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Predictions of sediment toxicity using consensus-based freshwater sediment quality guidelines
C G Ingersoll1, D D MacDonald, N Wang
1Columbia Environmental Research Center, US Geological Survey, 4200 New Haven Road, Columbia, Missouri 65201, USA. chris_ingersoll@usgs.gov
Summary
This study shows that consensus-based probable effect concentrations (PECs) effectively predict sediment toxicity nationally and regionally. Longer-term aquatic toxicity tests, like those with Hyalella azteca, are more sensitive to chemical mixtures.
Area of Science:
- Environmental Toxicology
- Ecotoxicology
- Sediment Quality Assessment
Background:
- Evaluating combined chemical effects on sediment toxicity is crucial for ecological risk assessment.
- Consensus-based Probable Effect Concentrations (PECs) offer a standardized approach to assessing chemical contamination.
- Understanding regional and national variations in sediment toxicity prediction is essential.
Purpose of the Study:
- To compare methods for assessing the combined toxicity of chemical mixtures in field-collected sediments.
- To evaluate the predictive power of consensus-based PECs for freshwater sediment toxicity across North America.
- To analyze the influence of different chemical contaminants on observed toxicity patterns.
Main Methods:
- Compilation of a large North American database (1,657 samples) from 92 published reports, integrating sediment toxicity and chemistry data.
- Utilization of standardized toxicity tests, primarily with the amphipod Hyalella azteca (HA10, HA28) and midges Chironomus tentans/C. riparius (CS10).
- Calculation of mean PEC quotients to quantify chemical contamination and assess combined effects of multiple contaminants.
Main Results:
- A positive correlation was observed between increasing mean PEC quotients and the incidence of sediment toxicity across all tested species.
- Longer-term toxicity tests (HA28) demonstrated higher sensitivity to chemical mixtures compared to shorter-term tests, with acute to chronic ratios around six for H. azteca.
- Distinct toxicity patterns emerged based on the dominant contaminants (e.g., PCBs, PAHs), suggesting unique chemical signals influencing toxicity.
Conclusions:
- Consensus-based PECs reliably predict sediment toxicity at both regional and national scales in North America.
- Mean PEC quotients can classify sediment samples as toxic or non-toxic, while individual quotients may help identify specific causative agents.
- Longer-term sediment toxicity testing provides more sensitive assessments of combined chemical effects than shorter-term tests.