2023 Early Hearing Detection & Intervention Conference

March 5-7, 2023 • Cincinnati, OH

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5/23/2019  |   10:00 AM - 10:15 AM   |  STREAM MESOCOSM SALT ECOTOXICOLOGY STUDIES HELP INFORM AQUATIC LIFE CRITERIA   |  151 ABC

STREAM MESOCOSM SALT ECOTOXICOLOGY STUDIES HELP INFORM AQUATIC LIFE CRITERIA

Studies were undertaken to examine how different recipes of excess major ions (Na, Ca, Mg, SO4, HCO3, Cl) affect single-species toxicity and whole-community stream mesocosm responses. Using dose-response designs, effective concentrations (EC) for single species, community-level, and functional variables were modeled and ranked. Hazard concentrations (HCs) were then compared among different dosing recipes and field data. The performance of different measures for assessing the relative toxicity among recipes was also evaluated. For instance, the HCs for specific conductance from EC50-based response sensitivity distributions significantly differed between a recipe simulating oil and gas produced waters (HC5=792 µS/cm (685–933, 95% CI)) and one simulating leachate from surface coal mining (HC5=434 µS/cm (338–584, 95% CI)). Evaluating these different sensitivities within the context of a proposed TDS limit of 500 mg/l for NPDES permits applicable to Central Appalachian dischargers and a field-based conductivity benchmark (ca. 300 µS/cm) for the same region is relevant to the derivation and application of aquatic life criteria. Potentially important ambiguity in the way different measures of excess ionic content characterize relative toxicity also needs consideration.

  • Ecotoxicology
  • Mesocosm
  • Management

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Presenters/Authors

Christopher Nietch (), U.S. Environmental Protection Agency, nietch.christopher@epa.gov;


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Jim Lazorchak (), United States Environmental Protection Agency, Office of Research and Development, Center for Environmental Measurement and Modeling, Cincinnati, OH 45268, lazorchak.jim@epa.gov;


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Nathan Smucker (), U.S. Environmental Protection Agency, smucker.nathan@epa.gov;


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