Nov 01, 2010

Experiment Finds Rabbit Food Reduces Estrogen in Wastewater

Result could point to inexpensive solution for decreasing hormone levels in environment

The November 2010 issue of Environmental Pollution details successful experiments at the University of Cincinnati (UC) in which rabbit food resulted in the abiotic (non-biological) transformation and absorption of four different types of estrogen, reducing the levels of the hormones by more than 80% in wastewater.

The research has practical implications since it could point to inexpensive treatment technologies and materials for reducing estrogens in wastewater.

Currently, estrogen in wastewater represents a major conduit for the entry of the hormone, whether in its naturally occurring forms or synthetic form (birth control pills), into the environment. There, it is believed to cause responses in the endocrine systems of fish, birds and other wildlife in and around streams and rivers, groundwater, sediments and sludge. It can cause effects in wildlife such as the presence of both male and female sex organs, feminization of males, abnormal and malformed reproductive organs, skewed sex ratios, reduced fertility and more.

Population growth and the use of synthetic estrogens (birth control pills) have increased the presence of the hormone (both in its naturally occurring forms and its synthetic forms) in the environment.

In an article titled "Abiotic Transformation of Estrogen in Synthetic Municipal Wastewater: An Alternative for Treatment" in this month's issue of Environmental Pollution, authors Makram Suidan, UC professor of environmental engineering; Mark Mills, research engineer with the U.S. Environmental Protection Agency's National Risk Management Research Laboratory; and Ruth Marfil-Vega, UC doctoral student in environmental engineering, detail their success in harnessing natural materials in improving the removal of estrogen from the environment.

The experiments hold great promise, according to lead author Suidan, because "it would be an inexpensive process to replicate in wastewater treatment plants and because the UC experiments with the rabbit food proved effective in dramatically reducing the levels of naturally occurring estrogens but also the synthetic estrogen, which typically has the longest staying power in wastewater and the environment."

While the UC team tested a variety of materials, including clays, casein (a protein molecule found in cheese and milk), tryptone (an amino acid) and starch, only the rabbit food proved effective in greatly reducing estrogen levels. The UC experiments found that clays, casein, typtone and starch only reduced wastewater estrogen levels by 10%.

"We are now experimenting to find out, specifically, why the rabbit food proved so effective in reducing estrogen levels,” said Suidan. “Rabbit food was a material we chose because, unlike dog food, rabbit food is hormone-free. Rabbit food is merely ground up organic vegetable matter, not unlike vegetable matter that could safely be added to wastewater."

The experiments showed that the rabbit food did not have an effect on levels of male hormones in wastewater.