Pollution Characteristics Of Heavy Metals In Atmospheric Particulate Matter In Typical Area

To investigate the pollution characteristics and health risks of heavy metals in particulate matter of Chang-Zhu-Tan area,the northern area,the western cities,PM_2.5 samples were collected in 2 cities and 1 background site in each region.The concentrations of ten heavy metals?Cr,Mn,Ni,Cu,Zn,As,Cd,Co,Pb?were analyzed by inductively coupled plasma mass spectrometry.In order to assess the carcinogenic risk of Cr?VI?on human,Cr?VI?concentrations were calculated based on the reference ratio of 0.13 for Cr?VI?to total Cr.Also the health risk of heavy metals inhaled by respiratory system was assessed by the model recommended by US EPA,coupled by the exposure factors in China.The results of this research were listed as follows.?1?The average daily mass concentration of PM_2.5 in Changsha,Xiangtan,and background site-Hengshan Mountain were higher than the air quality standards in China.The heavy metals in winter were higher than those in summer.Enrichment factor analysis of heavy metals showed that Cd,Pb,Zn,Cu were significantly enriched,suggesting that they were mainly influenced by anthropogenic activities;while,Cr,Mn,Ni,As,Co were mainly form crustal materials.The health risk of heavy metals was estimated by Monte Carlo simulation.Results showed that the hazard index of different populations varies greatly,children>adult males>adult females.The non-carcinogenic risks were within the acceptable lever.The incremental lifetime cancer risk of Cr?VI?,Ni,As,Cd,Co for different populations varies greatly,adult males>adult females>children.The carcinogenic risks of As and Cr?VI?may be shown potential for adults.The adults exposed to Cd in winter of Changsha may have potential carcinogenic risk.?2?Beijing,Jinan and regional background site?Shangdianzi?are located in the northern area,the average daily mass concentration of PM_2.5 in the three sites were higher than the ambient air quality standards?GB 3095-2012?in China.The concentration of Zn and Pb were the highest in heavy metals of PM_2.5,the concentration of heavy metals in background were higher than those in city area.Enrichment factor analysis of heavy metals suggested that the 9 heavy metals were enriched in PM_2.5,suggesting the influences of anthropogenic sources.The risk assessment results showed that the hazard index for different populations were within the acceptable level.It should be noted that As and Cr???,as well as Cd may have potential carcinogenic risks for adults.?3?The average daily mass concentration of PM_2.5 in the two western cities?Baotou and Xining?and regional background site?the Yellow River in Baotou?were higher than the ambient air quality standards in China during winter.Results showed that Zn and Mn in PM_2.5 in two cities were higher than other heavy metals.Enrichment factor analysis of heavy metals indicated that Cd,Pb and Zn were significantly enriched in PM_2.5.The health risk assessment results showed that the hazard index for different populations within the acceptable lever.It was noted that the exposure to As and Cr?VI?have potential carcinogenic risks for populations.In addition,people who exposed to Ni,Cd,Co would have potential cancer risks in Baotou.