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Contaminants in sediment affecting health of Southeast urban streams

Sediment contamination of freshwater streams in urban areas is a recognized and growing concern. As a part of a comprehensive regional stream‐quality assessment, stream‐bed sediment was sampled from streams spanning a gradient of urban intensity in the Piedmont ecoregion of the southeastern United States.

USGS technicians collect streambed sediment at Suwannee Creek
USGS technicians collect streambed sediment at Suwannee Creek in Suwannee, Georgia. The sediment was analyzed for more than 200 contaminants.

Contaminants in sediment may be adversely affecting the ecological communities living in streams in the Southeastern U.S., reports a new USGS study.  Polycyclic aromatic hydrocarbons (PAHs), which have urban sources such as coal tar and automobile emissions, and the insecticides chlordane and bifenthrin were the chemicals in sediment most closely associated with changes in aquatic insect populations in the streams studied.

Sediment collected from 78 small streams across 5 Southeastern states was analyzed for more than 200 contaminants and tested for toxicity in the laboratory.  In addition, at each site the aquatic insects present, such as mayfly larvae, were inventoried. Scientist interpreted the results using a three-pronged approach—comparison of contaminant concentrations to ecological benchmarks, comparison of contaminant concentrations to aquatic insect communities, and sending sediments from the streams for laboratory toxicity testing. The combined results indicated that chlordane and bifenthrin, and to a lesser extent PAHs, are affecting stream health in the more urban watersheds investigated in the study.

For more information, contact Patrick Moran (

Citation:  Moran, P.W., Kemble, N.E., Waite, I.R., Mahler, B.J., Nowell, L.H., and Van Metre, P.C., 2002, Legacy and Current‐Use Contaminants in Sediments Alter

Macroinvertebrate Communities in Southeastern US Streams: Environmental Toxicology and Chemistry, 00 (00),  p. 1–14.