Assessment of risk from lead intake in mining areas: proposal of indicators

This study discusses an estimate of the risk associated with the intake of soil contaminated by lead, based on the nature of the source, through a detailed study of the parameters that can influence the bioaccessibility of the element from soil intake. Statistical variables that are related to the solubility and bioavailability of lead are used for this purpose. This includes considering the values of pH, electrical conductivity, particle size, mineralogical composition and the bioaccessibility/bioasimilability of lead. Obtaining an algorithm, represented by different probability distributions of the parameters considered, needs a thorough knowledge of the source materials, which may allow estimating/evaluating the intake health risk provided by the concentration of the metal present. The selected materials are from sites affected by mining activities in the Region of Murcia (SE of Spain) and soils in nearby areas, using a total of 186 samples. Soil samples, once screened and homogenized, were parameterized by determining pH, electrical conductivity, granulometry, both total and water-extractable Pb content. Oral bioaccessibility tests were also performed, and a detailed mineralogical analysis by X-ray diffraction was carried out.