| Resumo: |
It is understood that the rate of bioaccumulation and subsequent depuration of heavy metals in marine animals is influenced by the chemical state, as well as the kinetics of transformation between different species of chemical salts dissolved in water. The Indian Brown mussel, Perna indica, was exposed to copper nitrate and chloride, individually, to analyse the rate of accumulation, depuration, oxygen uptake and filtration rates. When supplied in very low quantities, environmentally realistic concentrations, the rate of accumulation of copper nitrate and chlorides showed variations. When the animals were transferred to sea water, these two salts did not show any clear cut differences in the depuration rate. Irrespective of the previous accumulation history, the quantity of metal thrown out was always more when the body burden was high. This indicates that irrespective of the salt form of metals, the rate of depuration was controlled by the quantity of copper rather than salt forms supplied. Further, animals exposed to copper nitrate consumed lesser quantity of oxygen, compared to those exposed to copper chloride, although the load in the whole tissue was low (during accumulation). However, the rate of filtration decreased as a function of time of exposure to these salts and during depuration, between periods, the rate of filtration by those animals exposed to copper chloride was significant.
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