Probabilistic risk assessment and spatial distribution of potentially toxic elements in groundwater sources in Southwestern Nigeria
No Thumbnail Available
Date
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Description
The study investigated the concentration of potentially toxic heavy metals
(PTHM) in groundwater sources (hand-dug wells and boreholes), spatial
distribution, source apportionment, and health risk impact on local inhabitants
in Ogun state. One hundred and eight water samples from 36 locations were
analysed for Cr, Ni, Pb, Fe, Mn, Mg, Ca and Al. Mean values of 0.013, 0.003,
0.010, 0.088, 0.004 and 3.906 mg/L were obtained for Pb, Cr, Ni, Fe, Mn, and Al
respectively at Iju district. Meanwhile, the average values of Pb, Ni, Fe, Mn, and
Al concentrations at Atan district were 0.008, 0.0023, 0.011, 0.003, and
1.319 mg/L respectively. Results also revealed that the 44.4% and 11.13% of
the borehole and well-water samples surpassed the World Health
Organization limits for Pb at Atan. In Iju, the concentration of Pb and Al were
relatively high, exceeding the stipulated standard in 100% of the samples. The
Multivariate statistical analysis employed produced principal factors that
accounted for 78.674% and 86.753% of the variance at Atan and Iju region
respectively. Based on this, PTHM were traced to geogenic sources
(weathering, dissolution, leaching) and anthropogenic emissions from
industrial activities. In addition, the hazard quotient values obtained from the
health risk assessment identified potential non-carcinogenic risk due to Pb via
ingestion route. Ni was found to have high carcinogenic risk on adult and
children, having exceeded the threshold limit. The outcome of the
carcinogenic risk assessment revealed that 88.67% (for adults) and 1.12% (for
children) of the cancer risk values surpassed the specified limits at Iju, whereas
the cancer risk values were considerably lesser at Atan. In conclusion, the
report of this study should serve as a beacon that will spark up strategic
planning, comprehensive water resource management, and extensive
treatment schemes in order to address the health complications linked with
environmental pollution.
Keywords
T Technology (General), TJ Mechanical engineering and machinery