Risk Assessment On Abandoned Sites

Pollution caused by contaminated sites has become a global environmental problem; it has caused serious damage to social and ecological environment. A large number of industrial and mining enterprises were closed down or moved, when the city's reconstruction and expansion, usually such contaminated sites are involved in all types of industries, and impact on the surrounding environment and have potential human health hazards, therefore analysis, statistics, classification and registration of the nature and degree of hazard on contaminated sites is necessary.In this study, we made an investigation on the abandoned manganese sulfate chemical plant of a certain county in Hunan province, and we have done some research such as:heavy metals species, Evaluation of soil environmental quality, Health risk assessment of heavy metal pollution about soil and water。It can provide theoretical and technical support when contaminated sites further restoration or reuse to be done. The main results are as follows:(1) Soil and water pH values of the abandoned chemical plant are acidic except one, pollution has regional differences, the pollution of the overlaying soil around the chemical plant is fairly light. The pollution of the southwest chemical plant is very serious;(2) Bioavailability factor analysis showed that the bioavailability of heavy metals in the order of Cd>Mn>Zn>Cu>Pb;The linear dependence of the total amount indicates that there was a good linear relationship between Cu,Zn and Mn. The relativity between Cu,Zn and Mn was significant under the given level. It illustrates the three heavy metal pollution provides with the same source of pollution;The relativity between the total amount and the species indicates:There was a good linear relationship between the total amount and F3,F4,F5 of Cu, the significant relativity under the given level shows that the total amount affects the three species; (3) The soil pollution evaluation results showed that the soil of the abandoned chemical plant has been seriously polluted. The levels of heavy metals are not appropriate for agriculture,forestry and fruit development;(4) The research about the potential ecological risk coursed by heavy metals shows that:Ecological harm of the plant was in different degrees. From the point of view of single factor the potential ecological harm coursed by cadmium pollution is the most prominent. The southwest of the plant the compositor of potential ecological harm of five kinds of heavy metals is Cd>Mn>Cu>Pb>Zn.;The research on heavy metal risk study found that:Human body can absorb heavy metals mainly through three ways, the order of intake of these ways:direct intake> absorbed through the skin intake> respiratory intake. The major contribution factors of non-cancer health risks are skin risk exposure of Pb and dust inhalation of soil risk of Cd;(5) The health risk assessments on heavy metals in water samples collected from the abandoned manganese sulfate site were studied. The results showed that the manganese sulfate chemical plant was closed, although the health risks of heavy metals to human maybe happened. The concentrations of Mn in drinking water were exceeded the standard values. Especially, the concentrations of Mn in surface water were much higher than the corresponding value, exceed standard ratio is 100%, The health risk level in terms of non-carcinogens to an adult who drink the water were Mn>Pb>Cu>Zn.