Fall 2000/Winter 2001 Table
Voelker's heart may not belong to Sewannee, but her lab work has
been tied to that river for the past couple years. An assistant
professor in MIT's Department of Civil and Environmental Engineering
(CEE), Voelker, along with CEE graduate student Megan Kogut, has
been studying how copper binds up with humic substances-the
tea-colored organic material found in soil and rivers and coastal
waters. And because far-flung researchers need some standard substance,
they get the stuff from the Georgia river.
Voelker began studying how copper binds, or
complexes, with humic substances while a masters student at MIT.
She received her doctorate at the Swiss Federal Institute for Environmental
Science. Later, as a post-doctoral researcher with Jim Moffett and
Ollie Zafiriou at WHOI, she learned more about strong copper binding
compounds present in coastal waters.
Why the interest in copper and humic substances?
Voelker explains that "most of the pipes in houses are copper, copper
sulfate is used in reservoirs to kill algal blooms, and copper is
a very prevalent metal in effluents." While the metal is not toxic
to humans, she says, "it is somewhat toxic to fish and very toxic
to phytoplankton"-a fundamental link in the food chain. And
natural humic substances and other copper binding compounds may
greatly affect the toxicity and bioavailability of metals in rivers
and coastal waters. When organic matter binds with metals, notes
Voelker, the metals often become less bioavailable. However, in
environments such as groundwater, they may also become more mobile.
Voelker and Kogut's recent work with copper
and humic substances has been funded by a Doherty Professorship
administered through MIT Sea Grant. Thus far her research has been
in the lab, but they intend to continue it in the field. "In the
long term," she says, "we'd really like to see if we're having some
effect on the ecology with all the copper
in the water in these densely populated areas."
Along with teaching undergraduates the chemistry
portion of a course on Environmental Chemistry and Biology, Voelker
keeps busy with a number of other projects exploring the behavior
of metals in aquatic environments. And with the big picture in mind,
she's exploring how the mobility and bioavailability of toxic metals
may play a role in larger environmental contexts, from water treatment
to global carbon cycling.
-Andrea Cohen, MIT Sea Grant