Pilot Studies

Exposure and Effects Pilot Study

The Exposure and Effects Pilot Study was initiated in 2002 to understand the biological effects of the chemical contamination observed in the Estuary. This pilot study enters its last year of earmarked funding. Biological effects of contaminants have increasing become more important to regulators and regulated community (e.g. mercury TMDL which establishes thresholds for birds and fish). As a result, the RMP has expanded its monitoring program to include impacts to biota.

In 2007, the EEPS workgroup is developing a five-year plan for monitoring biota. Integral to this plan is work on avian exposure and effects and fish exposure and effects. In keeping with this five-year plan, the EEPS committee has approved the following three studies for 2008:

Avian Exposure and Effects

Author: Josh Ackerman and Collin Eagles-Smith (USGS)

Mercury (Hg) and selenium (Se) are known to impair reproduction in wildlife and these contaminants can accumulate to high concentrations in waterbirds breeding in San Francisco Bay. Although Hg and Se have different mechanistic modes of action, the primary risk of each contaminant to wildlife populations is impaired reproduction. Moreover, both contaminants are toxicologically linked such that they may interact with one another in an antagonistic or synergistic fashion. Because of their toxicological relationships, individual assessments of reproductive impairment related to either contaminant may be confounded by the relationship with the other. This study will examine the interaction of Hg and Se on the reproductive success (i.e., hatchability, abandonment, and chick survival).

Impacts of PAH-contaminated Sediment of Early Life History Stages of Benthic Fish

Author: John Incardona (NOAA)

EEPS will fund a study evaluating the effects of PAH-contaminated sediments on the development of juvenile flatfish. The impacts of pyrogenic PAHs (like those detected in San Francisco Bay) on juvenile flatfish development are largely unknown. This is a two year study which in the first year will examine the effects of pyrogenic (higher molecular weight) PAHs on a model fish such as zebra fish. After the identification of biological endpoints with a model fish, in the second year, the study will examine a native species such as the California flat fish. In addition, environmental sediment samples with a PAH signature similar to San Francisco Bay will be used.

Spatial Patterns in Uptake of Methylmercury into the Food Web

Author: Ben Greenfield (SFEI)

Small fish are a good indicator of spatial and temporal variability in contaminants in the Bay food web. This study will examine methylmercury concentrations in pelagic and benthic fish less than one-year in age. Small fish tend to have small ranges in habitat and are dominant food-source for piscivorous fish. The purpose of this study is three-fold: to provide information of the accumulation of methyl mercury into the food web; to determine the impacts of management actions on biota (e.g., restoration of wetlands in the South bay), and to provide data for food web modeling of exposure to wildlife. This study is a four-year study that began in 2005. The primary focus of this study has been mercury; however, in 2007, small fish were collected for analysis of trace organic concentrations (i.e., PCB, pesticide, and PBDEs).

...