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Final Report: Site-specific Validation of a Chronic Toxicity Test with the Amphipod Hyalella azteca : An Integrated Study of Heavy Metal Contaminated Sediments in Peak Creek, Virginia
EPA Grant Number: R826198Title: Site-specific Validation of a Chronic Toxicity Test with the Amphipod Hyalella azteca : An Integrated Study of Heavy Metal Contaminated Sediments in Peak Creek, Virginia
Investigators: Cairns, John , Niederlehner, Barbara R. , Smith, Eric , Voshell, Joseph Reese
Institution: Virginia Polytechnic Institute and State University
EPA Project Officer: Reese, David H.
Project Period: January 2, 1998 through December 31, 1999
Project Amount: $211,116
RFA: Contaminated Sediments (1997)
Research Category: Hazardous Waste/Remediation
Description:
Objective:We conducted four integrated assessments of moderate impairment in a metal contaminated stream. In each assessment, the degree of correspondence between endpoints in chronic toxicity tests with the amphipod, Hyalella azteca, sediment, surface water, and pore-water chemistry, and a series of in situ macrobenthic community endpoints was determined. Characterizing the consistency of these observations facilitates inferences about the relationship between chronic toxicity tests with contaminated sediments and field response in general. Summary/Accomplishments (Outputs/Outcomes):
Peak Creek, Pulaski, VA, is a wadeable mountain stream affected by multiple sources of metal. As recently as 1989, there was no aquatic life at several stations on Peak Creek. Since then, improvements have restored aquatic life, but metal contamination in the sediments persists.
Riffle macroinvertebrate communities in Peak Creek were moderately impaired at the stations downstream from the on stream reference site. Analyses highlights include decreased number of taxa, decreased number of EPT taxa, decreased percentage Ephemeroptera, decreased number of intolerant taxa, and increased modified Hilsenhoff Biotic Index values at Sites 2-6 in Peak Creek. Macroinvertebrate Aggregated Index for Streams (MAIS) scores at the sites downstream from Peak Creek Site 1 were all below 12 for the four sample dates, indicating that biological communities at those sites are impaired.
The nominally depositional macroinvertebrate communities in Peak Creek were sampled from the most depositional habitat available, but, over time, these areas more closely resembled run rather than pool habitat. Depositional macroinvertebrate samples from impaired and references sites were not different, possibly due to the low amount of fine sediments found at all sites in this study.
Chemical analyses were consistent with the finding of moderate impairment to macrobenthic communities; Cu, Pb, and Zn levels in the sediments were often above Probable Effect Levels at downstream stations. Pore water and surface water concentrations of metals were occasionally elevated. Acid volatile sulfies (AVS) levels were detectable, but much lower than SEM concentrations, even at reference stations.
In four full-scale chronic toxicity tests with Hyalella azteca, only the December test found sediment toxicity at Sites 1, 2, and 6 in Peak Creek.
The concordance between laboratory tests with Hyalella azteca 12, chemical analyses, and macroinvertebrate community condition varied. Eight of twelve samples from reference sites provided strong evidence of no pollution-induced degradation. Two samples from Peak Creek provided strong evidence of pollution-induced degradation. However, in 22/32 samples, there was a discrepancy between effects in the laboratory test and effects in the macroinvertebrate communities. The majority of these discrepancies involved no toxicity in laboratory tests of sediment collected at sites with impaired riffle communities. Possible contributors to this lack of agreement include a general difficulty in detecting moderate impact, binding of metals to render them unavailable, and/or other, unidentified causative factors for field impairments.
The bioavailability of metals was assessed in two ways. First, while extracted metals in sediments were often elevated, pore-water concentrations of metals were elevated only occasionally. Second, body burdens of metals in Hydropsychidae collected from an impacted and a reference site were evaluated. Levels of Cu and Zn were significantly higher in insects collected at the impacted site, indicating that those metals were bioavailable at some times. While pore water determinations give an instantaneous measure of potential bioavailability through water, body burdens of indigenous insects integrate chemical conditions over a longer time period and through various media of exposure. Thus, metal impact may be through food rather than water, or may be intermittent.
It is more difficult to detect moderate impact than severe impact. When the level of contamination is sufficient to affect only some, but not all, indigenous organisms, the relative tolerance of organisms used in laboratory tests may be important. The chronic toxicity of pore water collected from the most impacted and a reference site was evaluated using Ceriodaphnia dubia, an organism known to be relatively sensitive to metals compared to other aquatic organisms. No adverse effects of pore water were observed. While not definitive, this finding suggests that the lack of response observed in tests with Hyalella was not due solely to relative insensitivity.
There are factors other than metals that might contribute to impairments in macroinvertebrate communities in Peak Creek. The Virginia Department of Environmental Quality sampled at three of our sites; Peak 1, Peak 4, and LW. They found no elevations in pesticide and polychlorinated biphenyl (PCB) levels in the sediments. These levels were consistently below detection (however, detection levels were above relevant probably effect levels [PELs]). However, there are intermittent problems with fecal coliform contamination and nutrient levels (sulfate and nitrate) at the downstream Peak Creek sites. Habitat quality may be an important factor. General urbanization is evident.
The associations between chemical and physical conditions and macroinvertebrate community structure in riffles were explored through canonical correspondence analysis. Reference and impacted riffle communities clustered separately. Among the most important environmental factors separating sites were conductivity and hardness, followed by embeddedness and sediment lead concentrations. In general, factors associated with effluent discharge were more important than sediment metal concentrations in distinguishing riffle communities.
Journal Articles:No journal articles submitted with this report: View all 1 publications for this project
Supplemental Keywords:ecological effects, integrated bioassessment, heavy metals, sediment, water. , Ecosystem Protection/Environmental Exposure & Risk, Toxics, Water, Geographic Area, Scientific Discipline, Waste, RFA, Ecosystem/Assessment/Indicators, exploratory research environmental biology, Ecological Risk Assessment, Ecological Indicators, Biochemistry, Environmental Microbiology, Ecological Effects - Environmental Exposure & Risk, Contaminated Sediments, National Recommended Water Quality, Ecology and Ecosystems, State, bioavailability, heavy metal contamination, water quality, Virginia (VA), amphipod hyalella azteca, ecology assessment models, lead, validation, stream ecosystems, macrobenthic community endpoints, sediment quality survey, sediment bioassay, contaminated sediment, ecotoxicology, correlation analysis , ecological exposure, amphipods, integrated assessment, Zinc, chronic toxicity test, ecological effects
Progress and Final Reports:
1998 Progress Report
Original Abstract