The physiological changes induced by Endosulfan and the subsequent depuration studies on Rasbora daniconius (Hamilton)

Abstract: Water is an essential element and foundation of life for all living organisms. However, it is increasingly being contaminated by various chemical substances, notably pesticides, which are commonly used in agriculture to safeguard crops from pests. A significant portion of these pesticides is washed away by air and water, adversely impacting non-target organisms, including beneficial invertebrates and vertebrates, as well as humans. In light of this issue, research was conducted to evaluate the effects of Endosulfan, a yellow-labeled insecticide, on the freshwater fish species Rasbora daniconius. Fish were collected from a local water body and acclimatized in a laboratory setting for one week. A stock solution of Endosulfan was prepared, and range-finding bio-assays were performed to establish the appropriate concentration for subsequent acute toxicity tests, which determined the LC50 to be 0.1 mg/l. Chronic toxicity tests were then conducted to assess the impact of the pesticide on the gill tissues and the oxygen consumption rate. The intoxicated fish were later placed in pesticide-free water for one month to evaluate their potential for recovery. The gills of the intoxicated fish exhibited significant degenerative changes compared to the positive control, which ultimately influenced their oxygen consumption rates. Depuration studies indicated that after one month, the intoxicated fish showed signs of recovery, displaying normal physiological functions. The findings suggest that Endosulfan severely disrupts the physiological processes in fish, warranting careful handling or a complete ban on its use in an environment