Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Medicated ecosystems: human drugs alter key aquatic organism

07.08.2002


The overuse of antibiotics not only leads to more resistant strains of infection, but, according to new research from the University of Wisconsin-Madison, antibiotics also may be adversely affecting zooplankton, tiny organisms that underpin the health of all freshwater ecosystems.



In the last decade, European and American researchers have found more evidence that lakes and streams are tainted by common drugs, ranging from caffeine to anticancer agents.

This pollution, says Colleen Flaherty, a UW-Madison zoologist, has direct ties to humans, either through the improper disposal of unwanted pharmaceuticals or through the ingestion of the drugs.


"Up to 80 percent of drugs taken by humans and domesticated animals can be excreted in their biologically active form," explains Flaherty. This means that the antibiotics, antidepressants and anti-inflammatory pills we either take or throw out can eventually end up polluting the environment and harming the organisms that live in it.

Says UW-Madison zoologist Stanley Dodson, who studies freshwater ecology, "Pharmaceuticals can be detected in many surface water streams and lakes, yet we know little about how these strongly biologically active chemicals affect the ecology of aquatic organisms."

Flaherty will present findings from her study -- one of the first to document the effects of commonly-prescribed drugs on Daphnia, a zooplankton integral to freshwater ecosystems -- Thursday, Aug. 7, at the annual meeting of the Ecological Society of America.

"Daphnia play a key ecological role in freshwater sources," says Flaherty. "They are an intermediate organism in these ecosystems -- they eat the algae and are eaten by the fish. If something happens to Daphnia, it could affect both the algae and the fish populations."

To determine the influence of pharmaceuticals on this key freshwater species, Flaherty tested Daphnia’s biological response to commonly prescribed drugs that have been found in European and U.S. waters; the drugs include a cholesterol-lowering one (clofibric acid), an antidepressant (fluoxetine) and five antibiotics.

Flaherty performed short- and long-term studies to find out what happens to a female Daphnia and her offspring when exposed to a particular drug. Flaherty measured the survival, growth, number and sex of each female’s offspring. While the short-term studies looked at a single brood, the long-term ones examined all the offspring the female produced during her life span (about 30 days).

The effects Flaherty found varied. In the short-term studies, the antibiotics and cholesterol drug at concentrations of just 10 parts per billion -- an environmentally relevant concentration, says Flaherty -- appear to stunt growth and result in more male offspring.

In the long-term studies, these differences were diminished: offspring exposed to the antibiotics tended to have longer lifespans; those exposed to the cholesterol-lowering drug showed no apparent effects. While the other drug, an antidepressant, produced no differences in the shorter trials, it did result in a greater number of offspring in the longer studies.

"When Daphnia were exposed to a single pharmaceutical throughout their entire lifespan, as in the long-term studies, they seemed to become acclimated to the polluted environment," Flaherty says.

But, as Flaherty points out, Daphnia swim in waters tainted with not just one drug, but many: "Some of these drugs may not have significant effects by themselves," she says, "but, when you combine them in a ’pharmaceutical cocktail,’ the effects can be lethal."

When Flaherty exposed the organisms to a combination of the cholesterol drug and the antidepressant during the short-term studies, she found that the offspring were more likely to be female, have more deformities that hinder swimming and up to a 90 percent mortality rate. Flaherty says, "I never expected that two drugs that had virtually no individual effects could be so lethal when combined."

Because of these findings, Flaherty says that, in order to fully understand the ecological effects of pharmaceuticals or other man-made chemicals on freshwater ecosystems, scientists should look at not just one chemical, but combinations of them.

Emily Carlson (608) 262-9772, emilycarlson@facstaff.wisc.edu


Colleen Flaherty | EurekAlert!
Further information:
http://www.wisc.edu/

More articles from Ecology, The Environment and Conservation:

nachricht Robotic fish to replace animal testing
17.06.2019 | Otto-von-Guericke-Universität Magdeburg

nachricht Marine oil snow
12.06.2019 | University of Delaware

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 hidden structure of the periodic system

The well-known representation of chemical elements is just one example of how objects can be arranged and classified

The periodic table of elements that most chemistry books depict is only one special case. This tabular overview of the chemical elements, which goes back to...

Im Focus: MPSD team discovers light-induced ferroelectricity in strontium titanate

Light can be used not only to measure materials’ properties, but also to change them. Especially interesting are those cases in which the function of a material can be modified, such as its ability to conduct electricity or to store information in its magnetic state. A team led by Andrea Cavalleri from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg used terahertz frequency light pulses to transform a non-ferroelectric material into a ferroelectric one.

Ferroelectricity is a state in which the constituent lattice “looks” in one specific direction, forming a macroscopic electrical polarisation. The ability to...

Im Focus: Determining the Earth’s gravity field more accurately than ever before

Researchers at TU Graz calculate the most accurate gravity field determination of the Earth using 1.16 billion satellite measurements. This yields valuable knowledge for climate research.

The Earth’s gravity fluctuates from place to place. Geodesists use this phenomenon to observe geodynamic and climatological processes. Using...

Im Focus: Tube anemone has the largest animal mitochondrial genome ever sequenced

Discovery by Brazilian and US researchers could change the classification of two species, which appear more akin to jellyfish than was thought.

The tube anemone Isarachnanthus nocturnus is only 15 cm long but has the largest mitochondrial genome of any animal sequenced to date, with 80,923 base pairs....

Im Focus: Tiny light box opens new doors into the nanoworld

Researchers at Chalmers University of Technology, Sweden, have discovered a completely new way of capturing, amplifying and linking light to matter at the nanolevel. Using a tiny box, built from stacked atomically thin material, they have succeeded in creating a type of feedback loop in which light and matter become one. The discovery, which was recently published in Nature Nanotechnology, opens up new possibilities in the world of nanophotonics.

Photonics is concerned with various means of using light. Fibre-optic communication is an example of photonics, as is the technology behind photodetectors and...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

SEMANTiCS 2019 brings together industry leaders and data scientists in Karlsruhe

29.04.2019 | Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

First dust conference in the Central Asian part of the earth’s dust belt

15.04.2019 | Event News

 
Latest News

Novel communications architecture for future ultra-high speed wireless networks

17.06.2019 | Information Technology

Climate Change in West Africa

17.06.2019 | Earth Sciences

Robotic fish to replace animal testing

17.06.2019 | Ecology, The Environment and Conservation

VideoLinks
Science & Research
Overview of more VideoLinks >>>