| As many studies reported,flame retardants,such as polybrominated diphenyl ether(PBDE),are the typical contaminants in the e-waste dismantling area.Meanwhile,polycyclic aromatic hydrocarbons(PAH)are also released during the heating processes involving in the e-waste dismantling activities.Therefore,people are exposed to multi－pollutants in the e-waste dismantling area.A series of complex reactions will be taken place to produce various metabolites after PBDE and PAH entering into human body,such as hydroxylated metabolites,which have comparable or higher toxicities than their parent congeners.Human biomonitoring is a common strategy to understand the levels and congener profiles of organic contaminants in human body.Compared with blood and urine samples,hair was introduced as a potential bioindicator to assess human exposure to PBDE and PAH due to numerous benefits such as an easy,non-invasive collection,possibility of long-term storage and wide range of information on short-and long-term exposure.However,one of the major difficulties for hair analysis is to distinguish external from internal contamination.Another limitation of hair analysis is the lack of multiclass methods to simultaneously analyze different chemical classes(with different physico-chemical properties).Moreover,to our knowledge,few data are available on the metabolites in hair sample for occupational exposure to brominated flame retardantsIn this study,pairs of human hair and urine samples were collected from an e-waste dismantling area.The participants included 27 e-waste workers who directly engaged in e-waste dismantling activities,29 non-e-waste workers who engaged in other activities at the e-waste dismantling industrial park and 40 residents living in the surrounding area(21 adults,>14 years old;and 19 children,≤14 years old).PAH,PBDE,hexabromobenzene(HBB),pentabromobenzene(PBB),1,2-bis(2,4,6-tribromophenoxy)ethane(BTBPE),dechlorane plus(DP),hydroxyl polycyclic aromatic hydrocarbon(OH-PAH),hydroxyl polybrominated diphenyl ether(OH-PBDE)and brominated phenol(BRP)in both external and internal hair,as well as OH-PAH,OH-PBDE and BRP in urine samples,were analyzed in this work.First,a new and reliable method was developed to simultaneously analyze parent compounds and their hydroxylated metabolites in human hair as well as to distinguish the internal from external pollution sources according to the analyzed compounds in hair samples;an effective and reliable method was also developed to achieve simultaneous qualitative and quantitate of multiple classes of phenols in urine samples by HPLC-MS/MS Second,the levels and congener profiles of the target analytes in hair external and internal samples were assessed from different populations.Moreover,the relationships between parent compounds and metabolites in hair samples were also investigated in order to screen the potential biomarker for the occupational exposure to multi-pollutants Finally,the levels and congener profiles of hydroxylated metabolites in urine samples were compared with those in hair internal samples in order to validate the utility of hydroxylated metabolites in hair as a biomarker and bioindicator for human health risk assessments from the exposure to pollutantsThe concentrations of the 15 PAHs(Σ15PAHs),Σ22PBDEs,HBB,PBB,BTBPE,ΣDP,Σ12OH-PAHs和ΣBRPs in hair external samples for all subjects were ranged from 6.24-692,7.58-4588,0.23-142,0.02-42.4,0.05-53.0,0.95-99.5,(below the limit of detection)n.d.-187 and 1.28-3299 ng/g dry weight(dw),respectively.Regarding OH-PBDE,only 6-OH-BDE-47 was detected in 4%of hair external samples from all subjects with the concentration of n.d.-1.02 ng/g dw.The concentrations of theΣ15PAHs,Σ22PBDEs,HBB,PBB,BTBPE,ΣDP,Σ12OH-PAHs和ΣBRPs in hair internal samples for all subjects were ranged from 31.7-738,0.85-7109,n.d.-36.1,n.d.-58.5,n.d.-15.7,0.86-39.9,21.6-1887 and 45.2-42229 ng/g dw.Only 6’-OH-BDE-99,6-OH-BDE-47 and 2’-OH-BDE-28 were detected in lower than 10%of hair internal samples from all subjects with the concentration of n.d.-4.50,n.d.-3.98 and n.d.-0.05 ng/g dw,respectivelyThere was hardly no significant difference in the Σ15PAH and Σ12OH-PAHs concentrations of hair samples between different populations(p>0.05).However,the concentrations of Σ22PBDEs,HBB,PBB,BTBPE,ΣDP and ΣBRPs in hair samples from e-waste workers were significantly higher than those from other populations(p<0.05).These results suggest the halogenated flame retardants(HFRs)and BRPs are found to be the exposured characteristic pollutants for people from e-waste dismantling area.Regarding parent compounds,BDE-209 was the predominant congener for all samples,and the concentration of BDE-209 was found to be 2 order magnitude higher than other HFRs.Regarding hydroxylated compounds,2,4,6-triBRPs was found to be the predominant congener for all samples.The concentration of 2,4,6-triBRPs was 2-4 order magnitude higher than other BRPs,and even 3-8 times higher than BDE-209 The concentrations of the parent compounds(PAHs and HFRs)in hair external and internal samples were comparable(p>0.05),while the concentrations of the hydroxylated compounds(OH-PAH,BRP and OH-PBDE)in hair internal samples were 1-2 order magnitude higher than those in hair external samples(p<0.05).This suggests that the hydroxylated compounds in hair samples were from human body rather than from environmental pollutants,which could exactly reflect the human internal exposure Although 2,4,6-triBRP was found to be the predominant congener in hair samples,it is not only the metabolites of PBDEs but also the materials of flame retardants.Therefore,2,4,6-triBRP is not an ideal biomarker.However,tetraBRP,2’-OH-BDE-28 and 6’-OH-BDE-99 were only detected in hair internal samples,neither natural compounds nor commercial materials.Therefore,tetraBRP,2’-OH-BDE-28 and 6’-OH-BDE-99 can be considered as the hair biomarkers for the occupational exposure to PBDE.Above all,more attention should be paid to hydroxylated compounds in hair sample,which will help to obtain more reliable and comprehensive information on health risk assessmentsThe concentrations of the Σ12OH-PAHs and ΣBRPs in urine samples for all subjects ranged from 0.52-155 and 0.44-99.3 μg/g creatinine,respectively.3,4-diBRP,2,4,5-triBRP,2,3,4,6-tetraBRP and 2’-OH-BDE-28 were firstly tentatively detected in human urine samples from e-waste dismantling workers,and they can be considered as the urinary biomarkers for the occupational exposure to PBDE.Due to different exposure times and metabolites processes of hydroxylated compounds between hair internal and urine samples,there was lack of a significant correlation between the levels of most OH-PAH and BRP congeners in the hair internal samples and in the urine samples.There was hardly no significant difference in the Σ12OH-PAHs concentrations of urine samples between different populations(p>0.05),which was similar to the results of hair and may be attributed to the diversity of sources of their parent PAHs However,the concentrations of BRPs in urine samples from e-waste workers and child residents were comparable(p>0.05),which was in contrast to the results in hair samples It suggests that urine does not perform as well as hair to indicate the e-waste occupational or non-occupational exposure through the distribution characteristics of BRP.Therefore,hair and hydroxylated compounds are reliable bioindicator and biomarkers,respectively,for human biomonitoring of long-term e-waste pollution exposure. |
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