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

Table 6

Methylmercury concentrations in representative trophic level V organisms.

Trophic level V	Methylmercury (CH3Hg) concentration	Comments	Literature citation
Apex predators: highest level consumers in food chains	Range: 1.0–6.1 ppm	Organisms in this level contain the highest levels of methylmercury, as MeHg has biomagnified up through the food web. Concentrations are species specific.	[49, 53, 58]
Largemouth bass	6.6 ppm		[53]
Selected shark species	1.0–4.0 ppm		[49]
Three-spined stickleback	Seasonal range: 0.6–1 ppm (dry weight)	Sticklebacks collected from the Alviso Slough, South San Francisco Bay.	[59]