Linking oral bioaccessibility and solid phase distribution of potentially toxic elements in extractive waste and soil from an abandoned mine site: Case study in Campello Monti, NW Italy

• Published in: The Science of the total environment Vol. 651; no. Pt 2; pp. 2799 - 2810
• Main Authors: Mehta, Neha, Cocerva, Tatiana, Cipullo, Sabrina, Padoan, Elio, Dino, Giovanna Antonella, Ajmone-Marsan, Franco, Cox, Siobhan Fiona, Coulon, Frederic, De Luca, Domenico Antonio
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.02.2019
• Subjects: Abandoned mine site; Dietary Exposure - analysis; Dietary Exposure - statistics & numerical data; Environmental Monitoring; Hazardous Substances - analysis; Hazardous Substances - toxicity; Humans; Italy; Metals - analysis; Metals - toxicity; Mining; Oral bioaccessibility; Potentially toxic elements (PTE); Risk assessment; Soil Pollutants - analysis; Soil Pollutants - toxicity; Solid phase distribution; Italy; Potentially toxic elements (PTE); Abandoned mine site; Solid phase distribution; Risk assessment; Oral bioaccessibility
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2018.10.115

Oral bioaccessibility and solid phase distribution of potentially toxic elements (PTE) from extractive waste streams were investigated to assess the potential human health risk posed by abandoned mines. The solid phase distribution along with micro-X-ray fluorescence (micro-XRF) and scanning electron microscopy (SEM) analysis were also performed. The results showed that the total concentrations of PTE were higher in <250 μm size fractions of waste rock and soil samples in comparison to the <2 mm size fractions. Mean value of total concentrations of chromium(Cr), copper (Cu), and nickel (Ni) in waste rocks (size fractions <250 μm) were found to be 1299, 1570, and 4010 mg/kg respectively due to the parent material. However, only 11% of Ni in this sample was orally bioaccessible. Detailed analysis of the oral bioaccessible fraction (BAF, reported as the ratio of highest bioaccessible concentration compared with the total concentration from the 250 μm fraction) across all samples showed that Cr, Cu, and Ni varied from 1 to 6%, 14 to 47%, and 5 to 21%, respectively. The variation can be attributed to the difference in pH, organic matter content and mineralogical composition of the samples. Non-specific sequential extraction showed that the non-mobile forms of PTE were associated with the clay and Fe oxide components of the environmental matrices. The present study demonstrates how oral bioaccessibility, solid phase distribution and mineralogical analysis can provide insights into the distribution, fate and behaviour of PTE in waste streams from abandoned mine sites and inform human health risk posed by such sites . [Display omitted] •Extractive waste and soil at abandoned mines pose a risk to human health.•Cr, Cu and Ni were present in high total concentrations at Campello Monti site.•Potentially toxic elements were associated with clay and Fe oxide fractions.•Mean BAF <11% for both Cr and Ni. Non-mobile form in Fe oxide fraction.•PTE were found to be embedded in mineral grains of soil.