铅锌矿区耕地重金属污染土壤环境磁学监测方法研究

Study on Environmental Magnetic Monitoring of Heavy Metal Contaminated Farmland Soil in Lead-Zinc Mining Area

用环境磁学方法对甘肃徽县铅锌矿区典型耕地污染土壤、自然土壤和修复土壤进行监测研究,结果表明:污染土壤的磁化率(χ_(lf))与频率磁化率(χfd)呈显著的负相关,表明污染土壤磁性增强主要由铅锌矿厂在选矿冶炼过程中释放的含铁矿物所致;污染土壤χ_(lf)值在0 cm~30 cm深度范围内最高,污染严重;χ_(lf)值在30 cm~60 cm深度范围内明显降低,污染程度减弱;在60 cm~70 cm深度范围内与自然土壤的χ_(lf)值接近,污染基本消失。土壤污染程度随深度增加而降低,污染深度范围为0 cm~60 cm;从污染土壤、修复土壤到自然土壤χ_(lf)值依次降低,且污染土壤χ_(lf)值与重金属元素Pb、Zn等的变化趋势一致。

The typical contaminated farmland soil,natural soil and remediated soil in a lead-zinc mining area in Hui County,Gansu Province were monitored by environmental magnetic method.The results showed that there was a significant negative correlation between magnetic susceptibility(χ_(lf))and frequency magnetic susceptibility(χfd)of contaminated soil,indicating that the magnetic enhancement of contaminated soil was mainly caused by the release of iron-bearing minerals during the beneficiation and smelting process.Theχ_(lf)of contaminated soil was the highest in 0 cm~30 cm soil depth,indicating serious pollution,it decreased significantly in the depth from 30 cm to 60 cm,showing the pollution level was weakened,and in 60 cm~70 cm depth,theχ_(lf)was close to that of natural soil,showing the pollution was basically disappeared.The soil pollution level decreased with increasing depth ranging from 0 cm to 60 cm.Theχ_(lf)decreased sequentially from contaminated soil,remediated soil to natural soil.The change trend ofχ_(lf)of contaminated soil was consistent with the content of heavy metal elements such as Pb,Zn.