The November 2010 issue of Environmental Pollution details successful experiments at the University of Cincinnati where rabbit's food resulted in the abiotic (non-biological) transformation and absorption of four different types of estrogen, reducing the levels of these estrogen hormones by more than 80% 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. 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.
It is believed that the hormone causes responses in the endocrine systems of fish, birds and other wildlife in and around streams and rivers, groundwater, sediments and sludge. In other words, the hormone causes effects 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.
In an article entitled ‘Abiotic Transformation of Estrogen in Synthetic Municipal Wastewater: An Alternative for Treatment' in this month's issue of Environmental Pollution, the authors detail their success in harnessing natural materials to improve the removal of estrogen from the environment. The experiments hold great promise, according to lead author Makram 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 - 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. In fact, in testing the clays, casein, typtone and starch for effects on wastewater hormone levels, the UC experiments found that these four alternate materials only reduced wastewater estrogen levels by 10%.
Suidan stated 'We are now experimenting to find out, specifically, why the rabbit food proved so effective in reducing estrogen levels. 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 were repeated several times using synthetic wastewater in stainless steel containers (to avoid any absorption of the tested hormones that might have been possible with plastic containers). As stated, the rabbit food reduced the levels of the four estrogens by more than 80% after a 72-hour contact period.
Suidan explained that 'While absorption of estrogen by the rabbit food played some role, we believe that a catalytic process occurred, meaning the estrogen compounds appeared to bind to the rabbit food when oxygen was present.'
In the experiments, the UC team not only tested materials that might reduce estrogen levels in wastewater but also tested the efficacy of these same materials (rabbit food, casein, clays, tryptone and starch) in reducing the levels of male hormones (testosterone, androstenedione and progesterone) in wastewater. However, none of the treatment materials - including the rabbit food - had any effect on the presence of these male hormone levels in the wastewater.