Hazard Quotient and Bioaccumulation Assessment of 26 Organochlorine Pesticides in Water, Sediment and Fish (Tilapia zilli) Warri River, Niger Delta Region - Southern Nigeria

Abstract

A pesticide is any substance or mixture of substances used to destroy, suppress or alter the life cycle of any pest. Organochlorine pesticides (OCPs) have been known to resist biodegradation, persist in the environment and thus can concentrate through food chains and produce a significant magnification that can pose severe toxic risk to human health. Bioaccumulation and concentration levels of 26 Organochlorine Pesticides were assessed in water, sediment and fish samples from the Warri River, Nigeria. Samples were collected across the two predominant seasons - rainy and the dry season. The results obtained reveal the presence of 22 of the investigated 26 OCPs in the dry season whereas 19 were detected in the rainy season. Results obtained revealed p,p’-DDT, γ-HCH, and aldrin as the most predominant pesticides detected in the water samples with concentrations of 0.588; 0.160 and 0.092 μg/L, respectively. γ-HCH, p’-DDD and aldrin (29.00; 23.00 and 22.00 ng/g, respectively) for the sediment samples. The most predominant contaminants in the fish samples were HCB, o,p’-DDT, γ-HCH (60.00; 29.00 and 27.00 ng/g, respectively). The Hazard Quotient (HQ) analysis was carried out on the fish samples collected revealed factors of 1.34 to 3.17 indicating a moderate hazard while the Bioaccumulation Index (BI) was found to be below 1 indicating their suitability for consumption. However, the risk of toxicity and bioaccumulation arising from long-term consumption of the OCP-contaminated fish may still exist.