Pesticide induced changes in the proximate composition of a freshwater fish for estimating maximum allowable toxicant concentration of the pesticide under tropical conditions

Abstract

The proximate composition is used to assess the nature and extent of pesticide induced pathogenesis in Etroplus maculatus, which is a true denizen in the paddy fields of Kuttanand. E. maculatus was subjected to long term exposure to sublethal concentrations of monocrotophos, which is a widely used organophosphate pesticide in the paddy fields of Kuttanad. The results showed that, the Maximum Allowable Toxicant Concentration (MATC) end points of carbohydrate and ash gave sensitive end points whereas that of protein and fat was less sensitive. For monitoring early changes, biochemical biomarkers can be used as sensitive end points. The application factors (AF), derived from the laboratory studies can be directly assigned to the field conditions of Kuttanad, as the experimental fishes are the true denizens of Kuttanad water bodies. If we know the application factor of one pesticide, the MATC for other related pesticides could be easily calculated provided its 48 h LC50 is known. This knowledge of fundamental toxicological and pathological processes is not only important for the regulations of chemicals that are potential aquatic pollutants, but also for the researchers who are involved in similar field studies.