Affiliations: Institute of Environment & Health Related Product Safety, Chinese Center for Disease Control and Prevention, Beijing 100021, China | Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
Abstract: The sunlight photodegradation half-lives of 20 mg/L acetochlor were 151, 154 and 169 days in de-ionized water, river water and paddy water, respectively. When exposed to ultraviolet (UV) light, acetochlor in aqueous solution was rapidly degraded. The half-lives were 7.1, 10.1, and 11. 5 min in de-ionized water, river water and paddy water, respectively. Photoproducts of acetochlor were identified by gas chromatography/mass spectrometry (GC/MS) and found at least twelve photoproducts resulted from dechlorination with subsequent hydroxylation and cyclization processes. The chemical structures of ten photoproducts were presumed on the basis of mass spectrum interpretation and literature data. Photoproducts are identified as 2-ethyl-6-methylaniline; N,N-diethylaniline; 4,8-dimethyl-2-oxo-1,2,3,4-tetrahydroquinoline; 2-oxo-N-(2-ethyl-6-methylphenyl)-N-(ethoxymethyl)acetamide; N-(ethoxymethyl)-2'-ethyl-6'-methylformanilide; 1-hydroxyacetyl-2-ethoxyl-7-ethylind ole; 8-ethyl-1-ethoxymethyl-2-oxo-1,2,3,4-tetrahydroquinoline; 4,8-dimethyl-1-ethoxymethyl-2-oxo-1,2,3,4-tetrahydroquinoline; 2-hydroxy-2'-ethyl-6'-methyl-N-(ethoxymethyl)acetanilide and a compound related to acetochlor. The other two photoproducts were detected by GC/MS although their chemical structure was unknown.