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Tina Voelker

Photo of Tina VoelkerTina 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


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