Department of Environmental Toxicology, University of California, Davis, Davis, California 95616, USA.
J Agric Food Chem. 2010 Mar 24;58(6):3674-80. doi: 10.1021/jf903957j.
Clomazone (trade names Cerano and Command) is a popular herbicide used on California rice fields to control aquatic weeds. Its physicochemical characteristics indicate that it will persist primarily in the water column, where microbial degradation may drive its environmental fate. The objectives were to determine microbial degradation rates and compare the metabolic products under aerobic and anaerobic conditions similar to those in California rice fields during the summer. Time-series samples were extracted and analyzed by LC/MS/MS. Metabolic profiling revealed the following clomazone-derived transitions: m/z 240 --> 125 (clomazone), m/z 242 --> 125 (ring-open clomazone), m/z 256 --> 125 (5-hydroxyclomazone), m/z 256 --> 141 (aromatic hydroxyclomazone), m/z 268 --> 125 (unknown metabolite), and m/z 272 --> 141 (4'5-dihydroxyclomazone). Results indicate an anaerobic half-life of 7.9 days, with ring-open clomazone reaching 67.4% of application at 38 days. Aerobically, clomazone degraded more slowly (t(1/2) = 47.3 days), forming mostly soil-bound residues. Thus, under summer conditions, clomazone is likely to dissipate rapidly from fields via anaerobic degradation.
氯甲唑草酮（商品名 Cerano 和 Command）是一种常用于加利福尼亚稻田控制水生杂草的流行除草剂。其物理化学特性表明，它将主要存在于水柱中，微生物降解可能会影响其环境归宿。本研究的目的是确定氯甲唑草酮在有氧和无氧条件下的微生物降解速率，并比较其代谢产物，这些条件类似于加利福尼亚稻田夏季的条件。采用 LC/MS/MS 对时间序列样品进行提取和分析。代谢组学分析揭示了以下氯甲唑草酮衍生的转化：m/z 240 --> 125（氯甲唑草酮）、m/z 242 --> 125（开环氯甲唑草酮）、m/z 256 --> 125（5-羟基氯甲唑草酮）、m/z 256 --> 141（芳香族羟基氯甲唑草酮）、m/z 268 --> 125（未知代谢物）和 m/z 272 --> 141（4'-5-二羟基氯甲唑草酮）。结果表明，在无氧条件下的半衰期为 7.9 天，在 38 天时开环氯甲唑草酮达到施用量的 67.4%。有氧条件下，氯甲唑草酮降解速度较慢（t(1/2) = 47.3 天），主要形成土壤结合残留。因此，在夏季条件下，氯甲唑草酮可能会通过厌氧降解迅速从田间消散。
