Dermal Exposure Assessment Of Selected Organic Flame Retardants

Organic flame retardants(FRs)are a class of pollutants with emerging concerns.Human exposure to these ubiquitous chemicals which may be associated with adverse health effects through various pathways,e.g.food and dust ingestion,inhalation and dermal absorption.Dermal absorption was considered as a potential significant contributor of FRs body burden.However,the current understanding of this pathway is quite insufficient.In this study,assessment methods,dose and influence factors of the dermal exposure pathway have been investigated.Skin wipe samples were collected from different skin locations of a student population.The concentrations of FRs varied on hands,forearms,shank,back and forehead.Concentrations of most FRs were strong reliable in repeated measurements from four participants over a three-month period and one participant over consecutive five days.Two methods: relative absorption and permeability coefficient,were used for dermal exposure assessments.However,there were orders of magnitude differences between the dermal absorbed doses calculated by these two methods.In addition,the dermal absorption dose from hands,arms and legs only take account of 50% of the total dermal exposure.Taking into account the difference of levels on different skin location,a new methodology for assessment of total dermal exposure is proposed.Three typical occupation populations in indoor,vehicle and outdoor,namely white-collar workers,taxi drivers and outdoor securities were selected,and paired floor dust,surface dust and hand wipe samples were collected.The concentrations in hand wipes and dust ranked as: taxi drivers > office workers > outside workers.The daily intakes through dermal absorption of individual FRs were at least three orders of magnitude lower than corresponding reference doses.In addition,compared to the estimated dermal exposure by using concentrations in handwipes,there was an overestimation by using concentrations in dust.The correlations between FRs in dust and handwipes suggested there was a need to select particle size and type of dust for dermal exposure assessment.Dust and air samples were collected from consumer products or electronic products stores in Beijing,and hand wipe samples from the sellers were collected.Air,dust and handwipe samples had different detections and distribution patterns.There was no correlation neither between air and handwipes,nor between dust and handwipes.Daily intakes of inhalation,dust ingestion and dermal absorption for the same participants showed dermal absorption is an important exposure pathway for organophosphate flame retardants(PFRs)and low brominated polybrominated diphenyl ethers(PBDEs).Contacting with products contain FRs might be the major contributor of FRs on hands surface lipids.Results of multiple linear regression analyses showed concentrations of FRs in dust,gender,whether smoke or not and whether used skincare products on hands will significantly influence FR concentrations in hand wipes.