Prediction Of Gas/particle Partition And Human Intake Of Brominated Flame Retardants In Atmospheric Size-resolved Particles

The brominated flame retardants(BFRs)are toxic,b bioaccumulative and persistent,and the harm of atmospheric BFRs to human health in the atmosphere has been paid more and more attention by scientists and public.At present,many scientists have conducted in-depth studies on the partitioning behavior of BFRs in the bulk atmosphere as well as the risk to human health caused by BFRs in gas and bulk-particle phase.However,the distribution of particulate BFRs is not uniform among different particle size ranges,and the gas/particule(G/P)partitioning BFRs in different particle size ranges are also different,leading to different hazards of BFRs to human health in different particle size ranges.Currently,the health exposure assessment of BFRs in the atmosphere is mainly at the monitoring level.Only a few scholars used the G/P partitioning theory to predict and evaluate the health exposure of BFRS in the atmosphere,and all of them took particulate BFRs as bulk,and failed to consider the exposure intakes of BFRS in different size-ranges.An important reason is that there is no model that can accurately predict the gas/particle partitioning quotients of BFRS in different size-ranges.In order to establish gas/particle partitioning models for BFRS with different size-ranges and to evaluate the health exposure of BFRS in the atmosphere considering particle size-distribution,this study synchronously collected total suspended particles(TSP),11 size-segregated particles and gaseous samples in the atmosphere of Harbin,and the pollution characteristics of atmospheric BFRs and the role of G/P partition for BFRs in different size-ranges were studied in Harbin.The genmentric concentration of TSP in Harbin atmosphere was 109?g/m³.The concentrations of TSP were low in non-heating season with the major peak in size-range of 3.2-5.6?m,while the concentrations were high in heating season with the major peak in size-range of 0.56-1?m.The concentrations PBDEs(57 pg/m³)and NBFRs(70 pg/m³)in Harbin atmosphere were at relatively low level in China,and at medium level around the world.The size-distribution of BFRs was unimodal in the size-range of 0.56?1?m.The mass concentration of BFRs in each size-range of particles was significant positive correlated with fraction of organic matter in the corresponding size-range(f _OMi),providing that the f _OMi was an important factor to determine the absorption of gaseous pollutant by particles.The parameters(A and B values)to calculate the octanol-air partitioning coefficient(K_OA)were obtained for the first time.In this section,a theorecial model(K_PS-Ri)that could predict the G/P partitioning quotient of BFRs in size-range i(K_Pi)was deduced,based on the size-distribution of BFRs(R_CPi)and particles(R_PMi).To optimized the theoretical model,we discussed the relation of deviation value(?log K_Pi)with f _OMi and particle size(d_i),and obtained two steady state models to predict the K_Pi based on the f _OMi(K_PS-OMi)and d_i(K_PS-di),respectively.In comparison to K_PS-Ri,K_PS-OMi is more conveniently to predict the K_Pi of NBFRs,only with the knowledge of temperature and f _OMi.More importantly,K_PS-OMi gives an ecidence that the f _OMi is the decisive factor affecting the gas-particle partition of BFRs.The application of K_PS-di is further more conveniently than K_PS-OMi that,only ambient temperature is necessary to predict K_Pi of BFRs in size-range i.The prediction results of K_PS-Ri and K_PS-OMi are very close to the theoretical model,with the similarity reaching 81.1%-96.6%and87.4%-97.1%,respectively.K_PS-Ri and K_PS-OMi can well predict the K_Pi of atmospheric BFRs in the research area of this study and other studies in Shanghai,Guangzhou,Xinxiang in China,Bron of Czech Republic and Thessaloniki of Greece.The prediction deviation is within one order of magnitude compared with the monitoring data,which is obviously better than the obvious equilibrium state model.The monitoring inhalation intakes and dermal intakes of gaseouse BFRs and size-resolved particulate BFRs in Harbin atmosphere were evaluated.The inhalation intake of BFRs was dominated by particle phase(DI_P,pg/(day?kg)),which was higher than that of gaseous BFRs(DI_G,4.63 pg/(day?kg)).Dermal intake was dominated by gas phase(DD_G,7.43 pg/(day?kg)),which was significantly higher than that of particulate BFRs(DD_P,0.84pg/(day?kg)).The individual particulate BFRs congeners were mainly entered human body through inhalation route(>90%).The greatest risk to human body was caused by size-range of 0.56-3.2?m,for the reason that BFRs in this size-range entering the alveolar region of human body was the highest.Inhalation exposure was still the dominated pathway entering human boday for gaseous BFR with light mole.Dermal exposure proportion increases,with the increases of mole weight,especially large mole weight NBFRs congeners,dermal exposure was the dominated pathway entering the human body.A method for predicting the DI_P and DD_P of BFRs considering the particle size-distribution were established based on the K_Pi.The size-resolved DI_P and DD_P of BFRs in the atmosphere of Harbin,Shanghai and Guangzhou were well predited by their gaseous concentrations and ambient temperature with the application of K_PS-di.The effects of ambient temperature,K_OA,TSP and dermal permeability coefficient(k_p-g)on the healthy exposure of BFRs in the atmosphere were investigated.It was determined that the DI_P and DD_P of BFRs could reach the maximum value under certain gaseous concentration,when the ambient temperature was lower than certain ambient temperature and log K_OA>12.5.The DI_P/DI_G and DD_P/DD_G of BDE-209,BTBPE,BEHTBP and DBDPE do not change with the change of ambient temperature and K_OA in any living environment that human can live.When log K_OA<11.2,the inhalation intake was dominated by gas phase,and when log log K_OA>11.2,the inhalation intake was dominated by particle phase.The dermal intake is mainly from gas phase.DI_P and DD_P increase with TSP;DI_P/DD_P is simply affected by k_p-g of BFRS,and decreases with the increase of k_p-g.Based on the relationship among DI_P,DI_G,DD_P and DD_G,exposure intake of BFRs in either phase for either pathway in atmosphere,can be predicted by the exposure intake of BFRS in one phase for one pathway,and the complete atmospheric BFRS exposure data can be quickly completed by partial exposure data.In this study,size-resolved G/P partitioning models for BFRS were derived,which have a good prediction ability.A method that can inhalation intake and dermal intake of size-resolved particulate BFRs was established.The effects of temperature,TSP,K_OA and k_p-g on inhalation and dermal intake in the atmosphere were investigated,and the following results were achieved:1)accurate prediction of the G/P partitioning quotients BFRs in different size-ranges,and 2)the prediction of size-resolved inhalation and dermal intake of particulate BFRs.It provides an important tool for the in-depth study of environmental behavior of BFRs in gas and in particles with different particle size ranges in the atmosphere and their effects on human health,which can be used in health risk assessment.