我国主要有色金属矿区尾矿库重金属污染及土壤酶活性研究

Study on heavy metal contamination and soil enzyme activities in nonferrous metal mine wastelands in China

关键词:  有色金属矿区  尾矿库  土壤酶活性  重金属污染  营养元素循环  影响因子

Key words:  nonferrous metal mining area  mine tailings ponds  soil enzyme activity  heavy metal contamination  soil nutrient cycling  inf luencing factors

摘要:

矿山废弃物的堆积导致矿区及周边环境严重污染。探讨尾矿库中土壤酶活性与土壤重金属污染程度的关系，有助于为矿山生态修复提供数据支撑。对21个省（自治区）的37个有色金属矿区尾矿库进行土壤样品采集，分析了土壤理化性质、重金属含量与酸性磷酸酶、脲酶和β-葡萄糖苷酶活性的相关性。结果表明：有色金属矿区尾矿库土壤酶活性整体偏低。主要受土壤pH、含水量（SMC）、总磷（TP）、Zn和Pb的影响。养分不足的尾矿库土壤会刺激微生物分泌更多酶以获取所需养分。Zn和Pd可能对β-葡萄糖苷酶和酸性磷酸酶具有激活作用，而Pb则可能对脲酶产生抑制作用。研究结果为通过调控土壤酶活性推进有色金属尾矿库修复提供了重要的理论支持和参考。

Abstract:

Background, aim, and scope Mining waste accumulation has led to severe environmental contamination in and around mine tailings ponds. Soil enzymes serve as sensitive indicators of soil ecological quality and play an essential role in evaluating the impact of heavy metal contamination in these environments. This study aims to clarify the relationships between soil enzyme activities and heavy metal contamination levels in major nonferrous metal mine tailings ponds across China, thereby providing a scientific basis for the development of targeted remediation strategies. The findings underscore the value of soil enzyme activities as ecological risk indicators and offer theoretical support for remediation strategies centered on enzyme activity regulation. Materials and methods Soil samples were collected from 37 nonferrous metal mine tailings ponds across 21 provinces or autonomous regions in China. The physicochemical properties and concentrations of heavy metals (Cd, Cu, Pb and Zn) were measured. Additionally, the activities of key soil enzymes (acid phosphatase, urease and β-glucosidase) were analyzed, and their correlations with soil properties were evaluated. Results Soil enzyme activities in the tailings ponds were generally low, with significant variations observed among different sample types. The main influencing enzyme activities included pH, soil moisture content (SMC), total phosphorus (TP), and Zn, and Pb concentrations. Discussion Soil pH, nutrient content, and heavy metals were identified as primary factors affecting enzyme activities. pH exerted considerable influence by modulating ions adsorption and nutrient transformation processes. Soil nutrients influenced enzyme production through microbial resource allocation and shifts in the abundance of enzyme-producing microorganisms. Under low nutrient availability, microorganisms tended to secrete more enzymes to facilitate nutrient acquisition. Heavy metal ions may act as enzymatic cofactors that facilitate the coordination and binding between the enzyme active site and its substrates, thereby potentially enhancing certain soil enzyme activities. Conversely, these ions can also form stable complexes with functional groups on enzyme molecules, leading to competitive inhibition of enzyme—substrate interactions and resulting in the suppression of enzymatic function. Conclusions Within the pH range of 1.95—9.01, a significant negative correlation was observed between pH and the activities of soil urease, β-glucosidase, and acid phosphatase. The generally poor nutrient conditions in tailings ponds stimulated microbial enzyme secretion. The concentration of nutrients was typically negatively correlated with the activity of nutrient-releasing enzymes. Zn and Pb appeared to activate β-glucosidase and acid phosphatase, whereas Pb likely inhibited urease activities. Recommendations and perspectives This study provides a theoretical foundation and practical reference for the remediation of nonferrous metal tailings ponds via regulation of soil enzyme activity.