以植物、土壤元素含量评价天津大气环境质量

EVALUATION OF ENVIRONMENTAL QUALITY OF ATMOSPHERE BY DETERMINATION OF ELEMENT CONTENT IN PLANTS AND SOILS IN TIANJIN

本文以天津主要绿化植物及土壤受污染的状况来说明不同功能区大气颗粒物污染的程度。结果看出:工业污染区冶炼厂的植物 Zn、Cu、Cd、Pb 的含量都是最高的 Ni、S 的含量也较高。冶炼厂植物重金属含量一般为自然背景值的3—11倍或更高些;其次为商业交通区及公园,Zn、Cu、Ni、Cd 为自然背景值的1.5—3.5倍。其他如文教区、市郊公路、各郊区植物均无明显污染,对照区盘山植物各元素含量都很低。土壤也以工业污染区冶炼厂及东郊化工厂污染最明显,冶炼厂 Pb、Cu、Cd、Zn 在土壤中的含量可为自然背景值的725,348,9,3倍;S 为14倍,而其中 Pb、Cu 大部分以粉尘的状态沉积在土壤表层。商业交通区及公园的污染也较明显,Pb、Cu、Cd、Zn 及 S 可为自然背景值的2—10倍,对照区土壤各元素含量都最低。从植物的气孔受飘尘堵塞所引起的扩散阻力增大的趋势也可看出各功能区飘尘污染的特点,气孔阻力增大的顺序是工业污染区>公园>商业交通区>市郊公路>对照区,这与上述功能区植物和土壤受污染的规律是相符的。

165 plants and 40 soil samples were collected at seven areas in Tianjin.The analysis of sulphur and heavy metals in these samples showed the polluted degree of the air.It is indica- ted that the plants at smeltery(polluted industry area)contain Zn,Cu,Cd,Pb highest and Ni, S higher.The content of heavy metals in these plants were 3—11 times higher than that of the background value.In business-traffic area and park,the amount of Zn,Cu,Ni,Cd in the plants were 1.5—3.5 times higher than the background value.In the other area,such as culture-education area,road and suburbs,the pollution is not significant,and in the clean area (Panshan),all elements in the plants are the lowest.As to the soils in polluted industry area (Smeltery),the amount of Pb,Cu,Cd,Zn and S was 725,348,9,3 and 14 times higher than that of the background value respectively.Among them,most of Pb,Cu were deposited in sur- face layer.In soil of business-traffic area,Pb,Cu,Cd,Zn and S were 2—10 times higher than the background value,and in the soil of clean area,all elements are also the lowest. The stomata of plants which were blocked by the particles going down from the air.resulted in increase in the stamotal diffusive resistance and the order of the resistance in the different places are as follows:polluted industry areas>parks>business-traffic areas>road>clean areas. These results are in agreement with the polluted state of the plants and soils in above mention- ed areas.