半壁山金矿矿业活动区砷赋存的矿物特征及其对农田土壤砷累积的影响  

Mineral Characteristics of Arsenic in the Active Area of the Banbishan Gold Mine and Its Effect on Arsenic Accumulation in Farmland Soil

作　　者：温其谦 阎秀兰[1] 申俊峰[2] 李鸣凤[3] WEN Qi-qian;YAN Xiu-lan;SHEN Jun-feng;LI Ming-feng(Institute of Geographic Sciences and Natural Resources Research,Chinese Academy of Sciences,Beijing 100101,China;College of Earth Sciences and Resources,China University of Geosciences,Beijing 100083,China;College of Resources and Environment,Huazhong Agricultural University,Wuhan 430070,China)

机构地区：[1]中国科学院地理科学与资源研究所,北京100101 [2]中国地质大学(北京)地球科学与资源学院,北京100083 [3]华中农业大学资源与环境学院,武汉430070

出　　处：《环境科学》2019年第11期5090-5097,共8页Environmental Science

基　　金：国家自然科学基金项目(41571309)

摘　　要：为探索青龙满族自治县半壁山金矿矿业活动地区砷赋存的矿物特征及其对农田土壤砷的污染特征,应用矿物学和化学分析方法对矿业周边的矿石、废石、底泥、河流及土壤样品进行分析.在偏光显微镜下发现半壁山金矿周边的土壤与矿石、废石中均存在含砷矿物--毒砂,且废石中的毒砂已出现风化氧化现象,氧化的毒砂容易在土壤中迁移释放砷,存在较大的潜在危害.由于矿业运输活动以及土法冶炼的影响,砷主要分布在道路两旁或村民聚集地的农田耕层土壤0~20 cm,但在小巫岚村中也发现个别点位深层土壤砷含量高的现象.小巫岚村和高杖子村土壤砷的含量范围在7.2~196.2 mg·kg^-1之间,砷的超标率分别为45.9%和82.1%.根据RAC法评估,小巫岚村和高杖子村农田土壤主要处于低-中等风险,其中小巫岚村部分土壤点位已处于高风险.总体上,半壁山矿业活动周边含砷矿物毒砂部分已出现氧化现象且农田土壤砷的累积明显,可能会对当地的农作物以及长期居住在矿区周边的居民产生危害.建议对土壤-农作物-大气-人体系统开展砷的风险评估,并进一步对含砷矿物毒砂风化过程中的转换规律和机制进行研究,为耕地环境保护提供科学指导.To explore the source and pollution characteristics of soil arsenic,mineralogy and chemical analysis methods were used to analyze the ore,waste rock,sediment,and river and soil samples around the mining area.Under a polarized light microscope,Asbearing mineral-arsenopyrite was found in the soil,ore,and waste rock around the Banbishan gold mine.Moreover,arsenopyrite in the waste rock has already experienced weathering and oxidation,and the oxidized arsenopyrite easily migrates and is released in the soil,which is potentially harmful.Because of the effect of mining transportation activities and indigenous smelting,arsenic was mainly distributed in the topsoil,at a depth of 0-20 cm,in the farmland on both sides of the road and in the places where villagers were gathered.The soil arsenic content in Xiaowulan Village and Gaozhangzi Village ranged from 7.2 to 196.2 mg·kg^-1 and exceeded the rate of arsenic by 45.9%and 82.1%.According to the assessment by the RAC method,the farmland soil in Xiaowulan Village and Gaozhangzi Village were mainly at low to medium risk,although some soil points in Xiaowulan Village were at high risk.In general,the effects of the mining activities of the surrounding environment were not optimistic.As-bearing minerals in the oxidation of long-term weathering can cause much arsenic to be activated,which in turn,affects the local crops and long-term residents living around the mining area.It is suggested to carry out risk assessments for arsenic in the soil-crop-atmospheric-human system,and further study the conversion rules and mechanisms of arsenopyrite during weathering,to provide scientific guidance for the environmental protection of cultivated land.

关 键 词：金矿 矿业活动 砷 矿物 土壤污染 

分 类 号：X53[环境科学与工程—环境工程]