Determination of a Distribution Coefficient

Environmental chemistry is a new field of study in many chemistry departments and only three published summaries of environmental laboratory experiments are available (1–3). While these laboratory manuals contain excellent experiments for the training of students in environmental monitoring, relatively few standardized procedures have been published for broader issues such as the measuring of fate and transport parameters. Perhaps the most important fate and transport parameter is the distribution coefficient, Kd. The distribution (or partition) coefficient is a measure of absorption phenomena between the aqueous and solid phases. It is fundamental to understanding processes responsible for the distribution of pollutants in aquatic systems (groundwater, lakes, rivers, and estuaries). Mathematically it can be represented as the ratio of the equilibrium pollutant concentration in the solid (sediment or soil) phase to the pollutant concentration in the dissolved (aqueous) phase