Organochlorine Pesticides Contamination of Some Rivers in Abia State- Nigeria

Abstract

The use of pesticides by most Nigerian farmers to control pests and increase crop yield has been severally reported by many agricultural scientists in Nigeria. Hence this study is aimed at evaluating the level of pesticide contamination of some selected river waters in Abia State, Nigeria. The contamination of organochlorine pesticides (OCPs) from nine selected rivers in Abia State Nigeria was investigated to estimate the current level of pollution in these rivers. The Iyi Achi river in Ndielu-Ugwueke, Iyi Oba river in Okanu Ohafia and Iyi Ivere Atani in Arochukwu were selected from the North Senatorial zone. While Iyi Ocha river in Umukabia-Umuahia, Iyi Okwuta river in Okwuta Ibeku- Umuahia and Iyi Ogba Lelu river in Old Umuahia were selected from the Central Senatorial zone. For the South Senatorial zone, Ojii river in Ihie Ngwa, Azumini blue river in Azumini Ndoki and the Asa river in Ohambele- Ndoki were selected for this study. The total pesticides concentration was in the range of 0.039 – 0.192 mg/L in the rivers water. The common OCPs detected in these river water were α-BHC, β – BHC, Dieldrin and endrin. Iyi-Ocha river had the highest concentration of total OCPs (0.192 mg/L), followed by Azumini river 0.126 mg/L, Ojii river 0.120 mg/L, Iyi Okwuta 0.113 mg/L, Iyi Ogba Lelu 0.104 mg/L. While Iyi Ivere Atani in Arochukwu and Iyi Oba river had 0.067 mg//L and 0.039 mg/L respectively. α - BHC, β – BHC, Dieldrin and endrin were the most common OCPs detected. Various concentration patterns between the selected river waters were observed. Iyi Ocha river, Iyi Okwuta river and Ogba Lelu river were contaminated with α-BHC, β – BHC, and endrin. Ojii river and Azumini river were contaminated with α-BHC and β – BHC only, while Iyi Achi, Iyi Oba, Iyi Ivere Atani in Arochukwu and Iyi Asa river is contaminated with α-BHC, β – BHC, Dieldrin and endrin. The OCPs levels in all the rivers sampled were generally below the WHO standard levels.