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Quantum Yield for the Aqueous Photochemical Degradation of Chlorantraniliprole and Simulation of Its Environmental Fate in a Model California Rice Field
Author(s) -
Redman Zachary C.,
Anastasio Cort,
Tjeerdema Ronald S.
Publication year - 2020
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.4827
Subject(s) - quantum yield , photodegradation , aqueous solution , degradation (telecommunications) , paddy field , environmental chemistry , chemistry , pesticide , photochemistry , sunlight , environmental science , hydrolysis , photocatalysis , organic chemistry , agronomy , physics , telecommunications , quantum mechanics , astronomy , computer science , fluorescence , biology , catalysis
The photochemical degradation of chlorantraniliprole (3‐bromo‐N‐[4‐chloro‐2‐methyl‐6‐(methylcarbamoyl)phenyl]‐1‐(3‐chloro‐2‐pyridine‐2‐yl)‐1H‐pyrazole‐5‐carboxamide; CAP) was characterized under simulated solar light with 2‐nitrobenzaldehyde (2NB) actinometry. Overall, aqueous CAP degraded quickly via direct photodegradation with no significant difference observed between high‐purity water and filtered rice field water. The 24‐h average half‐life normalized to summer sunlight using 2NB was 34.5 ± 4.0 h ( j CAP,env = 0.020 ± 0.0023 h −1 , n = 3), and the calculated apparent quantum yield in simulated sunlight was 0.0099 ± 0.00060. These new values were used—alongside previously characterized data for air/and soil/water partitioning, degradation in soil, and hydrolysis—in the Pesticides in Flooded Applications Model to simulate CAP dissipation in a model California (USA) rice field. The model estimates an environmental half‐life of 26 d in the aqueous phase, but the bulk of applied CAP remains in the benthic zone and degrades, with estimated half‐lives of 29 and 92 d in flooded and drained fields, respectively. Environ Toxicol Chem 2020;39:1929–1935. © 2020 SETAC