U.S. Geological Survey Toxic Substances Hydrology Program--Proceedings of the Technical Meeting, Colorado Springs, Colorado, September 20-24, 1993, Water-Resources Investigations Report 94-4015

Distributions of Organochlorine Compounds in Sediments and Livers of Striped Bass (Morone Saxatilis) in San Francisco Bay-Delta Estuary

Abstract

A preliminary assessment was made in 1992 of chlorinated organic compounds in sediments and in livers of striped bass from the San Francisco Bay-Delta Estuary. Samples of sediment and striped bass livers contain DDT (ethane, 1,1,1-trichloro-2,2-bis (p-chlorophenyl)-) and its degradation products, DDD(ethane, 1,1-dichloro-2,2-bis(p-chlorophenyl)-) and DDE (ethylene, 1,1-dichloro-2,2-bis (p-chlorophenyl)); polychlorinated biphenyls (PCB's); alpha and gamma chlordane, and cis and trans nonachlor. In addition, livers of striped bass contained small concentrations of DCPA (dimethyl tetrachloroterephthalate), a pre-emergent herbicide. The major source of DDT in the bay probably is from runoff from the San Joaquin and Sacramento Rivers. A point source of DDT near Richmond also may be responsible for the high concentrations of DDT in the Central Bay. Ratios of pentachloro to hexachloro isomers of PCB's suggest that sources of PCB's to the South, Central, and North Bays differ. Concentrations of alpha chlordane in livers of striped bass were greater than those of gamma chlordane suggesting a greater environmental stability and persistence of alpha chlordane. Trans nonachlor, a minor component of technical chlordane, was present in greater concentrations than alpha and gamma chlordane and cis nonachlor. Trans nonachlor is more resistant to metabolism than alpha and gamma chlordane and cis nonachlor, and serves as an environmentally stable marker compound. Chlorinated organic compounds are bioaccumulated in livers of striped bass. These compounds may contribute to the decline of striped bass in San Francisco Bay-Delta Estuary.