RAW SEWAGE INDUCED BIOCHEMICAL CHANGES IN THE LIVER OF EDIBLE FISH, CHANNASTRIATA

Abstract

Untreated sewage (raw sewage) contains high levels of biochemical oxygen demand (BOD), suspended solids (SS), nitrogenous compounds, nutritive salts, bacteria and other pollutants. High BOD causes decrease in DO while DO lowers the lethal concentrations for various toxicants. Raw sewage is indiscriminately discharged into the various freshwater sources near metropolitan cities. Indiscriminate discharge of untreated sewage is a serious concern for freshwater fish culture in and around major cities. Very little information is available on the effects of raw sewage on the biochemical composition of freshwater food fishes, though a lot of studies have been conducted to assess the sublethal effects of environmental stresses on fish. Raw sewage (10%) exposure for 30 days inhibited the liver protein (-18.06%.; P<0.05) and lipid content (-51.65%.06; P<0.05) significantly in the edible fish, Channastriata. However, the cholesterol content (+51.21%.06; P<0.05) increased considerably. Changes in the pharmacological properties of the nervous system and damage to gills were also recorded for prolonged exposure. These results suggest that fish exposed to sewage are subject to severe biochemical perturbations and damage to vital organs.