Research Areas > Contaminants > Sediment Quality Assessment > Indirect Effects

Project Group: Indirect Effects on Humans and Wildlife

SCCWRP Research

Indirect effects act on organisms that do not reside permanently within sediments, but are exposed to sediment contaminants through the food chain. Key receptor organisms are marine birds, fish, and humans. It is important to assess both the indirect and direct effects of sediment contamination at a site because the nature of the effects and the contaminants that cause them may differ. The assessment of indirect effects due to sediment contamination is more complex and requires a different conceptual approach than that used to assess direct effects. The potential for indirect effects on a particular organism is influenced by several factors. These include: the portion of sediment contaminants biologically available to prey species, the complexity of the food web, movements of the receptor organisms, food consumption rate, and species-specific variations in chemical sensitivity. The goal of this research program is to develop measurement tools and an assessment framework to evaluate the indirect effects of sediment contaminants on humans and wildlife. This assessment framework will integrate information on sediment contaminant concentration, bioavailability of sediment contaminants, and prey tissue contaminant concentration.

The initial focus of this research is to develop a human health assessment framework for PCBs and chlorinated pesticides, chemicals that are widespread in California bays and estuaries and are bioconcentrated many fold in species at the top of the food web.

• Framework to Assess Indirect Impacts from Sediment Contaminant Bioaccumulation