• Bioconcentration of gaseous organic chemicals in plant leaves: comparison of experimental data with model predictions

      Polder MD; Hulzebos EM, Jager DT; CSR; ECO (Rijksinstituut voor Volksgezondheid en Milieu RIVM, 1997-03-31)
      Chemical substances are distributed in the environment between compartments such as soil, water, air, and biota. Chemicals may be concentrated by plants from soil and air, and therefore plants may contribute substantially to the total daily intake of humans. This study was performed to support the implementation of two models in USES 1.0 and in the European version EUSES, which will become available in May this year. The Uniform System for the Evaluation of Substances, USES 1.0, was developed to assess the lifetime risk of indirect exposure of man and top predators. One of the exposure pathways of plants included in USES 1.0 is the transfer of gaseous substances from air to plant leaves by means of the model of Riederer. A model similar to that of Riederer but having a more refined approach is carried out by Trapp and Matthies. The model of Trapp and Matthies takes the dynamics of the uptake processes into account, and will be implemented in the new European version EUSES. Purpose of this literature study is to evaluate the models of Riederer and Trapp and Matthies by comparing their results with experimental data on leaf-air partition coefficients (K l/a) found in the literature. The data set was limited and therefore conclusions can only be drawn with reservations. For herbaceous plants both models give good estimations for the leaf-air partition coefficient up to 1.0 E+7, with deviations for most substances within a factor 5. For substances for which Riederer predicts a leaf-air partition coefficient above 1.0 E+7, the approach of Trapp and Matthies may be more adequate.