The Effects of Acute Aldrin Exposure on the Liver and Kidney of the African Sharptooth Catfish, Clarias gariepinus (Burchell, 1822)

Despite being banned since 1992, the organochlorine pesticide aldrin was recently detected in the Albasini Dam in Limpopo Province, South Africa. Aldrin is listed in the initial twelve persistent organic pollutants (POPs) and is rapidly broken down into dieldrin. Therefore, the presence of aldrin in the Albasini Dam indicates recent exposure and poses an environmental concern. Since 2006, a decline in fish numbers and adverse health effects have been reported in fish from the dam. This study aimed to investigate the potential effects of aldrin on the health of male African sharptooth catfish (Clarias gariepinus) through acute exposure to an environmentally relevant concentration of aldrin (0.14 µg/L) and an increased concentration (1.40 µg/L) under controlled laboratory conditions (28.7 °C; pH 8). The liver and kidney showed histological changes in both organs without significant differences between the groups for the 0.14 µ/L aldrin concentration. However, a significant difference was found in the kidney histological indices between the control fish and fish exposed to the high aldrin concentration (p = 0.014). A significant difference in kidney indices was observed between the two aldrin concentrations (p = 0.001). It was evident that histological changes in the kidney were prevalent and severe in fish exposed to 1.40 µg/L aldrin. This means that the observed levels of aldrin in Albasini Dam water (0.14 µg/L) may not pose a direct danger to the fish liver and kidney; however, as aldrin was banned for use, its presence in the dam is concerning, as at 1.40 µg/L, it may impair fish health.