【摘要】 在调查研究工业区、交通区和公园绿地土壤重金属Cd和Hg含量的基础上,对其污染程度进行了评价,结果表明:重金属Cd在工业区和交通区绿地土壤中的平均含量接近,均约为国家环境质量背景标准值的2倍,但在公园绿地土壤中没有明显的积累现象;与Cd不同的是重金属Hg在3种不同功能区中均有明显的积累现象,尤其是公园土壤中重金属Hg的含量为国家背景值的4倍。采用单项污染指数评价法对2种重金属的污染程度进行评价表明,工业区、交通区、公园绿地土壤中Hg的重度污染分别占28%、25%和50%,Cd的重度污染则分别占30.0%、37.5%和0%。通过种子发芽指数评价法进行评价得知,重金属对植物造成影响有一临界值,其含量只有超过该临界值才能对植物造成毒害,小于其临界值时对植物的影响不明显,但关于该临界值的确定还有待进一步研究。更多还原

【Abstract】 Based on the contents of Cd and Hg of the green-belts soils from industrial districts,traffic areas and parks,the green-belts soils were evaluated for heavy metal pollution.The results showed that the average contents of Cd in the green-belts soils from industrial districts and traffic areas were similar,which were twice more than its background values.However,no significant Cd accumulation occured in green-belts soils from the parks.And,compared with Cd,the significant pollution of Hg occurred in green-belts soils from the three different functional areas.Especially,the average contents of Hg were four times more than its background values in parks.Single factor pollution index of Cd and Hg were then utilized to evaluate soil pollution,the results indicated 28% soil samples from industrial districts,25% from traffic areas and 50% from parks were seriously contaminated by Hg.While for Cd,the ratio of heavily polluted soil samples was 30.0%,37.5% and zero,respectively.The results of seed germination index also indicated that the impact of heavy metals on plants had a critical value,and the heavy metal contents only exceeded its critical value,the posioning would be caused,otherwise,the impacts were not obvious.However,the determination the critical values need to be further studied.更多还原