Dermal bioaccessibility and health risk of potential toxic elements (PTE) in mining environments (San Quintín Pb-Zn-Ag Mining Group and San Antonio Sb-W Mine, Spain).

Metallic mining was very relevant in Spain last century. Because of this, currently there are numerous abandoned mines that suppose an environmental and human health risk. San Quintín Mining District (Ciudad Real) and San Antonio (Badajoz) are two examples of ancient metallic mining in Spain. In both mines there are a large volume of wastes like tailings, dumps or contaminated soils enriched with Zn, Pb, As, Cd, and Sb. San Quintín is currently being part of a project restoration that involves movement of tons of contaminated material. Twelve soil samples were collected from San Quintín Mining District and twenty-one were collected from San Antonio mine.

In these samples, the total trace element content was determined by X-Ray fluorescence spectrometry (XRF), in addition to other physicochemical parameters, such as pH and EC. To assess the human health risk, dermal bioaccessibility tests were carried out mixing wastes samples and two different synthetic sweats (EN1811 and NIHS96-10) during 2 and 8 hours.

The obtained results suggested that extraction interval percentages were: 0.01-57.29% for Cd, 0.001-55.768% for Pb, 0.001-93.180% for Zn, for San Quintín samples, 0.002-2.825% for Sb, for San Antonio samples and 0.001-0.707% for As, for all samples considered. The highest values correspond to extraction carried out with the lowest pH synthetic sweat (NIHS96-10) and specially for Zn, Cd and Pb. Metalloids appear to be less available or bioaccessible than heavy metals. Direct dermal contact between mine wastes and human skin, could mean the absorption of elements extremely harmful to health, thus restoration workers and anyone who can have contact with wastes, can be in danger if there are no security measures.

Contact with these mining residues poses a risk to human health, highlighting the necessity to assess not only dermal exposure but also inhalation and oral pathways for a comprehensive human risk assessment.