September 27, 2013
Steroids Capable Of Regenerating Themselves In The Environment
redOrbit Staff & Wire Reports - Your Universe Online
A steroid currently used in the beef industry does not fully break down in water as previously thought, new research examining the impact of pharmaceutical substances on aquatic organisms has revealed.
The paper, which was published online Thursday in the journal Science, challenges the longstanding belief that these products become less ecologically harmful as they degrade. Experts are increasingly concerned that once these substances enter the environment, some of their bioactive organic compounds could be altered in a way that makes their behavior more uncertain.
Cwiertny’s team conducted both lab tests and field experiments and found that the steroid does not completely break down in water as believed. Instead, it maintains enough of a chemical residue to regenerate itself in the environment under specific conditions, even to the extent that the drugs’ lifespans could be prolonged in trace amounts.
The study authors said that this is an important step towards better understanding “the environmental role and impact of steroids and pharmaceutical products, all of which have been approved by the federal government for various uses and that have been shown to improve food availability, environmental sustainability and human health.”
“We're finding a chemical that is broadly utilized, to behave in a way that is different from all our existing regulatory and risk-assessment paradigms,” explained Cwiertny, a co-corresponding author on the paper. “What our work hopefully will do is help us better understand and assess the environmental fate of emerging contaminant classes.”
“There are a variety of bioactive pharmaceuticals and personal-care products that we know are present in trace amounts in our water supply,” he added. “We should use what we're learning about trenbolone to more closely scrutinize the fate and better mitigate the impact of these products in the environment.”
Similar results were reported for the other two substances tested: dienogest, a hormone used as an ingredient in the birth-control pill Natazia, and dienedone, an anabolic steroid that has been banned but is nonetheless marketed as a bodybuilding supplement. The research was funded by the US Department of Agriculture (USDA), the National Institutes of Health (NIH), and the National Science Foundation (NSF).
While the steroid has been considered safe due to its rapid degradation (research has suggested it has an environmental half-life of less than a day), there had been concern as to whether or not it and other types of synthetic drugs can be harmful to aquatic lifeforms and the environment in concentrated amounts. Studies have suggested that these substances can cause female fish to produce fewer eggs and skew the sex of some species.
“We rarely see fish kills anymore, and we probably aren't discharging many carcinogens into surface waters anymore. But I don't believe this necessarily means that our water is safe for aquatic organisms,” explained University of Nevada-Reno associate engineering professor and corresponding author Edward Kolodziej. “It just might be harder to characterize the adverse effects associated with contaminant exposures these days.”
Sunlight was found to be one catalyst for breaking down the compounds, but the researchers simulated the day-night cycle and found that trenbolone acetate never completely disappeared in daylight. Furthermore, they found that during a simulated night and under typical surface water conditions, some of the compounds managed to regenerate themselves – up to 60 percent of the metabolite's initial mass over a 120-hour period.
“More of the drug's mass was regenerated – up to 88 percent in one highly acidic state (pH 2) – when water temperature was higher and when it was more acidic or alkaline,” the University of Iowa said in a statement. They added that the lab results were later verified through a pair of field experiments, “one with water culled 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 run by the University of California.”