Tetrahalobisphenol A derivatives (TXPBAs; X = Br or Cl), TBBPA and TCBPA, are utilized for flame retardants that are disposed to landfills. In landfills, TXBPAs are oxidized via oxidative enzymes like peroxidases, and are incorporated into humic acids (HAs) via oxidative coupling to form coupling products (HA-TXBPAs). This leads to the detoxification of TXBPAs. However, the stability or degradability of HA-TXBPAs under various conditions in landfills (e.g., hydrolase presence) has not been elucidated. In this study, the degradability for HA-TXBPAs was monitored during 30 days of incubation, where HA-TXBPAs were prepared as described in a previous report [1]. TXBPAs were incubated in the presence of amylase at 37 degrees centigrade and the ether extract from the reaction mixtures were analyzed by GC/MS (Figure). The higher level of TBBPA elution was found after 1 day in HA-TBBPA, being attributed to the loosely bound TBBPA via hydrophobic interactions. However, the level of TBBPA elution did not increased after 30 days, suggesting that TBBPA incorporated into HA covalently is stable. For HA-TCBPA, trace 2-hydroxyisopropyl-2,6-dichlorophenol (2HIP) was eluted after 1 day, while small amounts of TCBPA were eluted after 30 days. Regarding to TXBPAs that are incorporated into HA via covalent bonding, HA-TBBPA is more stable than HA-TCBPA. The results for tests under other conditions will also be reported.<br/>[1] R. Kodama et al., 249-th ACS National Meeting, Denver, USA, ENVR-128, 2015.

Stability of the tetrahalobisphenol A incorporated into humic acid via oxidative coupling

251st National Meeting (2016)

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