Elucidating Levels and Pathways of Human Exposure in Ireland to POP-BFRs and PFOS (ELEVATE)
N. Wemken1, D.S. Drage2, M. Coggins1, M. Abdallah2, S. Harrad2
1School of Physics, National University of Ireland, Galway, H91TK33, Ireland
2School of Geography, Earth & Environmental Sciences, University of Birmingham, Birmingham B15 2TT, U.K
Project website: http://www.nuigalway.ie/elevate/
As a signatory of the UNEP Stockholm Convention on persistent organic pollutants (POPs), the Irish government is required to eliminate or restrict the use and release to the environment of POPs in Ireland. Among the POPs covered by the Convention are a number of brominated flame retardants (BFRs). Such BFRs, namely hexabromocyclododecane (HBCDD) and polybrominated diphenyl ethers (PBDEs) (collectively referred to here as POP-BFRs) were used as flame retardants in a variety of soft furnishings, building insulation foams, electronic and electrical goods. To characterise human exposure to these contaminants bio-monitoring studies[2,3,4] coupled with environmental measurements in food, household dust and air have been conducted in numerous countries[3,4,5,6].
Previous human bio-monitoring data in Ireland and information regarding concentrations in foodstuffs suggests that exposures to these contaminants in Ireland are low[2,8,9,10,11]. However, there is a dearth of data on concentrations of BFRs in indoor air and dust in different microenvironments within Ireland, information required to fully understand both the overall magnitude of exposure and the relative contributions of different exposure pathways.
ELEVATE Project Objectives
The ELEVATE project will conduct the first study of levels of BFRs (tri- through deca-PBDEs, and -,- and -HBCDD) and perfluorooctane sulfonate (PFOS) in indoor air, dust and water in common Irish microenvironments (homes, cars, primary schools and offices). Data will be combined with existing data on concentrations in the Irish diet to evaluate the relative contribution of the different exposure pathways. A human biomonitoring study will also be carried out (by analysing human milk samples) to provide information on body burdens in the Irish population. Comparison with a previous such study will facilitate assessment of the impact on body burdens of restrictions on the manufacture and use of these chemicals. Specific project objectives are to:
Ø Evaluate the relative contributions of different exposure pathways (diet, indoor air and dust) to POP-BFRs and PFOS in Ireland
Ø Establish the current body burdens of POP-BFRs and PFOS in the Irish population and by comparison with previous biomonitoring data in Ireland, assess the impact of recent restrictions on the manufacture and use of these contaminants
Ø Evaluate the relationships between external and internal exposure of the Irish population to POP-BFRs and PFOS using simple one compartment pharmacokinetic models.
Materials and methods
Approximately 32 samples each of air, dust and tap water were collected from Irish microenvironments such as homes, cars, primary schools and offices between August 2016 and January 2017 (Figure 1). Air samples were collected by deploying passive air samplers for approximately 60 days (Figure 2). The samplers have been placed on elevated surfaces in homes, offices, and schools, and on the floor behind the passenger or driver’s seat in cars. The air sampler consisted of a sorbent (XAD-3) impregnated polyurethane foam disk (PUF), (pre-cleaned by Soxhlet extraction with dichloromethane). Dust samples were collected by vacuuming floors following methods previously described by Abdallah and Harrad and Goosey and Harrad  respectively. A member of the research team vacuumed a measured area of the floor (1 m2 of carpet floor and 4 m2 for tiles/wood) in each home and office for 4 minutes. By comparison, for classrooms and cars, vacuuming was conducted for as long as required to remove all visible dust across the entire floor (classrooms) or the surfaces of seats, gear lever and dashboard (cars). The dust was collected in a nylon sock (25 µm pore size). Participants were asked not to clean their cars for 2 weeks and to not vacuum the floors for 2 days prior to the sampling visit (homes and offices), with the exception of schools, where cleaning is conducted daily.