Risk assessment of agricultural pesticides in water, sediment, and fish from Owan River, Edo State, Nigeria

Abstract

The distribution of pesticides in water, sediments, Clarias gariepinus, and Tilapia zilli from the Owan River was investigated to evaluate the pollution status and potential hazard in the river system. A total of 16 pesticides were analyzed using gas chromatography (GC) equipped with electron capture detector (ECD). The concentration of pesticide residues ranged from ND to 0.43 μg/l for water samples, 0.82 to 2.14 μg/kg/dw for sediment, 0.04 to 2.34 μg/kg/ww for C. gariepinus, and 0.02 to 1.73 μg/kg/ww for T. zilli. High concentrations of organochlorine pesticides, specifically benzenehexachloride (α-BHC, γ-BHC, and β-BHC) observed in all environmental media, are an indication of the current illegal use of banned pesticides for agricultural activities in the region. Analysis of data showed a strong correlation (r (2) = 0.7) between total organic carbon (TOC) and total pesticide residues in sediment samples. Meanwhile, risk quotient estimates for heptachlor epoxide, dieldrin, endrin, dichlorodiphenyltrichloroethane (4,4'-DDT), endosulfan I, endosulfan II, endosulfan aldehyde, and phosphomethylglycine showed potential risk to aquatic organism under observed mean concentrations (risk quotient (RQ) ≥ 1). Estimated average daily intake (EADI) for organochlorine pesticides (γ-BHC, heptachlor epoxide, aldrin, dieldrin, and endrin) was above their respective acceptable average daily intake (ADI), while hazard quotient for each of these pesticides was above the unity value (1). This indicates that there is a potential cancer risk for the local residents with life time consumption of pesticide-contaminated fish.

Pesticide Accumulation in Turkey’s Meriç River Basinwater and Sediment

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Pesticides in Worldwide Aquatic Systems: Part II

“…Dietary pesticide risks can be estimated through well-established indices and defined and used by US Environmental Protection Agency (EPA) [ When no specific MRL is published, a 0.01 mg/kg value is applied [8]. Additionally, hazard quotients (HQs)-which measure the potential exposure for developing non-carcinogenic health effects-may be calculated using several assumptions [65].…”

Environmental Concerns and Toxicogenetic Endpoints of Priority Substances (PSs) and Contaminants of Emerging Concerns (CECs): A Comprehensive Review

“…The lack of ecological risk inventory for acute and chronic adverse effects of organic pollutants in the aquatic environment demands precautionary measures (Deblonde et al, 2011;Gavrilescu et al, 2015). Ecological risk/hazard assessment is to investigate the changes in aquatic species as result of exposure to environmental stressors, such as organic contaminants (Ogbeide et al, 2015). The tracking of ecological risks of organic pollutants is of critical importance to regulate the PSs and CECs and the adverse effects may accumulate continuously to cause irreversible molecular damages to the aquatic ecosystems (Jjemba, 2006).…”