B.T. SULEKHA AND T.V. ANNA MERCY
Abstract
Histological alterations are sensitive biomarkers for xenobiotic effects and it is a tool for thediagnosis of direct and indirect toxic effects that affect the animal tissues. Fish gills aremultifunctional organs involved in ion transport, gas exchange, acidâ base regulation and wasteexcretion. Furthermore, the gills are the main route of toxicants penetration into the fish organism,thus they are the first organ, which comes in contact with environmental pollutants and aresensitive subjects for identifying the effects of water toxicants on the fish tissues. Therefore, it isconsidered as an excellent method for assessing environmental quality. Histopathologicalanalysis of gills of Anabas testudineus exposed to sublethal concentrations of monocrotophos wasstudied. Estimation of the maximum allowable toxicant concentration of monocrotophos (MATC) andits application factor (AF) for the Anabas testudineus, was derived based on no observable effectconcentration (NOEC) and the least observable effect concentration (LOEC). MATC and AFcalculated for the pesticide was 13.4164ppm and 0.1308 respectively. The Application Factor, whichis worked out for one species can be used for other related species also, provided their 48hr LC50is known. From this the MATC for latter species can be conveniently found out. This will be animportant tool for the farmers in deciding the concentrations of pesticides before its applicationinto the paddy fields.