E. MURALI MOHAN, C.A.Y. BANLTPRIYA, K. ANITHA, S. RAMAMOORTHY, K.S. PILLAI AND P. BALAKRISHNAMURTHY
Abstract
A group of Wistar rats was given 1/2 LD 50 of chlorpyrifos 48% EC, cypermethrin 25% EC or combination of 1/4 LD 50 chlorpyrifos + 1/4 LD 50 cypermethrin for two days by oral incubation and the animals were observed for ten days for toxic signs and mortality. In rats given 1/2 LD 50 ehlorpyrifos, one died one day after second day of dosing. No mortality occurred in other groups of animals. In all the groups, animals showed paralysis and tremor which persisted for seven days. Blood samples were analysed for haematology and blood chemistry, thereafter animals were sacrificed and organ weights were determined. None of the haematological parameters analysed on day I I was affected in any of the groups. SGPT decreased significantly in all the treated groups and SGOT decreased significantly 1/2 LD 50 chlorpyrifos treated rats. Since decrease in brain AChE in rats given 1/4 LD 50 chlorpyrifos + 1/4 LD 50 cypermethrin was greater than that of those given 1/2 LD 50 of chlorpyrifos or 1/2 LD 50 of cyperinethrin, it may be stated that toxicity of combination of chlorpyrifos and cypermethrin to AChE which is considered to be target enzyme of organophosphorous poisoning is greater than the toxicity of individual pesticide in the combination.