LETHAL EFFECTS OF PESTICIDES ON THE NAUPLII FAIRY SHRIMP, BRANCHINELLA THAILANDENSIS.

During agricultural activities, large amounts of insecticides and herbicides are used for controlling pests. The overspraying of pesticides may contaminate freshwater bodies, as well as having a significant effect on aquatic animals. To determine the potential risk of pesticides, the acute toxicity of insecticides and herbicides on the nauplii fairy shrimp, Branchinella thailandensis were evaluated. The organisms were exposed to different concentrations of insecticides (chlorpyrifos and carbaryl), and herbicides (paraquat and 2,4-D) for 24 h, after which the LC50 values were compared. The acute toxicity tests determined that the LC50 values of chlorpyrifos and carbaryl after 24 h were 0.00186 mg/L and 0.21 mg/L, respectively. For herbicides, paraquat and 2,4-D, the LC50 values were 0.11 mg/L and 27.91 mg/L. Therefore, chlorpyrifos insecticides were found to be more toxic than herbicides (2,4-D and paraquat) with regard to the nauplii fairy shrimp. The high toxicity of pesticides has a long-term, and potentially damaging effect on aquatic organisms in the application areas.