冶炼厂污灌区土壤铜和锌污染与土壤酶活性

Cu and Zn pollution and soil enzyme activities in sewage irrigation area near smeltery.

通过对冶炼厂污灌区土壤和水稻中Cu、Zn含量分析以及土壤酶活性的测定,研究了距冶炼厂不同距离土壤Cu、Zn含量状况、水稻对它们的吸收和分配以及土壤酶活性的变化.结果表明,冶炼厂造成了周围农田土壤的Cu、Zn污染,其中Cu污染较严重,距离冶炼厂100m处的全量和提取态Cu分别为18245和8191mg·kg-1,是对照的103和35倍.污灌区水稻各器官Cu、Zn的分布规律是,Cu根>茎叶>米;Zn茎叶>根>米.Zn在水稻体内的移动能力大于Cu,Cu主要累积在水稻根部,根可作为一种屏障阻碍Cu向地上部分迁移,使地上部分免受其害.水稻茎叶Cu含量和土壤中Cu的浓度密切相关.对蔗糖酶、过氧化氢酶和脲酶活性测定表明,脲酶活性变化最显著,其活性与土壤中Cu的浓度显著相关,建议用脲酶活性作为污灌区Cu污染指标.

This paper studied the Cu and Zn status in soil and rice plant as well as the soil enzyme activities in the sewage irrigation area near a smeltery.The results showed that the soils near the smeltery were polluted.The soil total and extractable Cu contents at the distance of 100 m were 182.45 and 81.91 mg·kg^-1 ,respectively,9.3 and 34 times higher than the control.The Cu concentration in different parts of rice was in order of root>leaf and stem>grain,while the Zn concentration was in order of leaf and stem>root>grain.Zn was more mobile than Cu which was likely to accumulate in rice root.It was considered that root could act as a barrier which retarded the upwards transport of Cu and protected the above ground parts of rice from toxication.The Cu contents of rice stem and leaf had a significant correlation with soil Cu contents in the sewage irrigation area.Among the three test enzymes,urease was the most sensitive one to Cu,and its activity had a significant correlation with soil Cu content.Therefore,it is feasible to use soil urease activity as an indicator of soil Cu pollution in sewage irrigation area near the smeltery.