You are here:
Sorption and migration of organophosphate flame retardants between sources and settled dust
Citation:
Liu, X. AND E. Folk. Sorption and migration of organophosphate flame retardants between sources and settled dust. CHEMOSPHERE. Elsevier Science Ltd, New York, NY, 278:00, (2021).
Impact/Purpose:
Many industrial and consumer products, such as electrical and electronic products, furniture, plastics, textile, and building materials are manufactured with organophosphorus flame retardants (OPFRs). Due to their adverse health effects, US EPA released a problem formulation for chlorinated phosphate esters, which include tris(2-chloroethyl) phosphate (TCEP, CAS# 115-96-8), tris(1-chloro-2-propyl) phosphate (TCPP, CAS# 13674-84-5), and tris(1,3-dichloro-2-propyl) phosphate (TDCPP, CAS# 13674-87-8), used as flame retardants in furniture foams and textiles. In December 2019, EPA designated TCEP as one of the twenty high-priority substances for risk evaluation under the Toxic Substances Control Act (TSCA) amended by the Frank R. Lautenberg Chemical Safety for the 21st Century Act. This research studied the transfer of TCEP, TCPP, and TDCPP from polyisocyanurate rigid polyurethane foam (PIR-PUF) and dry alky paint to settled house dust and Arizona Test Dust on surfaces through direct contact and the sorption of these three compounds from the air to the dust. This work enlightens the correlations between OPFR concentrations in settled dust, surface materials, and air. The data can be used to determine partitioning of OPFRs between the gas phase and settled dust indoors and to inform EPA program offices and other government agencies on strategies to reduce exposure and risk.
Description:
Dust serves as a strong sink for indoor pollutants, such as organophosphorus flame retardants (OPFRs). OPFRs are semivolatile chemicals that are slow in emissions but have long-term effects in indoor environments. This research studied the emission, sorption, and migration of OPFRs tris(2-chloroethyl) phosphate (TCEP, CAS# 115-96-8), tris(1-chloro-2-propyl) phosphate (TCPP, CAS# 13674-84-5), and tris(1,3-dichloro-2-propyl) phosphate (TDCPP, CAS# 13674-87-8), from different sources to settled dust on OPFR source surfaces and OPFR-free surfaces. Four sink effect tests and six dust-source migration tests, including direct contact and sorption tests were conducted in 53L stainless steel small chambers at 23°C and 50% relative humidity. OPFR emission concentrations, and sorption and migration rates were determined. The dust-air and dust-material partition coefficients were estimated based on the experimental data and compared with those from the literature obtained by empirical equations. They are in the range of 6.2¿106 to 1.19¿1011 (dimensionless) for the dust-air equilibrium partition coefficients and 2.38 ¿ 10-3 to 1.34¿10-2 (dimensionless) for the dust-material equilibrium partition coefficients. The impacts of different types of dust, air change rates (ACH), dust loadings, and source materials on the OPFR emission, sorption, and migration from source surface to dust were also examined. It was observed that the dust with less organic content and smaller size tended to absorb more OPFRs, but different dust did not significantly affect the source emission of OPFRs from the same source to the chamber air. The dust-air partition favored the less volatile OPFRs in the house dust, whereas the emission from the source favored the volatile chemicals. Volatility of the chemicals had much less effect on dust-source partitioning than on dust-air partitioning. The results from this work improve our understating of the fate and mass transfer mechanisms between OPFRs sources, indoor air, surface, and dust.
