Sustainable Minerals Institute-International Centre of Excellence Chile (SMI-ICE Chile), The University of Queensland, Australia. Av. Apoquindo 2929, 3rd Floor Of. 301, Las Condes, Santiago, Chile.
Instituto de Geología Económica Aplicada (GEA), University of Concepción, Chile. Barrio Universitario S/N, Concepción, Chile.
Environ Sci Pollut Res Int. 2021 Nov;28(41):57499-57529. doi: 10.1007/s11356-021-12844-7. Epub 2021 Jun 5.
The geochemical stability, in terms of potential mobility and derived ecological and human health risks of potentially toxic elements (PTEs), of diverse fresh and old porphyry Cu-mine tailings from Chile was assessed through an integrated methodology comprising four interrelated investigation levels: (1) chemical composition and contamination degree of tailings by PTEs, (2) mineralogical characterization by X-ray diffraction and quantitative automated mineralogy analysis by scanning electron microscopy (QEMSCAN), (3) partitioning and potential mobility of PTEs within the tailings by a sequential extraction procedure (SEP) and leaching tests, and (4) ecological risk assessment (ERA) and human health risk assessment (HHRA). According to pollution indices, Cu, As, Pb, and Mo are most concerning PTEs present in the tailings. SEP shows that major portion of the PTEs are strongly fixed as residual fraction, and thus are poorly mobilizable and bioavailable. Among the PTEs, Cu, As, and Mo were identified as the PTEs most prone to mobilization. Leaching tests show that a low fraction of PTEs is water-leachable. Seawater enhances Mn and As leaching, while process water increases the leaching of Cu, Mn, and Mo. Phosphate particularly promotes leaching of As and Cu, whereas it does not mobilize or even immobilize Pb in the tailings. ERA suggests that mainly old tailings pose a very high potential risk for ecological receptors (PERI = 663-3356), mostly due to Cu and As. HHRA indicates that the old tailings pose higher potential non-carcinogenic and carcinogenic health risks, while the risk decreases in the order ingestion > dermal > inhalation for both children and adults. Non carcinogenic and carcinogenic HHRA points to As as the main PTE of concern via ingestion pathway in the tailings. Overall, the results revealed that particularly old tailings, containing mixed slag-tailings, pose considerable risks to the environment and human health due to potential PTEs mobilization and this aspect requires scrutiny for proper tailings management, including storage, sealing, and eventual tailings reprocessing and/or site rehabilitation after closure.
对智利不同新鲜和陈旧斑岩铜矿尾矿中潜在有毒元素（PTE）的地球化学稳定性（潜在迁移能力以及由此产生的生态和人类健康风险），采用了一种综合方法进行了评估，该方法包括四个相互关联的研究层次：（1）PTE 对尾矿的化学组成和污染程度，（2）X 射线衍射的矿物学特征和扫描电子显微镜（QEMSCAN）的定量自动矿物学分析，（3）顺序提取程序（SEP）和浸出试验中 PTE 在尾矿中的分配和潜在迁移能力，以及（4）生态风险评估（ERA）和人类健康风险评估（HHRA）。根据污染指数，Cu、As、Pb 和 Mo 是尾矿中最受关注的 PTE。SEP 表明，大部分 PTE 作为残余物强烈固定，因此迁移能力差且生物可利用性低。在 PTE 中，Cu、As 和 Mo 被确定为最容易迁移的 PTE。浸出试验表明，只有一小部分 PTE 是水溶的。海水会增强 Mn 和 As 的浸出，而工艺用水会增加 Cu、Mn 和 Mo 的浸出。磷酸盐特别促进 As 和 Cu 的浸出，而在尾矿中不移动甚至固定 Pb。ERA 表明，主要是陈旧的尾矿对生态受体（PERI=663-3356）构成极高的潜在风险，主要是由于 Cu 和 As。HHRA 表明，陈旧的尾矿对儿童和成人的非致癌和致癌健康风险更高，而风险顺序为摄入>皮肤>吸入。非致癌和致癌 HHRA 表明，通过摄入途径，As 是尾矿中最主要的 PTE。总体而言，研究结果表明，尤其是陈旧的尾矿，由于潜在的 PTE 迁移，对环境和人类健康构成相当大的风险，这方面需要仔细审查，以进行适当的尾矿管理，包括储存、密封以及最终关闭后尾矿的再加工和/或场地修复。
