Aging Effects on the Availability of Herbicides to Runoff Transfer

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• 作者：Xavier Louchart ; Marc Voltz
• 刊名：Environmental Science & Technology
• 出版年：2007
• 出版时间：February 15, 2007
• 年：2007
• 卷：41
• 期：4
• 页码：1137 - 1144
• 全文大小：377K
• 年卷期：v.41,no.4(February 15, 2007)
• ISSN：1520-5851

文摘

Realistic estimation of sorption parameters is essential topredict long-term herbicide availability in soils and theircontamination of surface water and groundwater. This studyexamined the temporal change of an effective partitioncoefficient K_d^eff for the herbicides simazine, diuron, andoryzalin from a 0.12 ha field experiment during 7 vineyardgrowing seasons. K_d^eff is the ratio of solvent extractableherbicide concentrations in the top soil (0-2 cm) to theaverage concentrations in runoff water and is consideredto assess the effective availability of herbicides to runofftransfer. K_d^eff increased largely with aging time sinceapplication, from values similar to those of the literature(determined in 24 h batch conditions, K_d^ref), up to 88, 164, and30 times these initial values for simazine, diuron, andoryzalin respectively. The seasonal variation of K_d^eff valuesbetween years and compounds could be adequatelydescribed by a unique model, taking into account thecumulative rainfall since application and K_d^ref of eachcompound. This simple model was able to represent theinfluence of the soil moisture content and its changes in thedifferent biological and physicochemical processes thatmay contribute to the (bio)available, sorbed, or entrappedstate of any of the studied herbicides with aging timeunder Mediterranean climate.