| The heavy metal soil pollution caused by“running,emitting,driping and leaking of the wastewater”in the production process of the electroplating industry is characterized by chronicity,concealment and irreversibility,which makes most of the sites of relocated or closing electroplating enterprises become highly polluted or high risk areas.Therefore,to carry out the repair project of typical electroplated contaminated sites is of practical significance for protecting the physical and mental health of the public.The establishment of restoration target values is the core of soil restoration,directly relating to the restoration costs.Meanwhile,to build up a health risk assessment technology framework and model is the key sector in the establishment of repair target values.At present,there are five types of health risk assessment models that are highly recognized at home and abroad and widely used.There are different emphases in different models.The application without systematic sesearch and analysis will adversely influence the scientific establishment of target values for the remediation.This paper compares and analyzes the relevant theories of soil remediation target values at home and abroad.By means of data research,field visits and experimental analysis,the concentration range of electroplating characteristic pollutants and the localization parameters of the health risk assessment model are determined.The principles,steps and methods for value development are also discussed.Based on these,taking a typical electroplating contaminated site in the Pearl River Delta region as an example,the restoration target values of zinc,copper,and nickel under sensitive land conditions were calculated,which were compared to the original report carried out under non-sensitive land conditions for rationality analysis The main conclusions are as follows:?1?The principles for the establishment of the remediation target value are based on the health risk assessment of different exposure pathways and are calculated by the exposure assessment model of the contaminated site.The remediation target value should be comprehensively considered with the background level of pollutants,instrument detection limits,other relevant environmental standard values,etc.Different countries have significant differences in target values due to factors such as the natural environment,economy conditions,and social development stage.According to the future functions,protection objectives,and exposure methods of contaminated soil,it is currently widely used in developed countries to set standards or guidance values using corresponding ecotoxicological data and health risk assessment methods.?2?By means of data research,field visits and experimental testing,the concentration range of electroplating characteristic pollutants and the localized parameters of the health risk assessment model were preliminarily analyzed,and the calculation methods for target value of soil remediation for typical electroplating contaminated sites based on non-carcinogenic and carcinogenic risks was determined.?3?Taking a typical electroplated contaminated site in the Pearl River Delta as a sensitive land example,a case study on the establishment of target values for remediation of contaminated sites was carried out.The main soil pollutants on the site are copper,zinc and nickel,with concentrations ranging from 18 to 2270 mg/kg,7.5 to 7470 mg/kg,and 12 to902 mg/kg.The carcinogenic risk of copper and zinc is 0,and the carcinogenic risk of nickel is 1.50×10-6?8.94×10-6.The non-carcinogenic hazard quotients of copper,zinc and nickel are 3.42,1.05×10-1?8.64×10-1,1.67?9.96.Under sensitive circumstances,the pollutants copper,zinc,nickel repair target values are 663 mg/kg,4970 mg/kg,90.5 mg/kg,all of which are less than the target value in original survey with non-sensitive background,with copper of 6630 mg/kg,zinc of 49800 mg/kg and nickel of 200 mg/kg. |
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