Investigation of acut toxic effects of thiacloprid and trifloxystrobin on xenopus laevis tadpoles

The chemical methods are the most widely used one for pest control around the world. Agricultural ingredients are synthetic chemicals called pesticides on the basis of the struggle. This study aimed to evaluate toxicity of neonikotinoid insecticide thiacloprid, strobilurin fungicide trifloxystrobin and their mixtures on early developmental stages of Xenopus laevis by using various biochemical markers. In the result of 96-hour test, median lethal concentration (LC50) values of thiacloprid and trifloxystrobin were determined as 3.41 mg AI/L and 0.09 mg AI/L, respectively. The application concentrations of selected pesticides were determined according to the 96-hour LC50. Tadpoles in stage 50 to 58. were exposed to LC50, LC50/2, LC50/10, LC50/20, LC50/50 and LC50/100 concentrations of thiacloprid and trifloxystrobin separately and also double mixtures (1:1) of these concentration in 96-hour static renewal test system. In addition to the 96-hour tests, tadpoles were also exposed to pesticide mixtures for 24-hours using LC50, LC50/2, LC50/10, LC50/20, LC50/50 and LC50/100 values. Furthermore, effects of pesticides were determined by using glutathione S-transferase (GST), glutathione reductase (GR), acethylcholinesterase (AChE), carboxylesterase (CaE), glutathione peroxidase (GPx), catalase (CAT), alanine amino transferase (ALT), aspartate amino transferase (AST), lactate dehydrogenase (LDH), Na+/K+-ATPase, Ca+2-ATPase, Mg+2-ATPase ve total ATPase as biomarkers in amphibian tadpoles. In the results of 96-hour pesticide or pesticide mixture applications, mixtures of Thiacloprid and Trifloxystrobin in LC50 value caused to the death of all tadpoles. The individual values of both pesticides and the lowest concentrations of pesticide mixtures significantly affected (inhibited/activated) selected enzyme markers. The enzyme activities were also affected in tadpoles exposed to mixtures of pesticides using the application values of LC50, LC50/2, LC50/10, LC50/20, LC50/50 and LC50/100 of 96-hour exposure time for 24-hour exposure. The results indicated that selected pesticide and pesticide mixtures have toxic potential on X. laevis tadpoles in stage 50 to 58. Furthermore, when applied as mixtures, the pesticides showed a toxic effect on tadpoles at concentrations much lower than their LC50/2 or LC50 values. Also, our results showed that X. laevis tadpoles at stage 50 to 58 can be used as a suitable test organism and the selected biochemical markers may also serve well for studies with the aim of determining pesticide pollution in aquatic ecosystems.