Component Variation Characteristics Of Novel Brominated Flame Retardants In Typical Sewage Treatment Plant And Wetland

As a class of alternative flame retardants,novel brominated flame retardants(NBFRs)have been widely used in clothing,textiles,electronics,building materials,plastics and were frequently found in environmental samples.Although the use and production of NBFRs are increasing all over the world,little information was found about the removal mechanism and concentration of NBFRs in sewage treatment plants and wetland environment.This study investigated the occurrences and fate of NBFRs included pentabromobenzyl acrylate(PBBA),1,2-dibromo-4-(1,2-dibromoethyl)cyclohexane(TBECH),2,4,6-tribromophenyl allyl ether(ATE),decabromodiphenyl ethane(DBDPE),bis(2-ethylhexyl)-3,4,5,6-tetrabromo-phthalate(TBPH),1,2-bis(2,4,6-tribromophenoxy)ethane(BTBPE)and tetrabromo-o-chlorotoluene(TBCT)in the Beijing Qinghe Sewage treatment plant and Olympic Forest Park Wetland by using an optimized analytical method.Four NBFRs including ATE,BTBPE,TBPH and DBDPE were detected in all samples in the sewage treatment plant.According to mass balance calculation,it was found that such NBFRs may undergo biodegradation slowly during the aerobic treatment stage.Mass balance results showed that 91%,68%,72%and 77%of the initial mass loadings of ATE,BTBPE,TBPH and DBDPE,respectively,were found in the dehydrated sludge,and the total mass fraction loss due to biodegradation is only-60%-16%.The investigation results show that the four NBFRs removal pathways are mainly sorption in sewage treatment plants.In addition,the sludge produced by the sewage treatment plants is a huge reservoir of NBFRs including ATE,BTBPE,TBPH and DBDPE.Proper management of reducing the potential risks of NBFRs in sludge is critical.In the wetland environment,more aTBECH and ?TBECH substances were detected than in the sewage treatment plant.The wetland environment is also an important accumulation area for these 6 NBFRs.The study found that the entire Olympic Forest Park wetland system has a high percentage of concentration reduction of NBFRs in wastewater.Through detecting the concentration of NBFRs in various units of wetland plants(emergent aquatic plants),we found that the concentration of NBFRs in wetland plants was high(2.4-10362 pg/g dw).In conclusion,plants play an important role in the adsorption and enrichment of NBFRs in wetland environment.