| Persistent organic pollutants (POPs) have been of great concern due to their persistence in the environment, their bioaccumulation potential in the tissues of animals and humans.Organochlorine pesticides and brominated flame retardants is typical with carcinogenic, teratogenic, mutagenic of POPs substances. It is important to study the residues level, mode of occurrence and environmental behavior for the guidance to control pollution and reduce emissions. Urban are densely populated areas, POPs level in air and soil directly affect the health of urban residents, the atmosphere is the major media for human exposure to POPs pollution and the soil are the sinks of POPs in the surface environment. So it has great significance to study OCPs and BFRs on of urban atmospheric and soil environment for the study of the ecological environment in urban. Harbin is the study area to investigate the OCPs and BFRs residue levels in atmosphere and soil environment to study the pollution characteristics, migration and fate.Study of the city and its surrounding areas of organochlorine pesticides in the soils of the residual levels, results show that the concentration of the soilΣHCH ranged from 136 pg g-1 dw to 51760 pg g-1 dw, with mean of 7120 pg g-1 dw,ΣDDT concentration ranged from 72 to 28222 pg g-1 dw, with mean of 5425 pg g-1 dw, HCB concentration ranged from 64 to 3942 pg g-1 dw, with mean of 1039 pg g-1 dw. Molecular markers was used to analyze the source of organochlorine pesticides, results show that the industrial HCH and lindane haven't new source for a long time at the local, the HCH residues in soil from the history with very lower amount of usage, or come from long-distance migration. Chlordane residues in the soil from the long-distance migration, endosulfan is from localtion with very low usage or long-distance migration. Principal component analysis of OCPs draw the same conclusion.HBCD is the predominate compound in soils, followed by BDE-209, both compounds contributed more than 90%, this also indicated that HBCD and PBDE 209 are the most large of consumption. Concentration of PBDE and non-PBDEs BFRs were significantly higher than those of agricultural land and background, reflects the city is the source BFRs, urban fractionation phenomenon was observed occurred, and also indicated urban was the sources of PBDE, HBCD and BTBPE. The largest amount of OCPs in atmospheric is HCB, followed byα-HCH and p, p'-DDT. The highest concentration of HCH in atmosphere is in the rural areas, indicating that HCH was used in agricultural land, The highest concentration of endosulfan in the suburban are probably from a small amount of vegetable land use, HCB was the highest in the city, followed by suburban, rual and background indicated industrial production process is the emissions source. There was no significant change amount DDT and chlordane in urban, suburban and rural areas, so DDT and chlordane may not be use in location and also come from long-distance transport.The highest amount of BFRs in atmospheric was BDE 209 followed by HBCD, university campuses was detected the concentration higher than that of other sampling points so it was found that the population density are important influencing factor for BFRs concentration. PBDE Homologues was influented by seasonal temperature. PBDEs (excluding 209) in gas were positively correlated with temperature, and BDE 209 in particle phase was positively correlated with temperature, it can be assumed PBDE (non-BDE 209) from the gas condensation to the particle phase controlled by temperature, and BDE 209 from the particle to the gas controlled by temperature. The ratios of gas to particle were temperature-related for low-bromine compounds, but for high bromine compounds, this trend is not obvious.OCPs concentration in the atmosphere is relatively uniform, while large changes in soil concentrations. Fugacity fraction was applied to study the soil– air distribution in the process exchanged, Fugacity fraction of HCH and HCB in soil/air exchanged are more close to 0.5, that is, more close to reaching a balanced, pp'-DDE and pp'-DDT may probably closed to balance, and other organochlorine pesticides such as chlordane and endosulfan for fugacity fraction was far less than 0.15, atmospheric deposition was mainly action. Fugacity fraction of PBDEs in the atmosphere is much higher than that in the soil, fugacity fraction ranged from 10-2 to 10-5 far below 0.5 for balance, which mean that dry deposition of atmosphere to soil is the main exchange process.Multi-media fugacity model was used to simulated the distribution and fate of p,p'-DDT in Harbin. The results show that p, p'-DDT is trended to distribute in the soil, followed by the sediment, water and atmospheric. p,p'-DDT will accumulate eventually in soil, accounting for 99.4% of total, followed by sediment total 0.589%, p,p'-DDT will finally transform to the degradation products undergo microbial decomposition, hydrolysis or photolysis process. |
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