广西石漠化地区多金属矿采废弃地复垦效应、演变规律及调控机制研究

There are a lot of multi-metal ores in rocky desertification areas in Guangxi province. However, mining activities and inappropriate management modes of mining wastelands which had caused heavy metals pollution around the mining areas, and had made the fragile ecological environment more serious. Our research team will carry out comprehensive diagnosis and investigations and evaluations to typical multi-metal mining wastelands according to the major environmental problems and weaknesses in the remediation process and the significant demand of social and economic development in Guangxi in the project. We will also get the qualification level and spatial scale transformation of soil health and ecological risk factors combining laboratory simulation, and then to establish "three-dimensional" spatial differentiation characteristics and the pollution degree zoning system in heavy metal polluted mining soils in Typical Karst region multi-metal ores area. At the same time, on this basis, for the status quo of reclamation of mining wastelands in rocky desertification areas in Guangxi province, in order to reveal the evolved mechanisms of soil quality during reclaimed process and interpret multi-metal mine wasteland quality evolution in reclamation lands in multi-metal ores area, our team will do comprehensive evaluate and tracking and positioning study on soils quality in reclamation lands in multi-metal ores area according to time and space and classification, using the physical , chemical and biological , etc. indicator system. These results will provide the theoretical basis and methodology for soil contamination diagnosis, pollution prevention and control, and management of multi-metal mining wastelands in rocky desertification area, and will also provide data support for remediation and management system of contamination soils in multi-metal mining ores in rocky desertification area in Guangxi.

广西石漠化区多金属矿藏丰富，但矿业废弃地不适宜管理方式造成周边环境重金属污染严重，使本已脆弱的生态环境雪上加霜。本课题面向广西社会经济发展重大需求，针对广西目前石漠化区矿冶活动带来的主要生态环境问题及整治过程中的薄弱环节，开展多金属矿废弃地污染土壤综合诊断与调查评价，与实验室模拟相结合，实现污染土壤健康和生态风险因子的等级量化与空间尺度转化，建立典型石漠化区多金属矿污染土壤“立体”的空间分异特征及污染程度分区体系。在此基础上，针对广西石漠化区多金属矿废弃地的土壤复垦现状，运用物理、化学和生物学等评估指标体系，分时分类进行复垦土壤质量综合评价和定位跟踪研究，以期揭示石漠化地区多金属矿废弃地复垦过程土壤质量演变机制，诠释多金属矿废弃地复垦质量演变规律。本项目的完成为我国石漠化地区多金属矿废弃地土壤污染甄别、防治和管理提供理论基础和方法论，为广西石漠化地区矿山污染土壤整治与修复管理系统提供支撑。

广西有色金属矿产丰富，其开采过程导致区域生态环境破坏和重金属污染扩散，特别是喀斯特石漠化地区该问题较突出。复垦是矿区重金属污染控制的重要举措。该项目以广西典型露天铝土矿及八一锰矿为研究区，主要通过野外采样分析结合实验室培养试验，研究了两个具有典型特色的有色金属矿复垦地土壤质量演变特征，特别是复垦土壤中重金属污染物赋存与分布。结果表明铝土矿区复垦土壤肥力质量较低，土壤中主要重金属污染物为镉和砷，且部分复垦地该污染物超过农用地筛选值甚至管控值。通过盆栽试验研究了铝土矿区复垦土壤中不同铝浓度的生物毒性，结果表明铝土矿复垦土壤中铝主要存在形态为结合态，而交换态比例较低，复垦土壤中铝对三种作物毒性影响较小。因此，铝土矿区复垦土壤主要的生产障碍因子为肥力低下及重金属（Cd和As）污染较高。铝土矿复垦土壤改良和培肥是解决当前复垦土壤适耕性低下的主要手段。复垦土壤改良剂结合氮磷钾（NPK）肥料调控试验结果表明生物质炭结合NPK效果较好，能够提高作物生长及降低安全风险。矿区高污染土壤种植经济作物也是重要的利用途径，盆栽实验结果表明，薰衣草对高铬污染土壤具有很高耐性，且能够积累铬，其在高铬污染土壤中具有一定的应用前景。锰矿污染调查结果表明，其复垦土壤肥力低下，重金属污染严重，其中镉和特征污染物锰是该矿区主要的重金属污染物，严重制约复垦土壤的安全利用。已经发表或录用研究论文7篇。