Suter H C, White R E, Heng L K, Douglas L A
School of Resource Management, University of Melbourne, Victoria 3010, Australia.
J Environ Qual. 2002 Sep-Oct;31(5):1630-5. doi: 10.2134/jeq2002.1630.
The organophosphate insecticide phosmet [phosphorodithioic acid, s-((1,3-dihydro-1,3-dioxo-2H-isoindol-2yl)methyl), o,o-dimethyl ester] is used to control red-legged earth mites (Halotydeus destructor), lucerne flea (Sminthurus viridis), and Oriental fruit moth (Cydia molesta) in horticulture and vegetable growing. This study was undertaken with two soils of contrasting properties to determine the extent to which sorption and degradation of the insecticide might influence its potential to leach from soil into receiving waters. Two soils were used: a highly organic, oxidic clay soil (Ferrosol) and a sandy soil low in organic matter (Podosol), sampled to 0.3 m depth. The extent of sorption and decomposition rate of a phosmet commercial formulation were measured in laboratory experiments. Sorption followed a Freundlich isotherm at all depths. The Freundlich coefficient K was significantly correlated (p = 0.005) with organic C content in the Podosol, and significantly correlated (p = 0.005) with organic C and clay content in the Ferrosol. K was highest (48.8 L kg-1) in the 0- to 0.05-m depth of the Ferrosol, but lowest (1.0 L kg-1) at this depth in the Podosol. Degradation followed first-order kinetics, with the phosmet half-life ranging from 14 h (0-0.05 m depth) to 187 h (0.2-0.3 m depth) in the Ferrosol. The half-life was much longer in the sandy Podosol, ranging from 462 to 866 h, and did not change significantly with depth. Soil organic C and to a lesser degree clay content influenced phosmet sorption and degradation, but the interaction was complex and possibly affected by co-solvents present in the commercial formulation.
有机磷酸酯杀虫剂亚胺硫磷[二硫代磷酸酯，S-((1,3-二氢-1,3-二氧代-2H-异吲哚-2-基)甲基)，O,O-二甲基酯]用于园艺和蔬菜种植中防治红腿土螨（卤螨）、苜蓿蚤（绿圆跳虫）和东方果蛾（苹小食心虫）。本研究采用两种性质截然不同的土壤，以确定杀虫剂的吸附和降解对其从土壤中淋溶到接受水体中的可能性的影响程度。使用了两种土壤：一种是高有机质的氧化粘土土壤（铁铝土）和一种低有机质的沙质土壤（灰化土），采样深度为0.3米。在实验室实验中测量了亚胺硫磷商业制剂的吸附程度和分解速率。在所有深度下，吸附均符合弗伦德利希等温线。弗伦德利希系数K与灰化土中的有机碳含量显著相关（p = 0.005），与铁铝土中的有机碳和粘土含量显著相关（p = 0.005）。K在铁铝土的0至0.05米深度处最高（48.8 L kg-1），但在灰化土的该深度处最低（1.0 L kg-1）。降解遵循一级动力学，在铁铝土中，亚胺硫磷的半衰期从14小时（0至0.05米深度）到187小时（0.2至0.3米深度）不等。在沙质灰化土中半衰期长得多，从462至866小时不等，且随深度变化不显著。土壤有机碳以及在较小程度上粘土含量影响亚胺硫磷的吸附和降解，但相互作用复杂，可能受到商业制剂中存在的共溶剂的影响。
