environmental risks of agricultural growth promoters, and similar
human pharmaceuticals, following research that shows a newly found
reversion mechanism allows unexpected persistence of the steroidal
substances in aquatic environments.
Results of the research will be published in an article in the
renowned journal Science — the weekly journal of AAAS, the science
society — next month and are available immediately online in Science
“We investigated trenbolone, an anabolic steroid, and found that the
photochemical breakdown isn’t the end of its life cycle,” Ed
Kolodziej, co-author of the paper and environmental engineering
professor at the University of Nevada, Reno, said. “Our team found
that these substances, after a rapid breakdown in sunlight, are
capable of a unique transformation in aquatic environments under
various temperature and light-cycle scenarios where the process is
Kolodziej, project leader of a collaborative multi-disciplinary
research team that includes the University of Iowa and Truman State,
said this newly found mechanism may account for unexplained
observations of endocrine disruption in aquatic organisms.
“Right now, I’m not alarmed, just concerned and interested in defining
the real ecological risks associated with the widespread use of potent
steroidal pharmaceuticals,” Kolodziej, who has been studying the
effects of these substances on aquatic ecosystems for 12 years, said.
“This implies uncertainty with the current environmental risk
assessments or ecotoxicology studies used by regulatory agencies,
researchers and pharmaceutical companies.”
The team used laboratory and field studies to explore the process.
They found that the steroid’s chemical compounds, while breaking down
as expected in sunlight, never fully disappeared; even in conditions
that mimicked surface water, a small percentage of the chemical
structure remained after extended sunlight. The remains regenerated
themselves at night, in some cases to up to 70 percent of the
metabolites initial mass.”
“We knew something unique was going on,” David Cwiertny, Kolodziej’s
research partner from the University of Iowa, said. “In daylight, it
essentially hides in another form, to evade analysis and detection,
and then at nighttime it readily transforms back to a state that we
The researchers validated the lab results with two experiments in the
field — one with water taken from the Iowa River in Iowa City, Iowa
and the other from samples taken from a collection pond at a cattle
rangeland and research operation in California’s Central Valley run by
the University of California, Davis.
Trenbolone is a federally approved drug widely used by the beef
industry to promote weight gain and to increase feeding efficiency in
cattle. The drug, although popular in the bodybuilding and
weightlifting communities, and as an athletic performance enhancer,
has long been banned for human use, and also is banned for
agricultural uses in the E.U.
Trenbolone has been considered safe for ecosystems due to its
initially rapid degradation, with studies pointing to an environmental
half-life of less than a day. Studies have indicated that low
concentrations of these endocrine disrupting environmental steroids
affect fish, by reducing egg production of females and skewing the sex
of some species.
The article can be found at the Science Express website:
Kolodziej is an associate professor in the University of Nevada,
Reno’s College of Engineering. His website can found at