Source, Transport, and Fate of Arsenic in the Pocomoke River Basin, a Poultry Dominated Chesapeake Bay Watershed

The source, transport, and fate of several arsenic compounds are being investigated in water, soil, and sediment of the Pocomoke River Basin in Maryland and Delaware, an area in the Chesapeake Bay Watershed that has a high concentration of poultry-feeding operations and where arsenic feed amendments are used extensively. Organic arsenic compounds are commonly added to the feed of animals, particularly poultry and swine, in the United States to control parasites, thereby improving animal growth rates. Poultry manure, which is typically spread on agricultural fields for disposal and as fertilizer, can contain from 15-35 mg/kg total arsenic (Morrison, 1969). An estimated 600 million chickens are raised annually on the Delmarva Peninsula (based on 1992 U.S. Department of Agriculture data); these animals produce more than 1.5 billion kg of raw manure (Sims and Wolf, 1994). Therefore, about 20-50 thousand kg of arsenic are delivered annually to the Delmarva peninsula. The fate of these arsenic feed amendments in the environment is not well understood.