An assessment of the environmental fate of mercury species in highly polluted brownfields by means of thermal desorption

• Published in: Journal of hazardous materials Vol. 325; pp. 1 - 7
• Main Authors: Rumayor, M., Gallego, J.R., Rodríguez-Valdés, E., Díaz-Somoano, M.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 05.03.2017
• Subjects: Assessments; Bioavailability; Brownfields; Contamination; Desorption; Heat treatment; Land; Mercury; Mercury (metal); Mercury fate; Remediation; Speciation; Thermal-desorption; Mercury fate; Thermal-desorption; Brownfields; Mercury; Speciation
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2016.11.068

[Display omitted] •Identification of mercury species in highly polluted brownfields by thermal desorption.•Assessment of Hg fate and bioavailability in old mining-metallurgy sites.•Hg is transported to soil and sediments in stable forms, HgS and Hg bound to pyrite.•Methylation can be discarded in these sites.•Utility of thermal desorption technique for parameterizing a remediation treatment. High contents of mercury (Hg) have been found in old mining-metallurgy sites occurring a widespread contamination and degradation of the land. The ability to identify the Hg species present in these areas is essential to clarify fate of Hg and its bioavailability and additionally, to be able to parameterize remediation techniques based on thermal desorption in order to carry out a full-scale decontamination of the land. This study has proven the usefulness of a thermal programmed desorption procedure (Hg-TPD) for identifying Hg species in contaminated samples related to mining-metallurgy activities. Hg bound to organic matter (Hg-OM) and to pyrite (Hg-FeS2), HgS red, HgCl2, Hg0 and HgO were identified in most of waste samples. The absence of mobile Hg species in soils and sediments showed both its re-emission to the atmosphere (Hg0) or of its oxidation and lixiviation (HgO and HgCl2) over the years. The results have demonstrated that most of these polluted solids can be remediated by thermal treatment at temperatures ranging between 150 and 600°C. The study evidence that Hg-TPD is useful either for parameterizing a thermal remediation or for identifying the evolution pathways of Hg species in different environmental compartments and in general, for any environmental remediation treatment.