Dismantling Of Discarded Electronic Products On The Compound Pollution Of Farmland Soil Characteristics And Regulation Of Repair

Electrical and electronic waste(e-waste)has become the fastest growing stream among all the solid waste around the world. In China, the amounts of e-waste increases rapidly in recent years; these e-wastes can be sourced both domestically discarded products and imported waste. The demand for materials is on the increase with expanding economy. Recycling materials from e-waste is an effective way to obtain scarce industry raw materials. There are about 80 to 90 percent of substances in e-waste are valuable and reusable. The demand for recycled materials and the potential economy benefit are promoting the development of disassembly industry of e-waste in littoral. Guiyu, Guangdong and Taizhou, Zhejiang are the two largest e-waste disassembling areas in China. Since the early days of the development for dismantling industry, there many wrong ways to dismantling e-waste, leading to the some kinds of pollution of the soil nearby. The pollution change from single and simpleness to combined and complexity. In this study, we investigations and studies main pollution and the contents of the substances distribution of farmland soil surrounding a typical waste electronic products dismantling area in Yangtze River Delta systematically, and select the area near the acid pollution, do some indoor and Outdoor remediation. The results showed that:(1): 19 kinds of PCBs homologue can be detected in soil near the five main sources of pollution. The values of PCBs in soil of this area were in a range of 0- 106 1μg/kg, the values of PCBs in soil of Acid Washing sources were in a range of 15.07-106 1μg/kg, the values of PCBs in soil of Abandoned. Disassembly sources were in a range of 8.12-110.9μg/kg, the values of PCBs in soil of Transformer Disassembly sources were in a range of 37.45-104.1μg/kg, the values of PCBs in soil of Fire Disassembly sources were in a range of 8.20 - 135.9μg/kg, the values of PCBs in soil of Electroplating sources were in a range of 0.92- 143.1μg kg-1. The results also found that under the influence of different sources of pollution, PCBs accumulated in soil differ from land use patterns. The concentration of PCBs in paddy fields (an average of 98.97μg/kg) >vegetable soil (an average of 40.35μg/kg) >woodland soil (average of 10.63μg/kg).Regarding spatial distribution, Fire Disassembly sources and Electroplating sources affect by wind and the soil PCBs migrate by the impact of alternating wet and dry in the prevailing wind direction. Distribution of soil near Acid Washing sources may be mainly caused by the sewage irrigation. No significant PCBs distribution was found near Abandoned Disassembly and Transformer Disassembly sources, it may correlate with the place where disassembly occurred.(2): The soil Cu, Cd, Pb and Zn contents in typical surface area of farmland in the whole range of 11.2 to 721.2 m/kg, 0.3 - 15.3mg/kg, 5.0 to 157.2mg/kg, 53.5 to 758.2 mg/kg, the average contents was 115.1 mg/kg, 1.9mg/kg,51.8 mg/kg, 209.8 mg/kg, which were significantly higher than those background values in the region of Zhejiang Province soil (Cu: 19.8 m/kg, Cd: 0.20 mg/kg, Pb: 24.5 mg/kg, Zn: 84.8 mg/kg). Compared with the second national environmental quality standards of soil ,the average contents of Cu, Cd and Zn respectively-wide more than second soil environmental quality standard value (Cu: 50.0 mg/kg, Cd: 0.30 mg/kg, Zn : 200.0 mg/kg) 2 times, 6 times, doubled. Pb not exceed the second soil environmental quality standard value (Pb: 250.0 mg/kg). It had hazards on the local environment And the sources of heavy metals in soils of different migration, acid source and the burning sources exist on the prevailing wind direction during the migration, transformers disassembling and dismantling migration of waste in a similar, smelters Zn main cause of pollution in all directions all a migration. In the region there are various heavy metals and organic pollutants in the combined pollution, the sources of pollution and the presence of small dispersed sources of pollution, pollution in the complex.(3): We have do softie preliminary study of multi-objective restoration measures on the PCBs and heavy metals contamination soil. Through the application of acidification improver (lime) and the heavy metal deactivator (FCMP) coupled with reasonable tillage management measures can effectively reduce pollution of the soil available heavy metals content, thus reducing toxic heavy metals in soils, and enhance indigenous microbial activity so improve its Degradation of organic pollutants PCBs efficiency, achieve multi-target repair. Acidification improver (lime) application amount determined after an initial test of 120 kg / mu, heavy metal deactivator (FCMP) 30 kg / mu, the repair can be achieved relatively good results, and plants can provide better soil environment, To lay the groundwork for phytoremediation.