TY - JOUR
T1 - Uptake, metabolism, and toxicity of methyl tert-butyl ether (MTBE) in weeping willows
AU - Yu, Xiao Zhang
AU - Gu, Ji Dong
N1 - Funding Information:
This work was supported by a Ph.D. studentship from The University of Hong Kong.
PY - 2006/10/11
Y1 - 2006/10/11
N2 - Methyl tert-butyl ether (MTBE) is a high volume production chemical and the most commonly used gasoline oxygenate. Uptake, metabolism and toxicity of MTBE in trees were investigated in this study. Pre-rooted weeping willows (Salix babylonica L.) were exposed to hydroponic solution spiked with MTBE and incubated at 25.0 ± 1 °C for 168 h. The normalized relative transpiration (NRT) rate of weeping willows was used to determine toxicity. MTBE and possible intermediate tert-butyl alcohol (TBA) in solution, tissues of aerial parts of plants, and air were analyzed. Results from the toxicity test showed that severe signs of toxicity (the reduction of the NRT ≥35%) were only found at the treatment group with high doses of MTBE 400 mg L-1. Neither chlorosis of leaves nor large reduction in the NRT was observed at MTBE exposure to weeping willows ≤200 mg L-1. Almost all applied MTBE was removed from the hydroponic solution by plants in all treatment groups. Small amounts of MTBE were detected in the plant tissues, but a large fraction of the applied MTBE was found in the air through plant transpiration. Mass balance studies showed that MTBE was assimilated into the plants from hydroponic solution but was not metabolized during transport in the plant. Phytovolatilization was the only relevant removal process for MTBE. Transpiration stream concentration factor (TSCF), an important parameter for design of engineered MTBE phytoremediation systems, was estimated to be 1.12. In conclusion, although this compound is persistent to the attack by plant enzymes, atmospheric MTBE is much more susceptible to photo-oxidation for decomposition. Phytoremediation of MTBE polluted soils and groundwater is an alternative to presently available remediation technologies.
AB - Methyl tert-butyl ether (MTBE) is a high volume production chemical and the most commonly used gasoline oxygenate. Uptake, metabolism and toxicity of MTBE in trees were investigated in this study. Pre-rooted weeping willows (Salix babylonica L.) were exposed to hydroponic solution spiked with MTBE and incubated at 25.0 ± 1 °C for 168 h. The normalized relative transpiration (NRT) rate of weeping willows was used to determine toxicity. MTBE and possible intermediate tert-butyl alcohol (TBA) in solution, tissues of aerial parts of plants, and air were analyzed. Results from the toxicity test showed that severe signs of toxicity (the reduction of the NRT ≥35%) were only found at the treatment group with high doses of MTBE 400 mg L-1. Neither chlorosis of leaves nor large reduction in the NRT was observed at MTBE exposure to weeping willows ≤200 mg L-1. Almost all applied MTBE was removed from the hydroponic solution by plants in all treatment groups. Small amounts of MTBE were detected in the plant tissues, but a large fraction of the applied MTBE was found in the air through plant transpiration. Mass balance studies showed that MTBE was assimilated into the plants from hydroponic solution but was not metabolized during transport in the plant. Phytovolatilization was the only relevant removal process for MTBE. Transpiration stream concentration factor (TSCF), an important parameter for design of engineered MTBE phytoremediation systems, was estimated to be 1.12. In conclusion, although this compound is persistent to the attack by plant enzymes, atmospheric MTBE is much more susceptible to photo-oxidation for decomposition. Phytoremediation of MTBE polluted soils and groundwater is an alternative to presently available remediation technologies.
KW - Metabolism
KW - Methyl tert-butyl ether (MTBE)
KW - Phytoremediation
KW - Toxicity
KW - Willows
UR - http://www.scopus.com/inward/record.url?scp=33748904983&partnerID=8YFLogxK
U2 - 10.1016/j.jhazmat.2006.04.024
DO - 10.1016/j.jhazmat.2006.04.024
M3 - 文章
C2 - 16723185
AN - SCOPUS:33748904983
SN - 0304-3894
VL - 137
SP - 1417
EP - 1423
JO - Journal of Hazardous Materials
JF - Journal of Hazardous Materials
IS - 3
ER -