OECD 106: Adsorption-desorption using a batch equilibrium method

The behavior of chemicals in soils and aquatic sediments strongly depend on adsorption and desorption phenomena. Measuring adsorption/desorption is useful for obtaining information on the prediction or estimation of various characteristics of the chemical, such as its availability for degradation, transformation and uptake by organisms; leaching through the soil, volatility from the soil, and run-off from land surfaces into water. In the batch equilibrium method, chemical adsorption in the soil is characterized by determining partitioning of the chemical between soil and solution, resulting in equilibrium adsorption coefficients. This is obtained on various soil types that differ in content (organic carbon, clay), soil texture and pH. Adsorption-desorption isotherms are described by Freundlich models.