Size-dependence of mercury (II) accumulation kinetics in the mosquitofish, Gambusia affinis (Baird and Girard).

Size-dependence of mercury (II) accumulation from water by the mosquitofish, Gambusia affinis was assessed under controlled laboratory conditions. Uptake rates were higher for smaller fish than for larger fish. Mean (+/- S.D.) uptake rate for mosquitofish exposed to 0.24 micrograms/L of Hg was 0.32 +/- 0.15 micrograms/g dry wt/day. Uptake rate constants were similar for the Hg (II) and elemental Hg as reported elsewhere. Both inorganic species (Hg(II) and elemental Hg) were accumulated faster than methylmercury. Elimination rate constants averaged 0.53 +/- 0.14 per day (mean +/- 1 S.D.). No significant size effects on elimination rate constants were detected. Elimination constants were similar to those reported elsewhere for elemental Hg elimination but larger than those for methylmercury elimination.