As the industry is developed more and the population is increased, the environmental concerns are increasingly being focused on the toxic pollutants. The types of toxic pollutants becomes more various, but their physical and chemical properties are not well known, therefore the effective controls of these chemicals are very difficult.
As a rule, the first polluting environment by toxic materials is the unsaturated soil zone, then they are transported into the air or groundwater, and threaten the human health and aguatic life, or are accumulated in plants. Two knowledge of the three-phase equilibrium distribution of these toxic organic pollutants in unsaturated soil zone is essential to foresee the behaviors of the materials and provide the method of their control and treatment.
The soil system is composed of the air, water and solid phases, the equilibrium distribution between air and water phases is subject to the Henry's law. But the partitioning between soil water and solid phases is determined by the principles of solvent system of soil organics and water, which was first proved experimentally by Lambert in 1976. By his theory, the organic components in soil is the major part to sorb the organic toxic pollutants onto soil particles, therefore as the soil organic fraction is increased, the amounts of toxic organic pollutants distributed into soil solid phase is increased.
Based on this theory, the model was developed in a considerably simplified fashion for the engineering practices. Also the effects of the temperature on the equilibrium distribution of toxic organic pollutants in soil system was considered in the model. The computer program for the general graphical presentation of the distribution patterns of all the toxic pollutants for the effective usage in the management of hazardous materials.
Soil organic carbon content, water content, temperature, and physico-chemical parameters ( vapor pressure, water solubility, logKow ) are parameterized to see the effects of them on the equilibrium distribution in unsaturated three-phase soil system.
Finally the general methods of toxic pollutant treatment and disposal were reviewed and the suggestions based on the result were presented for the effective management of toxic pollutants.
