Affiliations: Institute of Environmental Science, Zhejiang
University, Hangzhou 310029, China | State Key Laboratory of Marine Environmental
Science, Environmental Science Research Center, Xiamen University, Xiamen
361005, China
Abstract: This work presents laboratory studies on the degradation of
triazophos in intertidal sediment. The overall degradations were found to
follow the first-order decay model. After being incubated for 6 d, the
percentage of degradations of triazophos in unsterilized and sterilized
sediments were 94.5% and 20.5%, respectively. Between the temperatures of
15°C and 35°C, the observed degradation rate constant
(k_{obsd}) enhanced as the incubation temperature increased.
Triazophos in sediment degraded faster under aerobic condition than under
anaerobic one. The water content of sediment had little influence on the
degradation when it was in the range of 50%–100%. The values of
k_{obsd} decreased with increasing initial concentration of
triazophos in sediment, which could result from the microorganism inhibition by
triazophos. Four major degradation products, o, o-diethyl phosphorothioic acid,
monoethyl phosphorothioic acid, phosphorothioic acid, and
1-phenyl-3-hydroxy-1,2,4-triazole, were tentatively identified as their
corresponding trimethylsilyl derivatives with a gas chromato-graphy-mass
spectrometer. The possible degradation pathway of triazophos in intertidal
sediment was proposed. The results revealed that triazophos in intertidal
sediment was relatively unstable and could be easily degraded.
