The physical, chemical and biological variables and pollution of river Cooum with sewage and heavy metal were studied in 4 stations within Madras city for a period of one year from August 1982 to July 1983. The physical, chemical and biological parameters presented complex pattern of variations indicating that the biotic life of Cooum river is severely affected by the excessive discharge of sewage effluents within the city limits which excessively eutrophicate the river water. The number of species and density of zooplankton are very low. Heavy metals such as iron, nickel, lead and zinc are recorded to be above permissible levels.

Effect of phenol at different salinities on the phosphomonoesterases and adenosine triphosphatase activity in the liver, muscle and brain of cichlid fish Sarotherodo« mossambicus (Peters) is studied. Results indicate a general decrease in the activity of aU the three enzymes assayed. The pattern of decrease shows a direct linear relationship with salinity and the toxicity is enhanced as salinity increases. The possible causes for the reduction in the activity of the enzymes are discussed.