Seawater samples collected in the vicinity of MAPS (Madras Atomic Power Station) from 17 stations covering an area of 4 km(2) were analysed for distribution of heavy metals viz, iron, copper, cadmium and mercury. Mercury was analysed by cold vapor Atomic Absorption Spectrometry (AAS) and the other heavy metals by Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES). Water samples were found to have heavy metals such as Fe (26-85 µg l^-1), Cu (0.05-5.1 µgl^-1; Cd (0.5-1.7 µg l^-1) and Hg (0.03-1.5 µg l^-1)). Samples from the power plant cooling system and condenser outfall were specifically analysed for copper and primary production. Copper concentrations were in the range 1 2.2 µg l^-1. Primary productivity was low on passing through the power plant cooling circuit. However, it was found to recover once the effluent mixed with the ambient sea. Present study infers that heavy metal concentrations in the vicinity of the power station outfall are comparable to unpolluted pelagic waters of the Bay.