Interspecies Variability of the Plant/Air Partitioning of Polychlorinated Biphenyls

Abstract

The plant/air partition coefficients (KPA) of a range of PCB congeners were determined in five different grass and herb species common to Central Europe [ryegrass (Lolium multiflorum), clover (Trifolium repens), plantain (Plantago lanceolata), hawk's beard (Crepis biennis), and yarrow (Achil lea millefolium)]. The measurements were conducted between 10 and 35 °C using a solid-phase fugacity meter. Large differences in the partitioning behavior between the plants were observed, with the partition coefficient varying by up to a factor of 20 between the five species. There was also considerable interspecies variability in the enthalpy of phase change (plant to air), but these differences were not related to the differences in the partition coefficients. A good linear relationship between log KPA and experimentally determined log KOA values (octanol/air partition coef ficients) was obtained for each plant species (r 2 between 0.86 and 0.98). However, the slope of the regression lines ranged from 0.57 to 1.15....