Dermal bioaccessibility and health risk assessment associated with mining production of metals (Pb-Zn-Ag) and critical raw materials (Sb-W) in the Iberian Peninsula

Abstract

The exploitation of crucial materials for economic development, and exposure to waste enriched with potentially toxic elements (PTEs) has recently increased, requiring risk assessment to protect the health of workers. In this work, residua from two derelict mines have been studied to determine the health risks associated with direct dermal contact. Using in vitro tests with synthetic sweat (EN 1811 and NIHS 96–10) to simulate PTE bioaccessibility for children (2-h exposure) and adults (8-h exposure). The results showed that the more acidic sweat (NIHS 96–10) yielded higher levels of PTEs. Tailings and dumps had higher bioaccessibility than soils, with Pb and Zn being the most extracted PTEs and As and Sb had low mobility. Higher bioaccessibility levels were observed after 2 h of exposure, highlighting greater risks for children due to their greater vulnerability. Cadmium levels were sufficient to cause non-carcinogenic effects, whereas Pb and As posed carcinogenic risks. Although bioaccessibility data do not imply bioavailability of the element, as some species have been reported to be unable to cross the skin, penetration of PTEs through existing lesions may occur. Methodologies used to obtain Dermal Average Dose (DAD) showed that the use of generic parameters and the exclusion of bioaccessibility data underestimates results for non-carcinogenic assessment. For carcinogenic effects, results from both methods were similar. This validates the soil-skin approach as an efficient and cost-effective tool for health risk assessment.