Environmental persistence of trenbolone metabolites

  

Research conducted by an environmental scientist at Indiana University and his colleagues at Iowa and Washington University found that potentially harmful growth promoting hormones used in beef production are expected to last longer in the environment at higher concentrations than previous

Research conducted by an environmental scientist at Indiana University and his colleagues at Iowa and Washington University found that potentially harmful growth promoting hormones used in beef production are expected to last longer in the environment at higher concentrations than previously thought.


Adam Ward, the lead author of the study and assistant professor of the Bloomington School of Public and Environmental Affairs at Indiana University, said: "The substances we release into the environment are just the starting point of a series of complex chemical reactions, which may occur and sometimes have unexpected consequences." "When compounds react in ways we didn't expect - when they switch between species, when they still exist after we think they disappear - this challenges our regulatory system."


The numerical simulation conducted in this study can help predict the potential impact of environmental processes on the fate of pollutants, so as to better understand the possibility of these unexpected impacts.


This study reveals the potential weaknesses of the hazardous substances regulatory system in the United States, which focuses on single compounds and often fails to take into account the complex and sometimes surprising chemical reactions that occur in the environment.


This paper entitled "Coupled reduction and flow underflow exchange processes increase the environmental persistence of trenbolone metabolites" was published in the journal Nature Communications and can now be found online. Co authors are David M. Cwiertny and Colleen C. Brehm of the University of Iowa and Edward P. Kolodziej of the University of Washington (Tacoma/Seattle).


The focus of this study is the environmental fate of TBA, a powerful testosterone like substance, which is used to promote the weight gain of beef cattle. Most beef cattle produced in the United States are treated with TBA or one of five other growth hormones approved for animal husbandry.


This compound and its by-products are examples of emerging pollutants known as endocrine disruptors. In the environment, they can interfere with the reproductive process and behavior of fish and other aquatic organisms.


TBA was implanted into the ears of beef cattle. Cattle metabolize this compound to produce 17- α - Trenbolone, which is an endocrine disruptor with chemical properties close to TBA. Metabolites enter streams and rivers through feces washed from feedlots, or are applied to the land as fertilizers.


This compound will decompose rapidly when exposed to sunlight, which was once considered by regulators to greatly reduce its environmental risk. However, Cwiertny, Kolodziej and others found in a study in 2013 that in the dark, the decomposition product would be reduced to 17- α - trenbolone. This means that this compound will not be permanently removed in the sun, but is expected to continue to exist in the stream environment, and recover its early form at night. In the dark shallow riverbed, streams mix with groundwater, which is called the low potential zone.


Ward and his collaborators set out to study how long trenbolone can last in the environment due to its unique reactivity, and whether this increased persistence has an impact on aquatic ecosystems. They used mathematical modeling technology to show that the concentration of TBA metabolites in rivers may be about 35% higher than previously thought. These compounds last longer, resulting in 50% more biological exposure than expected.


Ward said that this is a problem, because even the low concentration of these powerful endocrine disruptors has been proven to have a significant impact on river organisms.


"These compounds may damage the entire ecosystem by changing the reproductive cycle of many species, including fish," Ward said "We expect that the impact will extend to the aquatic food web."


Studies by the United States Geological Survey and other institutions have found that endocrine disruptors exist in many streams, rivers and lakes, and several similar compounds have even been found in drinking water.


Ward said that although TBA and its metabolites are the focus of this study, these compounds are representative of many other compounds, which indicates that it may be time to update the regulatory method to better include the extensive findings from modern research.


"Our focus on individual compounds has been very successful, bringing us to today's level, which is the cleanest water in the world," Ward said "The next step is to think about the unexpected reactions that occur in the environment and how we manage the various potential products and their combined impact on the environment and human health."

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Lillian Tong

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