PHONE: (313) 593-5644
DATE: June 2, 2004
Prof. John Thomas awarded grant to study safer cleanup of toxic waste
DEARBORN---John Thomas, associate professor of biology at the University
of Michigan-Dearborn, received a grant from the Consortium
for Plant Biotechnology Research, Inc. (CPBR) to research a safer
method of cleaning up toxic waste sites. The field work will be done near
Ford's Rouge Plant.
Thomas received $63,301 for a two-year period, with Ford
Motor Company awarding $20,592 in matching funds for the first year.
An application for additional funds from Ford for a second year is under
Thomas will work in collaboration with Clayton
Rugh, assistant professor of phytoremediation at Michigan State University,
to screen a selection of native Michigan plants for effective phytoremediation
of harmful environmental contaminants. Phytoremediation is the use of
plants to extract harmful elements from soil for safe disposal, a desirable
and effective alternative to costly and disruptive engineering approaches,
such as excavation, landfilling and incineration, according to Thomas.
"We are working hand-in-hand with Ford Motor Company and CPBR to
develop practical phytoremediation strategies to mitigate polycyclic aromatic
hydrocarbons (PAHs)," Thomas said.
"PAHs are produced from the burning of coal or diesel fuel and are
water insoluble, very stable and of concern to the environment,"
he said. "Our approach is to grow select native Michigan plant species
in former industrial soils to detoxify PAH contaminants into harmless
Many scientific studies have discovered PAH-metabolizing microbial strains,
but the major problem with directly applying these microbes to PAH-laden
soils is that the microbial populations decline rapidly in the field,
Thomas said. Planted systems may promote the establishment of helpful
microbial populations and sustain PAH-bioremediation by enriching the
soils with plant-produced products, generally classified as plant root
"exudates," he noted.
Unlike animal secretions, plant root exudates are not waste products,
but rather the products of photosynthesis and metabolism including sugars,
amino acids and secondary metabolites, Thomas said.
"Root exudates are thought to act as chemical signals for soil-borne
bacteria," he said. "We believe that plants produce signals
that favor some microbial communities while at the same time discouraging
others. The resulting shift in microbial populations together with plant
metabolism may be responsible for enhanced PAH metabolism and destruction
during the phytoremediation process."