Chemical speciation and health risk of heavy metals in atmospheric PM2.5 in Urumqi City
Objective To understand the chemical speciation of heavy metals in PM2.5 and the people health risks in Urumqi.Methods In 2020,the content of heavy metals,Chromium(Cr),nickel(Ni),copper(Cu),manganese(Mn),lead(Pb),zinc(Zn)and cadmium(Cd)in PM2.5 in typical areas of Urumqi was continuously monitored,followed by analysis of their chemical speciation,identification of the source of PM2.5 and health riskassessment.Results In 2020,the average annual content of PM2.5 exceeded the limit of 35 μg/m3 stipulated in China's Ambient air quality standards(GB 3095-2012).The total heavy metal content of in 1#(major transportation area),2#(industrial concentration area),and 3#(agricultural area)monitoring points accounted for 1.57％,2.48％and 0.68％of the PM2.5 mass concentration,respectively.The elements of Cu,Cr,Zn and Mn were of higher mass concentrations in PM2.5 at different monitoring points in Urumqi.The heavy metal contents in PM2.5 at the three monitoring points were as follows from high to low:2# monitoring point＞l# monitoring point＞3# monitoring point.The main source of heavy metals in PM2.5 at 1# monitoring point,2 # monitoring point,and 3# monitoring point were fire coal,industry and transportation.Cu and Cd in PM2.5 at the three monitoring points were mainly in the residue state.Zn,Ni and Pb in soluble and exchangeable states accounted for more than 10％of the total.Cr and Mn were mainly in the combined state of organic matter,oxide and sulfide.The non-carcinogenic risks of Cr,Ni,Mn,and Cd to children and adults at the three monitoring points from high to low were:Mn＞Cd＞Cr＞Ni.The total hazard Index(HI)of the four metal elements at the three monitoring points was 0.181,0.314,and 0.090,respectively,and none exceeded 1.These four metals in PM2.5 had no obvious non-carcinogenic risks to the population.The carcinogenic risks of Cr,Ni,Cd,and Pb to children and adults at the three monitoring points ranked as Cr＞Ni＞Cd＞Pb,and all were at acceptable.Conclusion The content of Zn,Ni,and Pb in soluble and exchangeable states in PM2.5in this surveyed area was higher than that of other heavy metals,which requires more attention.The heavy metals in PM2.5 posed a lower health risk to residents.
UrumqiSource of PM2.5Chemical formHealth risk assessment
NETL
NSTL
万方数据
