ABSTRACT

Heavy metals contamination in soil from copper mine areas is a serious and widespread problem in China. In this study, the content of Tl, Hg, Cu, Cd, Ni, Pb and As and probabilistic human health risks were investigated in a typical copper mining city. Copper showed the highest average content of 184.29 mg/kg, followed by Pb, As, Ni, Tl, Cd and Hg. Approximately 54.2% of study sites were moderately contaminated by Cu, Cd, As and Tl. Among the heavy metals, Hg, Cu and Cd showed relatively high mobility and medium risk in the environment based on the chemical speciation. In particular, Tl was mainly present as Tl(I) in soil with more biovailability and solubility. Moreover, the probabilistic human health risk assessment using Monte-Carlo approach revealed that heavy metals in soil can cause non-carcinogenic risks (adults: 0.03%, children: 48.45%) and carcinogenic risks (adults: 41.79%; children 61.98%). The soil oral ingestion is the main exposure pathway for human exposed to heavy metals. Our findings indicate that the copper mining activities can cause high level of heavy metals in soils, and corresponding health risks. Meanwhile, these results could provide important information and theoretical support the development of precise soil pollution management strategies in copper mining areas.

摘要

铜矿区土壤重金属污染是我国普遍存在的严重问题。本研究对典型铜矿城市的 Tl、Hg、Cu、Cd、Ni、Pb 和 As 含量以及人类健康风险进行了调查。铜的平均含量最高，为 184.29 mg/kg，其次是 Pb、As、Ni、Tl、Cd 和 Hg。大约 54.2% 的研究地点受到铜、镉、砷和铊的中度污染。重金属中，从化学形态来看，Hg、Cu和Cd在环境中的迁移性相对较高，风险中等。特别是，Tl在土壤中主要以Tl(I)形式存在，具有更高的生物利用度和溶解度。此外，采用蒙特卡罗方法进行的概率人类健康风险评估显示，土壤中的重金属可引起非致癌风险（成人：0.03%，儿童：48. 45%）和致癌风险（成人：41.79%；儿童 61.98%）。土壤经口摄入是人体重金属暴露的主要暴露途径。我们的研究结果表明，铜矿开采活动可能导致土壤中重金属含量过高，并产生相应的健康风险。同时，这些研究成果可为铜矿区土壤污染精准治理策略的制定提供重要信息和理论支持。