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MA1 Large-Scale Investigations of Contaminated Sediments
() The condition of the estuarine sediments of the United States: National Coastal Assessment.
Summers, J.1, 1 US EPA, ORD/NHEERL/GED, Gulf Breeze, FL, USA
ABSTRACT- The purpose of the EPA National Coastal Assessment (NCA) program is to estimate the status and trends of the condition of the coastal resources of the United States on state, regional and national scales. During 1999-2003, 100% of the nation's estuarine waters were representatively sampled at over 4500 locations using indicators and indices which describe the condition or health of the benthic and fish communities, water quality, sediment and tissue contamination, sediment toxicity, and SAV. Data from the NCA survey were used to assess sediment quality using an index based on bulk sediment chemistry, sediment toxicity using the 10-day Ampelisca test, and sediment total organic carbon (TOC). The estuarine sediments of the United States were rated fair to poor with 13% of sediments receiving a poor rating for one of these sediment quality components. The largest proportional areas of estuarine sediment in poor condition occurred in Puerto Rico (61%), the Northeast (16%) and the West Coast (14%). Sediment toxicity was characterized by statistically significant Ampelisca mortalities in 6% of the estuarine sediments of the US; 7% showed exceedances of sediment contaminant guidance values; and, 3% displayed high TOC content greater than 5%. Using a set of benthic indices and measures developed by the NCA program, 18% of estuarine sediments did not support the expected abundances and types of benthic organisms. Seventy-one percent of sediments, characterized by poor benthic communities, co-occurred with poor sediment quality.
Key words: contaminants, NCA, sediment, monitoring
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