Aquatic biota mercury

The most obvious impact of sediment-associated pollutants on aquatic biota is direct acute toxicity and there is considerable literature on both laboratory and field effects of toxic substances on marine and freshwater invertebrates (Baker, 1980 Reynoldson, 1987). For example, Warwick (1980) and Wiederholm (1984) observed deformities in chironomid larvae mouthparts at polluted sites of lakes in Canada and Sweden Milbrink (1983) has shown setal deformities in oligochaetes exposed to high sediment mercury levels. Indirect effects resulting from sediment contamination oftenly include changes in benthic invertebrate community structure. For example, Lock et al. (1981) evidenced increased growth of bacterial flora and algal cells on oiled substrates and a consequent stimulation of macroinvertebrates. Chapman et al. (1982) have shown effects of life history alterations (e.g., impairment of reproduction and age selective toxicity) which have been linked to sediment contaminants. ... 

Mercury in the water column, in the sediment, and in other aquatic biota appears to be available to aquatic organisms for uptake. Methylation is the key step in this entrance of mercury into the food chain (Sorenson et al. 1990). 

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