Quantitative Review and Analysis of Pesticide Sorption and Its Effect on Degradation in Relation to Soil and Climate
When pesticides are applied to the field for crop protection, they undergo two important processes: binding to the soil surfaces (sorption), and degradation in the porous media through either chemical or biological pathways. These two processes largely govern pesticide fate and transport behavior in the environment and are critical for pesticide environmental exposure assessments. Several public databases (e.g., The FOOTPRINT Pesticide Properties Database, <www.eu-footprint.org/ppdb.html>) have accumulated a significant amount of sorption and degradation data from published literature. The majority of these data originated from studies in Europe and North America; thus they may not represent regions in other parts of the world. In regions in other parts of the world, local data on pesticide sorption and degradation are often unavailable; thus environmental exposure assessments often rely on databases that are drawn primarily from regions that may have very different soil and environmental conditions. Obviously such data extrapolation requires careful quantitative analysis of sorption and degradation in relationship with environmental factors (soil and climate conditions).
Although sorption and degradation in soil may depend on environmental conditions differently, research has increasingly shown that the two processes are dynamically interrelated. Sorption in soil is a microscopically heterogeneous and time-dependent process,1,2 which may depend on not only the content but also the chemistry of soil organic matter and mineralogy.3,4,5 Degradation through biological pathways relies on microbial populations that are highly localized in the partially water-filled soil pore space, with limited mobility to reach out for adsorbed substrates.6,7,8 Because of this, binding to or release from the soil microscopic surfaces plays a critical role in determining the overall rate of degradation. It is expected that this effect varies among different classes of pesticide chemistry, soil types, and climatic zones.
The goal of this project is to focus on the quantitative evaluation of the relationship between sorption and broader soil properties, the coupling effect of sorption on degradation, and potential molecular structure-activity relationships that differentiate environmental fate behavior. The project will take advantage of IUPAC worldwide expertise to assemble and assimilate diverse data from published literature around the world. The outcome from the completed project may offer a set of quantitative tools for estimating sorption and degradation based on local environmental conditions and pesticide structural activity. This effort is expected to help address data deficiency problems in regions of the world with limited pesticide degradation studies and provide refinement of pesticide environmental exposure assessment models in general.
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For more information, contact Task Group Chair Wenlin Chen <email@example.com>.
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Published Online: 2011-03-01
Published in Print: 2011-03-01