Uptake Pathways of Chlorobenzenes in Plants and Their Correlation with N-Octanol/Water Partition Coefficients

Abstract The bioconcentration factors of 14 C-labeled chlorinated benzenes in plants from soil were quantified in short-term laboratory experiments and correlated to K OW . The correlation was negative for barley and positive for cress. In order to interpret these opposite results, the log/log correlation between partition coefficients and K OW of the chemicals was established also for each step of the uptake, via both roots and leaves. For the first step of root uptake-the partition of the chemicals from soil solids into soil water-the correlation with K OW was negative, whereas it was positive for the second step, the partition roots/soil water, of both plant species. Similarly, the correlation between the first step of foliar uptake-the partition of the chemical from soil into air-and K OW was negative, and that between the second step-the partition between aerial plant parts and air-and K OW was positive for both plant species. The slopes of the regression lines differed between plant species. It may be concluded that K OW can be used as a parameter to predict the uptake of chemicals from soil by plants only if the same class of chemicals and the same plant species is considered.