Characteristics And Risk Assessment Of Dioxin And Heavy Metal Pollution In The Surrounding Environment Of A Waste Incineration Plant In South China

With the continuous increase of population and the rapid development of social economy,municipal solid waste is also increasing,and the composition is increasingly complex.Waste incineration becomes the main treatment of municipal solid waste and have been widely used because of its capacity reduction,reduction,small footprint,mature technology.At the same time,the secondary pollution caused by waste incineration can not be ignored,especially dioxin and heavy metals.They can not only through the atmosphere diffusion,wet and dry settlement into the agricultural environment,being harmful to crops,but also having a serious impact on human health through respiration.In this study,our team selected a waste incineration plant in southern China as the research area,analyzed the contents of dioxin and heavy metals in the surrounding environment by the monitoring for 2015 and 2016,and carry out the risk assessment.The main conclusions are as follows:(1)In 2015,the levels of dioxins in the three farmland soil samples all met the most stringent control criteria(5 ng TEQ/kg)for dioxin in German soils,although both increased in 2016,but both served in New Zealand's agricultural land Soil standard(10 ng TEQ/kg).The concentrations of dioxin in the four air samples in 2015 and 2016 were 0.0922 to 0.206 pg TEQ/m3 and 0.290 to 0.543 pg TEQ/m3,which did not exceed the Japanese ambient air quality standards(0.6 pg TEQ/m3).The concentration of water samples in 2015 and 2016 ranges from 1.19 to 1.89 pg TEQ/L and 0.590 to 0.749 pg TEQ/L.The concentration of dioxin in the water at three points is at the same concentration level.Most of the soil fingerprints are similar to those of ambient air and water in dioxin fingerprints.Among them,2,3,4,7,8,-PeCDF monomer contributes the most.This suggests that the possible source of dioxin in the soil is mainly the transfer of dioxin in the air,wet and dry sedimentation and surface runoff.(2)Compared with 2015,the content of heavy metals in farmland soils increased slightly in 2016,but all met the requirements of Grade 2 of the Soil Environmental Quality Standard(GB15618-1995).The concentrations of Cd in the four points of 2015 and 2016 were between 2.35 and 11.6 ng/m3 and 0.20 to 4.10 ng/m3.The ambient air concentrations of Pb were between 85.2 and 422 ng/m3 and 12.2 to 118.4 ng/m3,they are below the standard limit(Cd:0.01375?g/m3,Pb:1.375?g/m3);Hg is not detected in the ambient air during the monitoring period;In the samples,Pb,Cd and Cr6 + were not detected in 2015 and 2016.The contents of Hg and As in the groundwater and reservoir water were similar,and the contents of Hg and As in surface water were significantly higher than those in the other two points.According to the on-site investigation,this point brings together landfill and nearby landfill leachate;(3)By assessing the health risks of dioxin in adults and children in the study area,we found that children's respiratory exposure was almost twice that of adults,but they were well below the acceptable daily intake of 10%,Which is at an acceptable lower level;comparing soil/dust intake with skin uptake exposure,we found that soil/dust intake was higher than skin absorption,whether adults or children;(4)Using the single factor index method,it is calculated that the single factor index of heavy metals in soil is<1,which meet the needs of agricultural farming;the non-carcinogenic risk index(HI)of the six kinds of heavy metals treated by hand-mouth,skin contact and respiration was<1,which indicated that the non-carcinogenic risk of heavy metals in the farmland of waste incineration plant was negligible;The carcinogenic risk of Cd and As was<1,which can be negligible,The carcinogenic risk of Cr was 10-6<CRCr<10-4,which was within acceptable limits.In summary,there is no significant impact on the surrounding farmland ecosystem and human health For the B plant.