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Aqueous photolysis of triclopyr and its butoxyethyl ester and calculated environmental photodecomposition rates
Author(s) -
Mccall P. J.,
Gavit P. D.
Publication year - 1986
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620051003
Subject(s) - triclopyr , photodissociation , aqueous solution , environmental chemistry , chemistry , photochemistry , acetic acid , decomposition , organic chemistry , glyphosate , ecology , biology
Studies determining the photochemical quantum yields of [(3,5,6‐trichloro‐2‐pyridinyl) oxy]acetic acid (triclopyr) and its butoxyethyl ester are reported. Values of 0.040 ± 0.003 and 0.0084 ± 0.0008, respectively, were obtained using 313‐nm light at pH 5 in a dilute aqueous solution at 35°C. Quantum yields were used to compute half‐lives for direct photolysis under seasonal and locational sunlight conditions with the computer program SOLAR. Triclopyr was observed to photodegrade approximately six times faster than the ester, with typical calculated midday, midsummer half‐lives of 2.1 and 12.5 h, respectively, at the water's surface at 40°C latitude. The relative importance of photolysis to other environmental transport and transformation mechanisms of the chemicals is discussed.