The Risk Assessment In Soil Of Electronic Waste Recycling Site

Heavy metals are one of typical persistent organic pollutants which have the property of persistent, bioaccumulative and toxic.Electronic Waste disassembling was an important factor causing soil heavy metals pollution.So this study was made to investigate the heavy metals polltion status in the soils of guiyu, and investigated heavy metals in the region around a point of E-waste dumps in electronic waste disassembling area with ICP-OES analysis methods. With collecting e-waste at the point of the surrounding soil, we planted two kinds of typical vegetables—Water spinach and Lettuce in the indoor. Test explored the subject of electronic waste piling up contaminated soil on the planting of these two kinds of vegetables were affected, providing reference data and scientific evidence of the e-waste leaching material impact on plant resistance of animals and plants. The main results were as follows:(1) For the radius of 100 meters of the soil around the waste recycling site , the results showed that contents of heavy metals such as copper, zinc, lead,cadmium in the soil were 2-200 times more than the background value of heavy metals in Shantou City, exceeded the "soil environmental quality standards" secondary standards .The concentration of Cd,Cu,Pb,Zn showed a rapid decrease within a short distance of 5 m , after that, the concentration of heavy metals in soil decreased slowly with the distance from e-waste reactors The nearer from accumulation point of demolition waste material, the higher were theirs contents. Heavy metals, such as copper, cadmium, zinc, lead were higher accumulation of points from the more recent trends in its distribution of the higher levels. The distribution trends of relatively low contents of mercury and chromium were not so obvious. The contents of heavy metals were high in the trigeminal river near the e-wastes recycling site . The north side of the river was not flowed, which had higher level content of heavy metals , but the trend was not obvious.(2) Study showed that the heavy metals distribution in plants of water spinach and lettuce planted on e-waste contaminated soil was root> stem> leaf. Lettuce was affected by heavy metal pollution, that can hardly grow in more serious contamination cases, while water spinach was negligible, whose different height growth was within 10%.(3) Research showed that chlorophyll on water spinach in the most contaminated soil was 44% of Shantou's, whill chlorophyll on lettuce was 22.1%. The chlorophyll content of water spinach planted on other soil was 74% ~ 88.7%, and lettuce was between 23% ~ 74.1%. Compared with water spinach, when Lettuce was under contamination stress, whose photosynthetic capacity decrease much more.(4) Research showed that the less vegetables were polluted by e-waste, the smaller activity of catalase and peroxidase will be. In the growing period, Water spinach had a little effect by contaminated stress, indicating it can adapted to the environment in a period of time. But Lettuce had always been affected, which telled Lettuce had poor self-regulation.