| With the rapid development of the international metropolis economy in Shanghai,China.The living standard of the city is getting better and better.The amount of municipal solid waste produced in the daily life has also been multiplying increasing,and the composition of the garbage is becoming more and more complex.Especially the environmental toxicity of dioxin and the health hazards to the population,has gradually attracted the attention of the whole society.For the newly built waste incineration plant,it is more necessary to follow the environmental impact of the surrounding environment and assess the risk of health in order to ensure the vital interests of the people nearby.Under this circumstance,this study using the China’s national standard HJ 77.2 and HJ 77.3 and the related sampling,analysis and quality control requirements,the dioxin in the ambient air and soil around a new domestic waste incineration plant in Shanghai was studied and analyzed.The main goal fo the study is to focus on the public complaints in the surrounding area,evaluate the relevant criteria,and the exposure dose and health risk of the surrounding population,and provide effective data support for the project,and theoretical basis for the all new waste incineration projects in the future.The main study contents and conclusions are as follows:1.Monitored and analyzed the concentration of dioxin in 192 ambient air samples around 6 sensitive sampling sites around the waste incineration plant.The results show that the concentration of dioxin in the ambient air of all 6 monitoring sites is at a relatively low level of 0.023 to 0.53pg I-TEQ/m3,which are much lower than most of the cities of our country.The concentration of environmental dioxins is also lower than that of China’s environmental air quality standard,which is 0.6 Pg I-TEQ/m3.In the analysis of dioxin concentration fingerprints of the study area,it was found that the highest concentration of all 6 points was 2,3,4,7,8-PeCDF,and the contribution rate was about 40%.This result was in accordance with the usually higher fingerprint characteristics of the exhaust dioxin,indicating that the main contribution of the dioxin concentration in the region came from the municipal waste incineration plant.2.The fingerprints of dioxin concentration and toxic equivalent concentration in the soil surrounding the waste incineration plant showed that the fingerprints of dioxin isomers in the 4 sampling sites and the characteristics of the environmental air were basically the same,indicating that the dioxin in the soil was mainly from the dry and wet sedimentation in the ambient air.The concentration level of soil dioxin in 1#and 3#points is high,and the 1#point in the two points is the normal wind direction of the perennial wind direction,and the 3#point is the downward wind direction of the annual wind direction.It also confirms that the waste incineration plant is the main source of dioxin content in the soil.3.Daily average respiratory exposure of adults to dioxin is 1.33×10-5 to 1.71×10-5ng I-TEQ kg-1day-1,and children are 3.18×10-5 to 4.09×10-5 ng I-TEQ kg-1day-1.Children’s respiratory exposure is more than twice that of adults,indicating that children are significantly more vulnerable to the risk of dioxin contamination.Both adults and children were lower than the dioxin health risk assessment standard of human body daily tolerable intake(4pg TEQ/kg)10%,they’re all at a very low level of pollution.However,the risk of respiratory exposure in children is almost 2 times more than that of adults,so when the concentration of dioxin is high,it is necessary to bring enough attention to the exposure of children and to do the corresponding emergency measures.The main exposure risk of people around the waste incineration plant is respiratory exposure.When only the daily exposure dose is considered,the risk of dioxin exposure of adults and children around the waste incineration plant is far less than 1,and the R value of the carcinogenic risk is below 10-6,and the risk of carcinogenesis is basically negligible.4.Daily average soil/dust intake of adult and children was 1.071×10-6～1.7×10-6 ng I-TEQ kg·kg-1·day-1、2.355×10-6～3.278×10-6 ng I-TEQ kg·kg-1·day-1.The soil/dust absorption and exposure of adults and children was 1.088×10-7～1.24×10-6ng I-TEQ kg ·kg-1·day-1、6.81×10-7～1.081×10-6ng I-TEQ kg ·kg-1·day-1,the exposure risk of children through soil/dust is much larger than that of adults,and adults are higher than children by skin absorption and exposure,so when the concentration of dioxin in the soil is high,both adults and children need to be given high attention and protection. |
