Catalytic Process Breaks Down Hormones In Wastewater

Scientists from Carnegie Mellon University and the U.S. Department of Agriculture (USDA) announced on June 26 they have found that a rapid, environmentally friendly catalytic process involving Fe-TAML® activators and hydrogen peroxide breaks down two types of estrogenic compounds. These natural and synthetic estrogenic compounds can mimic or block the activities of hormones in wildlife and humans, which may disrupt the normal functions of the endocrine system and impair development. They also could contaminate drinking water.

The results were presented by Nancy Shappell, a research physiologist with the USDA's Agricultural Research Service (ARS), on June 29, at the 10th annual Green Chemistry and Engineering Conference in Washington, D.C. Shappell will present her paper, "Degradation of Estradiol and Ethinylestradiol With an Fe-TAML® Oxidant Activator and Hydrogen Peroxide," during the Frontiers in Green Chemistry and Green Engineering section of the conference. Estradiol is a natural form of the female hormone estrogen, and ethinylestradiol is a synthetic version used in contraceptives.

Fe-TAML (tetra-amido macrocyclic ligand) activators, which are synthetic catalysts made with elements found in nature, originated at Carnegie Mellon's Institute for Green Oxidation Chemistry under the leadership of Terry Collins, the Thomas Lord Professor of Chemistry in the Mellon College of Science.

"Environmental studies on various wildlife species have shown evidence that endocrine disruptors interfere with reproductive, immune and neurological capabilities and cause developmental abnormalities," Collins said. "We need to quickly develop a suite of standardized assays that test for estrogen-like activity of introduced chemicals and their byproducts so that anyone developing a new chemical technology can assess whether or not their technology is associated with endocrine disruption."

Waste from animal-rearing facilities across the United States constitutes a major concentrated source of estrogens. Millions of pigs housed in these facilities produce tons of waste products laden with estrogens that can enter the water. In addition, synthetic versions of estrogen found in birth control pills can enter surface water as a result of incomplete wastewater treatment, according to Shappell. Some scientists have suggested that these environmental estrogens could interfere with estrogen-controlled systems in wildlife and humans, disrupting innate regulatory mechanisms and leading to developmental disorders, infertility and other reproductive complications.

"Our results show that Fe-TAML activators are capable of breaking down two types of estrogenic compounds found as contaminants in surface water," Shappell said. "These promising results also indicate the potential use of Fe-TAML activators to destroy estrogenic compounds in municipal and agricultural wastewaters."

Shappell and colleagues found that the Fe-TAML activator, used with hydrogen peroxide, almost completely degraded estradiol and ethinylestradiol in the laboratory. According to the researchers, ethinylestradiol is resistant to most biological degradation processes, but Fe-TAML activators break down more than 95 percent of this chemical within five minutes.

"Our next step would be to advance testing to the field. Fe-TAML activators have been field-tested in the pulp and paper industry and textile industry with promising results," said Colin Horwitz, research professor at Carnegie Mellon. ARS scientists Pat Hunt and Kyoung Ro from the Florence, S.C., Coastal Plains Plant, Soil and Water Research Center were instrumental in making the connection between Shappell and the Institute for Green Oxidation Chemistry, and will be involved in field-testing swine wastewater.

Past studies with Fe-TAML activators have shown their enormous potential to provide clean, safe alternatives to existing industrial practices and provide ways to remediate other pressing environmental problems that currently lack solutions. Specific applications of Fe-TAML activators have included cleaning wastewater from textile manufacturing, reducing fuel pollutants, treating pulp and paper processing byproducts, and decontaminating a benign simulant of anthrax.

Nancy Shappell:

Terry Collins:

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