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A method for quantifying the effect of medium composition on the diffusive mass transfer of hydrophobic organic chemicals through thin layers was applied to plant tissue. The method employs two silicone disks, one serving as source and one as sink for a series of PAHs diffusing through thin layers of water, potato tissue, and carrot tissue. Naphthalene, phenanthrene, anthracene, and fluoranthene served as model substances. Their transfer from source to sink disk was measured by HPLC to determine a velocity rate constant proportional to the diffusive conductivity. The diffusive flux through the plant tissue was modeled using Fick's first law of diffusion. Both the experimental results and the model suggest that mass transfer through plant tissue occurs predominantly through pore water and that, therefore, the mass transfer ratio between plant tissue and water is independent of the hydrophobicity of the chemical. The findings of this study provide a convenient method to estimate the diffusion of nonvolatile organic chemicals through various plant materials. The application to a radial diffusion model suggests that “growth dilution” renders the concentration of highly hydrophobic chemicals in potatoes below their equilibrium partitioning level. This is in agreement with field results for the bioconcentration of PAHs in potatoes.

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The copper content of grape and wine from 16 wine-farms in Italy was studied during the harvest of 2003. The influence of the number of copper applications, the period between the last application and harvest, and the total amount of copper applied was examined. Of the total number of samples analysed, 13% of grape samples and 18% of wine samples exceeded the maximum residue level (MRL). The total amount of copper applied and the number of days between the last application and harvest explained 44% of the concentration of copper in grape. This low correlation may be due to other influencing factors, such as meteorology and the application method. In 2003, conditions were unusually dry and the recommended safety interval for copper application (20 days) was not sufficient to guarantee a residue level in grape below the MRL (20 mg kg(-1)). In order to reduce the probability of copper residues being close to the MRL, a period of 40-50 days between the last application and harvest is suggested. Furthermore, the copper content of grape and wine was not dependent on the pest management strategy of the farm (conventional, integrated or organic). A more important factor influencing copper residue levels may be that copper applications are made in response to the prediction of a disease outbreak rather than being dependent on the pest management strategy in place. No difference in copper content was observed between red and white grape or wine.

Classic (polybromodiphenyl ethers, PBDEs) and emerging halogenated flame retardants (HFRs) such as decabromodiphenyl ethane (DBDPE) and halogenated norbornenes, as well as organophosphate flame retardants (OPFRs) were analysed in 52 sediments and 27 fish samples from three European river basins, namely the Evrotas (Greece), the Adige (Italy) and the Sava (Slovenia, Croatia, Bosnia and Herzegovina and Serbia). This is the first time that FR levels have been reported in these three European river basins. The highest contamination was found in the Adige and Sava rivers, whereas lower values were obtained for the Evrotas. The levels in sediment samples ranged between 0.25 and 34.0ng/g dw, and between 0.31 and 549ng/g dw, for HFRs and OPFRs respectively. As regards levels in fish, concentrations ranged between 9.32 and 461ng/g lw and between 14.4 and 650ng/g lw, for HFRs and OPFRs, respectively. Thus, whereas OPFR values were higher in sediments, similar concentrations (in the Evrotas) and even lower concentrations than HFRs (Sava) were found for OPFRs in the fish samples, indicating the lower bioaccumulation potential of OPFRs. Biota to sediment accumulation factors (BSAFs) were calculated and higher values were obtained for HFRs compared to those assessed for OPFRs.