Acetochlor Persistence in Surface and Subsurface Soil Samples
Acetochlor Persistence in Surface and Subsurface Soil Samples
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DOI：
10.1007/s11270-013-1747-2
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发表时间：
2013-09
期刊：
影响因子：
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通讯作者：
R. Oliveira;W. C. Koskinen;C. Graff;James L. Anderson;D. Mulla;E. Nater;D. G. Alonso
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文献类型：
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作者：
R. Oliveira;W. C. Koskinen;C. Graff;James L. Anderson;D. Mulla;E. Nater;D. G. Alonso
尽管除草剂的降解数据对于了解其成为污染物的潜力至关重要，并且是基于计算机的除草剂在环境中的命运建模中不可或缺的输入，但大多数现有数据仅涉及表层土壤。土壤样品，收集在两个深度从四个代表性的网站的31.4公顷的领域位于美国明尼苏达州蓝地球县，被用来确定乙草胺消散在实验室条件下。在美国明尼苏达州达科他县的一个16公顷的分水岭内进行了实地研究，对38个地点进行了取样，以获得分水岭内土壤特性全方位的代表性样品。地表土壤的乙草胺DT 50值范围为6.51至13.9天，地下土壤的DT 50值范围为20.3至26.7天。DT 90值是DT 50值的四倍。乙草胺消散的田间DT 50值在2年内没有显著差异，分别为5.7 ± 2.5和7.7 ± 4.5天。与实验室相比，田间消散略快;然而，鉴于明尼苏达州土壤性质的广泛范围，差异似乎微不足道。在这两项研究中，乙草胺都被归类为具有轻微持久性。对于乙草胺，实验室消散研究可以被认为是本研究中土壤和气候条件下田间消散的代表。在地下水风险评估的数学模型中纳入底土退化数据可能会提高预测乙草胺向地下水的潜在移动的能力。
Although degradation data for herbicides are essential in understanding their potential to be contaminants and are indispensable inputs in computer-based modeling of their fate in environment, most available data only concern surface soils. Soil samples, collected at two depths from four representative sites of a 31.4-ha field located in Blue Earth County, MN, USA, were used to determine acetochlor dissipation under laboratory conditions. A field study was also carried out within a 16-ha watershed in Dakota County, MN, USA, where 38 locations were sampled to obtain sample representative of the full range of soil properties found within the watershed. Acetochlor DT50values ranged from 6.51 to 13.9 days for surface soils and from 20.3 to 26.7 days for subsurface soils. DT90values were a factor of four times longer than for DT50 values. Field DT50values for acetochlor dissipation were not significantly different for the 2 years, 5.7 ± 2.5 and 7.7 ± 4.5 days. Dissipation was slightly faster in the field as compared to the laboratory; however, the difference seems insignificant in view of the wide range in soil properties in Minnesota. In both studies, acetochlor would be classified as slightly persistent. For acetochlor, laboratory dissipation studies can be considered representative of field dissipation for the soils and climatic conditions in this study. Inclusion of subsoil degradation data in mathematical models used for ground water risk assessment may improve their capability of predicting potential movement of acetochlor to groundwater.