Document Type : Original Research Paper
Authors
School of Mining Engineering, College of Engineering, University of Tehran, Tehran, Iran
Abstract
Porphyry copper mining generates substantial volumes of tailings, which pose considerable environmental and public health hazards due to their capacity for acid generation and the release of potentially toxic elements (PTEs). This study provides an integrated environmental and human health risk assessment of tailings from the Sungun porphyry copper mine in northwestern Iran. A comprehensive and multidisciplinary approach was employed, combining physicochemical, mineralogical and geochemical analyses with statistical methods. Chemical speciation was done by employing a modified procedure suggested by the BCR (European Community Bureau of Reference) which has also been used in numerous studies to assess the geochemical fractionation and mobility of elements. The main goal was to advance from total concentration analysis to a more precise, bioavailability-based risk evaluation utilizing the USEPA framework for both children and adults. Mineralogical investigation indicated a net acid-generating capability, with pyrite content (~4%) typically surpassing that of the principal neutralizing mineral, calcite (~2%). Geochemical analyses verified that the tailings exhibit significant enrichment in Cu and Mo, along with moderate enrichment of As and Co. Among the studied elements, the highest mobility factors belonged to Cu (81.49%), Pb (76.71%), Zn (71.65%) and Mo (59.27%), respectively. The non-carcinogenic hazard index (HI) for children was 2.04, exceeding the safety threshold of 1.0, with bioavailable vanadium recognized as the principal risk factor. These findings highlight that relying solely on total PTE concentrations can be misleading, reinforcing the need for speciation-based assessments to accurately characterize the environmental behavior and health risks of mine tailings.
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