| The PM2.5 samples of fugitive dust(road dust,construction dust and soil dust)were collected in Nanchang city.The contents of inorganic elements,water-soluble ions,polycyclic aromatic hydrocarbons(PAHs),and the isotopic compositions of Pb,Sr and Nd in the PM2.5 samples were detected.The sources and relative contributions to above PM2.5 were analyzed,and the main research achievements are as follows:Crustal elements were the major elements in the PM2.5 of soil dust in Nanchang City.The PM2.5 of road dust was related to human activities,and the proportion of Ca in construction dust was the highest.There was a similarity among the PM2.5 fractions of road dust,construction dust and soil dust.The rare earth elements(REEs)in PM2.5 of fugitive dust and potential-source showed the enrichment of light rare earth elements(LREE)relative to heavy rare earth elements(HREE).The fugitive dust PM2.5 was greatly affected by natural sources and coal combustion.Cluster analysis showed that the main sources of heavy metals in the fugitive dust PM2.5 were transportation,industrial emissions,soil dust and coal combustion.The results of principal component analysis showed that the sources of heavy metals in PM2.5 of road dust in Nanchang city included motor vehicle emissions and industrial activities,soil sources,metal smelting and coal burning sources with the contribution rates of 71.81%,2.24%,24.56%and 1.39%,respectively.The contents of PAHs in PM2.5 of road dust,soil dust and construction dust ranged from 48.85-166.16 ?g·kg-1,31.05-62.92 ?g·kg-1 and 60.61-74.95 ?g·kg-1,respectively.The order of the number of rings of PAHs in the PM2.5 of three fugitive dusts was 5 rings>4 rings>3 rings>2 rings>6 rings.The PAHs in the three fugitive dusts might have the same sources.The ratios of characteristic compounds indicated that combustion was the main source of PAHs in the PM2.5 of three fugitive dusts,and the petroleum source existed in road dust PM2.5.The results of principal component analysis combined multiple linear regression analysis showed that the sources of PAHs in PM2.5 of road dust in Nanchang included motor vehicles emissions and coal-fired sources,and oil spills,contributed 51.7%and 48.3%,respectively.Combination tracing of the isotopic compositions of Pb,Sr and Nd showed that the PM2.5 of the three fugitive dusts mainly came from metallurgical smelting dust and coal combustion,while the traffic emission to the PM2.5 of road dust could not be ignored.Natural sources contributed more to the PM2.5 of soil dust than to the PM2.5 of road dust and construction dust.The results of enrichment factors showed that Hg and Mn in the PM2.5 of three fugitive dusts were significantly enriched,while Co and V were sligtly enriched.The geoaccumulation indexes showed that Hg and Mn in the PM2.5 of three fugitive dusts presented moderate pollution,while Cr,Co and V presented no pollution.Non-carcinogenic risks of heavy metals in fugitive dusts were less than 1,and the ingestion was the main pathway for non-carcinogenic risk in PM2.5 of fugitive dusts.Except for 0-<3 years old,total non-carcinogenic risk value(HQT)generally showed a trend of decreasing with age.The total carcinogenic risk values(ILCRT)of heavy metals were less than 10-6,and increased with age.Benzopyrene(BaP)had the highest toxic equivalent content in the PM2.5 of fugitive dusts,and carcinogenic PAHs were the main contributors to the toxic equivalent.The carcinogenic risks of PAHs in different exposure pathways were less than 10'6,and increased with the age of the population.Among different exposure pathways,the carcinogenic risk of PAHs in the PM2.5 of road dust was the highest,and the carcinogenic risk of PAHs in the PM2.5 of soil dust was higher than that in the PM2.5 of construction dust.The order of carcinogenic risk through the three exposure pathways decreased as dermal contact(ILCRderm)>ingestion(ILCRing)>inhalation pathway(ILCRinh),with ILCRderm slightly larger than ILCRing. |
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