University of Basrah, Iraq
Title: The most important factors influencing human exposure assessments of brominated flame retardants (BFRs) via indoor dust ingestion
Biography: Layla Salih Al-Omran
Brominated flame retardants (BFRs) are industrial chemicals widely used in consumer products to enhance their ignition resistance. Since in most applications these chemicals are used additively, they can transfer from such products into the environment. The toxicity of some BFRs has led to concern about human exposure. Ingestion of indoor settled dust appears to represent a major pathway of exposure to BFRs. However, assessment of human exposure is rendered uncertain because of a lack of knowledge about spatial and temporal variation, dust particle size and sampling collection method. Thus, the study aims to investigate the most important factors influencing human exposure assessments of BFRs via indoor dust ingestion. Concentrations of polybrominated diphenyl ethers (PBDEs) and selected novel brominated flame retardants (NBFRs) were measured in 305 indoor dust samples from different homes in Birmingham, UK. Our results revealed that substantial withinroom and within-home spatial variability in BFR concentrations was apparent between two floor areas and between elevated surface and floor dust, due to the varying distances of sampled surfaces from potential BFR sources. BFR concentrations in elevated surface dust exceeded significantly those in floor dust from the same rooms. Considerable within-room and withinhome temporal variability in BFR concentrations was apparent over a nine month sampling period, that is likely attributable to changes in room contents. Exposure estimates based on analysis of a dust sample taken from one specific floor area at one specific point in time may not be entirely representative of human exposure in that room. While concentrations of higher brominated compounds did not differ significantly between different dust particle size fractions, those of lower brominated compounds were significantly higher in the finest particle size, underlining the importance of selecting the most appropriate dust particle size for the purpose of exposure assessment. BFR concentrations in researcher-collected dust were higher than those in household vacuum dust. Recent Publications 1. Bj�rklund, J A, U Sellstrom, C A de Wit, M Aune, S Lignell and P O Darnerud (2012) Comparisons of polybrominated diphenyl ether and hexabromocyclododecane concentrations in dust collected with two sampling methods and matched breast milk samples. Indoor Air 22(4):279-288. 2. Cao Z G, G Yu, Y S Chen, Q M Cao, H Fiedler, S B Deng, J Huang and B Wang (2012) Particle size: a missing factor in risk assessment of human exposure to toxic chemicals in settled indoor dust. Environment International 49:24-30. 3. Fang M and H M Stapleton (2014) Evaluating the bioaccessibility of flame retardants in house dust using an in vitro tenax bead-assisted sorptive physiologically based method. Environmental Science & Technology 48(22):13323-13330. 4. Mercier F, P Glorennec, O Thomas and B Le Bot (2011) Organic contamination of settled house dust, a review for exposure assessment purposes. Environmental Science & Technology 45(16):6716-6727. 5. Muenhor D and S Harrad (2012) Within-room and within-building temporal and spatial variations in concentrations of polybrominated diphenyl ethers (PBDEs) in indoor dust. Environment International 47:23-27.