Examining the biochemical effect of malathion pesticide on gammarus pulex (l., 1798)

This study determined the effect of a pesticide with malathion as active substance on Gammams pulex in terms of oxidative stress and antioxidant status. Firstly, 96-hours LC50 value of malathion on G. pulex was determined. Then, the organisms were exposed to determined sublethal concentrations (at the rate of 1/40, 1/20 and 1/10 LC50 value) of malathion for 24 and 96 hours. Thiobarbituric Acid Rcactive Substances (TBARS), rcduccd glutathione (GSH) levels, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) enzyme activities in the control group and samples that were exposed to malathion for 24 and 96 hours were determined. The results showed that TBARS level significantly increased in G. pulex that was exposed to malathion for 24 and 96 hours compared to the control group (p <0.05). However, GSH level, SOD, CAT and GPx activities dccrcascd (p <0.05). Malathion exposure caused oxidative stress in G. pulex. These results revealed that MDA, GSH levels, SOD, CAT and CiPx activities can be used as effective biomarkcrs in G. pulex.