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ENVIRONMENTAL MANAGEMENT
CAN GREEN PLANTS CLEAN UP
INDUSTRIAL POLLUTION ?
—
With the assistance of a grant from the Massachusetts
Department of Environmental Management (DEM), a
multidisciplinary team of scientists from the University of
Massachusetts is testing ways to use common pond plants to
stabilize and decontaminate seriously polluted areas of the
historic Blackstone River Watershed. Extending from south
central Massachusetts to Pawtucket, R.I., the Blackstone has
been designated an American Heritage River by Congress, and
its surrounding area, the Blackstone River Valley, is a
National Heritage Corridor.
It was along
the Blackstone that the first water-powered cotton-spinning
mill in the U.S. was built in 1790, laying the foundation
for the American Industrial Revolution and New England's
successful textile industry. The by-product of that success
was a legacy of millions of tons of heavy metals - mercury,
zinc, cadmium, arsenic, tin, copper, and others - left
behind, embedded in the sediment at the bottom of the river.
These pollutants continue to impact on the health of the
region's human and wildlife populations all the way to the
Narragansett Bay, according to environmental microbiologist
Guy R. Lanza, head of the environmental sciences program at
UMass, and leader of the Blackstone research project.
Over the
course of the project, the UMass team will study ways to
clean up pollution from heavy metals and organic chemicals
in the Blackstone sediment, through research conducted by
Baoshan Xing, of the department of plant and soil sciences,
and by environmental microbiologist Klaus Nuesslein, of the
microbiology department. Xing's basic research into the
remediation of organic chemicals and metals in soils and
sediments will setstandards for risk assessment related to
this and similarly contaminated sediments. Nuesslein will
study native plants and beneficial microbial communities
that can be used to stabilize, remove, or degrade
contaminants
from this and similar sites.
Phytoremediation,
or the use of plants to remove, degrade or stabilize complex
environmental contaminants, is an alternative technology for
remediating sites contaminated with heavy metals, some
radioactive materials, and hazardous organic materials at a
fraction of the cost of many conventional treatment
technologies. Although not a new technology,
phytoremediation has gained recognition in recent decades as
science has searched for technologies that are both
practical and safe, says Lanza.
"We know
phytoremediation works in many instances, and the beauty of
it is, it doesn't leave behind its own pollution, it doesn't
require an unsightly treatment facility, and the tools you
need - usually quite ordinary plants - are readily available
and inexpensive," said Lanza. "It's
such an elegant system: The sun is the engine, the
pollutants themselves can supply some of the fuel, and green
plants work like well-oiled machinery in this safe and sound
clean-up technology."
Lanza points
out that dredging, incineration, precipitation technology,
soil-venting, or filtration generally is used to accomplish
soil remediation. In some cases, remediation by bacteria
alone will convert the agents of pollution into something
more manageable to handle. Phytoremediation, on the other
hand, works by letting plants, and the microbes that live on
their root systems, absorb, oxidize, and store pollutants
within their cells, or by breaking down the chemicals to
less toxic forms. Plants often can stabilize pollutants,
keeping them from expanding their reach into the
environment.
Lanza says
phytoremediation has many advantages over other remediation
methods, but its downside is that living creatures,
including humans, fish, and birds, must be prevented from
eating the plants that take up the pollutants. "Even
so, it's still easier to isolate, cut down and remove plants
growing on the surface of the water or in sediments, than it
is to dig under a river and take up sediments without
letting pollutants loose in the environment," explains
Lanza. After the plants are harvested, they can be burned to
concentrate heavy metals in ash, and buried in contained
landfills.
The DEM grant
has provided funding for two graduate students - one from
the plant and soil sciences department, and one from
microbiology - to help develop methods to remove pollutants
and detoxify the region. If successful, this model project
could pave the way for a larger, more comprehensive
exploration of phytoremediation applications to reduce
environmental toxicity emanating from the Blackstone site
into the interiors of Massachusetts, Rhode Island, and
Connecticut, according to Lanza.
In addition
to state grants, alumna Alice K. Shepard of Rhode Island has
funded two additional graduate students to work on the
project, in keeping with her life-long interest in the
solution of complex environmental problems. The Class of
1943 grad, and her husband, Larry, have long supported
projects promoting the protection of natural resources.
The project
is expected to run through 2001, and involves the UMass
departments of microbiology, and plant and soil sciences, as
well as the environmental sciences program, all part of the
College of Food and Natural Resources. Cleve Willis, dean of
CFNR, notes, "This exciting project brings together
several outstanding scientists from different departments
who will gain evidence on the feasibility of using
phytoremediation to remove contaminants from our waterways
in an environmentally friendly and economic way. It is a
bonus that the research will remove contaminants from a
polluted historic American Heritage River."
From
University of Massachusetts
Tuesday, March 13, 2001
Guy Lanza can be reached at
413/545-3747 or glanza@fnr.umass.edu; Baoshan
Xing at 413/545-5212, bx@pssci.umass.edu; and Klaus
Nuesslein at
413/545-1356, nusslein@microbio.umass.edu.
associate news editor
University of Massachusetts
413-545-2987`
phcohen@admin.umass.edu
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