Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

SMCM professor discovers cattle hormones that leak into streams and alter fish reproduction

19.12.2003


Scientist plans similar studies on tributaries of the Chesapeake Bay



A study released in early December by a group of scientists shows that hormones leaking into streams from cattle feedlots are altering the sexual characteristics of wild fish.

Edward Orlando, assistant professor of biology at St. Mary’s College of Maryland (SMCM), was the leading author in the study that included researchers from five U.S. institutions. The scientists examined minnows in three streams that flow into Nebraska’s Elkhorn River. Their findings showed "significant alterations in the reproductive biology" of fish immediately downstream from a large Nebraska cattle feedlot.


The scientists said they do not know whether the damage was caused by natural hormones in cattle or by synthetic ones administered to the animals. Their report states that the findings "clearly demonstrate" that effluent from feedlots is hormonally active, whether it is natural or synthetic. About 30 million head of cattle are raised in U.S. feedlots each year, and nearly all are implanted with growth-promoting synthetic hormones.

Orlando said the scientists took their samples from a site directly connected to a retention pond at the base of a large feedlot. Several spots along the river contained hormones, indicating that "this [result] is not due to one farm in one location." Orlando added that laboratory tests from the study showed that the feed-lot effluent-receiving site contained a complex and potent mix of androgens (male sex hormones), and estrogens (female hormones).

According to the study, published in the online version of the scientific journal Environmental Health Perspectives, the male fish had one-third less testosterone and their testes were about half as big as those of unexposed fish upstream. The female fish had about 20 percent less estrogen and 45 percent more testosterone than females from the uncontaminated stream.

The scientists caution that further investigation of livestock farms is "urgently needed if we are to understand the possible adverse effects of these compounds on aquatic ecosystem health." They say the priority should be to identify the compounds that altered the fish, and "determine whether they were natural or pharmaceutical in origin."

Hormones are used to stimulate growth in cattle and help them produce more meat and less fat. According to a 1999 survey by the U.S. Department of Agriculture, about 99% of the nation’s largest, factory-sized cattle feedlots use hormonal implants.

"Cattle can be treated with any number of androgenic or estrogenic chemicals, or combinations of synthetic androgens and estrogens," said Orlando. "We do not know what the cattle in this feedlot were treated with or what was in the effluent. This is really the first study of this kind, and there are lots of questions, but few answers, so far."

This study was conducted on wild fish in Nebraska’s Elkhorn River. It is unknown whether the hormones implanted into cattle have any effect on human beings, "but, we do know that human exposure is minimal, given that only trace amounts of these synthetic hormones remain in the meat. In contrast to humans, aquatic wildlife is exposed to an unknown concentration of synthetic and natural hormones excreted by the cattle. We know little about the potential effects of hormone containing effluent from cattle feedlots or other concentrated animal feeding operations on fish and other aquatic wildlife," said Orlando.

Orlando plans similar studies for the tributaries of the Chesapeake Bay. He is currently submitting proposals to various funding sources to conduct research.


SMCM is consistently ranked one of the best public liberal arts colleges in the na-tion by U.S. News & World Report and The Princeton Review. The Washington Post called St. Mary’s College of Maryland "a place to get an Ivy League education at a public school price."

Marc Apter | EurekAlert!
Further information:
http://www.smcm.edu/

More articles from Ecology, The Environment and Conservation:

nachricht Scientists on the road to discovering impact of urban road dust
18.01.2018 | University of Alberta

nachricht Gran Chaco: Biodiversity at High Risk
17.01.2018 | Humboldt-Universität zu Berlin

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Optical Nanoscope Allows Imaging of Quantum Dots

Physicists have developed a technique based on optical microscopy that can be used to create images of atoms on the nanoscale. In particular, the new method allows the imaging of quantum dots in a semiconductor chip. Together with colleagues from the University of Bochum, scientists from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute reported the findings in the journal Nature Photonics.

Microscopes allow us to see structures that are otherwise invisible to the human eye. However, conventional optical microscopes cannot be used to image...

Im Focus: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Researchers reveal how microbes cope in phosphorus-deficient tropical soil

23.01.2018 | Earth Sciences

Opening the cavity floodgates

23.01.2018 | Life Sciences

Siberian scientists suggested a new method for synthesizing a promising magnetic material

23.01.2018 | Materials Sciences

VideoLinks Science & Research
Overview of more VideoLinks >>>