AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
OH Initiated Heterogeneous Degradation of Organophosphorus Compounds
LIU YONGCHUN, Liggio John, Harner Tom, Jantunen Liisa, Shoeib Mahiba, Shao-Meng Li, Environment Canada
Abstract Number: 618 Working Group: Aerosol Chemistry
Abstract Organophosphorus compounds (OPs) have been extensively used worldwide as flame retardants, plasticizers, antifoaming agents, and additives because of their favorable physicochemical characteristics. In 2004, the global consumption of OPs used as flame retardants was 209,000 tons [Möller et al., 2012]. However, the global consumption of OPs may increase greatly due to the phasing out of bromine-containing flame retardants (BFRs) and OPs are identified as possible substitutes. In most applications, OPs easily leach out of the material into the environment via volatilization, abrasion, and dissolution. OPs have been observed widely in atmospheric particles even in polar regions [Möller et al., 2012]. However, little is known about their atmospheric fate. The Canadian Chemicals Management Plan (CMP) has targeted OP FRs for risk assessment, including assessing stability and atmospheric transport potential of OP FRs and other priority chemicals that are associated primarily with particles.
In the current study, OH initiated heterogeneous reaction kinetics of tris(1,3-dichloro-2-propyl) phosphate (TDCPP), tris-2-ethylhexyl-phosphate (TEHP), tris-2-butoxyethyl-phosphate (TBEP), and tri-phenyl phosphate (TPhP) coated on (NH4)2SO4 were investigated using a photo-chemical flow tube which was coupled to an Aerosol Mass Spectrometer (AMS) and Proton Transfer Reaction Mass Spectrometer (PTR-MS). The second order rate constants (k2) for these compounds with OH were measured at 298 K. The k2 of TDCPP was measured to be (1.30±0.42)×10-11 cm3 molecule-1 s-1. Based on 12 h-average OH concentration (1.5×106 molecule cm-3), its life-time is estimated to be (1.3±0.4) days in the troposphere. This relatively short atmospheric life-time represents a lower limit for persistence in air. Future work will evaluate atmospheric lifetimes of OP FRs using more complex and realistic particles, which is expected to increase their persistence.
References:
Möller, A., R. Sturm, Z. Xie, M. Cai, J. He, and R. Ebinghaus (2012), Organophosphorus flame retardants and plasticizers in airborne particles over the Northern Pacific and Indian Ocean toward the polar regions: Evidence for global occurrence, Environmental Science and Technology, 46(6), 3127-3134.