Persistent Organic Pollutants Of Organochlorine Pesticides (OCPs) And Polycyclic Aromatic Hydrocarbons (PAHs) Innroad Dust From Xinxiang

Persistent organic pollutants (POPs) have the characteristics of long residual property,higher bioaccumulation potential, semivolatility and high toxicity. They could bring on theeffects of ecological toxicology in food chain, the effects of carcinogenicity, teratogenesis,mutagenesis and feminization in environment. For persistent organic pollutants (POPs) are badlyendangering the human healthy and aquicolous biogeocenose, they have now represented aglobal environmental problem given great attention all the world. Urban road dusts pose greatrisks to ecosystems and human health. As one of important repositories of POPs, road dust couldbe resuspended or volatilized into atomsphere under favorable conditions, which result in secondcontamination of POPs. The paper concerned with Xinxiang in Henan province. The levels ofPAHs and OCPs in urban road dust from Xinxiang have been detected. The source of PAHs andOCPs in road dusts has been identified and their ecological risk has been evaluated, which willprovide scientific based for urban environmental protection and management. The mainconclusions in the paper were as follows:1.The results showed that all the16U.S.EPA priority control PAHs have been detectedwith a large amount. Total concentrations of16PAHs ranged from42.06~8720.82ng/g, with anaverage level of3223.11ng/g. Compared with those from other cities in the word, road dusts fromXinxiang had a little lower PAHs pollution.2.Composition analysis showed that4-ring PAH, accounting for40.18%of total PAHs,was the predominant species in road dust from Xinxiang. Some diagnostic ratios were used forsource identification, which indicated that PAHs in the road dusts from Xinxiang were mostlygenerated by incomplete combustion. Further analysis showed that contributions of coalcombustion, gas engine and diesel emissions were50.5%,33.6%and15.9%using factor analysiswith multivariate linear regression, respectively.3.Evaluation ecological risks of PAHs in road dust with single index indicated that therewas some heavily polluted by PAHs in Xinxiang city. Assessment of PAHs in road dusts with theN.L. Nemerow composite index and the standard of agricultural soils in Canada showed that Pvalues ranged from0.09~9.95, with a mean value of3.38. All in all, road dusts in Xinxiang have been polluted by PAHs, with high ecological risk.4.Organochlorine pesticides (OCPs) were measured in road dust samples collected fromXinxiang in Henan Province. Total concentration of16OCPs ranged from2.37~724.74ng/g, withan average level of155.54ng/g. Dichlorodiphenyltrichloroethanes (DDTs), Hexachlorobenzene(HCB) and Hexachlorcyclohexane (HCHs), with detection rates of100%, were identified to be thepredominant components of OCPs, accounting for40.18%45.16%,39.07%and10.98%of totalOCPs, respectively. The average concentration of DDTs,HCB,HCHs were114.96ng/g(0.58~693.28ng/g),32.26ng/g(1.09~165.31ng/g)and4.51ng/(g0.36~14.1ng/g), respectively.Relatively high concentration of HCB in samples was likely due to the emissions and transport ofpollutants from the industrial sources.5.Composition analysis of HCHs indicated historical usage was the main source ofOCPs in road dust from Xinxiang. The same conclusion was summarized from the ratio of(DDE+DDD)/DDTs and trans-chlordane (TC)/cis-chlordane (CC).6.According to risk evaluation which can also be applied for sediment, OCPs pollutionin road dust from Xinxiang posed a little high ecological risk.