Phytoremediation of organic xenobiotics - Glutathione dependent detoxification in Phragmites plants from European treatment sites.

Studies on the uptake of several organic xenobiotics and on their subsequent conjugation to biomolecules have been performed to elucidate the use of reed plants in phytoremediation of polluted water. Phragmites australis plants were able to accumulate organic xenobiotics in their rhizomes. The uptake was correlated to the logKOW and pKa of the xenobiotics and highest with compounds exhibiting logKOWs between 1 and 3. Detoxification of xenobiotics was demonstrated when the activity of glutathione S-transferase was determined in plants from various treatment sites. Enzyme activities were strongly dependent on the provenience of the plant and the history of the stand. Detoxification enzymes were also inducible. Naphthylic acetic acid (NAA), 2,4-dichlorophenol and BION were tested as potential inducers. BION was able to induce the GST activity 5-fold, albeit only for a short period of hours. The mechanism of induction and the flexibility of the detoxification system of certain ecotypes of reed toward stress or the pollution level will require further investigation.