文摘
In situ bioremediation of the nitroaromatic explosive2,4,6-trinitrotoluene (TNT) provides a cost-effective alternativefor cleaning up contaminated sites. Here we comparethe effectiveness of several bioremediation techniques:natural attenuation, bioaugmentation with TNT-degradingPseudomonas putida JLR11, phytoremediation with maize (Zeamays L.) and broad beans (Vicia faba L.), and rhizoremediationwith maize and broad beans inoculated with P. putidaJLR11. Experiments in spiked hydroponic mediumdemonstrated that inoculation with bacteria did not affectTNT levels. On the other hand, axenic plants were ableto remove 32% to 38% of the TNT from the medium. However,when plants were inoculated with bacteria, TNT disappearedto an even greater extent (80% to 88%), a result thatadvocates a role for P. putida JLR11 in rhizoremediation.In field experiments neither natural attenuation norbioaugmentation with P. putida JLR11 affected TNT levelsto a significant degree. However, the extractable TNTcontent in rhizosphere soil associated to maize rootsdecreased by more than 96% in 60 days regardless ofinoculation. This indicates that under these field conditions,the effect of phytoremediation by maize overshadowedany effect of rhizoremediation by P. putida JLR11.