Exposure to Polybrominated Diphenyl Ethers in Indoor Environments

Abstract

S-30C2-2 Background/Aims: Polybrominated diphenyl ethers (PBDEs) are a family of semivolatile organic compounds used as additive flame retardants in consumer products at percent levels. PentaBDE was predominantly used in polyurethane foam furniture and DecaBDE in electronics. Typical human exposure in North America is predominantly from indoor sources, although diet may become more important as these products are discarded. Methods: We have been examining the links between indoor sources, concentrations in indoor dust and air, personal exposure (eg, hand wipes), and internal dose (eg, serum concentrations). Results: Initial attempts to link PBDEs in dust with counts of products were not successful, but associations improved when products were screened for bromine using X-ray fluorescence: the initial lack of association was due to measurement error that occurred when counting all products, including those with no or little PBDE content. Volatilization from products has been proposed as the primary route from products to the indoor environment, but this did not seem to explain the high concentrations of the relatively non-volatile DecaBDE found in some dust. Using micro-x-ray fluorescence and scanning electron microscopes, we showed that micro-fragmentation of polymer containing flame retardant could provide another transfer mechanism. Correlations between air and dust concentrations of the more volatile PentaBDE were stronger than for DecaBDE. While we had found associations between PBDE body burdens and dust concentrations, this does not distinguish between dust ingestion, dermal absorption following contact with dust (or air-to-skin transfer), or inhalation as routes of exposure. Personal air monitors measured higher concentrations of DecaBDE than the more volatile PentaBDE, suggesting a personal cloud effect, but inhalation still appears minor. We recently found associations between PBDE concentrations in dust, handwipes, and serum (and reduced by handwashing). Conclusion: Systematic experimental investigation of the source to internal dose provides a powerful approach for understanding exposure and can be applied to other semivolatile organic compounds.