Absorption, assimilation and uptake of metals by zooplankton provides entry for heavy metals into the cycling process and to be passed on and concentrated at higher trophic levels through food- chain. The present report focusses attention on the levels of heavy metals (Cu, Zn, Ni, Co, Cd and Hg) in the costal waters of Coromandel coast. Annual mean concentration of heavy metals in  zooplankton varied spatially, as the concentrations of Cu and Hg and Zn, Ni, Co and Cd were high at stations 1 and 2 respectively. Concentrations of these metals were high during the postmonsoon season at station 1. At station 2, Zn, Co and Hg concentrations were high during the postmonsoon season whereas, Cu, Ni and Cd concentrations were high during the summer seasons. High concentrations of these metals in zooplankton coincided with their higher concentrations in the phytoplankton, facilitating metals to the direct absorption from water and also by assimilation through food substances by zooplankton. This is substantiated by higher concentration factors (CFs) exhibited by zooplankton and the order of metals abundance in these phytoplankton (food) and seawater.

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