Health Risk Assessment Of Contaminated Sites

With the relocation or suspension of industrial enterprises,bankruptcy has resulted in a large number of diverse and complex contaminated sites.Therefore,it is important to assess the degree of pollution of heavy metal contaminated sites and to assess the adverse effects of heavy metal pollution on human health.The spatial and temporal analysis of health risks of heavy metal contaminated sites is based on spatial risk assessments developed in specific regions.Through analysis and evaluation,it can not only comprehensively and accurately assess the unfavorable health risks and potential hazards of heavy metals in humans contaminated by heavy metals;it can also provide reliable theoretical support for subsequent government enterprises to repair contaminated sites through systematic evaluation.Based on health risk assessment,heavy metal morphology and spatio-temporal analysis,this paper takes heavy metal pollution in Jiangxi research area and Jiangsu research area as the cases.The heavy metal arsenic and lead were taken as target heavy metal pollution to conduct a comprehensive and accurate assessment.The main research contents and research results were obtained as follows:(1)In the Jiangxi research area,after the data optimization and simulation,the dominant arsenic species were found to be H3AsO3,AsS(OH)HS-,H2AsO4-,H2AsO3-and HAsO4-2.The size of carcinogenic and non-carcinogenic risks in the study area is in descending order:HAsO4-2>H3AsO3>H2AsO4->H2AsO3->AsS(OH)HS->AsO4-3>H3AsO4>HAsO3-2>As3S4(HS)-.The highest cancer risk is 0.004(HAsO4-2,S9)and the highest non-oncogenic risk is 27(HAsO4-2,S12).(2)After the data analysis was corrected and simulated in the Jiangsu research area,it was found that the nine major Pb(?)forms contributed a lot to the total amount of Pb(?):Pb(CO3)2-2,Pb(HS)2,Pb+2,Pb3(OH)4+2,Pb4(OH)4+4,PbCl+,PbCO3,PbHCO3+ and PbOH+.The non-carcinogenic risk reduction order of the six major Pb(?)forms was residue state>carbonate bound state>weak organic bound state>exchangeable state>lead sulfide state>sulfate bound state.(3)The toxicity of the modified heavy metal is reduced as compared with the unoptimized modified heavy metal.The unoptimized corrected arsenic speciation concentration is lower than the corrected arsenic speciation concentration,the corrected trivalent arsenic concentration is lowered,the pentavalent arsenic concentration is increased,and the total concentration is decreased.The total concentration of lead is reduced after correction.(4)Through concentration prediction and blood lead prediction,when the initial concentration of the sampling point is large,its concentration has been decreasing for 20 years(as in S9 and S7);at other sampling points,the concentration of Pb(II)is increasing.(as in S5).The predicted blood lead levels increased over the 20-year period until the maximum blood lead level was reached after 20 years(child:S9,156 ?g dL-1;adult:S9,121.8 ?g dL-1)In summary,it can be seen that considering heavy metal morphology and space-time analysis is indispensable for comprehensive and accurate assessment of health risks on heavy metal contaminated sites.It could be seen from the two health risk assessment cases of contaminated sites based on this analysis that the remaining sites are subject to severe heavy metal pollution.Considering the time effect at the same time,it can be seen that although the initial pollution level of some research areas is not high,the pollution will further deepen with time,and natural degradation alone is far from sufficient.More systematic and comprehensive assessment of site pollution,provides a reliable theoretical basis for government decision-making.