Two Johns Hopkins chemists — one bioinorganic
and the other environmental — have joined forces
to create a new approach for studying pollutant reactions
in the environment. By drawing on their
different areas of expertise, researchers
Justine P.
Roth and Alan T.
Stone hope to develop a better
way to predict the behavior of previously unexplored
pollutants, including some hazardous metals.
Roth, an assistant professor in the Krieger School's
Department of
Chemistry, develops
methods to examine how enzyme-bound metals gain or lose
electrons, most notably in response to
reactions with oxygen. A number of elements, including
oxygen, exist as two or more natural isotopes,
meaning their atoms possess the same number of protons but
different numbers of neutrons.
Molecules made up of different isotopes react at slightly
different rates when the electrons move
from one position to another. By comparing these rates,
Roth is able to collect important information
about the reactions and interpret the results using
computational chemistry.
Stone, an environmental chemist in the Whiting
School's Department of
Geography and
Environmental Engineering, realized that Roth's
approach could uncover critical new data about how
pollutant molecules react with chemicals that are naturally
present in water, soils and sediments.
Their decision to pool their skills recently received
a key endorsement from the Camille and
Henry Dreyfus Foundation, which allocated a $120,000
fellowship grant to the faculty members. The
money will support two years of research by a postdoctoral
scientist who will be supervised by both
Stone and Roth. The researcher will seek to develop
fundamental models that describe the transfer
of electrons to and from dissolved chemicals and mineral
surfaces.
Roth and Stone are especially interested in gains or
losses of electrons that occur when
pollutants react with naturally occurring minerals. For
example, manganese oxide minerals, which
appear black, and iron oxide minerals, with red, yellow,
orange and brown hues, are believed to play a
particularly important role when they make contact with
some hazardous metals. When these minerals
take electrons away from the toxic metal chromium, the
metal is less likely to stick to soils and is
often carried away by water. In contrast, taking electrons
away from the toxic metal lead causes the
metal to precipitate, forming solid particles that separate
from the water instead of dissolving in it.
The Johns Hopkins scientists say that the Dreyfus
Foundation funding should bolster their
efforts to use advanced chemistry lab techniques to help
remedy real-world concerns.
"With this fellowship, a traditional chemist or
chemical engineer will be able to apply his or her
skills toward an urgent environmental pollution problem,"
Stone said. "We need a better understanding
of what kind of chemical reactions occur when hazardous
metals and other waste materials come in
contact with minerals that are already there in the
environmental."
Added Roth: "In the past, these types of questions
haven't been addressed because the tools
weren't available. This is a chance to apply some of our
new lab techniques to practical problems
encountered in the Chesapeake Bay and other ecosystems.
Appreciating the mechanisms of chemical
reactions is something Alan and I have in common. We're
really forging a new field in environmental
science by focusing on the fundamental reactions that are
taking place when contaminants are present
in soil and water."
Within the next six months, Stone and Roth plan to use
the Dreyfus Foundation grant to hire a
postdoctoral fellow who can be trained in their
interdisciplinary research approach. They also will
guide the scientist in refining computational tools that
can be used to make better predictions about
which pollutants must be addressed most promptly to avert
public health and environmental problems.
The Camille and Henry Dreyfus Foundation, based in New
York City, was established in 1946 by
chemist, inventor and businessman Camille Dreyfus as a
memorial to his brother Henry, also a chemist
and his partner in developing the first commercially
successful system of cellulose acetate fiber
production. In creating the foundation, Camille Dreyfus
directed that its purpose be "to advance the
science of chemistry, chemical engineering and related
sciences as a means of improving human
relations and circumstances around the world."
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