Human Health Risk Assessment of Organochlorine Pesticides in Commercial Fish from Qua Iboe River, Nigeria

Organochlorine pesticides (OCPs) is a class of persistent organic pollutants in an environment that attracts global concern due to their persistency in the environment, chemical stability, long range of transport and tendency to bioaccumulate in plants, animals and humans. Their bioaccumulation in food chain has severe carcinogenic effects on humans. In this research, OCPs were determined in water and fish samples from Qua Iboe River, Oruk Anam, Nigeria to assess human health risk via fish consumption. The quantification of the detectable OCPs was done using a Hewlett Packard 6890 series Gas Chromatography (GC) – Electron Capture Detector (ECD). The GC column employed was a 30m HP-5 capillary column coated with 0.25µm film thickness of 100% dimethyl polysiloxane. Separately, OCPs such as DDT and their metabolites, examples, DDTs: p,p’-DDD, and p,p’DDE including dieldrin, aldrin, endrin, endrin aldehydes, endrin ketone, methoxychlor, endosulfan-sulphate, endosulfan I, endosulfan II, alpha-chlordane, gamma-chlordane, beta-benzene hexachloride (BHC) and delta-BHC were measured. The detected OCPs concentrations in water samples were calculated from the peak area. Risk assessment of human exposure via consumption of the tested fish was done using hazard quotient (HQ). The generated OCPs data were subjected to statistical analysis using statistical package for social science for sperman correlation test. The results revealed that levels of Alpha-BHC recorded in water samples across all sampling locations in both seasons ranged between 0.01±0.01 and 0.73±0.03; Heptachlor ranged between 0.24±0.32 and 0.99±0.07; p,p’DDT between 0.05±0.01 and 0.34±0.47. The data of the fish samples indicated that DDT and its metabolites (DDE and DDD) were the major OCPs measured. Concentrations of p,p’DDT recorded ranged between 0.81±0.07 and 1.60±1.07; p,p’-DDD (0.40 – 0.51); p,p’-DDE (0.78 – 0.99); aldrin ranged between 0.21±0.01 and 1.04±0.01, endrin ranged from 0.60±0.07 and 0.87 ±0.07 across all the sampling locations in both seasons. Results in Tables 1 - 4 revealed that OCPs not reported were not detected. Human exposure to OCPs in fish via consumption indicated that the levels OCPs detected in water and fish samples were within permissible limits except p,p’DDE whose levels (0.78 – 0.99) were approaching unity in some fish samples from some locations. It is worthy of note that Hazard quotient (HQ) < 1 indicates low risk while HQ > 1 indicates high risk of exposure. Statistically, levels of OCPs detected in the commercial fish in both seasons were less than unity, implying that the commercial fish from the studied river are suitability for human consumption. Thus for sustainability of the commercial fish for human consumption by present and future generations, strict compliance to good agricultural practices in the area and routine monitoring of these recalcitrant pollutants in studied river through researches are strongly recommended.