October 2006, Vol. 18, No.10

Research Notes

Research Notes - Green Catalyst Takes on Hormones in Wastewater

 Hydrogen peroxide, known for its bubbly cleansing of minor cuts and scrapes, may work well as a special catalyst to combat hormones found in wastewater. According to the U.S. Agricultural Research Service (ARS), by combining hydrogen peroxide with the enzymelike catalyst Fe-TAML®, dyes, pesticides, and other environmental pollutants deteriorate. A June ARS news release reported that the duo’s powers of degradation may include neutralizing hormones in municipal and agricultural wastewater.

ARS animal physiologist Nancy Shappell conducted 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, an ARS news release notes.

Shappell’s collaborators are Terry Collins and Colin Horwitz of the Carnegie Mellon University Institute for Green Oxidation Chemistry (Pittsburgh), where Fe-TAML was developed, and Patrick Hunt and Kyoung Ro, who work at the ARS Coastal Plains Soil, Water, and Plant Research Center in Florence, S.C.

According to Shappell, who is based at the ARS Red River Valley Agricultural Research Center in Fargo, N.D., the study dovetails with growing concern that hormones — whether flushed into wastewater or excreted by livestock — can disrupt the endocrine systems of fish, other wildlife, and potentially humans. Shappell noted that while wastewater treatment plants remove most pollutants, contamination of surface and groundwater still can occur.

According to ARS, ethinylestradiol is troublesome 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 were able to break down hormones. Indeed, more than 95% were degraded within 5 minutes following exposure to the reaction. Estradiol met a similar fate, said Shappell, who used high-performance liquid chromatography and tandem mass-spectrometry analysis to confirm the results.

Shappell, ARS says, plans to team with the Florence lab to test Fe-TAML on hormones in effluent from hog-farm lagoons.

For more information, contact Shappell at shappeln@fargo.ars.usda.gov.

Soybean Scraps: Nature’s Pollution Solution?

 The answer to tomorrow’s water pollution problems could come from soybeans, according to U.S. Agricultural Research Service (ARS) scientists. The answer comes not from the legumes themselves but from the hulls that often end up as a livestock feed.

ARS chemists Wayne Marshall and Lynda Wartelle have discovered that these undervalued hulls — as well as leftover stalks and stems from picked corn and sugar cane plants — make the ideal foundation for a potent filtering agent that can adsorb harmful levels of lead, chromium, copper, and cadmium from contaminated waters.

Marshall and Wartelle, who work at the ARS Southern Regional Research Center (SRRC) in New Orleans, have found that it takes only two steps to convert these affordable and abundant crop residues into a powerful magnet capable of snagging both positively and negatively charged particles of heavy metals in water, according to an ARS news release.

The material the scientists have created is known as a dual-functioning ion-exchange resin. These resins, commonly used for treating industrial and municipal wastewaters and for recycling heavy metals from solutions, typically are effective in capturing only one kind of particle with either a positive or negative charge.

But the SRRC researchers’ resins can grab both, and Marshall has found they are more cost-effective than two synthetically made resins currently in use. Ion-exchange resins, according to ARS, work by swapping, or exchanging, the undesirable ions in a water supply with benign ones. For example, water softeners work by drawing out and replacing unwanted “hard water” particles, such as calcium and magnesium, with ions from sodium.

Marshall and Wartelle give their plant residues a negative charge by adding citric acid, a common food industry additive, ARS notes. The positive charge comes from choline chloride, which the researchers bind to plant fibers by adding dimethyloldihydroxyethylene urea, a chemical already known for making molecules “stick,” according to ARS.

For more information, contact Marshall at marshall@srrc.ars.usda.gov or Wartell at wartelle@srrc.ars.usda.gov.

Feed Additives Help Agriculture and the Environment

 Talk about killing two birds with one stone. U.S. Agricultural Research Service (ARS) researchers have designed feed supplements for poultry and other farm animals that not only boost nutrition but also reduce the amount of potentially harmful phosphorus escaping into the environment.

ARS researchers Ed Mullaney and Jaffor Ullah have designed phytase enzymes that help chickens and swine digest more of the phosphorus found in their plant-based diets.

Twenty years ago, Mullaney and Ullah were the first to characterize a natural, fungal-based enzyme — called phytase — which could improve animal nutrition, save on feed costs, and reduce phosphorus losses from farms. Mullaney, a geneticist, and Ullah, a biochemist, both work at the ARS Southern Regional Research Center in New Orleans.

Building on previous work, the scientists have created new and improved enzymes especially suited for working in the stomachs of chickens and swine. They recognized that phytase is an impressive catalyst for breaking down the tied-up phosphorus in animals’ plant-based diets, but its performance isn’t optimal in the microenvironments typical of many animal stomachs.

To get around this obstacle, the researchers made over the enzyme on a molecular scale. Its new look is making all the difference. In fact, Mullaney and collaborators discovered that swine fed the redesigned phytase additive for only 5 weeks gained 13% more weight than swine fed the original enzyme. And if the animals are absorbing more phosphorus, they are excreting less in their manure.

Read more about the research in the July 2006 edition of Agricultural Research magazine, available at www.usda.gov.

Mobile Machine Quickly Measures Manure Nitrogen

Many farmers apply manure to their crops as an organic fertilizer, but it can sometimes be too much of a good thing, according to a U.S. Agricultural Research Service (ARS) news release.

Farmers may apply too much manure to their crops because they’re not sure how much nitrogen or phosphorus might be in it, so they decide to err on the side of excess, the news release notes. However, these extra nutrients can run off in rainwater and eventually pollute streams, lakes, and other waterbodies.

A prototype manure-analyzing device powered by a car or truck battery has been built by ARS chemist James B. Reeves, the news release says.

Reeves, who works at the ARS Environmental Management and Byproduct Utilization Laboratory in Beltsville, Md., designed the portable analyzer so farmers can quickly tell how much nitrogen and water are in a sample of manure.

To determine how much nitrogen or phosphorus manure contains, farmers can send samples to a laboratory for analysis, but this takes time and money — and they usually send only one sample from the large pit into which they flush their manure. According to Reeves, a one-sample analysis can’t reflect the nutrient levels that often vary throughout a manure pit.

The prototype analyzer passes invisible, near-infrared light through filters onto about 2 tablespoons of manure placed in a small cup. The amount of light reflected back allows a filter spectrometer to quantify both the nitrogen and water content. Manure samples require no preparation or chemicals, and the analysis takes about a minute.

Having access to an accurate, inexpensive manure analyzer will become even more important to farmers if nutrient-management regulations tighten further.

Read more about the research in the July 2006 edition of Agricultural Research magazine, accessible at www.ars.usda.gov. Contact Reeves at jreeves@anri.barc.usda.gov