DISTRIBUTION AND RISK ASSESSMENTS OF HEXACHLOROCYCLOHEXANES (HCHS) AND ENDOSULFANS IN WATER, SEDIMENTS AND FISH FROM HAWUL RIVER BASIN, NORTH-EAST NIGERIA

ABSTRACT

Hexachlorocyclohexanes (HCHs) and endolsulfans organochlorines were investigated to assess the levels of contamination in water, sediment and fish from River Hawul basin. Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method was employed for the extraction and clean-up of the residues while GC-MS was used for identification and quantification of the pesticides residues. The concentration of HCHs in water from all the sampling locations are greater than the recommended maximum residues limit (MRL) value of 0.01 mg/L. This study reports 𝛼/𝛾 ratio of 1 and below for all sampling sites indicating recent usage in the areas despite it ban. Endosulfan I and II are detected in all the samples from all sampling locations but their metabolite which is endosulfan sulphate was absent. Hazard Quotients (HQ) for the organochlorine pesticides (OCPs) in water are by far > 1, indicating high probabilities of non-carcinogenic health hazards occurring in children due to consumption of the water from the sampling locations in the study area. The Hazard Index (HI) which is the cumulative effect of the individual OCPs is in the sequence Kopri > Garkida (WB) > Garkida > Daba > kiri > Ndabna. β- HCH had the highest contribution to cancer risk in water with a range of 1.27 x 10^-1 – 5.28 x 10^-3. The incremental life time cancer risk ranges between 1.85 x 10^-1 - 4.09 x 10^-2. The incremental lifetime cancer risk for fish consumption ranges between 8.33 x 10^-4 - 3.32 x 10^-3 and 5.00 x 10^-3 - 1.99 x 10^-2 for an Adult and a child of 10Kg weight respectively.

Keyword: Hexachlorocyclohexanes (HCHs); Endolsulfans; Organochlorines; QuEChERS