Open-File Report 99-57

Organic Compounds and Trace Elements in the Pocomoke River and Tributaries, Maryland

By Cherie V. Miller (U.S. Geological Survey), Gregory D. Foster (George Mason University), Thomas B. Huff (George Mason University) and John R. Garbarino (U.S. Geological Survey)


This report is available as a pdf.



In response to concern about recent blooms of the dinoflagellate, Pfiesteria piscicida, samples of sediment and water were collected from the lower Pocomoke River Basin and were screened for trace elements, pesticides, and other organic compounds. A large group of steroid and fatty acid methyl-ester compounds was detected in streamwater using gas chromatography/mass spectroscopy in scan mode. Some of these steroid compounds have been identified and further quantified in bed-sediment extracts. Spatial patterns of the concentrations of cholesterol suggest that these compounds are linked to the runoff of animal wastes into the river. Many of the organic compounds found in the Pocomoke River sediments have not yet been identified, but at least several are in the class of hormone compounds related to estradiols and have the potential to promote endocrine-disrupting effects in aquatic life. Particulate forms of arsenic and zinc are slightly elevated above normal levels for streams, but the sources for these elements are still undetermined. Several pesticides were found in low, parts-per-trillion concentrations, but were within the ranges commonly found in streams of this region.






Description of Study Area


Sample Collection and Handling

Analysis of Samples

Field Conditions at Time of Sampling

Results of Trace-Element Analysis

Results of Organic-Compound Analysis

Summary and Implications

References Cited

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For more information about USGS activities in Maryland, Delaware and the District of Columbia contact:


MD-DE-DC Water Science Center
U.S. Geological Survey
8987 Yellow Brick Road
Baltimore, MD 21237
Telephone: (410) 238-4200
Fax: (410) 238-4210


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