() The USEPA National Sediment Quality Survey: A National Perspective.
Ireland, D1, Berry, W2, Field, L3, Harcum, J4, Ingersoll, C5, Mount, D6, 1 USEPA, Great Lakes National Program Office, Chicago, IL, USA2 USEPA, Office of Research and Development, Atlantic Ecology Division, Narragansett, RI, USA3 NOAA, Office of Response and Restoration, Seattle, WA, USA4 Tetra Tech, Inc, Clemson, SC, USA5 USGS, Columbia Environmental Research Center, Columbia, MO, USA6 USEPA, Office of Research and Development, Mid-Continent Ecological Division, Duluth, MN, USA
ABSTRACT- The Water Resources Development Act of 1992 (WRDA) requires EPA to develop the National Sediment Quality Survey, a national evaluation of sediment quality in the United States. The first report was prepared in 1997 and described the incidence and severity of sediment contamination nationwide. The first update to this report is being finalized and is designed to be a screening-level assessment for the identification of potentially contaminated sediments. While there are many challenges to assessing sediment contamination on a localized area, these are drastically magnified at a National scale. One of the biggest challenges was the reliance on existing sediment quality data (mostly with only a single line of evidence reported - sediment chemistry), not collected with the WRDA mandate in mind and providing a limited spatial coverage for most watersheds. To support the National assessment, the EPA developed the National Sediment Inventory (NSI) database. This database is a compilation of sediment quality data (sediment chemistry, sediment toxicity, and tissue residue), collected from 1980 to 1999. Out of the 19,398 stations evaluated in this report (using data from 1990 to 1999), 70% had data available for sediment chemistry only which precluded a weight-of-evidence approach at these stations. Therefore, sediment quality guidelines (SQGs - both empirical and mechanistic) were a primary tool for assessing sediment quality. Other sediment quality benchmarks used in this report included theoretical bioaccumulation potential (TBP), sediment toxicity, and tissue residues. Concordance among lines of evidence was evaluated for a limited number of samples. To develop criteria for classifying sediments according to possible hazard, some assumptions were made that may not reflect site-specific conditions. While recognizing the inherent limitations of the data and the assessment approach, this is a viable approach to broad scale sediment assessments.
Key words: sediment chemistry, sediment, assessments, NSI database