monocrotophos and Fish-Diseases

This study was conducted based on the evidence of fish habitats in North India being affected by organophosphate pesticides draining from agricultural fields into bodies of water, especially during the rainy season. Various tissues of fish such as scales, gills ovaries, kidney, and liver have been studied from the toxicological point of view, but the toxicological effects of aquatic pollutants on fish cornea have not been investigated to date. We conducted comparative toxicological studies on the cornea of Cyprinus carpio communis using two sublethal (0.038 and 0.126 ppm) concentrations of monocrotophos pesticide for 30 days. Corneas from all the groups were evaluated by a scanning electron microscope. The fish exposed to the monocrotophos pesticide developed corneal necrosis due to the formation of crystalloid-like structures, thinning and shrinkage of microridges on the corneal epithelium. After 30 days, fish from the monocrotophos-treated tank were transferred to normal environmental conditions. After 60 days under natural condition, epithelial cells did not fully recover. In conclusion, exposure to monocrotophos induces irreversible changes in the cornea of C. carpio communis. As fish and mammalian visual systems share many similarities, the reported finding may offer useful insights for further toxicological and ophthalmological studies in humans.

Topics: Animals; Carps; Epithelium, Corneal; Fish Diseases; Insecticides; Keratitis; Monocrotophos

Cytogenotoxic effects in the form of micronuclei and deformed nucleus, nuclear buds, binucleated cells, vacuolated nucleus, vacuolated cytoplasm, echinocytes, and enucleus induced by two compounds belonging to two different chemical classes of agrochemicals (monocrotophos and butachlor) at sublethal concentrations (0.625, 1.3, and 2.3 ppm and 0.016, 0.032, and 0.064 ppm) in single and combined chronic exposures were studied under laboratory conditions for a period of 35 days in the economically important Indian fish Catla catla. Statistically significant duration-dependent increases in the frequencies of micronucleus (MN) and other cytological anomalies were observed. Compared to single exposures, a twofold increase in micronuclei frequency was noted at combined exposures indicating the synergistic phenomenon. Binucleated and enucleated cells appeared only in fishes exposed to sublethal concentrations of butachlor. The present study is the first of its kind in exploring a significant positive correlation between micronuclei and other nuclear anomalies suggesting them as new possible biomarkers of genotoxicity after agrochemical exposures. The study highlights the sensitivity of the assay in exploring various predictive biomarkers of genotoxic and cytotoxic events and also elicits the synergistic effects of agrochemicals in apparently healthy fishes. C. catla can be considered as a suitable aquatic biomonitoring sentinel species of contaminated water bodies.

Topics: Acetanilides; Animals; Biomarkers; Cyprinidae; DNA Damage; Environmental Exposure; Fish Diseases; Monocrotophos; Water Pollutants, Chemical

Topics: Animals; Anura; Chlorpyrifos; Chromatography, Gas; Fish Diseases; Fishes; Insecticides; Methyl Parathion; Monocrotophos; Oryza; Pesticide Residues; Poisoning; Water Pollutants, Chemical