Soil geochemistry and health risk assessment: A study of Kabini Basin, southern Western Ghats, India with special reference to heavy metalloids

The present study analyzed the adulteration and health risk evaluation in the agricultural soil of Kabini basin. Along with the physico-chemical properties the geochemistry of ten heavy metalloids [HM(oids)] (V, Cr, Cu, Ni, Zn, Rb, Ga, Y, Ba, Zr, Sr) were studied by wavelength dispersive X-Ray Fluorescence Spectroscopy (WD-XRF) for monsoon and non-monsoon seasons. All the HM(oids) except for Sr and seasonal Zr are found to exceed the standards given by upper continental (UCC). The most diverse seasonal variation in the region is observed for Y (114%) and Rb (99%). The increasing population along the region demands higher resources and resulted in changing HM(oids) distribution along the basin. The evidence from the pollution assessment; geo-accumulation index (Igeo) and contamination factor (Cf) shows the moderate pollution risk due to Cr, V and Cu and overall evaluation as of pollution load index (PLI) shows low to moderate pollution conditions. The changing toxicity of HM(oids) in the soil imparts significant risk to the human health in all age groups. The common pathway; ingestion in the area shows high non-carcinogenic risk for both child and adult (for both seasons) and in dermal pathway Cu and Zr toxicity is observed among the child (both seasons). Additionally, Ni and Cr being the prominent carcinogens detected in the region, that might cause the chance of respiratory or lung related issues in the basin. The overall sources of these HM(oids)and their correlations was performed using PCA and Spearman’s rank correlation coefficient suggest both geogenic and anthropogenic activities in the region. The source of (V, Cr, Ni, Ga, Rb) are geogenic and (Cu, Zn, Y, Zr, Ba, Sr) are anthropogenic in the terrain.