The Concentrations And Health Risk Assessment Of Trace Elements In Household Dust From Urban Centers Of Chengdu,China

In this study,taking household dust from urban centers of Chengdu as our research target,investigating the concentration,enrichment and potential ecological risk of Pb,Zn,Cu,Cd,Cr,Ni,As,Hg in urban household dust,and exploring its possible sources and influencing factors.Simultaneously,analyzing the relationship between the trace elements in it and hair,to further understand the situation of trace elements accumulated in the urban residents.In addition,combined with bioavailability and health risk assessment model,the actual health risks of trace elements in household dust from Chengdu urban area were evaluated.It is great significance to reveal the risk of resident exposure to trace elements in the urban environment and to supplement the trace elements research data about ecological risk and toxicology in urban environment.The main findings are as follows:(1)The average contents of Pb,Zn,Cu,Cr,Cd,Ni,As and Hg in urban household dust from Chengdu were 123 mg·kg-1,675 mg·kg-1,161 mg·kg-1,82.7 mg·kg-1,2.37 mg·kg-1,52.6 mg·kg-1,19.3mg·kg-1,0.84 mg·kg-1,respectively,which were all higher than those in Chengdu soil background value.Compared with other countries or regions,the accumulation of trace elements in household dust from Chengdu was relatively low,but the average concentration of Cd is higher than that of most other countries or regions.(2)The enrichment factor values of trace elements in household dust were ranked in the order of Cd>Hg>Zn>Cu>Pb>As>Ni>Cr.Cr and Ni were weakly enriched,As was moderately enriched,Pb,Cu and Zn was significant enriched,Hg and Cd are highly enriched.Considering the toxicity factor of each trace element,the potential ecological risk index of trace elements in household dust were ranked in the order of Cd>Hg>Cu>Pb>As>Zn>Ni>Cr.Pb,Cu,As,Zn,Ni,Cr were the slight ecological risk,but for Pb,Cu,As and Ni,there are few sampling points for moderate ecological risk,Hg,Cd were extremely high ecological risk.(3)The cluster analysis of the trace elements in household dust from the urban centers of Chengdu was consistent with the principal component analysis results,and similar to the correlation analysis,that resulted in the three dusters including:(a)Pn,Zn,Cu,Ni;(b)Cd,As,Hg;(c)Cr.(4)There was a very significant positive correlation between smoking and Zn in household dust,and significant positive correlation with smoking and Pb,Cd.There were positive correlations between wall cover and 8 kinds of trace elements in household dust,among which Zn,Pb and Cu were significant.There was a very significant positive correlation between the time for last paint and Zn in household dust,and significant positive correlation with the time for last paint and As,Cd.There was a significant positive correlation between the age of building and Zn in household dust.There was a significant positive correlation between the number of occupants and Hg in household dust.There were negative correlation between the floor level and the sweeping frequency with the eight kinds of trace elements in household dust,in which the Ni and the floor level reached a significant level,Hg and the sweeping frequency reached a significant level.(5)The accumulation of Cd and Cu in hair from Chengdu was related to the household dust,while the accumulation of Pb,Zn,Cr,Ni and As was independent of the household dust.The average contents of Pb,Zn,Cu,Cr;Cd,Ni,As and Hg in hair were 1.30 mg·kg-1,294 mg·kg-1,20.3 mg·kg-1,0.24 mg·kg-1,0.17 mg·kg-1,1.05 mg·kg-1,0.12 mg·kg-1,0.25 mg·kg-1,respectively.(6)In combination with the bioavailability of trace elements,for non-carcinogenic risk,the hands-mouth intake pathway risk of exposure to children and adults was greatest,followed by skin contact,inhalation.The HI values for heavy metals in children were ranked in the order:Hg>As>Pb>Cr>Cd>Cu>Zn>Ni,and for adults,the HIs decreased in the order of Hg>As>Cr>Pb>Cd>Cu>Zn>Ni,the HI of trace elements for children is higher than that of adults,but all HI values were less than 1.For carcinogenic risk,the exposure risks of hands-mouth intake pathway for Cd and As were greatest,followed by skin contact,inhalation.The TR for four carcinogenic elements were ranked in the order:As>Cd>Cr>Ni.The TR of Cr and Ni were less 1 ×10-6,the TR of As and Cd were between 1 × 10-6 and 1 × 10-4.