David Mark B, Gentry Lowell E, Starks Karen M, Cooke Richard A
University of Illinois, Department of Natural Resources and Environmental Sciences, W-503 Turner Hall, 1102 South Goodwin Avenue, Urbana, IL 61801, USA.
J Environ Qual. 2003 Sep-Oct;32(5):1790-801. doi: 10.2134/jeq2003.1790.
The occurrence of metabolites of many commonly used herbicides in streams has not been studied extensively in tile-drained watersheds. We collected water samples throughout the Upper Embarras River watershed [92% corn, Zea mays L., and soybean, Glycine max (L.) Merr.] in east-central Illinois from March 1999 through September 2000 to study the occurrence of atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine), metolachlor 12-chloro-N-(2-ethyl-6-methylphenyl)-N-(methoxy-1-methylethyl) acetamide], alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl) acetamide], acetochlor [2-chloro-N-(ethoxymethyl)-N-(2-ethyl-6-methylphenyl) acetamide], and their metabolites. River water samples were collected from three subwatersheds of varying tile density (2.8-5.3 km tile km(-2)) and from the outlet (United States Geological Survey [USGS] gage site). Near-record-low totals for stream flow occurred during the study, and nearly all flow was from tiles. Concentrations of atrazine at the USGS gage site peaked at 15 and 17 microg L(-1) in 1999 and 2000, respectively, and metolachlor at 2.7 and 3.2 microg L(-1); this was during the first significant flow event following herbicide applications. Metabolites of the chloroacetanilide herbicides were detected more often than the parent compounds (evaluated during May to July each year, when tiles were flowing), with metolachlor ethanesulfonic acid [2-[(2-ethyl-6-methylphenyl)(2-methoxy-1-methylethyl)amino]-2-oxoethanesulfonic acid] detected most often (> 90% from all sites), and metolachlor oxanilic acid [2-[(2-ethyl-6-methylphenyl)(2-methoxy-1-methylethyl)amino]-2-oxoacetic acid] second (40-100% of samples at the four sites). When summed, the median concentration of the three chloroacetanilide parent compounds (acetochlor, alachlor, and metolachlor) at the USGS gage site was 3.4 microg L(-1), whereas it was 4.3 microg L(-1) for the six metabolites. These data confirm the importance of studying chloroacetanilide metabolites, along with parent compounds, in tile-drained watersheds.
在瓦管排水流域中，许多常用除草剂的代谢产物的出现情况尚未得到广泛研究。我们于1999年3月至2000年9月期间，在伊利诺伊州中东部的上恩巴拉斯河流域（92%为玉米，即玉米属的玉米，以及大豆，即大豆属的大豆）采集了水样，以研究莠去津（2-氯-4-乙氨基-6-异丙氨基-s-三嗪）、异丙甲草胺（2-氯-N-(2-乙基-6-甲基苯基)-N-(甲氧基-1-甲基乙基)乙酰胺）、甲草胺（2-氯-N-(2,6-二乙基苯基)-N-(甲氧基甲基)乙酰胺）、乙草胺（2-氯-N-(乙氧基甲基)-N-(2-乙基-6-甲基苯基)乙酰胺）及其代谢产物的出现情况。河水样本是从三个不同瓦管密度（2.8 - 5.3公里瓦管/平方公里）的子流域以及出水口（美国地质调查局[USGS]测量站点）采集的。在研究期间，溪流流量接近历史最低记录，几乎所有流量都来自瓦管。USGS测量站点的莠去津浓度在1999年和2000年分别达到峰值15和17微克/升，异丙甲草胺浓度为2.7和3.2微克/升；这是在除草剂施用后的首次显著流量事件期间。氯代乙酰胺类除草剂的代谢产物比母体化合物更常被检测到（在每年5月至7月瓦管流水时进行评估），其中异丙甲草胺乙磺酸[2-[(2-乙基-6-甲基苯基)(2-甲氧基-1-甲基乙基)氨基]-2-氧代乙磺酸]检测频率最高（所有站点中>90%），异丙甲草胺草氨酸[2-[(2-乙基-6-甲基苯基)(2-甲氧基-1-甲基乙基)氨基]-2-氧代乙酸]次之（四个站点的样本中有40 - 100%）。将三者相加，USGS测量站点的三种氯代乙酰胺母体化合物（乙草胺、甲草胺和异丙甲草胺）的中位浓度为3.4微克/升，而六种代谢产物的中位浓度为4.3微克/升。这些数据证实了在瓦管排水流域中研究氯代乙酰胺代谢产物以及母体化合物的重要性。
