Human Health Risk Assessment Quantification From Sources Of Topsoil Heavy Metals Using PMF-HRA Model

With the development of social economy of China,the pollution of heavy metal has attracted the attention of government managers and the public gradually.Since the sources of soil heavy metals are complex and widely distributed,the quantitative source analysis of soil heavy metals is particularly important for controlling heavy metal pollution from the source.Under different land use,the sources of soil heavy metals are different,and the exposure pathways that are harmful to human health are also different.Assessing the health risks quantification sources of soil heavy metals can avoid unnecessary economic losses due to the combined effects of heavy metals(overestimating or underestimating the value of health risks).And it can also provide the reference for the authorities and risk decision makers.In this study,the state of art and sources of heavy metal pollution,the health risk assessment model,and the method of source appointment were comprehensively analyzed firstly.Then a new health risk assessment model method was proposed.This model combined the receptor model-positive matrix factorization(PMF)model and health risk assessment(HRA)model.And it took the different land use types and the relevant historical data of research area into consideration at the same time to obtain the composite health risk assessment quantification from sources.In this study,we took the Xiang River New District(XRND)of Changsha City,Hunan Province as a case.A simple statistical method and the enrichment index method were used to identify the soil heavy metal(Cu,Zn,Pb,Cd,Cr,Mn,and Ni)pollution in the XRND.The results showed that except for Mn,the other 6 heavy metals were mild-strong pollution,especially Cd.The PMF model was taken to quantify the sources of soil heavy metals and the results showed the main source of heavy metals in the XRND may be natural sources,traffic emission,industrial discharge and agricultural activities,and the contributions were 19.4%,23.8%,33.5%,and 23.3%,respectively.Finally,according to the new proposed(PMF-HRA)model quantification the sources of soil heavy metal under three types of land use.It is found that on the residential-land and farmland,the non-carcinogenic risks of soil heavy metal pollution in children were not to ignore,however,the risks for adults was relatively small and in the acceptable range.On the forest land,the non-carcinogenic risks for adults and children were within acceptable range.As for the carcinogenic risk in the three types of land use,the risks for adults and children is greater than the sum of the other three sources.Besides,the non-cancer risk areas of adults affected by industrial discharge was higher than that of children,while the cancer risk areas of adults were on the contrary.The new exploration was useful to assess health risk quantification from sources under different land use,providing certain reference for the managers in land planning management and the prevention and control of soil heavy metal pollution.