| Halogenated polycyclic aromatic hydrocarbons are a new type of organic pollutants formed by chlorine or bromine atoms replaced the hydrogen atoms on the carbon framework of PAHs,including chlorinated polycyclic aromatic hydrocarbons and brominated polycyclic aromatic hydrocarbons,due to their long-distance migration,bioaccumulation and carcinogenic,teratogenic and mutagenic toxicity similar to dioxins(PCDD/FS),HPAHs have gradually attracted people's attention.At present,the formation mechanism,emission sources and pollution characteristics of ClPAHs in the environment have been widely studied.However,there are few studies on BrPAHs,the existed research are mainly concentrated in the eastern part of China.There are insufficient studies on the levels of BrPAHs compounds in soils around industrial areas in the northwest of China.Therefore,this study selected three industrial zones as the object,including a comprehensive industrial zone in the west of China,a typical Secondary copper smelting plant in the east and an e-waste dismantling plant in the southeast of China,and collected the surrounding soil samples.The concentrations of brominated polycyclic aromatic hydrocarbons and their parent aromatics were measured and analyzed,the effects of different emission sources on the surrounding environment were discussed.The main conclusions of this study are as follows:(1)In this paper,an accelerated solvent extraction method was established for extracted the target substance in soil samples,a neutral composite silica gel column tandem permeable gel column was used for purification and separation of target compounds,gas chromatography-triple quadrupole mass spectrometry was used for simultaneous determination of 20 BrPAHs and 16 PAHs.Among them,the extraction solution of ASE was n-hexane:dichloromethane(60:40,v/v),and the extraction temperature was set at 120?.The recovery rate of matrix soil showed that the extraction parameters were feasible.100mL n-hexane:dichloromethane(60:40,v/v)eluent was used to leach neutral alumina silica gel column and 150mL n-hexane:dichloromethane(1:1,v/v)eluent was used to activate and leach permeable gel column,which could achieve the purification and separation of the target substance from lipids,pigments and other impurities.BrPAHs and PAHs were quantitatively analyzed by GC-MS/MS under the multi-reaction monitoring mode.Instrumental analysis conditions:EI mode,ionization voltage 70 eV;DB-5 MS capillary column(30m×0.25mm I.D.,0.25 ? um);the temperature of the injector,ion source,quadrupole and transmission line were 280?,230?,150? and 300?,respectively.The carrier gas was helium(1.0 mL/min).The results showed that the blank control group's recoveries of BrPAHs were 73%?105%which added internal standard compound,the matrix group's recoveries were 59%?84%,the relative standard deviations were less than 7%,and the limit of detection of each BrPAHs monomers was 0.33?16 pg/g.The experimental method was feasible.(2)In this study,the concentrations of BrPAHs and PAHs were 77.1-6634 pg/g(average 1362 pg/g)and 146.2-2487 ng/g(average 1035 ng/g)in the E-waste recycling industrial zone in the southeast,the main monomers were 1-BrPyr and BaP,respectively.The ?TEQ concentration of PAHs ranged from 310 to 2075 ng BAPeq/g,and BrPAHs ranged from 34.8 to 400.7 pg BAPeq/g.In the plant area,the main monomers of BrPAH were Br-Phe and Br-Ant,while the main monomers of PAH were BaP and BaA,which did not form a correspondence.Considering the large amount of brominated flame retardants in the components of e-waste,it is speculated that in the process of e-waste dismantling,there is a way to produce brominated PAHs by PAHs free radicals reacted with chlorine-containing or bromine-containing unsaturated organic compounds;The concentration of BrPAHs in the western comprehensive industrial area ranged from 311.2 to 1792 pg/g(average 581.9 pg/g),and the concentration of PAHs ranged from 1716 to 48132 ng/g(average 13938 ng/g),the main monomers were 6-BrBaP and CHR,respectively.The ?TEQ concentration of PAHs in this area ranged from 125-7684 ng BAPeq/g,and the ?TEQ of BrPAHs ranged from 3.47 to 52.2 pg BAPeq/g.The ratios of 7-BrBaA/3-BrFlu and 7-BrBaA/1-BrPyr in the three sites were similar to those of specific homologues in the flue gas of iron and steel smelting plants,indicating that the distribution of BrPAHs in the soil was related to the production activities of iron and steel smelting.The concentrations of BrPAHs around the eastern secondary copper smelter were 106.6-1249 pg/g(average 307.4 pg/g),and the concentrations of PAHs were 430.1-6734 ng/g(average 2211 ng/g).The main monomers were 6-BrBaP and BaP,respectively.The?TEQ concentration of PAHs ranged from 48 to 2631 ng BAPeq/g,and the ?TEQ of BrPAHs ranged from 3.56 to 15.42 pg BAPeq/g.The correlation analysis shows that there is a significant correlation between BrPAH and PAH,which indicated that there is a way to produce brominated polycyclic aromatic hydrocarbons by added bromine directly to parent aromatic hydrocarbons in the smelting process of secondary copper.The ratio of 1-BrPyr/3-BrFlu specific monomers in the soil surrounding the secondary copper smelter in this industrial area was consistent with the proportion of homologues in the flue gas of other studied recycled copper smelters,suggesting that the distribution of brominated polycyclic aromatic hydrocarbons in the surrounding environment may be affected by the smelting of recycled copper.(3)Through comparison,it is found that the area with the most serious brominated PAHs pollution in the three industrial zones selected in this study was the e-waste diamantling site in the southeast,and the area with the most serious PAHs pollution was the comprehensive industrial park in the west.Compared with non-industrial urban areas such as Shenzhen,the concentrations of BrPAHs and PAHs compounds in soil of three typical industrial areas were at a higher level.In addition,the total carcinogenic risks of the three industrial zones were ranged from 1.12×10-8 to 3.64×10-6,and the pollution around the iron and steel smelters in Ningxia was the most serious,which need to be taken seriously. |
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