Exposure Study Of Phosphorus And Brominated Flame Retardants To Human And Marine Mammals

Phosphorus and brominated flame retardants(PFRs and BFRs)are two kinds of important flame retardants,which are widely added in various industrial materials and daily necessities.Most of the phosphorus and brominated flame retardants are volatile.PFRs and BFRs have been widely detected in various environmental medium,such as indoor and outdoor dust,air,and so on.However,the distribution characteristics,the potential health risk to humans of them in these medium haven’t been understood comprehensively.Moreover,the flame retardants in the dust and air can enter the aquatic environment through surface runoff and wet deposition.Ocean is believed to be the final destination of many organic pollutants in aquatic system.Knowledage on the transfer of PFRs in the marine food web/chain remains unclear.They are of great significance for evaluating health effects and ecological risk of PFRs and BFRs.Therefore,we selected 34 typical phosphorus and brominated flame retardants and conducted a series of internal and external exposure studies on human and endangered animal(finless porpoise),the national first/second class protected animals(spotted seal and minke whale),including dust and air particles investigation(human external exposure);human blood,urine and breast milk study(human internal exposure);seawater and sediment investigation(external exposure of marine organisms)and the muscle and visceral tissues of marine organisms study(internal exposure of marine organisms).In the human external exposure studies,outdoor dust samples,non-occupational indoor dust samples(urban and rural areas),outdoor PM10 samples,paired occupational(print shops,electronic retainer shops,furniture factories,repair shops and cybercafes)indoor dust and PM10 samples,non-occupational indoor PM10 samples and outdoor PM10 samples were collected in Chengdu of Sichuan.It was found that the levels of PFRs and BFRs in indoor environment were significantly higher than that in outdoor environment.The PFRs in the three categories of indoor dust(rural indoor dust,urban non-occupational dust,and occupational dust)displayed different compositions,and BFRs dispayed similar profiles.Among the five kinds of occupational indoor dust,the level of PFRs in the electronic repair shop was the highest,reaching 52569 ng/g.For the PM10,in occupational areas,cybercafe and print shop were exposed to higher levels of flame retardant pollution than the other three kind of occupational areas.Cl-PFRs were the most important PFRs in the four electronics-related occupational areas.The daily intake indicated that dust ingestion and inhalation were the main exposure pathways to FRs,and respiratory intake calculated based on static PM10 samples and individual PM10 differed sharply,suggesting that static PM10 samples might not be appropriate to estimate real respiratory intake.Health risk evaluation results indicated that FRs caused a very low health risk to Chengdu residents through the dust and PM10 intake.The children and occupational population might suffer from higher FRs exposure risks than others.To assess the internal exposure burden of PFRs in humans,we investigated the levels of PFRs and their metabolites in the human blood and urine.The results indicated EHDPP,TCIPP and TPh P were the major PFRs in the blood,and BCEP,BDCIPP,Dn BP and DPh P were the main metabolites in the urine.The levels ofΣPFRs,TPh P and TEHP in the blood,and the levels of BCEP and DPh P in the urine exhibited the trend of urban area > rural area.Significant differences were observed for PFRs concentrations in the blood from different age groups,but no significant differences were exhibited between female and male populations.Likewise,urinary PFRs metabolites displayed no significant difference among different age groups and sex groups.Urinary BCEP,Dn BP and DPh P showed significantly positive correlation with urinary 8-OHd G and MDA,suggesting that exposure to TCEP,Tn BP and TPh P may induce oxidative stress.The calculation results of internal body burden showed that the metabolites in the urine might be more representative of internal exposure of PFR than the maternal compounds in the blood.Principal component analysis showed that dust intake,skin exposure,inhalation and dietary intake may be the main source of TCEP,TBOEP,TCIPP and TEHP in the body.Dust intake and skin contact may be the main sources of TPh P in the body.In addition,we also developed a pretreatment method for the simultaneous analysis of nine PFRs metabolites(six diesters and three hydroxylated metabolites)in human breast milk by automatic online solid phase extraction combined with ultra performance liquid chromatography/tandem mass spectrometry.The investigation results of the nine metabolites in the breast milk samples from the Netherlands showed BBOEP was identified in the majority of the breast milk samples with a median concentration of0.058 ng/ml.The presence of PFRs metabolites in the breast milk suggested that PFRs metabolites can be passed on to the breastfeeding infants through breast milk ingestion,thereby causing certain health risks to babies.In the external exposure study of PFRs to the marine organism,we collected the marine water and sediment samples during the period of 2014-2017.Results showed that PFRs and BFRs were widespread in the seawater and sediments of Bohai Bay.ΣPFRs concentration in the seawater was up to thousands of ng/l,and Alkyl-PFRs were the main PFRs.Cl-PFRs and BDE-209 were the most important PFRs and BFRs in the sediments,respectively.TEP,TCEP and TBOEP levels in the sediments showed significant seasonal differences.On the whole,the concentration of PFRs in sediments showed a trend of rapid growth from 2014 to 2016,which is related to the migration of "High pollution,high energy consumption and high water consumption" enterprises from Beijing to the surrounding cities.The ecological risk assessment resulted revealed that BFRs in seawater had a high ecological risk to marine organisms in the investigated area,and PFRs in seawater and sediments had a low to medium ecological risk.In the internal study of PFRs to marine organisms,we investigated the concentrations of PFRs and their metabolites in muscle and visceral tissues from fifteen species of fish,ten minke whales,twenty spotted seals and twenty-seven finless porpoises from Liaodong Bay and northern Yellow Sea.The levels of metabolites between the muscle and visceral tissues of fish displayed obvious differences.In minke whales and spotted seals,TMP and TEHP were the main PFRs,and BCEP and Dn BP were the main metabolites.The levels of specific PFRs and metabolites were significantly different among the muscle,kidney,liver,heart and lung tissues.The ratio analysis of metabolites and parent compounds exhibited that TCEP and Tn BP existed mainly in the form of BCEP and Dn BP in marine organisms.The correlation results showed that the body length and age of spotted seal and finless porpoise had significant effects on the levels of PFRs and its metabolites in the various tissues.The TMFs of TCEP and TMP indicated they showed significant biodilution effect in the food web of minke whales.BBOEP and BEHP also showed significant biodilution in the harbor seals food web.TCEP and BBOEP showed significant biological dilution effect,and BCEP and TEHP exhibited significant biological magnification effect in the finless porpoises food web.