CROSS-CORRELATION OF POLARITY CURVES TO PREDICT PARTITION-COEFFICIENTS OF NONIONIC ORGANIC CONTAMINANTS

Accurate sorption coefficients are: important for models to predict fate and movement of organic chemicals in soils or sediments. We report here on a new method for predicting partition coefficients (K-d) of nonionic chemicals onto soils and geological materials. It includes properties of sorbents and of sorbates, thereby yielding more accurate organic carbon-normalized partition coefficients (K-oc) than a single value derived from an octanol-water partition coefficient (K-ow). A regression of log K-oc on log K-ow and polarity index (PI: [(O + N)/C]) was established using benzene, toluene, and o-xylene as sorbates and using model organic polymers as sorbents K-oc data for sorption of o-xylene onto soils and geological materials were used in a rearranged form of the regression equation to determine effective polarity of the soils, Effective polarity was then used together with the respective K-ow values to predict K-oc of benzene and toluene on each soil. This method provides a range of K-oc values that are soil sensitive. The effective polarity provides a new parameter to describe soil organic sorbents and includes any influence that mineral components may exert on the sorptive properties. of organic matter.