Research Article

Sources and Toxicity of Mercury in the San Francisco Bay Area, Spanning California and Beyond

Table 4

Methylmercury concentrations in representative trophic level III organisms.

Trophic level IIIMethylmercury (MeHg) concentrationCommentsLiterature citation

Secondary consumers: carnivores that consume herbivoresRange: 0.1–0.3 ppmMethylmercury is retained in tissues of organisms. Organisms of trophic level III are consumed by organisms in higher trophic levels IV and V; the toxin continues to accumulate.[49]
Herring0.1 ppm[49]
American lobster0.1 ppm[49]
Catfish0.2 ppm[49]
Black sea bass0.2 ppm[49]
Dragonfly larvae from Golden Gate National Recreation Area, San Francisco0.3 ppm (mean)[52]
California clapper rail (eggs)0.3–0.8 ppmAnemia, disturbed gait, feather abnormalities, neurological changes, and immunological damage.[53]