Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Fish devastated by sex-changing chemicals in municipal wastewater

18.02.2008
While most people understand the dangers of flushing toxic chemicals into the ecosystem through municipal sewer systems, one potentially devastating threat to wild fish populations comes from an unlikely source: estrogen.

After an exhaustive seven-year research effort, Canadian biologists found that miniscule amounts of estrogen present in municipal wastewater discharges can decimate wild fish populations living downstream.

The research, led by Dr. Karen Kidd, an NSERC-funded biology professor at the University of New Brunswick (Saint John) and the Canadian Rivers Institute, confirms that synthetic estrogen used in birth control pills can wreak havoc on the sex lives of fish. Small amounts of estrogen are excreted naturally by women whether or not they are taking birth control pills.

Male fish exposed to estrogen become feminized, producing egg protein normally synthesized by females. In female fish, estrogen often retards normal sexual maturation, including egg production.

“We’ve known for some time that estrogen can adversely affect the reproductive health of fish, but ours was the first study to show the long-term impact on the sustainability of wild fish populations,” explains Kidd. “What we demonstrated is that estrogen can wipe out entire populations of small fish — a key food source for larger fish whose survival could in turn be threatened over the longer term.”

Kidd and her colleagues reported the findings last year in the Proceedings of the National Academy of Sciences of the United States of America. She is also presenting the research at the prestigious 2008 American Association for the Advancement of Science (AAAS) Conference during a session entitled, From Kitchen Sinks to Ocean Basins: Emerging Chemical Contaminants and Human Health.

Estrogen is part of a broader class of sex-changing chemical compounds known as endocrine disrupting substances. These contaminants, also present in pulp mill effluents, can seriously interfere with normal hormonal processes, notes Kidd, the Canada Research Chair in Chemical Contamination of Food Webs.

To better understand the impacts of estrogen on fish, the researchers conducted a seven-year, whole-lake study at the Experimental Lakes Area in northwestern Ontario. Over three summers, they added tiny amounts — low parts per trillion — of the synthetic estrogen used in birth control pills to the lake to recreate concentrations measured in municipal wastewater.

During that period, they observed that chronic exposure to estrogen led to the near extinction of the lake’s fathead minnow population as well significant declines in larger fish, such as pearl dace and lake trout.

“Generally, the smaller the fish, the more vulnerable they are to estrogen,” remarks Kidd.

Part of the reason, she adds, is that smaller fish have a shorter lifespan and will often die after reproducing only once.

The researchers used synthetic estrogen because it tends to persist longer in the environment than natural estrogens. Yet the problem with estrogen is not its environmental persistence but rather its persistent discharge in municipal wastewater into surface waters.

Kidd says the risk is greatest for aquatic ecosystems downstream from municipalities that either discharge untreated wastewater or maintain only primary treatment facilities. On the flipside, the problem is of less concern near cities that remove a wide range of chemical contaminants, including estrogens, from wastewater using secondary and tertiary treatment processes.

It is now understood, she says, that removing estrogen through wastewater treatment can reverse the adverse impact of this substance/hormone on wild fish. In fact, three years after halting additions of synthetic estrogen to the experimental lake, the researchers discovered that the fathead minnow population was on the rebound.

“To me, that’s the good news. Once you take the stressor out the system, we now have ample evidence that suggests affected fish populations will recover.”

Doré Dunne | EurekAlert!
Further information:
http://www.nserc.ca

More articles from Ecology, The Environment and Conservation:

nachricht Five-point plan to integrate recreational fishers into fisheries and nature conservation policy
20.03.2019 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)

nachricht Rain is important for how carbon dioxide affects grasslands
06.03.2019 | University of Gothenburg

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: The taming of the light screw

DESY and MPSD scientists create high-order harmonics from solids with controlled polarization states, taking advantage of both crystal symmetry and attosecond electronic dynamics. The newly demonstrated technique might find intriguing applications in petahertz electronics and for spectroscopic studies of novel quantum materials.

The nonlinear process of high-order harmonic generation (HHG) in gases is one of the cornerstones of attosecond science (an attosecond is a billionth of a...

Im Focus: Magnetic micro-boats

Nano- and microtechnology are promising candidates not only for medical applications such as drug delivery but also for the creation of little robots or flexible integrated sensors. Scientists from the Max Planck Institute for Polymer Research (MPI-P) have created magnetic microparticles, with a newly developed method, that could pave the way for building micro-motors or guiding drugs in the human body to a target, like a tumor. The preparation of such structures as well as their remote-control can be regulated using magnetic fields and therefore can find application in an array of domains.

The magnetic properties of a material control how this material responds to the presence of a magnetic field. Iron oxide is the main component of rust but also...

Im Focus: Self-healing coating made of corn starch makes small scratches disappear through heat

Due to the special arrangement of its molecules, a new coating made of corn starch is able to repair small scratches by itself through heat: The cross-linking via ring-shaped molecules makes the material mobile, so that it compensates for the scratches and these disappear again.

Superficial micro-scratches on the car body or on other high-gloss surfaces are harmless, but annoying. Especially in the luxury segment such surfaces are...

Im Focus: Stellar cartography

The Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT) in Arizona released its first image of the surface magnetic field of another star. In a paper in the European journal Astronomy & Astrophysics, the PEPSI team presents a Zeeman- Doppler-Image of the surface of the magnetically active star II Pegasi.

A special technique allows astronomers to resolve the surfaces of faraway stars. Those are otherwise only seen as point sources, even in the largest telescopes...

Im Focus: Heading towards a tsunami of light

Researchers at Chalmers University of Technology and the University of Gothenburg, Sweden, have proposed a way to create a completely new source of radiation. Ultra-intense light pulses consist of the motion of a single wave and can be described as a tsunami of light. The strong wave can be used to study interactions between matter and light in a unique way. Their research is now published in the scientific journal Physical Review Letters.

"This source of radiation lets us look at reality through a new angle - it is like twisting a mirror and discovering something completely different," says...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International Modelica Conference with 330 visitors from 21 countries at OTH Regensburg

11.03.2019 | Event News

Selection Completed: 580 Young Scientists from 88 Countries at the Lindau Nobel Laureate Meeting

01.03.2019 | Event News

LightMAT 2019 – 3rd International Conference on Light Materials – Science and Technology

28.02.2019 | Event News

 
Latest News

Solving the efficiency of Gram-negative bacteria

22.03.2019 | Life Sciences

Bacteria bide their time when antibiotics attack

22.03.2019 | Life Sciences

Open source software helps researchers extract key insights from huge sensor datasets

22.03.2019 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>