The potential for phytoremediation of MTBE

Area of Science:

• Environmental Science
• Plant Biology
• Environmental Chemistry

Background:

• Methyl tert-butyl ether (MTBE) is a persistent groundwater pollutant originating from gasoline additives.
• Its non-sorbing and non-reactive properties in water make remediation challenging.
• Phytoremediation offers a potentially sustainable approach to address MTBE contamination.

Purpose of the Study:

• To investigate the efficacy of poplar trees in removing MTBE from hydroponic systems.
• To differentiate between active plant uptake and passive volatilization of MTBE.
• To quantify MTBE transport and transformation within poplar saplings.

Main Methods:

• Utilized a novel experimental design to measure MTBE uptake and transpiration in hydroponic systems.
• Employed a balsa wood control to isolate passive volatilization.
• Analyzed MTBE concentrations in water, plant biomass, and transpired air.
• Conducted mass balance analysis to assess MTBE transformation.

Main Results:

• Poplar saplings reduced MTBE mass in water by 30% within one week at varying concentrations (300-1600 ppb).
• Active plant uptake of MTBE was approximately double that of passive volatilization.
• MTBE was detected in plant biomass, confirming translocation.
• MTBE was largely untransformed during passage through the plants.

Conclusions:

• Small poplar saplings demonstrate significant potential for phytoremediation of MTBE-contaminated groundwater.
• MTBE removal correlated with water transpiration, with a calculated transpiration stream concentration factor of approximately 1.
• This finding is crucial for designing effective engineered phytoremediation systems for MTBE plumes.