Distribution of Organochlorine Pesticide Residues in Surface Water and Sediments of Ogun River at Kara Abattoir, Ogun State, Nigeria

In this study, the levels of organochlorine pesticide (OCPs) in Ogun River, at Kara abattoir were investigated to estimate the extent of pesticide pollution in the river. Two sets of water and sediment samples (A and B) were collected. Samples A were collected in April (during heavy downpour) and samples B in June (under dry weather condition). Most of the physico-chemical parameters in the water and sediment samples were within WHO limits, except the samples taken during heavy downpour. In the water samples, the DDT and metabolites (2.023±0.586 µg/L), endrin (0.671±0.256 µg/L) and aldrin and dieldrin (8.290±2.891 µg/L) exceeded 1 µg/L, 0.6 µg/L and 0.03 µg/L respectively in the WHO (2006) guideline, whereas lindane (0.046±0.034 µg/L) and methoxychlor (0.757±0.281 µg/L) were below 2 µg/L and 20 µg/L respectively in the guideline. OCP residual levels in samples A were much higher than in B. This could be attributed to the massive draining and heavy disturbance of the river during the heavy downpour when samples A were collected.