Vapor-phase 2,3,7,8-TCDD sorption to plant foliage — A species comparison

Abstract

Plant uptake rate constants (k 1) were determined for vapor-phase 2,3,7,8-TCDD using grass, azalea, spruce, kale and pepper foliage, and the fruit from apple, tomato and pepper. Plants were exposed to vapor-phase 3H-2,3,7,8-TCDD for 96 h, and the TCDD sorption rate constant for each plant species was determined from measured air and plant concentrations. Sorption rate constants for the different plant tissues, expressed on a fresh weight basis (k 1FWt with units of g Air g FWt −1 h −1), varied by two orders of magnitude. The rate constants were normalized for the exposed plant surface area (SA) by dividing k 1FWt by the SA/FWt ratio for each plant species. Normalizing the rate constants for exposed surface area resulted in significantly less variation between species (k 1SA = 1.2 g Air cm 2 −1 h −1 ± 0.2 SE). The cuticular wax content of the different plant species did not effect the short-term sorption kinetics of 2,3,7,8-TCDD.