New methods to measure and predict fate of chemicals in soil

这项研究的目的是为了更好地了解和更好地预测城市或农业土壤系统中环境化学物质的吸收、运输和命运。我们已经表明，小的土壤颗粒（胶体）比大块土壤吸附了更多的化学物质（农药），从而增加了胶体促进化学浸出的风险。这两种化学物质都表现出明显的吸附-解吸非奇异性（吸附滞后），因此在土壤修复和清理过程中有固定在土壤中的倾向。此外，我们还开发并测试了一种新的快速方法（[HPLC]微柱法），用于直接测量自然水流条件下土壤中溶解有机化学物质的运输和吸附。我们已经描述了水蒸气吸收与土壤空气湿度和土壤含水量、土壤比表面积和土壤质地的关系。这些研究涉及挥发性农药（二嗪农）和其他经常使用的有毒有机化合物（苯、甲苯和三氯乙烯）。我们进一步使用气相色谱[GC]微柱法直接测量了不饱和土壤中挥发性有机化合物的迁移，并在土壤蒸汽萃取清理污染土壤场地的相应条件下分析了结果。结果表明，蒸汽吸附空气和水的渗透性和气体扩散率对清理时间有显著影响。我们已经开发了一个孔隙大小依赖模型的空气和气体的渗透性在未扰动的土壤。我们已经开发了新的，更准确的模型，饱和和非饱和的水力导电性在未扰动的土壤，作为功能的土壤含水量和孔径分布。我们开发了第一个与空气渗透性、孔隙大小分布和土壤宏观孔隙度有关的未扰动土壤中气体扩散系数的现实模型。所有的新模型都与日本、欧洲和美国的土壤数据进行了测试，结果显示比以前的模型更准确。少

The objective of this research is to obtain a better understanding and better be able to predict sorption, transport and fate of environmental chemicals in urban or agricultural soil systems.We have shown that small soil particles (colloids) adsorbed relative more chemical (pesticide) than the bulk soil, thus giving an increased risk of colloid-facilitated chemical leaching. Both chemicals showed pronounced adsorption-desorption non-singularity (sorption hysteresis) and thus has a tendency to be immobilized in the soil during soil remediation and clean-up. Also, we have developed and tested a new, rapid method ( [HPLC] Micro-column Method) for direct measurement of dissolved organic chemical transport and sorption in soil during natural water flow conditions.We have described how the vapor sorption relates to soil-air humidity and soil-water content to soil specific surface area and soil texture. The studies concerns both volatile pesticides (diazinon) and other frequently used toxic v … More olatile organic compounds (benzene, toluene, and trichloroethylene). We have further used our Gas Chromatography [GC] Micro-column Method for direct measurement of VOC transport in unsaturated soil and analyzed the results under conditions corresponding to soil vapor extraction based clean-up of a polluted soil site. It was shown that both vapor sorption air and water permeability and gas diffusivity can significantly affect clean-up time.We have developed a pore-size dependent model for air and gas permeability in undisturbed soil. We have developed new, more accurate models for saturated and unsaturated hydraulic conductivity in undisturbed soils, as functions of soil-water content and pore-size distribution. We have developed the first realistic models for gas diffusion coefficients in undisturbed soil as related to air permeability, pore-size distribution, and soil macro-porosity. All the new models were tested against the data for Japanese, European and American soils and showed to be more accurate than previously existing models. Less