Mitigating water contamination by controlling anthropogenic activities of organochlorine pesticides (OCPs) for surface water quality assurance

Organochlorine pesticides (OCPs) have wide applications in agriculture, industry, and domestic uses. Unfortunately, they are resistant to photolytic biodegradation and exist for a very long time in the environment. Their bioaccumulation in humans and aquatic biota could lead to severe problems. In this study, surface water samples were collected from four sampling points along the Okura River in the Eastern Senatorial District of Kogi State, Nigeria. They were extracted with methylene chloride, reduced to small volume using a rotatory evaporator, subjected to clean-up, and analyzed with gas chromatography mass spectrometry (GC-MS). The results show that the level of OCPs in SP1, SP2, SP3 and SP4 are between ND - 0.1357 ± 6.3 × 10−5 mg/L, ND - 0.0767 ± 1.3 × 10−3, ND - 0.046 ± 7.5 × 10−4, and ND - 0.0211 ± 2.6 × 10−3 respectively. The health risk assessment was evaluated using United States Environmental Protection Agency (USEPA) methods for hazard quotient (HQ), average daily dose (ADD) and cancer risk (CR). The HQ, ADD and CR are less than the USEPA recommended risk permissible limit of 1, 10−4 and 10−6 respectively. Therefore, there is no health risk. However, the concentrations of the analytes detected were slightly above USEPA standard maximum limit of 100 ng/L. Therefore, all anthropogenic activities that could lead to the disposal of agrochemical wastes into Okura River should be controlled, for the provision of quality water for the inhabitants of this river.