Environmental Advances (Oct 2023)
Contributions of contamination sources to soil lead concentrations of a smelter-affected community in South Australia, Australia
Abstract
The prevalence of lead (Pb) contamination in the environment presents a potential health risk to exposed communities, particularly if an ongoing contamination source is present. In this study, soil samples (n = 201) across six transects were collected from a smelter impacted town in South Australia to quantify Pb distribution, elemental associations and Pb bioaccessibility. Soils were categorized into five types based on sample location and material composition (footpath material, non-residential soil, nature strip soil, parkland soil and vacant land soil). The primary element of concern in all soils was Pb with concentrations ranging from 33 to 10141 mg kg−1 and median Pb values across the six transect ranging from 324 to 1669 mg kg−1. Fifty three percent of samples exceeded the soil investigation level for Pb in non-residential soil (600 mg kg−1). Although significant variability in Pb concentration was observed for all sample types, non-residential soils had significantly higher Pb concentrations compared to other sample types (p < 0.05) presumably due to the undisturbed nature of these samples and their proximity to the smelter. Strong associations were observed between Pb and other elements of concern (As, Cd, Zn) across most samples / transects suggesting a commonality of source. However, despite these associations, co-contaminant concentrations (As: 2–155 mg kg−1; Cd: 0-59 mg kg−1; Zn: 66-28281 mg kg−1) did not exceed soil investigation levels for non-residential soil. When gastric phase Pb bioaccessibility was determined (using the SBRC assay), Pb bioaccessibility was high across all sample types and transects with mean and median values of 81 % and 83 %, respectively. Given the extent of Pb contamination with elevated Pb bioaccessibility, remediation and risk management strategies are an imperative to reduce the burden of Pb on the community.
