Accumulation, regulation and toxicity of copper, zinc, lead and mercury in Hyalella azteca

Abstract

Zinc, lead and mercury accumulation in the amphipod Hyalella azteca increases with increasing exposure to metals. During 10 week chronic toxicity tests, metal accumulated at the highest non-toxic/lowest toxic concentration was 126/136 µg Zn g−1, 7.1/16 µg Pb g−1 and 56/90 µg Hg g−1 dry weight. Concentrations of lead and mercyry in control animals were substantially lower (1.3 µg Pb g−1 and 0.4 µg Hg g−1), but concentrations of zinc in controls (74 µg g−1) were about one half those of the lowest toxic concentration. Copper was completely regulated. Accumulated copper concentrations after 10 weeks exposure to all waterborne copper concentrations resulting in less than 100% mortality were not significantly different from controls (79 µg g−1). Lead and mercury concentrations in wild H. azteca should be useful indicators of potential toxicity. Zinc accumulation may also be a useful indicator of zinc toxicity, but careful comparison with control or reference animals is necessary because of the small differences between toxic and control concentrations. Copper is not accumulated by H. azteca under chronic exposure conditions and body burdens of field animals cannot be used as an indicator of exposure or potential toxic effects. Short term exposures to copper, however, result in elevated copper concentrations in H. azteca, even at concentrations below those causing chronic toxicity. Short term bioaccumulation studies might, therefore, provide a useful indication of potential chronic copper toxicity.