It’s not that common to have important environmental news on the front page of The New York Times, but today is such a day. The Food and Drug Administration yesterday (December 12, 2013) announced a major new policy to phase out the “indiscriminate use” of antibiotics for livestock raised for meat. This is really important, and really good, news for the environment and human health.
For decades, a common practice in the livestock industry has been to feed low, or sub-therapeutic, doses of antibodies such as tetracycline and penicillin to animals throughout their lives. This practice caused the animals to grow faster and larger than normal, although when I read up on it a few years, nobody seemed to know exactly why this happened. We do know some of the results of this practice, however, and that was leaching of antibiotics and their breakdown products from animal waste into soils and water bodies. Some of these compounds have been shown to have negative effects on some aquatic biota. Another major concern is that the widespread and unregulated use of these antibiotics may potentially promote the development of antibiotic resistance.
Some antibiotics and their breakdown products can persist in the environment for a long time. I was part of a study a few years back at the Illinois State University (ISU) research farm with Dr. Paul Walker, an animal scientist. He dosed pigs with tetracycline and then applied the manure to experimental plots planted with corn or soybeans. We sampled the soil months after application, and found detected tetracycline and a number of breakdown products. In fact, two of the breakdown products, chlortetracycline and isohlortetracycline, were almost found at higher concentrations than the parent compound, tetracycline. This is a concern, because we almost always know less about the environmental effects of these breakdown products than the parent compounds.
