Fe-TAML is an enzyme-like catalyst
that, in lab tests, rapidly breaks down natural and synthetic forms of the
hormone estrogen. The catalyst has potential for preventing the hormone's
escape into the environment.
Carnegie Mellon University.
"Green" Catalyst Takes on Hormones in Wastewater
Suszkiw June 29, 2006
Hydrogen peroxide is best known for its bubbly cleansing of minor cuts
and scrapes. But combining it with an enzyme-like catalyst called Fe-TAML also
produces reactions that break down dyes, pesticides and other wayward chemicals
that have become environmental pollutants.
Now, the dynamic duo's powers of degradation may include neutralizing
hormones in municipal and agricultural wastewater, an Agricultural Research
Service (ARS) scientist reports today.
Speaking at an American Chemical Society
meeting in Washington, D.C., ARS animal physiologist
Shappell discussed the results of a laboratory study in which she combined
Fe-TAML with hydrogen peroxide to break down estradiol, a natural form of the
female hormone estrogen, and ethinylestradiol, a synthetic version used in
contraceptives. Fe-TAML is short for iron tetra-amido macrocyclic ligand.
Shappell's collaborators are Terry Collins and Colin Horwitz with
Carnegie Mellon University's
Institute for Green Oxidation Chemistry in Pittsburgh, Pa., where Fe-TAML
was developed; and
Ro with the
Coastal Plains Soil, Water and Plant Research Center, Florence, S.C.
According to Shappell, with the
Red River Valley Agricultural Research Center in Fargo, N.D., the study
dovetails with growing concern that hormoneswhether flushed into sewage
or excreted by livestockcan disrupt the endocrine systems of fish, other
wildlife and potentially humans. While wastewater treatment plants remove most
pollutants, contamination of surface and groundwater can still occur, notes
Shappell, who is in the Fargo center's
Metabolism-Agricultural Chemicals Research Unit.
Ethinylestradiol is particularly worrisome because it is more
resistant than estradiol to degradation by microbes and other natural
processes. But in Shappell's lab experiments, hydrogen-peroxide reactions
spurred by Fe-TAML made short work of the hormone. Indeed, more than 95 percent
of it degraded within five minutes' exposure to the reaction. Estradiol met a
similar fate, adds Shappell, who used high-performance liquid chromatography
and tandem mass-spectrometry analysis to confirm the results.
In the next step, she'll team with the Florence lab to test Fe-TAML on
hormones in effluent from hog-farm lagoons.
ARS is the U.S. Department of
Agriculture's chief scientific research agency.