Sensitivity of White Sturgeon (Acipenser transmontanus) to Selected Environmental Pollutants
David W. Vardy1, Jon A. Doering1, Shawn C. Beitel1, Brett T. Tendler1, Adam Ryan2 , Robert Santore2 John P. Giesy1,3,4, Markus Hecker1,5
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.
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.
• 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.
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.
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).
2.2 Sediment Exposures
[A]
40L stream
Head tank
40L stream
40L stream
• 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.
Passive Diffusive Gradient Thin Films (DGTs)
[C]
[B]
[A]
Suction Sampling Devices (Airstones)
85L
Reservoir
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.
Fig 2. [A] Flow-through experimental exposure system, [B] Experimental exposure
arrangement, [C] Exposure chamber with sediment and sturgeon.
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.
3.1 Aqueous Metal Exposures [1], [2], [3]
[B]
Fig 1. [A] Schematic of flow-through system layout
showing 3 exposure chambers. [B] Exposure
chamber design with egg hatching jar.
• 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.
• Newly hatched larvae were exposed to
sediments and controls for 60d in flow-through
experimental chambers (Fig 2).
SWI
1
PW (1 cm)
• 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].
DE
NP
LD UMF LMF
Sediments
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.
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%).
Body Condition Index (K)
• There were no significant differences (p > 0.05)
in K of fish exposed to treatment sediments
versus reference sediments at termination.
• 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).
• Acute LC50s: Cd (9 µg/L), Zn (104 µg/L), Pb (407), and Cu (Table 1).
Biotic Ligand Model Toxic Units
Comparison for Copper
10
1
0.1
< <
<
<<
<
<
<
OW
<
<
<
0.01
SWI
PW (1 cm)
PW (2.5 cm)
0.001
H20 CTRL LALL GE
DE
NP
LD UMF LMF
Sediments
• 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].
• 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).
• 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].
Conclusions
• 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.
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.
H2O CTRL LALL GE
• 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.
BLM Toxic Units
Pump
Water chiller
OW
Passive Diffusive Sampling Devices (Peepers)
Metering
pump
Outflow to
drain
10
0.1
Metal Analyses
100%
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
“<“ when more than 80% of measurements were below DL
or associated with a contaminated blank.
• 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.)
SSD Copper
90%
80%
White sturgeon (8 dph)
White sturgeon (15 dph)
70%
White Sturgeon (40 dph)
White sturgeon (45 dph)
60%
Fish Species
• 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).
White sturgeon
(Acipenser
transmontanus)
Yolksac
(8 dph)
22 (20 – 25)
Swim-up
(15 dph)
10 (8 – 12)
96hr LC50 for Copper Exposure (μg/L)
Life stage
Juvenile
Juvenile
(40 dph)
(45 dph)
9 (7 – 12)
17 (14 – 21)
Water Quality Criteria
Later Juvenile
(100 dph)
54 (47 – 62)
SMAV
a
CMC
b
CWQG
c
Percentile
2.1 Aqueous Metal Exposures
100
PW (2.5 cm)
Photo by Michael Gallacher
2.0 Objectives
Cu Concentrations in Matrices
Geometric mean of Cu Toxic Units
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
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, βnaphthoflavone (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.
3.3 Sediment Exposures [5]
Copper (µg/L)
1.0 Introduction
Rainbow trout (8 dph)
50%
Rainbow trout (15 dph)
40%
Rainbow trout (40 dph)
Rainbow trout (45 dph)
30%
18
7.9 (± 1.5)
2
• 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.
White sturgeon (100 dph)
Rainbow trout
References and Publications
Fathead minnow (8 dph)
20%
Fathead minnow
Atlantic sturgeon
Rainbow trout
(Oncorhynchus
mykiss)
Fathead minnows
(Pimephales
promelas)
a
10%
40 (34 – 46)
21 (18 – 23)
22 (20 – 25)
24 (20 – 28)
26
8.5 (± 3.0)
2
Map 1. Treatment sediment locations on the
Columbia River
Shovelnose sturgeon
0%
1
10
100
1000
10000
SMAV (µg/L)
102 (78 – 135)
102
11.8
2
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
• Biological endpoints included mortality, growth
and body condition.
Shortnose sturgeon
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.
[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)
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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/
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