Removal of indoor odors via phytoremediation: interaction between aromatic hydrocarbon odorants decreases toluene removal

The composition of volatile organic compounds (VOCs) in the air of homes and offices is often complex and can have a significant effect on the health of individuals exposed. Certain plant species and their associated microorganisms are known to remove VOCs from the air; however, the rate of removal of one VOC may be influenced by the presence of others. We investigated the effect of VOCs on toluene phytoremediation rate by comparing the interaction of toluene, xylene, and benzene, common indoor odorants. Golden pothos (Epipremnum aureum (L.) Engl.) and Cornstalk (Dracaena fragrans (L.) Ker Gawl.) were exposed to different concentrations of one or more gases in a sealed chamber. The removal of 0.9 mu L L-1 toluene was little affected by the addition of 0.9 mu L L-1 xylene until the concentration was >= 1.8 mu L L-1. At 1.8 and 2.7 mu L L-1 xylene, there was a progressive decline in toluene removal. Similarly, at 1 mu L L-1 toluene, 1 mu L L-1 of xylene did not have a significant effect on phytoremediation; however, with the addition of 1.0 mu L L-1 benzene, removal of toluene declined an average of 50% in both plant species. The addition of xylene reduced toluene removal by 39% and with xylene + benzene 58% when the total VOC concentration remained constant, but total VOC removal by the plants was similar. Since homes and offices generally have a much more diverse VOC composition than described in this study, VOC interaction effects on phytoremediation are probably more complex in real-world situations.