Problem

Hydrophobic organic contaminants, derived from point and non-point sources around the bay, are associated mainly with estuarine sediments and the lipid tissues of biota. These compounds include the first generation chlorinated insecticides DDT and its degradates (DDD and DDE), chlordanes, PCBs, and PAHs. Many of these compounds are toxic to estuarine biota. Little information is known about historic and recent trends in the inputs of contaminants in the bay.

Approach

Sediment cores were used to reconstruct contaminant chronologies, thus providing a time-line that is useful for assessing sources and inputs of contaminants to San Francisco Bay. Surficial bottom sediments provide information about recent inputs of contaminants to the bay. Pre-anthropogenic levels of contaminants were compared to more recent inputs. Bioaccumulation of contaminants in livers of striped bass provide information about contaminants that pose a potential problem to the health of biota in the bay.

Conclusion

• Bottom sediments and livers of striped bass (Morone saxatilis) are contaminated with significant levels of PAHs and organochlorine compounds derived from industrial and agricultural sources.
• The sedimentary record of PAHs indicates inputs are greater in recent sediments than to sediments deposited before the turn of the century.
• The sedimentary record of DDT and its degradates reflect the recent history of river supply to the bay from agricultural activities in the Central Valley of California.

Organochlorine compounds bioaccumulate in the livers of striped bass and possibly other biota. Compounds such as DDE and PCBs are known to be endocrine disruptors that cause emasculization, abnormal sexual development and impaired reproduction in fish and wildlife. They may contribute to the decline in the population of striped bass in the estuary.