Chemical partitioning to foliage: the contribution and legacy of Davide Calamari.
BACKGROUND
Davide Calamari and his colleagues were among the first to appreciate that vegetation could play a key role in determining the fate and effects of organic contaminants. They conducted pioneering experiments to investigate the uptake of contaminants by plants from the atmosphere and they sought to model the observed phenomena. In the nearly two decades since there has been a marked increase in understanding of these phenomena as a result of both experimental and modelling studies.


OBJECTIVE
In this study we briefly review our current understanding of chemical partitioning between foliage and air. A model in both fugacity and concentration format is described, based on that of Tolls and McLachlan (1994), in which the leaf is treated as consisting of two layers, a waxy cuticle with an underlying 'reservoir' layer, the cuticle being surrounded by an air boundary layer and containing stomata that provide direct access from the air to the 'reservoir'. The model quantifies the dynamic penetration of a defined chemical into a defined leaf as a function of time.


METHODS
The model is applied for illustrative purposes to a hypothetical but typical leaf for a set of illustrative chemicals to demonstrate the effect of changes in physical-chemical properties and leaf characteristics.


CONCLUSIONS
The results are compared qualitatively with a variety of field and laboratory studies of foliage uptake and clearance of chemicals.


CONCLUSIONS
It is concluded that the model yields results that are generally consistent with observations. It is suggested that with appropriate parameterisation and validation, the model can contribute to an improved understanding of the process of foliage uptake from the atmosphere and to the development of an improved predictive capability.
Mackay
Donald
D
Canadian Environmental Modelling Centre, Trent University, 1600 West Bank Drive, Peterborough, ON, Canada, K9J 7B8. dmackay@trentu.ca
Foster
Karen L
KL
Patwa
Zaheerabbas
Z
Webster
Eva
E
D000393:Air Pollutants / Q000378:metabolism*; D003198:Computer Simulation; D008962:Models, Theoretical; D018515:Plant Leaves / Q000378:metabolism*
D000393:Air Pollutants