Ongoing soil arsenic exposure of children living in an historical gold mining area in regional Victoria, Australia: Identifying risk factors associated with uptake

Elevated levels of arsenic have been observed in some mine wastes and soils around historical gold mining areas in regional Victoria, Australia. Arsenic uptake from soil by children living in these areas has been demonstrated using toenail arsenic concentration as a biomarker, with evidence of some systemic absorption associated with periodic exposures. We conducted a follow-up study to ascertain if toenail arsenic concentrations, and risk factors for exposure, had changed over a five year period in an historical gold mining region in western regional Victoria, Australia. Residential soil samples (N = 14) and toenail clippings (N = 24) were analyzed for total arsenic using instrumental neutron activation analysis, including 19 toenail clippings samples that were obtained from the same study cohort in 2006. Toenail arsenic concentrations in 2011 (geometric mean, 0.171 μg/g; range, 0.030-0.540 μg/g) were significantly lower than those in 2006 (geometric mean, 0.464 μg/g; range, 0.150-2.10 μg/g; p < 0.001). However, toenail arsenic concentrations were again correlated with soil arsenic levels (Spearman's rho = 0.630; p = 0.001). Spending time outdoors more often and for longer periods correlates with increased arsenic uptake (p < 0.05). Mining-influenced residential soils represent a long-term continuing source for potential arsenic exposure for children living in this historical mining region.