Absorption of ozone and seven organic pollutants by Populus nigra and Camellia sasanqua

Foliar absorption of seven organic pollutants (acetone, acetonitrile, acrol ein, 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 (mu mol mol(-1)), and gas absorption and transpiration rates w ere measured simultaneously. Ozone and acrolein were effectively absorbed b y both species. MEK was absorbed by C. sasanqua only. A model analysis of g as exchange rates revealed that foliar absorption of the three pollutants w as predominantly through the stomata, and cuticular contribution on gas rem oval is, if any, very small. The plant leaves showed no detectable absorpti on 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 fa ctor 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.