aromatic hydrocarbonPCB polychlorinated biphenylTBP theoretical bioaccumulation potentialTOC total organic carbon



FIGURE 4-1Theoretical Bioaccumulation Potential for Dioxins/furans

0

200

400

600

800

1000

1200

1400

1600

1800

2000

AG02-08

-03AG02

-10-03

AG02-12

-03AG02

-14-03

AG02-16

-03AG02

-18-03

AG02-20

-03

MH/AC 99-10

WES-BM-13

-1-1

Sample

Con

cent

ratio

n (n

g/kg

) TissueSediment



FIGURE 4-2Theoretical Bioaccumulation Potential for Total PAH

0

100000

200000

300000

400000

500000

600000

AG02-08

-03AG02

-09-03

AG02-10

-03AG02

-11-03

AG02-12

-03AG02

-13-03

AG02-14

-03AG02

-15-03

AG02-16

-03AG02

-17-03

AG02-18

-03AG02

-19-03

AG02-20

-03MH/AC 99

-9MH/AC 99

-10

WES-BM-11

-1-1

WES-BM-13

-1-1

Sample

Con

cent

ratio

n (u

g/kg

)

TissueSedimentRef TBP



FIGURE 4-3Theoretical Bioaccumulation Potential for Total PCB

0

100

200

300

400

500

600

700

AG02-08

-03AG02

-09-03

AG02-10

-03AG02

-11-03

AG02-12

-03AG02

-13-03

AG02-14

-03AG02

-15-03

AG02-16

-03AG02

-17-03

AG02-18

-03AG02

-19-03

AG02-20

-03MH/AC 99

-9MH/AC 99

-10WES-B

M-11-1-

1WES-B

M-13-1-

1

Sample

Con

cent

ratio

n (u

g/kg

)




FIGURE 4-4Theoretical Bioaccumulation Potential for DDD

0

10

20

30

40

50

60

AG02-08

-03AG02

-09-03

AG02-10

-03AG02

-11-03

AG02-12

-03AG02

-13-03

AG02-14

-03AG02

-15-03

AG02-16

-03AG02

-17-03

AG02-18

-03AG02

-19-03

AG02-20

-03MH/AC 99

-9MH/AC 99

-10WES-B

M-11-1-

1WES-B

M-13-1-

1

Sample

Con

cent

ratio

n (u

g/kg

)




FIGURE 4-5Theoretical Bioaccumulation Potential for DDE

0

20

40

60

80

100

120

AG02-08

-03AG02

-09-03

AG02-10

-03AG02

-11-03

AG02-12

-03AG02

-13-03

AG02-14

-03AG02

-15-03

AG02-16

-03AG02

-17-03

AG02-18

-03AG02

-19-03

AG02-20

-03MH/AC 99

-9MH/AC 99

-10WES-B

M-11-1-

1WES-B

M-13-1-

1

Sample

Con

cent

ratio

n (u

g/kg

)




FIGURE 4-6Theoretical Bioaccumulation Potential for DDT

0

5

10

15

20

25

AG02-08

-03AG02

-09-03

AG02-10

-03AG02

-11-03

AG02-12

-03AG02

-13-03

AG02-14

-03AG02

-15-03

AG02-16

-03AG02

-17-03

AG02-18

-03AG02

-19-03

AG02-20

-03MH/AC 99

-9MH/AC 99

-10WES-B

M-11-1-

1WES-B

M-13-1-

1

Sample

Con

cent

ratio

n (u

g/kg

)



5. Results of Toxicity Testing

Acute bioassay toxicity tests were performed using elutriates prepared with whole coresediment composites from 10 stations. Purple sea urchin (Arbacia punctulata) larvae,opossum shrimp (Mysidopsis bahia), and sheepshead minnow (Cyprinidon variegatus) wereused as test organisms. Elutriates were acutely toxic to sea urchin larvae and mysid shrimp.The station demonstrating the greatest acute toxicity was MH/AC99-13.

Acute sediment toxicity tests were performed using whole sediments from 10 stations in thestudy area. Test organisms included the estuarine polychaete (Neanthes arenaceodentata) andthe estuarine amphipod (Leptocheirus plumulosus). Sediments were acutely toxic to the L.plumulosus at all 10 stations but were not toxic to N. arenaceodentata. MH/AC99-13demonstrated the greatest toxicity to L. plumulosus.


6. Supplemental Sampling Results

6.1 IntroductionAs indicated in Section 3, several chemicals exceeded the selected screening values andmethodology. Four chemicals were identified as COPCs:

• Lead• Mercury• Dioxin/furans• PAHs

The 1999 and 2002 investigations focused on the channel centerline and the channel shelfedge. Results of the eco-risk screening indicated there were four areas of concern.Information was lacking, however, on the area between the channels and the shoreline.Therefore, a supplemental investigation was conducted in April 2003 to fill the data gaps inthe distribution of these four compounds in four key areas. In addition, at the request ofone of the stakeholders, the U.S. Fish and Wildlife Service (USFWS), the pesticide DDT anddegradation products (DDD and DDE) were included in the bulk sediment chemistry. Boththe 4,4’ (p,p’) and 2,4’ (o,p’) isomers were included in the analytical program. TheTennessee Street and Southern Drains were investigated as possible continuing sources.There also was an interest in determining whether these chemicals were bioaccumulating inthe resident biota.

Results of the sampling are presented in Draft Garrows Bend Supplemental Sampling, GarrowsBend, Mobile Bay, Alabama (CH2M HILL, 2003). A total of 32 sediment samples and five biotasamples were collected for analysis. Sediment samples consisted of surface grab samples (0-to 0.5-ft interval) and core samples (0- to 3-ft interval). In the biota sampling, benthicmacroinvertebrates in the identified areas were targeted. Grass shrimp (Paleomenetes sp.)and common eastern oysters (Crassosstrea virginica) were the only organisms collected insufficient quantity for chemical analysis.

A preliminary risk evaluation of sediments extending beyond the channel margins is discussedin the following section. Results are compared to the channel and channel margin evaluationresults and provide initial characterization of the potential risks to aquatic receptors.

6.2 Preliminary Risk EvaluationDetected results were screened against the corresponding ESV value. Hazard quotients(HQs) were determined by taking the ratio of the detected concentration to the ESV. An HQgreater than 1 indicates the potential for impacts to aquatic receptors due to direct contact.An HQ exceeding 10 for any chemical is interpreted to indicate that this chemical is likely tocontribute substantially to the total risk for a receptor. Table 6-1 summarizes the sedimentchemistry results for all four areas and presents the preliminary estimated HQs based on themaximum detected concentration in each area. Maximum HQs for the channel and channelmargins are provided for comparison purposes. Results of the Tennessee Street and

6.0 SUPPLEMENTAL SAMPLING RESULTS


TABLE 6-1Estimation of Hazard QuotientsEvaluation of Arlington and Garrows Bend Channels and Adjacent Area Sediments

Channel and Channel Margins(EA, 2000 and EA, 2002) Area 1 Area 2 Area 3 Area 4

Chemical Units ESV N Minimum Maximum MeanMaxHQ N Minimum Maximum Mean

MaxHQ N Minimum Maximum Mean



MaxHQ

Lead mg/kg 30 17 8.1 363 62 12.1 6 24.7 30.4 26.8 1.0 14 15.9 184 68.54 6.1 9 24.8 161 112.6 5.4 3 6.71 58.1 24.5 1.9

Mercury mg/kg 0.13 17 0.02 2.5 0.69 19.2 6 0.28 0.62 0.43 4.8 14 0.02 9.16 1.651 70.5 9 0.07 1.03 0.547 7.9 3 0.051 0.21 0.12 1.6

Dioxin TEQ ng/kg 22 13 14 1738 413 79 6 34.9 274 112 12 10 2.87 1730 390 79 7 2.73 491 259.7 22 3 12.2 28.2 18.4 1

Total PAH ug/kg 1684 17 290 282335 54685 168 6 1869 18181 7181 11 14 464 243831 42129 145 9 684.5 370800 47805 220 3 817.5 2745.8 1572 2

DDD* ug/kg 3.3 14 0.195 9 2.5 2.73 6 1.92 2.32 2.0 0.70 14 1.68 27.35 6.0 8.29 9 1.2 6.89 3.1 2.09 3 1.14 1.98 1.5 0.60

DDE* ug/kg 3.3 14 0.52 22 5.9 6.7 6 2.92 9.02 4.8 2.7 14 1.8 13.5 6.1 4.1 9 1.84 8.32 5.6 2.5 3 0.82 1.98 1.3 0.6

DDT* ug/kg 3.3 14 0.18 10 1.8 3.03 6 1.68 2.9 2.1 0.88 14 1.88 11.98 5.8 3.63 9 2.29 20.39 11.1 6.18 3 1.14 1.98 1.6 0.60

* For Area 1, Area 2, Area 3, and Area 4, total included ortho-para and para-para isomers; Channel and Channel Margins data includes para-para isomer only



Southern Drains are included in the results summary of Areas 2 and 3, respectively. Thedata collected in the supplemental investigation resulted in a modification of the four areasof concern (Figure 6-1). Area 1 is larger and extends to the southwest. Areas 3 and 4 werereconfigured and extend further south into Garrows Bend Channel.

6.2.1 MetalsMetal HQs exceeded 1 in all areas. Area 2 had the highest lead and mercury HQs.

6.2.1.1 LeadThe HQs, based on the maximum concentrations in each of the four areas, ranged between1.0 and 6.1. The maximum HQ for the channel margins and channel was 12. Areas 2 had thehighest maximum HQ. The HQs in Areas 1 and 4 were at or just above the threshold level of1.0.

6.2.1.2 MercuryThe HQs based on the maximum concentrations in each of the four areas ranged between1.6 and 71. The HQ for the channel and channel margins was estimated to be 19. Area 2had the highest HQ. The next highest HQ was in Area 3, with an HQ of 7.9. Area 2 was theonly area that exceeded the maximum HQ in the channel and channel margins.

6.2.2 DioxinsDioxin/furan HQs were estimated based on the TEQs. The HQs in all areas ranged from1.0 to 79. Area 2 had the highest HQ, at 79. The maximum HQ in Areas 1 and 3 exceeded 10.The maximum HQ in the channel and channel margins was 79.

6.2.3 Total PAHThe HQs for total PAHs ranged between 2 and 220. Areas 2 and 3 had HQs of 145 and 220,respectively. The HQ for the channel and channel margins was 168. The HQs of Areas 1and 4 were much lower, at 11 and 2, respectively.

6.2.4 DDTTotal DDT (sum of DDT, DDE, and DDD; both ortho-para and para-para isomers)maximum HQ ranged between 1.8 and 16. The highest HQ was located in Area 2. Thechannel and channel margin maximum HQ was 16.

6.3 BioaccumulationLaboratory analyses were performed on shrimp and oyster samples collected in Areas 1, 2,and 4. Concentrations of the target analytes are presented in Table 6-2. All five targetanalytes were detected in the tissue samples. There are no ESVs or analogous screeningvalues for benthic invertebrate tissue. All five analytes are considered to be bioaccumulativeby USEPA (2000) and their presence at detectable levels in benthic invertebrate tissueindicates that sediment contaminants may be available to higher trophic level organismsthrough the ingestion of contaminated prey. This supports the need to evaluate the risksassociated with chemicals found in Garrows Bend, as well as the estimated effects onecological receptors.

WES-BM-04

WES-BM-02

WES-BM-12

AG02-01

AG02-02

AG02-03

AG02-04

AG02-05

AG02-06

AG02-07

AG02-08

AG02-09AG02-10

AG02-11AG02-12 AG02-13

AG02-14

AG02-15AG02-16

AG02-17

AG02-18 AG02-19

AG02-20

AC99-09

AC99-10

AC99-11

AC99-13

AC99-08

AC99-07

AC99-06

AC99-03

AC99-05

AC99-01

TurningBasin

Garrows Bend

McDuffieIsland

PintoIsland

Arlington Channel

Figure 6-1 Four Areas of ConcernEvaluation of Arlington and Garrows Bend Channels and Adjacent Area Sediments

Mobile Bay, Alabama0 1,500 3,000

Feet

File Path: \\Boomer\E\Projects\MobileBay\mxd\Figures\Figure 6-1 Four Areas of Concern.mxd, Date: Aug 25, 2003, User: JHenderson

Tennessee St. Drain

Southern Drain

Area 1 - 9 Acres

Area 2 - 50 Acres

Area 3 - 13 Acres

Area 4 - 17 Acres

1999 and 2002 Sample Location Station

Ship Channel

Little SandIsland



TABLE 6- 2Tissue Sample Analytical ResultsEvaluation of Arlington and Garrows Bend Channels and Adjacent Area Sediments

Sample ID Dioxin TEQ(ng/kg)

Lead(mg/kg)

Mercury(mg/kg)

DDD(µg/kg)

DDE(µg/kg)

DDT(µg/kg)

Total PAHs(µg/kg)

A01BS01ShrimpComp NA 0.33 0.016 3.84 5.47 3.84 123

A02BS01OysterComp 2.43 0.17 0.039 3.68 3.84 15.62 196

A02BS01ShrimpComp NA 0.37 0.017 4 8.76 17.1 11154

A04BS01OysterComp 1.48 0.16 0.018 3.84 3.84 8.82 435

A04BS01ShrimpComp NA 0.37 0.026 4 8.96 19.8 142

NA not analyzed

6.4 DiscussionResults of the preliminary risk evaluation for samples collected during the supplementalinvestigation indicate that concentrations of lead, mercury, dioxins, PAHs, and DDT presentin Areas 1, 2, 3, and 4 may pose a risk to aquatic receptors. In general, the preliminary riskevaluation indicates that Area 2 poses the greatest risk to aquatic receptors. Risks in Area 3are relatively high as well, particularly for total PAHs. Risks in Areas 1 and 4 are relativelylow compared to Areas 2 and 3.

The supplemental investigation extended from the channel edges to the shoreline. Adiverse assemblage of terrestrial and aquatic ecological receptors use this habitat.Additional evaluation of the available data is needed to refine the risks to ecologicalreceptors. If the risks are unacceptable, an ecological risk assessment could be used tosupport and refine the selection of alternatives.


7. Conclusions

Based upon the screening methodology outlined above, lead, mercury, dioxins/furans, andPAHs were identified as chemicals of potential concern (COPCs) ) for the 1999 and 2002investigations. The results of the supplemental investigation confirmed those compoundsas problematic and also suggested that DDT might be a COPC. These compounds weredetected in study area sediments at concentrations exceeding the selected screening valuesby at least an order of magnitude. The potential for adverse effects on benthic organismsmay exist due to the elevated concentrations above the ESVs. In general, the highestconcentrations were recorded from the 0- to 3-ft interval and declined with depth.However, underlying sediment layers may still have COPC concentrations at levels thatcould be considered adverse to benthic organisms. The inner-channel stations (AG02-17,AG02-18, AG02-19, and AG02-20) tended to have the highest concentrations of chemicalsexceeding the ESV values. Stations AG02-12, and AG02-15 have the first and third highestconcentrations of dioxin, respectively. Table 6-1 summarizes the depth and spatialdistribution of lead, mercury, dioxins/furans, and PAHs.

In addition, the laboratory toxicity and bioaccumulation studies support a finding that thehabitat is significantly degraded.

The available data do not allow for comparisons between sediment COPC concentrationsand toxicity. However, sediment toxicity in a portion of the study area identified as havingCOPC concentrations at levels considered a potential risk to ecological receptors certainlymerits consideration. From a weight-of-evidence perspective, the toxicity results do notdisprove the hypothesis that sediment COPCs may be a potential source for adverseecological effects on receptors in the northern reach of the project area.

Likewise, TBP calculations indicate that levels of bioaccumulative COPCs may be highenough to reach significantly elevated levels (relative to the reference area) for benthicmacroinvertebrates.

Based upon the results of the supplemental sediment and biota investigation, the potentialfor adverse effects to benthic organisms extends into the near-shore habitat of GarrowsBend. The area between the channel and the areas where the Tennessee Street and SouthernDrains enter the upper portion of Garrows Bend (designated as Areas 2 and 3) has thehighest concentrations of dioxins, PAHs, lead, and mercury outside of the channel itself. Inaddition, bioaccumulative chemicals were detected in benthic invertebrate tissues collectedin Areas 1, 2, and 4, indicating that a potential pathway for transfer of sedimentcontaminants to higher trophic level organisms may exist in Garrows Bend. Thisinformation supports the need to consider the risks to ecological receptors when evaluatingthe restoration alternatives in Garrows Bend.

7.0 CONCLUSIONS


TABLE 7-1Vertical Profile of Selected Contaminants Exceeding the Screening ValueEvaluation of Arlington and Garrows Bend Channels and Adjacent Area Sediments

Station:

Depth Interval(ft) Chemical Units MH/AC99-9 AG02-08 AG02-09 MH/AC99-10 AG02-11 AG02-10 AG02-12 WES-BM-11 AG02-13 AG02-14 AG02-15 AG02-16 WES-BM-13 AG02-18 AG02-17 AG02-19 AG02-20

0 – 3 Lead mg/kg 26 24 9.5 32 13 28 21 16 25 57 31 8.1 64 363 220 59 58

Mercury mg/kg 0.83 0.38 0.060 0.64 0.35 0.32 0.62 0.20 0.26 0.43 0.82 0.020 1.1 1.0 2.5 1.7 0.43

Total PAH µg/kg 645 3,688 864 919 10,297 5,623 67,413 290 3,327 36,250 137,576 2,608 7,366 282,335 178,665 45,123 146,660

TEQ ng/kg 134 17 65 149 116 1,738 101 390 535 14 345 1,290 472 373

3 – 6 Lead mg/kg 4.1 8.5 32 36 4.0 8.0 16 2.2 47 82 58 38

Mercury mg/kg 0.020 0.050 0.47 0.27 0.070 0.050 0.10 0.52 0.16 0.68 0.29

Total PAH µg/kg 55 492 7,697 4,397 272 323 6,521 115 3,864 188,300 14879

TEQ ng/kg 7.5 15 257 83 16 12 6.8 35 389 32

6 – 9 Lead mg/kg 2.7 3.7 27 11 3.5 18 1.7 38 44 37

Mercury mg/kg 0.030 0.83 0.060 0.020 0.080 0.38 0.38 0.38

Total PAH µg/kg 6.8 113 9,520 997 21 3,869 72 74,528 4753

TEQ ng/kg 6.7 10 316 22 6.9 9.3 6.6 338 22

9 – 12 Lead mg/kg 7.3 4.3 16 4.7 1.6 4.8 1.1 23 32 15

Mercury mg/kg 0.030 0.030 0.15 0.030 0.010 0.020 0.40 0.22 0.11

Total PAH µg/kg 6.8 78 1,282 98 10 764 24 3,105 83,774 1978

TEQ ng/kg 6.3 7.9 13 7.8 6.5 8.1 6.4 61 10

Shading represents concentrations exceeding the screening value; blank cells indicate chemical not analyzed for that interval.

TEQ toxicity equivalent quotientmg/kg milligrams per kilogram; parts per millionng/kg nanograms per kilograms parts per trillionµg/kg micrograms/kilograms; parts per billionPAH polynuclear aromatic hydrocarbonsPCBs polychlorinated biphenylsft feet

Source: USACE, 2000 and 2002


8. References

Ankley, et al. 1992. Bioaccumulation of PCB from sediments by oligochaetes and fish. Can.J. Fish. Aquat. Sci. 49:2080-2085. (Cited by USEPA/USACE, 1998)

Canadian Center of Ministry and Environment. 2001. Canadian Sediment QualityGuidelines for the Protection of Aquatic Life. Polychlorinated Dibenzo-p-dioxins andpolychlorinated dibenzofurans (PCDD/Fs).

CCME. 1995. Interim Sediment Quality Guidelines, Soil and Sediment Quality SectionGuidelines Division, Ecosystem Conservation Directorate, Evaluation and InterpretationBranch, Ottawa, Ontario.

CH2M HILL. 2003. Garrows Bend supplemental sampling. Garrows Bend, Mobile Bay, Alabama.Contract No. DACA01-01-D-0013. Prepared for USACE Mobile District.

Long, ER and LG Morgan. 1990. The potential for biological effects of sediment-sorbedcontaminants tested in the National Status and Trends Program. NOAA TechnicalMemorandum NOS OMA 52. National Oceanic and Atmospheric Administration. Seattle,Washington.

Long, ER, DD MacDonald, SL Smith, FD Calders. 1995. Incidence of adverse biologicaleffects within ranges of chemical concentrations in marine and estuarine sediments.Environ. Management. 19:81-97.

MacDonald, DD. 1994. Approach to the Assessment of Sediment Quality in Florida CoastalWaters. Volume I - Development and Evaluation of the Sediment Quality AssessmentGuidelines. Report prepared for Florida Department of Environmental Protection,Tallahassee, Florida.

MHSPE. May 1994. Intervention values and target values – soil quality standards.Directorate-General for Environmental Protection, Department of Soil Protection, TheHague, Netherlands.

NOAA. June 1999. Sediment Quality Guidelines Developed for the National Trends andStatus Program

O’Connor, TP, KD Daskalakis, JL Hyland, JF Paul, and JK Summers. 1998. Comparisons ofmeasured sediment toxicity with predictions based on chemical guidelines. Environ.Toxicol. Chem. 17:468-471.

USEPA. November 1995. In: Supplemental Guidance to RAGS: Region 4 Bulletins -Ecological Risk Assessment. Bulletin No. 2.Http://www.epa.gov/region4/wastepgs/oftecser/otsguid.htm

USEPA/USACE. 1998. Evaluation of dredged material proposed for discharge in waters ofthe U.S. - Inland Testing Manual (ITM). USEPA-823-B-98-00.

8.0 REFERENCES


USEPA, 2000. Bioaccumulation Testing and Interpretation for the Purpose of SedimentQuality Assessment, Status and Needs, EPA-823-R-00-001, February 2000.

United States Environmental Protection Agency. January 1996. Ecotox Thresholds, ECOUpdate, Office of Solid Waste and Emergency Response. Intermittent Bulletin Vol. 3, No.2, Publication 9345.0-12FSI, EPA 540/F-95-038 PB95-963324.

United States Army Corps of Engineers, 2000. Evaluation of Dredged Material Arlington-Garrows Bend Channel, Mobile Harbor, Alabama. Prepared by EA Engineering, Science,and Technology, Inc.

United States Army Corps of Engineers 2002. Sediment Quality Characterization of AreasAdjacent to Arlington and Garrows Bend Channels, Mobile, Alabama. Prepared by EAEngineering, Science, and Technology, Inc. under contract to The Louis Berger Group, Inc.

Documents

APPENDIX K USACE PRELIMINARY ECOLOGICAL RISK … · vides a preliminary assessment of sediment quality by comparing bulk sediment chemistry results to sediment quality guidelines