Analysis And Evaluation Of Heavy Metals Pollution In Water-soil-vegetable From Baima Village

In the environment, heavy metals pollution is not easy to be aware of because ofits hidden nature, but once generated, the consequences are often more severe. Soenhancing the monitoring on heavy metal elements in the environment becomes moreand more important to protect environment and safeguard human health. It is verycommon that soils and crops in suburb are contaminated by heavy metal elementspollution. This paper did some jobs to research the heavy metals pollution in Chengdusuburb, taking the white horse village as an example. There are26sampling sites ofsoil in the white horse village and46datum in total, for on10sampling points,itcollects3datum in different deep,0～10cm,10～20cm and20～30cm; Collectsamples of5kinds of vegetables (Pea sprouts, spinach, green beans, carrots, lettuce),there’re10samples for each kind of vegetable and50datum in all; collect theirrigation water sample on10consecutive days at the same time and the same place.Determine the content of heavy metal of including Cu, Pb, Cd and Cr in samplesthrough the flame atomic absorption spectrophotometric method. Using atomicfluorescence spectrophotometer to determine the content of Hg and As. This paperstudies on the distribution characteristics of heavy metals, the degree of the heavymetals pollution and also the sources of heavy metals, in order to provide referencefor the prevention of heavy metal pollution. Finally come to the conclusions asfollows:1、The concentration range of6kinds of heavy metal in irrigation water (copper, lead,cadmium, chromium, mercury, arsenic) is Cu：0.2168～0.8278mg/L，Pb：0.0485～0.1456mg/L，Cd：0.0074～0.0182mg/L，Cr：0.0288～0.0679mg/L，Hg：0.0006～0.0024mg/L，As：0.0632～0.1860mg/L; The pollution of irrigation water in this area ismainly due to heavy metals Cd and Hg, but the pollution is not so serious. Correlation analysis between heavy metal showed that, Cu-As, Pb-Cd, Hg-As has bettercorrelation. The highest correlation is between Cu-As.2、The contamination of heavy metals of soil in study area is from humanactivities and is mainly caused by the process of industry. In the0~30cm soil verticalprofile, the content of Cd, Pb and Cr decreased obviously with the increase of depth;the content of Cu in middle layer is lower than that of the layers above and below; thecontent of Hg、As do not change obviously with the increase of depth. Using singlefactor index, Nemerow index, geological cumulative index, potential ecological harmcoefficient and potential ecological harm index to evaluate pollution evaluation of soilheavy metal in the area, the results show that: the soils from Bai Ma village isuniversally polluted by Cu, Hg and Cd,among them Cu is at the level of lightpollution, Hg and Cd are at the level of severe pollution; In different samplinglocation,the contribution of heavy metal elements Hg and Cd leads soil withecological risk, the soil nearby Fu river is with moderate ecological harm, the rest ofthe soil sampling positions are with strong ecological risks, among them, theecological risk of soil near activity center is the highest.3、By the collection and determination of five kinds of different vegetables (Peasprouts, spinach, green beans, carrots, lettuce) growing in the study area, the resultshows that: the absorption of Cu、Cd is easily for the same kind of vegetables, whilethe absorption of Pb, Cr is harder compared with Cu、Cd element. The absorption forthe same heavy metal of different kinds of vegetables is: Cu: leaf vegetables>beans>roots;Pb、Cd、Cr、As: leaf vegetables> roots> beans; Hg: roots> leaf vegetables> beans.Vegetables from the study area are mainly polluted by the heavy metal elements Pb,Hg and Cd. The correlation between enrichment coefficients of different kinds ofvegetables to the same kind of heavy metal element and its single factor index issignificant. The content of heavy metal in vegetables and in soil are related, but nosignificant degree.