Index analysis and human health risk model application for evaluating ambient air-heavy metal contamination in Chemical Valley Sarnia.

The impacts of air emissions as a consequence of industrial activities around communities of human habitation have been extensively reported. This study is the first to assess potential adverse human health effects in the Chemical Valley Sarnia (CVS) area, around the St. Clair River, using health risk models, ecological and pollution indices. Large quantities of particulate matters (PM) are generated from anthropogenic activities, which contain several heavy metals in trace quantities with potentially adverse effects to humans and environmental health. The distribution, and human health impact assessment of trace element concentrations in PM fractions were examined. Elemental concentrations of As, Cd, Cr (VI), Cu, Fe, Mn, Pb, Ni, Zn were determined in the PM size-segregated samples collected from the CVS area between 2014 and 2017. The results showed relatively high concentration of PM<2.5 (87.19±8.1(mgm3)) which is approximately 4 times the WHO air quality guidelines. Pb concentration (143.03 ± 46.87ηg/m3) was 3.6 times higher than the air quality standards of NAAQS. Cr (VI) showed moderate to considerable contamination ( Cf=4) in the CVS while Cr (VI), Pb, and Ni had enrichment factor Ef < 3 (minimal), signifying contributions from anthropogenic activities. Pollution load index (PLi) value observed was 1.4 indicating human health risk from the PM, especially for the children in the area. The deposition fluxes (DΦ) showed that PM-bound metals could potentially bypass the head airways and cause damages to the tracheobronchial tree, increasing the human health risks of nephroblastomasis development. The main route of entry for the heavy metal bound PM in humans were observed as through ingestion and inhalation. The highest total excess cancer risks observed for children (6.7×10-4) and adult (1.0×10-4) indicating potential cancer effects. The Incremental Lifetime Cancer Risk (ILCR) increased from Pb < Ni < Cd < Cr (VI) < As. Overall, children are more likely to develop carcinogenic and non-carcinogenic health effects from exposures to elemental concentrations of airborne PM in the study area.