Health Risk Evaluation of Heavy Metals via Dermal Contact (Swimming) in Qua Iboe River, Nigeria

This research was carried out to assess human health risk through dermal exposures to heavy metals (Cadmium, Chromium, Copper, Nickel, Vanadium, Lead and Zinc) in Qua Iboe River, Nigeria. Water samples were collected from five sampling stations in wet and dry seasons for the analysis of physicochemical parameters and heavy metals. Physicochemical parameters were determined using standard methods. Heavy metals were determined using atomic absorption spectrometer. Levels of the physicochemical parameters in the water samples in both seasons were: temperature ranged from 27.0 – 29.0 oC; pH 6.5 - 7.2; electrical conductivity, 119.13 – 133.33 µS/cm. dissolved oxygen 5.53 – 6.13 mg/L; biochemical oxygen demand, 2.04 – 2.05 mgL. Hazard quotients for the heavy metals analysed were as shown, Cadmium 3.31E-4; Chromium, 4.65E-5; Nickel, 1.98E-6; Copper, 6.35E-6; Vanadium, 1.99E-6; Lead, 9.52E-5 and Tin, 1.35E-4. Generally, the measured values of both physicochemical parameters and heavy metals in study area were all within permissible limits set by World Health Organisation although some levels were close to maximum permissible limits in some locations. Hazard quotients (HQs) of the heavy metals exposure through dermal contact were all less than unity (HQs < 1), which implies that there is no significant human health risk of heavy metals through dermal contact. Elevated levels of some heavy metals at some locations, implies a likelihood of occurrence of actual risk in the future if the trend is not curbed. As a precautionary measure, monitoring of these these metals in the river is strongly advocated for sustainability of the river water for use by the present generation without compromising its use for future generations.