Trace element geochemical imprints and multi-path health risk assessment of potentially toxic elements in soils from the polymetallic area of tashan-jatau, northwestern nigeria

Abstract

The occurrence of Potentially toxic elements (PTEs) in the soil phase may portend environmental, ecological and health-related risks. Hence, this study has combined high-precision geochemical analyses (X-ray fluorescence (XRF) and inductively Coupled Plasma Mass Spectrometry (ICP-MS)), quantitative soil pollution indices and health risk assessment modelling for a holistic and precise assessment of the intrinsic vulnerability of the soil system to contamination. Geochemical analysis showed that the soils are highly enriched with PTEs such as V (mean = 449.5 mg/L), Cr (mean = 529.9 mg/L), Cu (mean = 374.4 mg/L), Sr (mean = 1365.3 mg/L), Zr (mean = 2703 mg/L), Zn (mean = 282.5 mg/L), and Pb (mean = 127.3 mg/L). Quantitative soil pollution assessment (contamination factor and enrichment factor) revealed that besides mining, the distribution and association between trace elements and oxides were from surface environmental conditions (including mobility potential, leaching metal-complexation, weathering and oxidation of parent material). Health risk assessment based on hazard quotient and hazard index revealed that the inhabitants are generally more exposed to risks from toxic elements ingestion than dermal contact and inhalation; the children are vulnerable to risks than adults. The cancer risks from ingestion and dermal contact of As and Cr for both children and adults are relatively higher (> 1.0E−04) than the acceptable range; although the children population seems to be more susceptible to cancer risks due to lower body weight.