Human Exposure To Flame Retardants Via Dust Ingestion And Hand-to-mouth Contact In Guangzhou

Flame Retardants（FRs）are a class of organic pollutants that are prevalent in the environment.Many flame retardants are persistent,bioaccumulative,semi-volatile and potential toxicity,which seriously affect human health.It is one of the hotspots of organic pollution research.People spend more than 80%of daily time in indoor environments,The indoor space is small and the items are complicated.A lot of research has shown that dust is an important sink of pollutants in the indoor environment.The human body can generate the risk of exposure of FRs through the way of dust intake.However,for the transfer of FRs in the indoor environment and the human-to-media transfer,there is no systematic study on the pollution patterns and distribution characteristics of FRs.In addition,exposure to flame retardants by hand-to-mouth contact has been scracely reported,and the contribution of hand-to-mouth exposure to human exposure to contaminants is still unclear.This study investigated several flame retardants,including polybrominated diphenyl ethers（PBDEs）,phosphate flame retardants（PFRs）,decabromodiphenyl ethane（DBDPE）,and 1,2-bis（2,4,6-tribromophenoxy）ethane（BTBPE）in indoor dust and on human hand surfaces.DBDPE,BDE 209,and tris-（2,3-dichloropropyl-phosphate,TDCPP）were the main pollutants in indoor dust,with concentrtaions of 1750,387 and 280 ng/g,respectively,and they were the main pollutants in dust.The main pollutants on the surfaces of human hands were tri-chloropropyl-phosphate（TCPP）,BDE 209,tri-phenyl-phosphate（TPh P）,DBDPE,and tris（2-ethylhexyl）phosphate,with concentrations of 127,93.8,46.8,41.7 and41.7 ng/m²,respectively.In this study,the internal dust and wipe samples of the upper and lower surfaces of 50laptops were collected.Differences were found in the compositions of FRs in the dust and upper and lower surfaces of the computer.The main pollutants in the internal dust were TPh P（1880 ng/g）and DBDPE（885 ng/g）.The main pollutants on the upper surface of the computer were TPh P（584 ng/m²）and TCPP（245 ng/m²）.The main pollutants on the lower surface of the computer were TPh P（522 ng/m²）and TCPP（287 ng/m²）.The DBDPE concentration in internal dust inside the computer was twice lower than those in indoor dust.TCPP concentrations on the upper and lower surfaces of computers differed significantly（p<0.01）,indicating that the sources of TCPP were different in these two types of samples.TCPP on the upper surface of computers may come from the pollution caused by human contact.Finally,this study used an in vitro physiologically based extraction method to assess the bioaccessibility of FRs in standard dust SRM 2585 with or without different food components（oil,protein,cellulose）and additives（chitosan,sucrose polyester,montmorillonite）.The bioavailability of FRs in dust exhibited a negative correlation with log K_OW of FRs for the FRs with log K_OW greater than 4.chitosan had a significant effect on reducing the bioaccessibility of FRs in dust.