Modeling Fate of Toxic Organic Compounds and Nitrogen in Soils.

在为期一年的时间里，在所有三个实验室的联合研究工作主要集中在一个两个领域，即（I）的移动和阻滞的有毒有机化合物（VOCs）在土壤中的分析和（II）建模和测量颗粒内孔隙空间和不动水对土壤中化学运动的影响。针对（I），提出了一种改进的微柱气相色谱法测定土壤中挥发性有机化合物的阻滞效应。实验表明，该方法具有快速、直接、准确测定多种挥发性有机物的阻滞因子的优点。采用土壤微柱法，研究了孔隙水流速、温度、土壤粒径和有机质含量等因素对土壤中挥发性有机化合物的阻滞作用。对于土壤中挥发性有机物的多组分，通过稳态模型模拟和相关的实验测量证实了多组分通量密度的存在。此外，瞬态传输模型采用菲克扩散定律和多组分非线性吸附等温线预测测量的VOCs浓度准确。关于（II），在微孔介质柱中的示踪溶质（氯化物）的运输进行了长期实验，结果与我们开发的一个新的运输模型是密切一致的。该模型将水分为移动的水、薄膜水和微孔隙水。这项研究于1993年11月在美国辛辛那提举行的美国土壤科学学会会议上发表。提出了一个评价18种VOCs对环境影响的筛选模型CRIOCATS。因此，在这两个研究领域（第一和第二）内，取得了适合在国际期刊上发表的重要新发现。

During the one-year period, the joint research effort in all of the three laboratories has mainly focused one two areas, namely (I) analysis of the movement and retardation of toxic organic compounds (VOCs) in soils and (II) modeling and measuring the effects of intra particle pore space and of immobile water on chemical movement in soils. With respect to (I), an improved micro-column gas-cromatograph-based method for measuring the retardation of VOCs in soils was developed. Tests showed the method to be promising for rapid, direct and accurate determination of the retardation factor for a number of VOCs. By using the soil micro-column, the effect of pore-water velocity, temperature, soil grain size, and organic matter content on retardation of VOCs was studied. Concerning the multicomponent of VOCs in soil, the presence of multicomponent flux densities was confirmed by the steady-state model simulation and its related experimental measurements. Furtheremore, a transient transport model using Fick's law for diffusion and multicomponent non-linear adsorption isotherm predicted measured VOCs concentrations accurately. With respect to(II), long-term experiments for transport of a tracer solute (chloride) in micro-porous media columns were carried out and results were in close agreement with a new transport model that we developed. The model partitions the water into mobile, film, and micro-pore water. The research was presented at the Soil Science Society of America meetings in Cincinnati, USA in November, 1993. Also, a screening model (CRIOCATS) to evaluate the effect of 18 kinds of VOCs to the environment was proposed. Thus, within both research areas (I and II), important new findings appropriate for publication in international journals were achieved.