某铅锌冶炼厂废弃地复垦整理区土壤重金属污染状况评价

Contamination of Heavy Metals in Soil of Abandoned Land Reclamation Area around a Pb-Zn Smelting Factory

在对贵州省六盘水市某铅锌冶炼厂废弃地复垦整理区进行详细踏勘调查的基础上,根据项目区分布状况,以拆毁的冶炼炉及矿渣场为中心划分为3个采样区域,采集土壤剖面的发生层混合样品9个和项目区外未受污染影响的耕作层混合土样1个以及矿渣样品1个,分别测定了样品中重金属Cu、Zn、Pb、Ni、Cd、Cr、Hg、As含量以及部分理化性质,应用单项污染指数和综合污染指数法对该区域重金属污染现状进行了评价。结果表明,废弃地上矿渣场堆放的铅锌冶炼矿渣中除Cu、Cr、Hg的含量较低、污染指数小于1之外,Zn、Pb、Ni、Cd、As的含量很高,其单项污染指数分别为2.95、45.14、1.00、10.67、50.41,综合污染指数高达36.98,属于剧烈污染源。项目区土壤综合污染指数在0.77～1.99之间,综合污染指数小于1的未受重金属污染的土壤占总样品数的50.00%,而综合污染指数大于1.00但没有超过2.00的样品数占总样品数的50.00%,表明项目区仅有部分土壤遭受重金属的轻度污染。在控制矿渣潜在污染扩散的前提下,采用适当的复垦整理、改良技术和合理的利用方式,可以促使该废弃地恢复农业生产能力。

A study was conducted on an abandoned land reclamation area around a Pb-Zn smelting factory,taken abandoned stoves and slag dump as center to evaluate pollution of heavy metals on soil.The research area was divided into three sample districts.Nine mixed samples of the genetic profile horizon in the polluted area,one mixed sample of plough layer in unpolluted area and one sample of slag were collected.The contents of Cu,Zn,Pb,Ni,Cd,Cr,Hg,As and some physical-chemical property were analyzed in lab,respectively.The results that were assessed by single contamination index method and comprehensive contamination index method showed that: exception of the contents of Cu,Cr,Hg(contamination index<1),the other were in high levels.The single contamination indexes were found to be 2.95,45.14,1.00,10.67,50.41,respectively and comprehensive contamination index was 36.98,belonging to a heavy contamination source.The comprehensive contamination indexes for the survey area were in a range between 0.77 and 1.99.The samples with the comprehensive indexes lower than 1 accounted for 50% in the studied area.In addition,the comprehensive contamination indexes for the rest area were below 2.These evidences indicated that the level of contamination in the research area was in low-grade and it was possible to restore agricultural productivity of soil by proper exploitation and reclamation.