Lead from mining and mineral processing activities to the community via the air-dust pathway: An example from Mount Isa city using human health risk assessment approach

Abstract

This study followed the Australian human health risk assessment procedure from enHealth and utilised an innovative approach of integrated methodologies to study the impacts of lead on the Mount Isa community. The aim of this study was to identify the significant sources of lead via the air-dust pathway at Mount Isa and to estimate the potential impact of the air-dust pathway on human health by using a human health risk assessment approach. The two research questions derived from aims were related to the "issue identification" "hazard assessment" "exposure assessment" and "risk characterisation" of the risk assessment procedure.The first research question considered if lead-containing particulates were dispersed from mining operations via air-dust pathway to the community using a statistically representative set of houses in the Mount Isa City (n=67) to examine the spatial distribution of chemical and physical characteristics, including heavy metal and metalloid total concentrations, lead isotopic feature of the potential sources associated with historical mining and mineral processing activities. High resolution lead isotope ratios for natural outcrops, mine site samples, community samples indicated that roof gutter dust, fallout dust, soil PM 10 , and outdoor air particulates, floor, interior window sill, window trough, veranda wipe and indoor carpet dust showed close feature to lead isotopic characteristics of the mine site lead ore samples (mean 208 showed that Urquhart Shale outcrops were not significantly different (p > 0.05) from the mine site haul road dust (p = 0.89) and surface tailings (p = 0.36) and dust from the city residential area roof gutter dust (p = 0.06) and window trough wipes (p = 0.37) for lead isotopic ratios.The second research question of evaluating the significant lead exposure route was answered by considering if lead-containing particulates at Mount Isa were a significant lead exposure source via inhalation and ingestion routes in the community regarding human health exposure assessment.Total concentrations of lead in soil, air particulates, house wipes were compared with Australian and international health risk guidelines. Lead speciation by synchrotron-based X-ray absorption spectroscopy using X-ray absorption near edge structure (XANES) technique and bioaccessibility of lead in samples using the physiologically-based extraction test (