Environmental Sciences Department, Washington State University Tri Cities, Richland, WA, USA.
Pest Manag Sci. 2013 May;69(5):620-6. doi: 10.1002/ps.3414. Epub 2012 Oct 16.
A fumigant volatilization emission was conducted in Washington State in the fall of 2008 to estimate flux following applications of metam sodium by modified low-boom-height (LBH) center-pivot chemigation and soil-incorporated shank injection. This study was performed in a commercial potato field circle to assess emission rates and total cumulative field loss of methyl isothiocyanate (MITC) (the biologically active conversion product of metam sodium) under conditions typical for fall Pacific Northwest potato preplant fumigation. This assessment provides regionally specific MITC emission rate information for modeling appropriate field-edge set-back buffer distances for bystander protection.
Soil-incorporated shank injection appreciably reduced MITC emissions, with lower periodic flux compared with low-drift surface-applied LBH chemigation during treatment applications and over the 4 day post-fumigation experimental timeframe. The estimated total cumulative fumigant loss was 13% by shank injection compared with 47% by LBH chemigation over the application/post-application monitoring period.
The greater adoption of shank-injection fumigation will immediately aid in reducing bystander inhalation exposure to MITC, especially in high-soil-fumigation regions existing at the rural-urban interface.
2008 年秋季，在美国华盛顿州进行了熏蒸挥发排放，以评估在采用改良低飘移高度（LBH）中心枢轴化学注入和土壤注入开沟器施用药剂甲拌磷后，甲基异硫氰酸酯（MITC）（甲拌磷的生物活性转化产物）的通量。这项研究在一个商业马铃薯田进行，以评估在典型的秋季太平洋西北地区马铃薯种植前熏蒸条件下，甲拌磷的排放率和田间总累积损失。这种评估为模型化适当的场边缓冲区距离以提供区域特定的 MITC 排放率信息，以保护旁观者。
土壤注入开沟器显著减少了 MITC 的排放，与低漂移表面应用 LBH 化学注入相比，在处理应用期间和熏蒸后 4 天的实验时间内，其周期性通量较低。在施药/施药后监测期间，通过开沟器注射的估计总累积熏蒸损失为 13%，而通过 LBH 化学注入的损失为 47%。
更广泛地采用土壤注入式熏蒸将立即有助于减少旁观者吸入 MITC 的风险，特别是在农村-城市界面存在高土壤熏蒸地区。
