Environmental and geochemical analysis of lead contamination: its sources and pathways of exposure and impact on children

Chenyin Dong
Resolving the source of environmental contamination is a critical first step in planning remediation and intervention strategies to adduce exposure prevention. However, a major challenge in established mining and smelting communities is that the sources of contamination and related potential health risks are often minimised by polluters and government agencies, often using unsupported scientific claims. A significant and longstanding example of this vexed issue is the protracted dispute over
more » ... tamination sources and causes of childhood blood Pb exposures in Broken Hill (New South Wales), Australia's longest-operating Pb-Ag-Zn mining city. In order to unravel the sources, causes and impacts of contemporary Pb contamination in Broken Hill, this study applied a multiple lines of evidence approach using a combination of geochemical analyses and human health data. The methods applied included analysis of trace element concentrations in soil, dust, tailing dumps and weathered ores, their Pb isotopic and chemical compositions and the morphological characteristics of individual Pb-rich particles. The results demonstrated that Broken Hill contemporary dust Pb deposits were primarily sourced from current mining emissions as opposed to naturally weathered or legacy source sheld in soil and dust around the city. Children living closest to the mining operations were found to be at an increased risk of Pb exposure due to higher dust Pb loading (mean 255μg/m2/day) and its high bioaccessibility (75% of total Pb). The effects of current mining emissions on the contemporary dust Pb loading were quantitatively estimated. The analysis showed that a 1% increase in distance away from the current mining operations was associated with -0.501% (95% CI: -0.728, -0.275) reduction in dust Pb loading, while a 1% increase in production intensity at the mine increased the expected amount of dust Pb loading by 1.487% (95% CI: 0.537, 2.437%). Consistent with the dust Pb decreasing with distance away from current active mining operations, contem [...]
doi:10.25949/19433726 fatcat:uxtpvbsx2favnjfzc6gefsgtbm