Outcome of the first survey of atrazine in drinking water from Ijebu-North, South-West, Nigeria: Human health risk and neurotoxicological implications

No recognised study has been conducted to monitor atrazine residue in drinking water from rural agricultural areas in Nigeria and its potential health implications. In this ecotoxicological study, we monitored atrazine residue in 69 hand-dug wells (HDW), 40 boreholes (BH) and 4 major streams from all the 6 communities (Ago-Iwoye, Ijebu-Igbo, Oru, Awa, Ilaporu and Mamu) in Ijebu North Local Government Area, Southwest Nigeria. Values of atrazine obtained were further used to evaluate the non-carcinogenic risk associated with ingestion and dermal contact in adults and children as well as neurotoxicity assessment. A total of 41 HDW, 22 BH and the 4 streams were tested positive for atrazine, which was higher in HDW than BH and stream. Ago-Iwoye recorded the highest concentration of 0.08 mg/L in its HDW while the lowest concentration of 0.01 mg/L was recorded in HDW from Oru. Hazard Index values associated with ingestion and dermal for children and adults were below the acceptable limit. Atrazine at 0.01, 0.03 and 0.04 mg/L concentrations appears to trigger defence mechanisms capable of protecting the structural integrity of the brain, but significant (p < 0.05) alterations in the oxidative stress parameters, acetylcholinesterase activity, membrane-bound ATPase enzymes, neurotransmitters as well as mild degenerative changes were observed in the brain of rats exposed to atrazine at 0.08 mg/L. Atrazine at 0.01, 0.03 and 0.04 mg/L concentrations found in drinking water from Ijebu-North may not pose any threat to brain function, but concern should be raised at 0.08 mg/L.