西安市污灌区土壤中重金属潜在生态危害评价

为摸清西安市污灌区土壤环境质量现状及变化趋势,本研究采用西安市污水灌区农业环境质量状况调查的部分数据资料,以Lars Hakanson的潜在生态危害指数对4种重金属的危害程度进行了评价。结果表明,西安污灌区Pb、Cd、Hg、As潜在生态危害系数差异不大,其中Pb、Cd、As的潜在生态危害系数都小于40,生态危害程度为轻度,Hg则大于40,生态危害程度为中等;从潜在生态危害指数看,1982和1998年两次调查结果都小于150,重金属潜在生态危害为轻度。1998年在污灌区各元素的实测结果表明Cd和As为非污染,Pb为轻微污染,Hg污染程度比较严重,且有加重趋势。

Evaluation on Potential Ecological Risk of Heavy Metals in Soils of Xi'an Sewage Irrigation Area

In order to find out present conditions of soil environment quality and change trends in X'ian sewage irrigation area,this research adopts parts of data that originate in inquisition of agricultural environment quality condition of Xi'an sewage irrigation area,and evaluates potential ecological risk of 4 heavy metals in soils by Lars Hakanson index.The results show that the differences of potential ecological risk coefficient among Pb,Cd,Hg and As are not significant.The potential ecological risk coefficients of Pb,Cd,As are all smaller than 40,the degree of ecological hazard is light.Hg belongs to middle potential ecological risk whoes the potential ecological risk coefficient is bigger than 40.The potential ecological risk indexes that calculate by twice investigation results in1982 and 1998 are both smaller than150,which shows ecological hazard of heavy metals is light.The determined results of 4 heavy metals of soils in 1998 show that Cd and As do not pollute the environment,Pb pollutes slightly,and Hg pollutes seriously and becomes heavier.