MA1 Large-Scale Investigations of Contaminated Sediments
256 Portland Ballroom
8:00 AM - 12:00 PM, Monday
() A Comparison Between Regional and National Data Sets for Freshwater Sediments.
MacDonald, D1, Ingersoll, C2, Smorong, D1, Sparks, D3, Smith, J4, Meyer, J5, Gouguet, R6, Wang, N2, Braun, G7, 1 MacDonald Environmental Sciences, Nanaimo, BC, Canada2 United States Geological Survey, Columbia, MO, USA3 United States Fish and Wildlife Service, Bloomington, IN, USA4 Indiana Department of Environmental Management, Indianapolis, IN, USA5 United States Environmental Protection Agency, Dallas, TX, USA6 National Oceanic and Atmospheric Administration, Seattle, WA, USA7 Tetra Tech FW, Inc., Bothell, WA, USA
ABSTRACT- Assessments of sediment quality conditions are typically conducted using multiple lines of evidence, including but not limited to whole-sediment chemistry, whole-sediment toxicity, and benthic invertebrate community structure. Interpretation of data on one of these lines of evidence, whole-sediment chemistry, necessitates the establishment of toxicity thresholds that define the concentrations of sediment-associated contaminants that are associated with adverse biological effects. Such toxicity thresholds, which are also termed sediment quality guidelines, have been developed using a wide variety of approaches and data sets. In this study, toxicity thresholds were derived for metals, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and mean probable effect concentrations-quotients (PEC-Qs) using matching sediment chemistry and sediment toxicity data from the Calcasieu Estuary, Louisiana, the Grand Calumet River, Indiana, and other locations in North America (i.e., national data set). More specifically, concentration-response relationships were developed for each of the chemicals of potential concern (COPCs) using each of the three data sets and used to establish the concentrations that corresponded to a 20% and 50% increase in the incidence of toxicity and 10% and 20% increase in the magnitude of toxicity, relative to reference conditions, to amphipods in 28-d whole-sediment toxicity tests. Subsequently, the reliability of the resultant toxicity thresholds were evaluated by determining the incidence of sediment toxicity above and below the toxicity thresholds within the selected data set. The implications of these results for developing preliminary remediation goals to guide remedial actions at sites with contaminated sediments are discussed.
Key words: toxicity thresholds, sediment quality, contaminants, preliminary remediation goals