I am an ecologist and ecotoxicologist with interests in the impact of human activities, particularly the release of toxic substances, on organisms at the individual, population, and community levels. I am most interested in applying basic ecological insights (e.g., feeding strategy, natural history) to toxicology in order to provide greater environmental realism to questions of pollutant exposure and bioaccumulation. Most of my research falls within the general area of pollutant bioavailability and bioaccumulation and the extension of these principles to assessment of ecological risk posed by contaminated aquatic sediments. Most of the current research in my laboratory is focused in either of two areas. First, we are developing a procedure to better quantify the bioavailable contaminant in sediment by extraction of the sediment using the digestive fluid of deposit-feeding invertebrates. Solubilization by this fluid, rather than an exotic chemical as would be used in a conventional extraction, has greater ecological relevance and provides a better basis for environmental management decisions. With funding from EPA, U.S. Navy, U.S. Army Corps of Engineers, U.S. Geological Survey and others, we are refining this technique for management of contaminated sediments. Secondly, we are examining the effects of agricultural pesticide use in the San Francisco Bay watershed on aquatic organisms, and particularly those species which are important prey for chinook salmon. Of particular interest is the bioavailability of particle-associated pesticides and the interactions of exposure duration, frequency and magnitude in determining toxic effect. Other recently completed projects in my laboratory include the rate and manner in which DDT residues move out of a contaminated food web after dredging and removal of DDT-contaminated sediments; and the environmental effects of antibiotics from aquaculture operations on natural microbial communities.
In the News
Pyrethroid pesticides were supposed to be a benign replacement for organophosphate use around the home, but UC Berkeley studies show that these insecticdes are showing up at toxic levels in storm runoff and even in the effluent from sewage treatment plants. While the levels are not high enough to harm fish, they may be enough to kill the mayfly, caddisfly and stonefly larvae upon which the fish feed.