Pollution of Estuarine Systems: Heavy Metal Contamination in the Sediments of Estuarine Systems around Madras

Comparative studies carried out on bottom sediment and water of Adyar, Ennore and lake Pulicat during 1984–85 revealed the presence of mercury, zinc, lead, copper, chromium, nickel and cadmium in the first two estuaries while lake Pulic at remained reasonably free from heavy metal pollution. In Ennore estuary, the concentration of metals in sediments were higher at the upper reaches (head of the estuary) and decreased towards the estuarine mouth while in Adyar estuary, higher concentrations were noted in the middle of the estuary. The observed results were compared with the concentrations for the unpolluted sediments. The concentrations of metals in all the sediments showed considerable seasonal variation.