Study On Health Risk Assessment Of Contaminated Land Based On Multiple Land Utilization Planning

In the process of modernization and rapid construction of “Vacating cage to change bird” in eastern China,there will be a large number of suspected high-risk contaminated sites.These contaminated sites due to the emissions of pollutants,leaks or accidents,not only does it will cause pollution to the surrounding soil and groundwater environment,and it also will destroy the balance of the ecosystem in the area.In order to avoid the adverse impact on the human health during the reuse of these contaminated sites,and to reduce development costs and to rationally plan the use of land,it is necessary to carry out health risk assessments for various land utilization planning scenarios for contaminated sites.Based on the analysis the health risk assessment model recommended in the Technical Guidelines for Risk Assessment of Contaminated Sites(hereinafter referred to as Guidelines)in China,and related research results at home and abroad are combined with,the health risk assessment model recommended by the Guidelines is appropriately improved.Taking a relocation chemical plant in Danyang City as a typical contaminated site,the health risk assessment models before and after the improvement were used to the actual cases,and the differences between these two health risk assessment models are analyzed specifically.The main progress is as follows:(1)According to Code for classification of urban land use and planning standards of development land(GB 50137-2011),the types of planning for reuse of contaminated sites can be classified into low-density residential,high-density residential,school-used land,leisure and sports land,commercial and service land,industrial storage land,underground facilities,road and track land.It is no longer confined to the health risk assessment of sensitive and non-sensitive land.(2)For toxic pollutants with vacant parameters,it is proposed to obtain more reasonable toxicity parameters by thresholding method,cross-reference method,etc.,to avoid ignoring the risk of certain toxic substances on human health.By considering the quantification of exposure at different physiological stages,the difference in tolerability of toxic substances at different physiological stages,and the model of groundwater seepage invasion,the results of risk characterization will be more accurate,and it will be conducive to the protection of human health.(3)In the application of actual cases,the results of the recommended health risk assessment model of Guidelines show that the non-carcinogenic health risks of both land use planning are acceptable for both sensitive and non-sensitive land.The results of the improved model show that,due to the actual situation,road and track land is not considered;without consideration of remediation work,the non-carcinogenic risk to human health is acceptable only during the reuse process of leisure and sports land planning;if the contaminated site is to be used as the remaining six types of land utilization planning,it is necessary to carry out appropriate remediation work on the underlying soil(1.5-4.5 m)or groundwater.In summary,the calculation results of the improved health risk assessment model will be more conducive to the rational planning of reuse of contaminated site.