Azizi M, Carmona D M, Faz A, Martínez-Martínez S, Acosta J A
Sustainable Use, Management and Reclamation of Soil and Water Research Group, Universidad Politécnica de Cartagena, Paseo Alfonso XIII 48, 30203 Cartagena, Spain.
Grupo de Investigaciones Ambientales, Universidad Pontificia Bolivariana, Circular 1, 70-01, 050031 Medellín, Colombia.
Sci Total Environ. 2025 Sep 3;1000:180368. doi: 10.1016/j.scitotenv.2025.180368.
Mining areas are highly susceptible to environmental contamination due to the accumulation of potentially toxic elements (PTEs), necessitating regular monitoring to assess environmental risks. In this study, soil samples were collected from two depths (0-15 cm and 15-30 cm) at 74 stations, along with deep waste samples (0-12 m) from three adjacent tailings ponds in the Mazarrón mining area, Spain. Soil/waste physicochemical properties and the Cd, Cu, Zn, and Pb concentrations of total, water-soluble, and bioavailable fractions were analyzed. Pollution indexes, spatial distribution maps and vertical profiles of metal concentrations in the tailings ponds were generated to evaluate contamination degree and distribution patterns. The results indicated highly acidic soil conditions (pH 4), and elevated electrical conductivity (3.8 dSm), particularly in the tailing ponds (pH 2.6 and EC: 8.3 dSm), which enhance metal solubility and mobility, and a significant mine drainage generation. Severe contamination was observed for Cd, Zn, and Pb, with Pb concentrations exceeding 10,000 mg kg in surface soils and Zn levels surpassing 16,000 mg kg in mining waste. Cd exhibited the highest bioavailability (up to 99 %), posing substantial environmental and ecological risks, whereas Pb remained largely immobile despite its high total concentration. Statistical analyses identified soil acidity and salinity as key factors controlling metal mobility, while anthropogenic inputs, from mining activities, contributed to Cd and Zn enrichment. The Pollution Load Index and Ecological Risk Index confirmed extreme contamination levels, particularly in the central region of the mining district, with Cd emerging as the primary ecological risk element. These findings highlight the urgent need for remediation strategies, including pH stabilization, containment of highly mobile metals, and continuous environmental monitoring to mitigate long-term ecological impacts.
由于潜在有毒元素（PTEs）的积累，矿区极易受到环境污染，因此需要定期监测以评估环境风险。在本研究中，从西班牙马扎隆矿区74个站点的两个深度（0 - 15厘米和15 - 30厘米）采集了土壤样本，并从三个相邻尾矿库采集了深度为0 - 12米的深层废物样本。分析了土壤/废物的理化性质以及镉、铜、锌和铅在总量、水溶性和生物可利用部分的浓度。生成了尾矿库中金属浓度的污染指数、空间分布图和垂直剖面图，以评估污染程度和分布模式。结果表明，土壤呈高酸性（pH值为4），电导率升高（3.8 dSm），特别是在尾矿库中（pH值为2.6，电导率为8.3 dSm），这增强了金属的溶解性和迁移性，并产生了大量的矿井排水。镉、锌和铅存在严重污染，表层土壤中铅浓度超过10000毫克/千克，采矿废物中锌含量超过16000毫克/千克。镉表现出最高的生物有效性（高达99%），带来了重大的环境和生态风险，而铅尽管总浓度很高，但在很大程度上仍保持不动。统计分析确定土壤酸度和盐度是控制金属迁移的关键因素，而采矿活动产生的人为输入导致了镉和锌的富集。污染负荷指数和生态风险指数证实了极端的污染水平，特别是在矿区中部地区，镉成为主要的生态风险元素。这些发现凸显了采取修复策略的迫切需求，包括稳定pH值、遏制高迁移性金属以及持续进行环境监测，以减轻长期的生态影响。
