Increased human health risks at a legacy mine site: copper and lead bioaccessibility of oxidised tailings.

With climate change, conditions for dust generation are expected to be more prevalent. A potential dust source of concern are mine wastes due to the likelihood of potentially toxic elements which pose a human health risk if ingested or inhaled. This study analysed sieved mine tailings from a legacy mine in Nova Scotia, Canada. The aim of the research was to analyse total concentrations of Cu and Pb in tailings samples sieved to represent dust; to determine gastric bioaccessibility of Cu and Pb in these samples; and to analyse the impact of mineralogy on Cu and Pb bioaccessibility. Mineralogy was determined with a scanning electron microscope and automated mineralogy software. Tailings were sampled from an uncovered, subaerial, tailings impoundment. Copper bioaccessibility had a strong positive correlation with carbonate and oxide copper hosts. Lead bioaccessibility had a strong positive correlation to one oxidation product, cerussite (lead carbonate). Lead was predominantly hosted in cerussite and had greater bioaccessibility than copper which was predominantly hosted in chalcopyrite. The results highlight the increased human-health risk posed by subaerial tailings at an abandoned mine.