85L Reservoir

Outflow to drain

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40L stream

40L stream

40L stream

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Head tank[A]

[B]

1Toxicology Centre, University of Saskatchewan, Saskatoon, SK, Canada. 2HDR | HydroQual, East Syracuse, NY, USA.

3Dept. Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon, SK, Canada. 4City University of Hong Kong, Hong Kong, China.

5Cardno ENTRIX Inc., Saskatoon, SK, Canada.

Sediment Toxicity and the Biotic Ligand Model

The Biotic Ligand Model (BLM), a metal speciation and predictive toxicity model, can be used to predict metal speciation for various metals as well as toxicity to a number of aquatic organisms depending on ambient water quality parameters. The most sensitive BLM parameter files that were developed for previous work with white sturgeon [1] were used to make predictions for 4 metals (Cu, Cd, Zn, and Pb) based on water quality values obtained from the different matrices in the sediment toxicity study. Toxic units (TUs) were then calculated by dividing the measured metal concentrations in the matrices by the associated BLM prediction.

3.0 Results and Discussion Overall, early life stage white sturgeon appear to be relatively sensitive to selected environmental pollutants. Concerning metal exposures, copper is of particular interest in some of the larger North American rivers, such as the Columbia, due to past and present activities of mines, metallurgical facilities, pulp and paper mills, as well as other industrial and municipal sources. Therefore, results of metal exposures presented herein will focus on this metal.

Table 1. Acute median lethal concentrations (LC50s) for Cu exposure for white sturgeon (Acipenser transmontanus), rainbow trout (Oncorhynchus mykiss), and fathead minnow (Pimephales promelas) early life stages expressed in days post hatch (dph). Values in brackets for LCs represent confidence intervals, values in brackets for water quality criteria represent standard deviation.

2.2 Sediment Exposures • Sediments were collected from seven locations along the Columbia River: two reference

and five exposure locations between the trans-boundary reach of Canada and the USA, representing a sediment exposure gradient for environmental pollutants (Map 1). A water only and an artificial sediment group were included as controls.

Survival Analyses

• Average survival in the reference groups was greater than 75%, and average survival in all treatment groups was greater than 70%.

• There were no significant differences in survival between treatment and reference groups at the

termination of the study (p > 0.05). NP treatment group had the greatest average survival (90%) while the UMF treatment group had the least average survival (70%).

3.3 Sediment Exposures [5] Results for the Columbia River sediment toxicity study presented here are preliminary and represent the opinion of the authors. Data from this study will be submitted for consideration as part of a baseline ecological risk assessment being conducted at the upper Columbia River in eastern Washington State. Metal Analyses • Concentrations of metals fluctuated throughout the

experiment within the matrices of the various sediments. There was a trend towards greater concentrations of metals in PW versus SWI and OW.

Conclusions • These studies provide a portion of much needed toxicity data for white sturgeon and identified

significant sensitivities among early life stages.

• The aqueous metal exposure studies outline the relative sensitivity of ELS WS to Cu, Cd, Zn, and Pb compared to other fishes.

• Concentrations of metals in sediment exposure matrices in the sediment exposure study were less than the most sensitive LC values determined in the aqueous metal exposure studies for Cd, Zn, and Pb, and only approached LC values in PW for Cu in DE and LD sediment exposures. This is consistent with the BLM toxic units comparison for Cu (Fig 7.)

• Results of the sediment toxicity study indicate that exposure to contaminants through sediments in the upper Columbia River is unlikely to significantly contribute to the poor recruitment of WS.

References and Publications [1] Vardy, D.W., Tompsett, A.R., Sigurdson, J.L., Doering, J.A., Zhang, X., Giesy, J.P., Hecker, M., 2011. Effects of sub-chronic exposure of early life

stages of white sturgeon (Acipenser transmontanus) to copper, cadmium and zinc. Environ. Toxicol. Chem. 30: pp 2497-2505. [2] Vardy, D.W., Oellers, J., Doering, J.A., Hollert, H., Giesy, J.P., Hecker, M. 2012. Sensitivity of early life stages of white sturgeon, rainbow trout, and

fathead minnow to copper. Ecotox. (In press). [3] Vardy, D.W., Oellers, J., Doering, J.A., Tompsett, A.R., Hollert, H., Giesy, J.P., Hecker, M. In preparation. Laboratory and site specific toxicity of

selected metals to early life stages of white sturgeon (Acipenser transmontanus). [4] Doering, J.A., Wiseman, S., Beitel, S.C., Tendler, B.J., Giesy, J.P., Hecker, M. 2012. Tissue specificity of aryl hydrocarbon receptor (AhR) mediated

responses and relative sensitivity of white sturgeon (Acipenser transmontanus) to an AhR agonist. Aquat. Toxicol.114-115: pp 125-133. [5] Vardy, D.W., Doering, J.A., Beitel, S.C., Tendler, B.J., Giesy, J.P., Hecker, M. In preparation. Assessment of Upper Columbia River sediment toxicity

to early life stages of white sturgeon (Acipenser transmontanus) Dwyer FJ, Mayer FL, Sappington LC, Buckler DR, Bridges CM, Greer IE, Hardesty DK, Henke CE, Ingersoll CG, Kunz JL, Whites DW, Augspurger T,

Mount DR, Hattala K, Neuderfer GN. 2005. Assessing contaminant sensitivity of endangered and threatened aquatic species: Part I. Acute toxicity of five chemicals. Arch Environ Contam Toxicol 48:143-154

EPA. 2007. ECOTOX User Guide: ECOTOXicology Database System. Version 4.0. U.S. Environmental Protection Agency, Washington, DC, USA. http:/www.epa.gov/ecotox/

Fig 7. Toxic unit (TU) analyses for copper based on Biotic Ligand Model predictions. Bars represent average TUs for overlying water (OW), sediment-water interface (SWI), and porewater (PW) for the various sediment exposures. Error bars represent standard deviation. TUs were considered “ 0.05)

in K of fish exposed to treatment sediments versus reference sediments at termination.

BLM Toxic Units • TUs were calculated for all matrices (OW, SWI,

and PW at 1 and 2.5 cm) for every exposure chamber (only Cu data shown; Fig 7).

• Mean TU values approached or exceeded the

threshold of 1.0 TU for only Cu in deep porewater (Fig 7) for DE and LD sediment exposures. TUs for Cd, Zn, and Pb were less than TU threshold values of 1.0 (data not shown).

[C]

Acknowledgments: Funding for this project was provided by an unrestricted grant from Teck American Incorporated to the Univ. Sask. Thanks to the Kootenay Trout Hatchery, the UofS graduate program and team, and the UofS ATRF

David W. Vardy1, Jon A. Doering1, Shawn C. Beitel1, Brett T. Tendler1, Adam Ryan2 , Robert Santore2 John P. Giesy1,3,4, Markus Hecker1,5

Sensitivity of White Sturgeon (Acipenser transmontanus) to Selected Environmental Pollutants

1.0 Introduction In the north-western USA and British Columbia, Canada, populations of white sturgeon (WS; Acipenser transmontanus) are declining, primarily due to poor annual recruitment. Pollution has been hypothesized as one potential cause for poor recruitment in the Columbia, Fraser, and Sacramento-San Joaquin rivers and their tributaries. Specifically, there are concerns about the potential toxicity to WS early life stages (ELS’s), a period of development when fish are often sensitive to the exposure of contaminants. ELS WS inhabit

2.0 Materials and Methods • Fertilized WS eggs were obtained from the Kootenay Trout Hatchery, Fort Steele, BC.

• All culturing and exposure experiments presented here were conducted in the Aquatic

Toxicology Research Facility (ATRF), University of Saskatchewan, Saskatoon, SK.

2.1 Aqueous Metal Exposures 1. Acute (96h) static renewal toxicity tests

were conducted with 8 day post hatch (dph) WS for Cd, Cu, Zn, and Pb exposures. In addition, two standard test species, rainbow trout (Oncorhynchus mykiss) and fathead minnow (Pimephales promelas), were exposed in parallel to Cu and Pb at 8 and 40 dph to determine relative sensitivity among species and life stages. WS were also exposed to Cu at 15, 45, and 100 dph.

2. Chronic toxicities of Cd, Cu, and Zn to ELS WS were investigated from 0 – 60 dph, under flow-through conditions (Fig 1).

3.1 Aqueous Metal Exposures [1], [2], [3] • Chronic lethal concentrations of Cd (1.5 µg/L), Cu (5.5 µg/L), and Zn (112 µg/L) at which 20% mortality

occurred (LC20s) obtained for WS were comparable to sensitive salmonid species [1].

• Acute LC50s: Cd (9 µg/L), Zn (104 µg/L), Pb (407), and Cu (Table 1).

• Construction of species sensitivity distributions (SSDs) based on the acute data from this study and US EPA’s ECOTOX database ranked WS yolk-sac and early juvenile life stages in the lower 15th centile for all metals tested [2], [3].

• For Cu exposures, WS were more sensitive than rainbow trout and fathead minnow at all comparable life stages tested (Table 1), and when plotted in a SSD with other fishes, the mean acute toxicity value for ELS WS was ranked between the 1st and 2nd centile (Fig 4), [2].

• ELS WS are relatively sensitive to Cd, Zn, and Pb, but LC values for chronic and acute exposures were greater than the water quality criteria and guidelines in both the United States and Canada. For Cu exposures, water quality guidelines in Canada remain protective but threshold values approach criteria in the US. Therefore, water quality guidelines and criteria for Cu may need to be evaluated on a site-by-site basis when WS early life stages are present in order to ensure protection.

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Fig 4. Species sensitivity distribution (SSDs) for copper. Values for species with life stages, expressed as days post hatch (dph), are from acute exposure experiments conducted at the University of Saskatchewan. Atlantic, shortnose, and shovelnose sturgeon values are from Dwyer et al. (2005), and all other species values are from the ECOTOX database (EPA 2007). The Species Mean Acute Value (SMAV) is the geometrical mean LC50 for a given species.

Fig 1. [A] Schematic of flow-through system layout showing 3 exposure chambers. [B] Exposure chamber design with egg hatching jar.

[A]

Suction Sampling Devices (Airstones)Passive Diffusive Sampling Devices (Peepers)

Passive Diffusive Gradient Thin Films (DGTs)

Fig 2. [A] Flow-through experimental exposure system, [B] Experimental exposure arrangement, [C] Exposure chamber with sediment and sturgeon.

Map 1. Treatment sediment locations on the Columbia River

Fig 3. Schematic of exposure chamber with DGTs and peepers for passive sampling (PW 1 cm) and airstones (PW 2.5 cm) for active sampling of porewater at 1 and 2.5 cm depths, respectively.

[B]

a SMAV refers to the species mean acute value b CMC refers to the Criteria Maximum Concentration for fresh water species. The mean freshwater

criteria is presented and calculated from the various life stage experiments for each specie using the Biotic Ligand Model

c CWQG refers to the Canadian Water Quality Guidelines for the protection of aquatic life adjusted to the present study’s hardness

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Fig 6. Average measured metal concentrations in control (H20, CTRL), reference (LALL, GE), and treatment exposures (DE, NP, LD, UMF, LMF) in overlying water (OW), sediment water interface water (SWI), and porewater at 1 cm (PW 1 cm) and 2.5 cm (PW 2.5 cm) depth.

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Fish Species Life stage Water Quality Criteria

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transmontanus)

22 (20 – 25) 10 (8 – 12) 9 (7 – 12) 17 (14 – 21) 54 (47 – 62) 18 7.9 (± 1.5) 2

Rainbow trout (Oncorhynchus

mykiss)

40 (34 – 46) 21 (18 – 23) 22 (20 – 25) 24 (20 – 28) 26 8.5 (± 3.0) 2

Fathead minnows (Pimephales promelas)

102 (78 – 135)

102 11.8 2

• Greatest Cu concentrations were measured in systems containing Deadman’s Eddy (DE), Northport (NP), Little Dallas (LD), and Lower Marcus Flats (LMF) sediments (Fig 6) while no such trends were observed for the other metals.

benthic habitats and live on the sediment surface or in the interstitial space between stones. Therefore, in addition to exposure to pollutants in the water column, sturgeon can be exposed to contaminants associated with sediments. Little is known about the potential toxicity of inorganic and organic pollutants, such as metals and dioxin-like compounds, to WS or the tolerance of WS in comparison to other fishes. Here, we present the results of studies that investigated the effects of selected metals to ELS WS, in both water and in sediments collected from the upper Columbia River that are hypothesized to be contaminated with metals. In addition, as part of an overall investigation into WS sensitivity, a study that characterized the molecular and biochemical responses of ELS WS to a model aryl hydrocarbon receptor agonist, β-naphthoflavone (BNF), was conducted. Details of this study will be presented in a platform presentation entitled “The aryl hydrocarbon receptor signalling pathway of fishes: implications for sturgeon sensitivity to dioxin-like compounds”.-Doering, J.A.

Photo by Michael Gallacher

2.0 Objectives • Aqueous metal exposures were conducted to establish acute and chronic toxicity data that

can be used in assessments of the potential risks associated with environmental exposure to metals.

• Sediment exposures were conducted to evaluate effects of metals in sediments collected from the Columbia River on ELS WS.

• Newly hatched larvae were exposed to sediments and controls for 60d in flow-through experimental chambers (Fig 2).

• Three potential points of exposure were sampled weekly for contaminant concentration assessment (Fig 3): overlying water (OW), sediment-water interface (SWI), and porewater (PW), by use of syringes, suction devices, and peepers and diffusive gradient thin films (DGTs).

• Biological endpoints included mortality, growth

and body condition.

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