Absorption of Ozone and Seven Organic Pollutants by <i>Populus nigra</i> and <i>Camellia sasanqua</i>

Abstract

Foliar absorption of seven organic pollutants (acetone, acetonitrile, acrolein, methyl ethyl ketone (MEK), isobutyl methyl ketone (IBMK), chloroform, and benzene), and ozone was examined. Two woody species (Populus nigra and Camellia sasanqua ) were exposed to each pollutant at a concentration of 0.5 or 1.0 ppmv (μmol mol-1), and gas absorption and transpiration rates were measured simultaneously. Ozone and acrolein were effectively absorbed by both species. MEK was absorbed by C. sasanqua only. A model analysis of gas exchange rates revealed that foliar absorption of the three pollutants was predominantly through the stomata, and cuticular contribution on gas removal is, if any, very small. The plant leaves showed no detectable absorption of the other five organic pollutants. We conclude that plant leaves act as an effective sink for some organic pollutants but not for others. The factor that determines whether plant leaves can effectively absorb pollutants in this study seems to be whether the pollutant is effectively metabolized in the leaf cells.