Progress 10/01/01 to 09/30/07
Outputs
OUTPUTS: This is the final portion of a multi-year project using plants as tools to help clean up environmental contamination. One graduate student, a visiting scholar and an undergraduate worked on this project during the final year. During this last time period we have focused on two specific abilities of plants. The first is to degrade certain diazo dyes commonly used in textile or or dying applications. The second is use trees to volatilize dioxane from the subsurface aquifer. We screened a large number of dyes and identified several that can be effectively degraded by sunflower root systems in hydroponic culture. We improved the assay of dioxane in water and plant leaf tissue by means of a specific salting-out effect. Dioxane was shown to be able to move through plants and volatilize to the atmosphere. Field studies were done in an effort to detect dioxane movement in a natural setting. We validated the dioxane assay for natural waters, and determined the role of interfering
substances in plant tissue extract.
PARTICIPANTS: L.C.Davis, principle investigator; A.J. Dickinson, undergraduate summer student
TARGET AUDIENCES: Primarily other researchers, also engineers attempting to clean up contaminants. Some outreach and education activities use textile dyes as examples of how plants are able to degrade contaminants in the environment.
Impacts
The root systems of plants possess enzymes that can effectively decolorize diazo dyes, and some other classes of dyes. This provides a cost-effective means to treat water from production facilities. Plants can translocate dioxane while removing water from a shallow aquifer providing a means to control seepage from contaminated sites.
Publications
- Dokken, K.M. and Davis, L.C. (2007) Infrared imaging of sunflower and maize root anatomy. Journal of Agricultural and Food Chemistry 55:10517-10530.
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Progress 01/01/06 to 12/31/06
Outputs
Many species of plants are able to detoxify organic chemicals that may be derived from waste streams of manufacturing industries, or as incidental contamination from agricultural chemicals including herbicides and pesticides. During 2006 we continued our studies of several compounds, finishing off work with a graduate student K.M. Dokken. We also completed studies of how potassium ferricyanide is detoxified by sunflower plants and showed that it can serve as a source of iron for those plants when their other sources of iron are removed. Two undergraduates were involved in this work. In collaborative efforts with the Kansas Department of Health and Environment, we did further studies at a field site to examine the role of different nutrients in cleaning up chlorinated solvents in an aquifer. Two graduate students were involved in this work. In addition a laboratory study using a "mesocosm" examined the impact of different nutrients on degradation of carbon
tetrachloride which is a problem at former grain storage sites. With the assistance of an undergraduate and a visiting scholar we have developed a method to detect dioxane in water that is several hundred times more sensitive than conventional headspace gas analysis, but also much less costly than the definitive isotope dilution mass spectrometry method that is used for regulatory purposes. A new area of study has been initiated, using plants to degrade textile dyes. A preliminary screen has verified that sunflowers are able to decolorize some azo dyes and has established limits for toxicity of some other classes of dyes to which plants have been exposed.
Impacts
Plants provide economical, efficient means to clean up a wide range of organic contaminants. Their root-associated enzymes effectively transform many organic chemicals. For some of these there is no readily available microbial system (such as in a sewage treatment plant) that will degrade them.
Publications
- Khaitan, S., Kalainesan, S., Erickson, L.E., Kulakow, P., Martin, S., Karthikeyan, R., Hutchinson, S.L.L., Davis, L.C., Illangesekare, T.H., and Ngoma, C. 2006. Remediation of Sites Contaminated by Oil Refinery Operations. Environmental Progress 25:20-31.
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Progress 01/01/05 to 12/31/05
Outputs
In 2005 we continued efforts to understand how plants are able to detoxify organic chemicals. This year we focused on studies of sunflower and maize roots exposed to highly toxic byproducts of manufacturing, including dinitrotoluenes and chlorophenols. By using advanced infra-red imaging we are able to identify where the chemicals are accumulated in plant roots in a form that cannot be extracted by common solvents. We also established that the presence of these compounds, as with benzotriazoles, has a very big effect on the structure of the plant roots, particularly lignin. The imaging we did at the National Synchrotron Light Source, at Brookhaven, NY, should be useful for many people studying the development of plants. Several presentations were made. We also have been working to improve the remediation of sites contaminated with chlorinated hydrocarbons including perchloroethylene used at drycleaners, and carbon tetrachloride, which was used at USDA grain storage
sites. Although active use of the chemicals ended long ago, there is still very significant contamination of groundwater, including drinking water source for a city. We successully developed microcosm studies, and then a field pilot study to enhance remediation of perchloroethylene with a specific microorganism consortium plus suitable nutrients including yeast extract and soy oil methyl ester (biodiesel). Finally, we are developing a strategy for control of a dioxane contaminant plume in water flowing under an old storage site owned by the university. We monitored dioxane movement through plants both in the lab and field. Four papers describing recent and earlier work, were published in 2004.
Impacts
Plants provide economical, efficient means to clean up a wide range of organic contaminants in soils. Their root-associated enzymes can effectively transform many organic chemicals. For some of these compounds, such as benzotriazole, and certain chlorophenols there is no effective pathway for degradation in microbes. For some volatile compounds, such as dioxane or chlorinated ethenes, plants can effectively move them to the atmosphere where they are photodegraded. Plants can help filter contaminants from water and have both economic and aesthetic value on-farm and within the landscape.
Publications
- Dokken, K.M., Davis, L.C., Erickson, L.E., Castro-Diaz, S., and Marinkovic, N.S.. 2005. Synchrotron fourier transform infrared microspectroscopy: A new tool to monitor the fate of organic contaminants in plants Microchemical Journal 81:86-91.
- Dokken, K.M., Davis, L.C., and Marinkovic, N.S. 2005. Using SR-IMS to study the fate and transport of organic contaminants in plants. Spectroscopy 20:14-17.
- K.M. Dokken, L.C. Davis and N.S. Marinkovic 2005. Use of infrared microspectroscopy in plant growth and development. Applied Spectroscopy Reviews 40:301-326.
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Progress 01/01/04 to 12/31/04
Outputs
In 2004 we continued efforts to understand how plants are able to detoxify organic chemicals. Much of our work was with benzotriazole derivitivies. They are used in antifreeze, aircraft deicing fluids, heat exchanger fluids, lubricants and oils. By using advanced techniques including infra-red imaging we are able to identify locations in the plant roots where the benzotriazoles are accumulated in a form that cannot be extracted by common solvents. We also established that the presence of the benzotriazoles had a very big effect on the structure of the plant roots, particularly lignin. The imaging we did at the National Synchrotron Light Source, at Brookhaven, NY, should be useful for many people studying the development of plants. Other important contaminants including TNT, and two of its common by-products were examined for their effect on both sunflower and maize roots. Several presentations were made at national meetings. We also have been working to improve the
remediation of sites contaminated with chlorinated hydrocarbons including perchloroethylene used at drycleaners, and carbon tetrachloride, which was used a USDA grain storage sites. Although active use of the chemicals ended long ago, there is still very significant contamination of groundwater, including drinking water source for a city. In the laboratory we identified conditions that allow complete removal of the contaminants without digging up soil or pumping out the water. Specific strategies are being proposed to our state regulatory agency for the site contaminated with perchloroethylene. Four papers describing earlier work, including two about the benzotriazoles, were published in 2004.
Impacts
Plants provide economical, efficient means to clean up organic contaminants (both halogenated and non-halogenated) in soils. Their root-associated enzymes can effectively transform many organic chemicals. For some of these compounds, such as benzotriazole, there is no known pathway for degradation in microbes. For some halogenated compounds, plants can effectively move them to the atmosphere where they are photodegraded. Plants can help filter contaminants from water and have both economic and aesthetic value on-farm and within the landscape.
Publications
- Hart, D.S., Davis, L.c., Erickson, L.E. and Callender, T.M. 2004. Sorption and partitioning parameters of benzotriazole compounds. Microchem. J. 77:9-17
- Karthikeyan,R., Davis, L.C., Erickson, L.E., Al-Khatib, K., Kulakow, P.A., Barnes, P.L., Hutchinson, S.L., and Nurzhanova, A.A. 2004. Potential for plant-based remediation of pesticide-contaminated soil and water using nontarget plants such as trees, shrubs, and grasses. Crit. Rev Pl. Sci. 23:91-101.
- Castro, S., Davis, L.C., and Erickson, L.E. 2004. Temperature and pH effects on plant uptake of benzotriazoles by sunflowers in hydroponic culture. Int. J. Phytorem. 6:209-225.
- Davis, L.C. and Erickson, L.E. 2004. A review of bioremediation and natural attenuation of MTBE. Env. Prog. 23:1-10.
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Progress 01/01/03 to 12/31/03
Outputs
This year we continued efforts to understand how plants are able to detoxify organic chemicals. The bulk of our work was with benzotriazole derivitives. They are used in antifreeze, aircraft deicing fluids, heat exchanger fluids, lubricants and oils. We obtained good evidence that the compounds are taken up by plants and stably incorporated into them. By using advanced techniques including infra-red imaging we are able to identify locations in the plant roots where the benzotriazoles are accumulated in a form that cannot be extracted by common solvents. We also established that the presence of the benzotriazoles had a very big effect on the structure of the plant roots. We can see changes in the amounts of lignin which is a key component in the cell walls of plants. The imaging technique which we are developing, using the National Synchrotron Light Source, at Brookhaven, NY, should be useful for many people studying the development of plants. We also have begun some
work trying to find ways to improve the remediation of sites contaminated with chlorinated hydrocarbons including perchloroethylene used at drycleaners, and carbon tetrachloride, which was used a USDA grain storage sites. Although in both cases, the active use fo the chemicals ended long ago, there is still very significant contamination of groundwater. In some cases that water is the sole, or main, drinking water source for a city. Funding for that work is just beginning. Three papers describing earlier work are in press for journal issues late in 2003. Two book chapters appeared in 2003.
Impacts
Plants provide economical, efficient means to clean up organic contaminants (both halogenated and non-halogenated) in soils. Their root-associated enzymes can effectively transform many organic chemicals. For some of these compounds, such as benzotriazole, there is no known pathway for degradation in microbes. For some halogenated compounds, plants can effectively move them to the atmosphere where they are photodegraded. Plants can help filter contaminants from water and have both economic and aesthetic value on-farm and within the landscape.
Publications
- Davis, L.C., Erickson, L.E., Narayanan, M. and Zhang, Q. 2003. Modeling and design of phytoremediation, in Phytoremediation. Transformation and control of contaminants, McCutcheon, S.C. and Schnoor, J.L. eds., Wiley Interscience, Hoboken, NJ. pp 663-694.
- Winneke-McMillan, S.K., Zhang, Q., Davis, L.C., Erickson, L.E. and Schnoor, J.L. 2003 in Phytoremediation. Transformation and control of contaminants, McCutcheon, S.C. and Schnoor, J.L. eds., Wiley Interscience, Hoboken, NJ. pp 805-828.
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Progress 01/01/02 to 12/31/02
Outputs
This year we continued efforts to understand how plants are able to detoxify organic contaminants, focusing primarily on one particular family of chemical compounds known as benzotriazles (Bz). Sunflower plants were used as the model system to examine effects of changing the relative root/liquid ratio in hydroponic solution, and the impact of mixing vs diffusive transport of Bz to the plant roots. the effect of reaction temperature on the rate of Bz removal from solution was also studied. For equal mass of fresh plant weight, the rate of Bz removal was independent of solution volume over a four-fold range and independent of stirring. Plants grew more vigorously with stirring, indicating that root aeration and nutrient acquisition were limited by mass transfer processes. The temperature dependence of Bz removal was very small, indicating that it also was limited not by enzymatic activity but by mass transfer. Plants were exposed to concentrations that showed minimal
toxicity (30-60 mg/L) for periods of 1-4 weeks. Examination of roots from these plants using infra-red spectrometry showed that there was incorporation of Bz into non-extractable forms. Root segments were embedded in epoxy plastic for electron microscopy. Thin sections examined by light microscopy indicated that treated plant has collapsed cell walls, similar to those observed in mutant Arabidopsis plants that have defects in lignin biosynthesis. The binding of Bz to soil organic matter and the ability of Bz to inhibit nitrification were also examined. Papers describing each of these research areas are submitted or in preparation. One lengthy review was published this year and two book chapters will appear in January of 2003. Three papers describing earlier work are under review or in press.
Impacts
Plants may serve as economical, efficient means to clean up organic contaminants in soils. They have root-associated enzymes that may effectively transform many organic chemicals. For some of these compounds, such as Bz, there is no known pathway for degradation in microbes. Plants can help filter contaminants from water and have both economic and aesthetic value on-farm and within the landscape.
Publications
- Davis, L. C., Castro-Diaz, S., Zhang, Q., and Erickson, L. E. 2002. Benefits of vegetation for soils with organic contaminants. Critical Reviews in Plant Sciences 21:457-491.
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Progress 01/01/01 to 12/31/01
Outputs
This project is a continuation of one under the same title which terminated this year. This year we made efforts to develop a better understanding of how plant roots are able to degrade and/or stably incorporate into their structure molecules of the benzotriazole (Bz) family of compounds. Bz derivitives are commonly used corrosion inhibitors in antifreeze, deicing fluids and heat exchanger fluids. Very large quantities (thousands of tons) may be released to the environment annually and there is not published evidence of microbial degradation. Detailed studies of the uptake and degradation were done with sunflower plants and Bz, 5-methyl or 4-methyl Bz and 1-hydroxy Bz as the reactive substrate. Plants in hydroponic culture are able to continually remove from solution levels up to 50 mg/L which is well above the levels likely to be encountered in waste streams from deicing operations or due to spillage. A bacterial consortium able to degrade 5-methyl (but not 4-methyl)
Bz was isolated and studied. It uses toluene or 5-methyl Bz equally well in an apparently competitive manner. The ability of fescue grass to tolerate the same levels of Bzs when growing in soil was studied to determine if plants are able to prevent accumulation of the Bzs. Studies have been initiated to determine the binding sites and mechanisms for the Bz, using infrared, and Raman spectroscopies. One major publication describing a portion of this work appeared this year. It is listed uner the previous project. In addition a M.S. thesis was completed and two review chapters describing this work, and some of our earlier work, were submitted for publication. They are accepted but not yet published.
Impacts
Plants provide an efficient means to clean up many organic compounds from soil and water, because they possess enzymes that can detoxify many organic molecules, and are relatively inexpensive to establish and maintain compared to mechanical systems. They also use large quantities of water which can reduce the migration of contaminated water plumes. In addition they have aesthetic advantages, improving the landscape and enhancing land value.
Publications
- No publications reported this period
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