四川典型废弃硫铁矿地块环境调查研究

Environmental Investigation of Typical Abandoned Pyrites Mine Land in Sichuan

在硫铁矿的开采过程中,重金属污染、酸性矿山废水和固体废物需要重点关注。以四川某硫铁矿废弃地块为例,针对其开采情况开展了土壤、地下水和固体废物环境调查,提出了风险管控方案。结果表明:区内土壤重金属砷(As)和钴(Co)的含量超过了《土壤环境质量建设用地土壤风险管控标准(试行)》(GB 36600—2018)第二类用地管制值,需采取风险管控措施。表层土壤重金属含量受硫铁矿开采活动影响较大。重金属易在土壤表层或中层富集,向深层迁移较缓慢。矿井涌水主要表现为低pH值、高氟化物、高硫酸盐、高溶解性总固体和高硬度的特征,为典型矿山酸性废水污染,可采取矿坑水工程封堵与人工干预相结合的方法治理。区内硫铁矿在空气、水和微生物的作用下极易产生酸性矿山废水,从而导致重金属污染。原矿石堆放区I区尾渣体积为5310.14±1062.03 m^(3),原矿石堆放II区尾渣体积为1070.36±214.07 m^(3),区内固体废物堆存场所土壤风险等级判断为高风险,建议采用原位填埋和部分资源化再利用进行风险管控。

Heavy metals pollution,acid mine wastewater,and solid waste gradually came into the limelight of the process of pyrite mining.In this paper,an abandoned pyrite mine in Sichuan was used as an example,the environmental investigation on the soil,groundwater,and solid waste was carried out and risk control plans were proposed.The results showed that the content of soil heavy metals As and Co in study area exceeded the control value of the second category of land use in the Soil Environmental Quality Construction Land Risk Control Standard(Trial)(GB 36600—2018),so risk control measures were required.The content of heavy metals in the surface soil was greatly influenced by pyrite mining activities.Heavy metals were easily enriched in the surface or middle layers of the soil,but migrated slowly to the deep layer.The mine-gushing water was mainly characterized by low pH,high fluoride,high sulfate,high total dissolved solids,and high hardness,which was typical of acid mine wastewater pollution,so it was feasible to resort to an approach to combine engineering plugging and manual intervention of pit water.Pyrite mines in the study area tended to produce acid mine wastewater and resulted in heavy metal pollution under the function of air,water,and microorganisms.The volume of solid waste storage site I was(5310.14±1062.03)m^(3),and the volume of solid waste storage site II was(1070.36±214.07)m^(3).The soil risk level of solid waste storage sites in study area was assessed to be high risk,so adopting in-situ landfill and partial reuse of resources for risk control was extremely imperative.