Effect of weathering product assemblages on Pb bioaccessibility in mine waste: implications for risk management

Palumbo-Roe, Barbara; Wragg, Joanna; Cave, Mark R.; Wagner, Doris. 2013 Effect of weathering product assemblages on Pb bioaccessibility in mine waste: implications for risk management. Environmental Science and Pollution Research, 20 (11). 7699-7710. 10.1007/s11356-013-1515-2

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Abstract/Summary

General assessments of orebody types and associated mine wastes with regards to their environmental signature and human health hazards are needed to help managing present and historical mine waste facilities. Bioaccessibility tests and mineralogical analysis were carried out on mine waste from a systematic sampling of mine sites from the Central Wales orefield, UK. The bioaccessible Pb widely ranged from 270 to 20300 mg/kg (mean 7250 mg/kg; median 4890 mg/kg) and the bioaccessible fraction from 4.53 % to >100 % (mean 33.2 %; median 32.2 %), with significant (p=0.001) differences among the mine sites. This implies sensitivity of bioaccessibility to site-specific conditions and suggests caution in the use of models to assess human health impacts generalised on the basis of the mineral deposit type. Mineralogical similarities of the oxidation products of primary galena provided a better control over the observed Pb bioaccessibility range. The higher Pb bioaccessibility (%) was related to samples containing cerussite, irrespective of the presence of other Pb minerals in the mineral assemblage; lower Pb bioaccessibility resulted where anglesite was the main Pb mineral phase and cerussite was absent. A solubility diagram for the various Pb minerals in the waste was derived using PHREEQC model and the experimental Pb concentration measured in the simulated gastric solution compared with the equilibrium modelling results. For samples containing cerussite, the model well predicted the soluble Pb concentrations measured in the experimental simulated gastric solution, indicative of the carbonate mineral phase control on the Pb in solution for these samples and little kinetic control on the dissolution of cerussite. On the contrary, most mine waste samples containing dominant anglesite and or plumbojarosite (no cerussite) had lower solution Pb values, falling at or below the anglesite and plumbojarosite solubility equilibrium concentrations, implying kinetic or textural factors hindering the dissolution.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1007/s11356-013-1515-2
ISSN:	0944-1344
NORA Subject Terms:	Earth Sciences Health Chemistry
Date made live:	21 Mar 2013 10:16 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/500579

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