A passive dosing method to determine fugacitycapacities and partitioning properties of leaves

• Published in: Environmental science--processes & impacts 2016, Vol.18, p.1325
• Main Authors: Bolinius, Dämien Johann, MacLeod, Matthew, McLachlan, Michael S., Mayer, Philipp, Jahnke, Annika
• Format: Article
• Language: English
• Subjects: Applied Environmental Science; Hydrophobic organic chemicals; leaves; passive dosing; tillämpad miljövetenskap
• ISSN: 2050-7887; 2050-7895
• DOI: 10.1039/c6em00423g

The capacity of leaves to take up chemicals from the atmosphere and water in fl uences how contaminantsare transferred into food webs and soil. We provide a proof of concept of a passive dosing method tomeasure leaf/polydimethylsiloxane partition ratios ( K leaf/PDMS ) for intact leaves, using polychlorinatedbiphenyls (PCBs) as model chemicals. Rhododendron leaves held in contact with PCB-loaded PDMSreached between 76 and 99% of equilibrium within 4 days for PCBs 3, 4, 28, 52, 101, 118, 138 and 180.Equilibrium K leaf/PDMS extrapolated from the uptake kinetics measured over 4 days ranged from 0.075(PCB 180) to 0.371 (PCB 3). The K leaf/PDMS data can readily be converted to fugacity capacities of leaves( Z leaf ) and subsequently leaf/water or leaf/air partition ratios ( K leaf/water and K leaf/air ) using partitioning datafrom the literature. Results of our measurements are within the variability observed for plant/air partitionratios ( K plant/air ) found in the literature. Log K leaf/air from this study ranged from 5.00 (PCB 3) to 8.30(PCB 180) compared to log K plant/air of 3.31 (PCB 3) to 8.88 (PCB 180) found in the literature. The methodwe describe could provide data to characterize the variability in sorptive capacities of leaves that wouldimprove descriptions of uptake of chemicals by leaves in multimedia fate models.