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Fate and Transport of Organophosphate Flame Retardants in Indoor Environments
Citation:
Liu, X. Fate and Transport of Organophosphate Flame Retardants in Indoor Environments. Healthy Buildings 2019 Asia, Indoor Air Quality and Climate (ISIAQ) Conference, Changsha, Hunan, CHINA, October 22 - 25, 2019.
Impact/Purpose:
Under the Toxic Substances Control Act (TSCA) amended by the Frank R. Lautenberg Chemical Safety for the 21st Century Act, U.S. Environmental Protection Agency (EPA) has been conducting research to support the evaluation of chemicals currently on the market for links between exposure and toxicity pathways.Organophosphorus flame retardants (OPFRs) are produced and used widely as alternative additives in building materials and consumer products such as polyvinyl chloride (PVC) flooring, electrical and electronic products, furniture, textile coatings and plastics. Acute adverse effects associated to humans and animals have been found for OPFRs, such as tris(2-chloroethyl) phosphate (TCEP), tris(1-chlor-2-propyl) phosphate (TCPP), and tris(1,3-dichloro-2-propyl) phosphate (TDCPP). Understanding the fate and transport mechanisms of OPFRs in indoor environments is a prerequisite to develop strategies to limit exposures and protect human health. Our research developed experimental methods and collected data for the investigation of the source emission, and fate and transport of these three OPFRs in the indoor environment and provide parameters associated with OPFRs in different environmental scenarios. The research directly supports Office of Pollution Prevention & Toxics (OPPT)’s risk assessment of flame retardants, Consumer Product Safety Commission (CPSC)’s risk assessment for organohalogen flame retardants, such as TDCPP, and the interagency working group on Spray Polyurethane Foam (SPF). The data collected are to be used as the basic model input for the development of exposure models.
Description:
Under the Toxic Substances Control Act (TSCA) amended by the Frank R. Lautenberg Chemical Safety for the 21st Century Act, U.S. Environmental Protection Agency (EPA) has been conducting research to support the evaluation of chemicals currently on the market for links between exposure and toxicity pathways. Organophosphorus flame retardants (OPFRs) are used in high amounts as additives in industrial and consumer products, such as electrical and electronic products, furniture, plastics, textile, and building construction materials. Understanding the fate and transport mechanisms of these compounds between the sources and the residential environment (air, dust, and interior surfaces) is important for researchers to more accurately characterize their human exposure, develop and refine exposure models, and provide tools that enlighten risk assessment and policy decisions to minimize exposure and protect human health. This presentation summarizes the work conducted at EPA’s National Risk Management Research Laboratory in the last few years on the fate and transport mechanism study of OPFRs in the indoor environment. The OPFRs studied included tris(2-chloroethyl) phosphate (TCEP, CAS# 115-96-8), tris(1-chloro-2-propyl) phosphate (TCIPP, CAS# 13674-84-5), and tris(1,3-dichloro-2-propyl) phosphate (TDCIPP, CAS# 13674-87-8). Our research developed methods for the investigation of OPFR (1) sorption on building materials and consumer products, (2) emission controlling mechanisms and key emission parameters, (3) temperature influence on emissions, and (4) migration from sources to settled dust, including direct contact and sorption. The data collected included emission rates, sorption rates, and critical parameters for exposure modeling such as material/air partition coefficients, solid-phase diffusion coefficients, sorption rate constants, and concentrations in the sources. These data support the development of quantitative structure-activity relationship (QSAR) models and mass transfer models to predict the OPFR emissions and transport in indoor environments. They are being used as the basic model input for the development of exposure models. These methods can be extended for the further study of the migration pathways and potential routes of human exposure of other semivolatile organic compounds (SVOCs).