Soil Pollution And Health Impact Assessment Of Relocation Enterprises In Chongqing

Urban Soil is one of main components of urban ecological environment which has a very important ecological, environmental and economic function, but also urban pollutants sources and sinks. Chongqing is a traditional comprehensive industrial city. And it is an important industrial region in southwest China. The layout of industrial in Chongqing is typical of delegation structure. And the majority of industrial enterprises located in the periphery of groups. With industrial development, urban-oriented, the original groups which located outlying industrial zone are located in the center of the city. The process and technology of these industrial established early are rather backward, so the aging problem of the equipment is serious. The supporting equipment of dealing with the "three wastes" is imperfect. The pollutants come into being from such an extensive mode of production generated in the venue had led to different levels of soil pollution.Nowadays, under the background of high-speed urbanization and shortage of land resource in urban center, the economical use of land and the contamination land recycled has become a more important ways for the sustainable use of urban soil. Moreover, with the concept of scientific development and the concept of people-oriented are bring forward, people pay more attention on the quality of the ecological environment. In order to improve the quality of the ecological environment, a readjustment of the industrial structure is putted in force in Chongqing. A majority of polluting enterprises, which located in the center of the city, are compelled liquidation or go bankrupt. Also they can move out from the center of the city.This research is about the soil pollution which coursed by the relocation of typical polluting enterprises. We monitoring and analysis soil from the venue. We want to identify the enrichment of heavy metals in soils and the potential ecological hazards of heavy metal contamination on human health risks which coursed by these enterprises factories. We also research the pollution coursed by oil and fluoride at some venue of the enterprises.We count the enrichment coefficient of heavy metal, and the result shows that the concentration of mercury, lead, arsenic and zinc in soil increase. Most enrichment coefficients of heavy metal are greater than 1. Some of the concentration coefficients were 72.0, 5.8, 1.8 and 2.3. We count the enrichment coefficients of nickel in soil near the plant of battery factory and the outfall site of wastewater plant. The enrichment coefficients are also greater than 1. The concentration coefficients were 15.0 and 7.2. The content of heavy metals in the soil surrounding the factory is increased. The enterprises factories do a greater contribution.We do heavy metal pollution evaluation via single factor index. The single factor index concluded that: all the content of heavy metals in the soil is not overrun limit of Grade B standard; but the content of heavy metals in some enterprises soils overrun limit of Grade A standard. The index of mercury pollution at the outfall of wastewater overrun limit of Grade A standard. The single factor index of cadmium pollution at a workshop one overrun limit of Grade A standard too. In addition, most index of nickel of batter)' plant overrun limit of Grade A standard, except the index of the bursary. All these soils are applicable to Class II land use types.The research about the potential ecological risk coursed by heavy metals shows that: the majority of factory pollution of heavy metals in soils subsist potential ecological harm in different degrees. From the point of view of single factor, the potential ecological harm coursed by mercury pollution is the most prominent, followed by the potential ecological harm coursed by the cadmium pollution. The compositor of potential ecological harm of seven kinds of heavy metals is Hg> Cd> As> Pb> Ni> Cr> Zn. The degree of potential ecological harm of some enterprises is higher than others, such as qianjin chemical plant and battery factory. The degree of potential ecological harm of three steel mills and the sixth pharmacy is at a low level. The degree of potential ecological harm of the point near the factories is also at a high level. We can conclude that these polluting enterprises do some impact on the surrounding soil.Some kinds of heavy metal are carcinogenic. The research on carcinogen risk study found that: human body absorb heavy metals mainly through three ways. The absorbency of these ways: direct intake> absorbed through the skin intake> respiratory intake. The absorbency of human body relate to the type of heavy metal. The gradation of absorbency roughly Zn> Pb> Cu> Ni> Cr> As> Hg≈Cd. Research of carcinogenic risk factor found that Cr for children and adults the range of coefficient of carcinogenic risk is in the 10^-9 to 10^-8, and it does not greater than 10"6. So it is an acceptable range. But the coefficient of carcinogenic risk coursed by As for is higher than Cr, in the scope of 10^-5 to 10^-4, over 10^-6, but not bigger than other 10^-4. Some expert say that the coefficient of carcinogenic risk is in the 10^-6 to 10^-4 is also an acceptable range. Generally speaking, the coefficient of carcinogenic risk of As has reached a higher level, we should pay attention to it. The coefficient of carcinogenic risk of Cd and Ni is at a low level, both of the coefficient is less than 10* , which is smaller the 10^-5, it is acceptable.At some factories venue we do research about other pollutants. The leachate toxicity of the residual solid waste deposited at the three steel mills and the sixth pharmacy is not overrun the standard. All the residual solid waste is not hazardous waste. The oil pollution in the soil of ink plant is not serious. The concentration of the oil in soil is far below the limit of Grade A standard. However, to the Qianjin chemical plant, the concentration of oil in the soil of fan is up to 3.82×10⁴mg/kg. It is a high concentration and overrun the limit of standard. The enrichment coefficient is 38.2, so we need do something to deal with it. The content of fluoride in soil of Qianjin chemical plant is 2-3 times content of the soil background value in Chongqing. It shows that the soil has been polluted by the production of phosphate fertilizer industry. In addition, the monitoring result shows that the concentration of the sulphur dioxide and nitrogen dioxide in the air near the Jialing chemical plant reached grade two of the national air quality standard, and the content of PM₁₀ in the air overrun the grade two of the national air quality standard. The content of PM₁₀ in the air near the Jialing chemical plant is 0.64-0.87 times the content of the grade two of the national air quality standard.