Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New study finds that even the cleanest wastewater contributes to more 'super bacteria'

15.11.2011
University of Minnesota research suggests that wastewater treated with standard technologies contributes far greater quantities

A new University of Minnesota study reveals that the release of treated municipal wastewater – even wastewater treated by the highest-quality treatment technology – can have a significant effect on the quantities of antibiotic-resistant bacteria, often referred to as "superbacteria," in surface waters.

The study also suggests that wastewater treated using standard technologies probably contains far greater quantities of antibiotic-resistant genes, but this likely goes unnoticed because background levels of bacteria are normally much higher than the water studied in this research.

The new study is led by civil engineering associate professor Timothy LaPara in the University of Minnesota, Twin Cities College of Science and Engineering. The study is published in the most recent issue of "Environmental Science and Technology," a journal of the American Chemical Society. The research was part of a unique class project in a graduate-level civil engineering class at the University of Minnesota focused on environmental microbiology.

Antibiotics are used to treat numerous bacterial infections, but the ever-increasing presence of antibiotic-resistant bacteria has raised substantial concern about the future effectiveness of antibiotics. In response, there has been increasing focus on environmental reservoirs of antibiotic resistance over the past several years. Antibiotic use in agriculture has been heavily scrutinized, while the role of treated municipal wastewater has received little attention as a reservoir of resistance.

Antibiotic-resistant bacteria develop in the gastrointestinal tracts of people taking antibiotics. These bacteria are then shed during defecation, which is collected by the existing sewer infrastructure and passed through a municipal wastewater treatment facility.

In this study, the Ph.D. students and professor examined the impact of municipal wastewater in Duluth, Minn., on pristine surface waters by gathering water samples from the St. Louis River, Duluth-Superior Harbor, and Lake Superior in northeastern Minnesota. The treatment facility in Duluth is considered one of the best. After solids and biological matter are removed, the Duluth wastewater treatment is one of only a few in the country that filter water a third time through a mixed media filter to remove additional particles of bacteria and nutrients. Standard wastewater treatment treats water twice to remove solids and biological matter.

"This was a unique and ideal location for this study because of the exemplary wastewater treatment mixed with surprisingly pristine surface waters with very low background levels of bacteria that wouldn't mask our results," LaPara said. "Previous studies in which treated municipal wastewater was implicated as a source of antibiotic resistance were more convoluted because multiple sources of antibiotic resistance genes existed, such as agricultural activity and industrial wastewater discharges."

While the levels of overall bacteria were still relatively low in the surface water samples, researchers in the University of Minnesota study found that the quantities of antibiotic-resistant genes and human-specific bacteria were typically 20-fold higher at the site where treated wastewater was released into the Duluth-Superior Harbor compared to nearby surface water samples.

"Current wastewater treatment removes a very large fraction of the antibiotic resistance genes," LaPara said. "But this study shows that wastewater treatment operations need to be carefully considered and more fully studied as an important factor in the global ecology of antibiotic resistance."

In addition to LaPara, researchers involved in the study include civil engineering Ph.D. students Tucker Burch, Patrick McNamara, David Tan; and bioproducts and biosystems engineering Ph.D. student Mi Yan, with help from soil, water and climate Ph.D. student Jessica Eichmiller.

The University of Minnesota research study was funded by the National Science Foundation's broader impacts effort, which combines research and education. The Minnesota Environment and Natural Resources Trust Fund paid for time on the R/V Blue Heron ship to collect water samples.

To read the full research paper, titled "Tertiary-Treated Municipal Wastewater is a Significant Point Source of Antibiotic Resistance Genes into Duluth-Superior Harbor," visit http://z.umn.edu/lapara11.

Rhonda Zurn | EurekAlert!
Further information:
http://www.umn.edu

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Extensive Funding for Research on Chromatin, Adrenal Gland, and Cancer Therapy

28.06.2017 | Awards Funding

Predicting eruptions using satellites and math

28.06.2017 | Earth Sciences

Extremely fine measurements of motion in orbiting supermassive black holes

28.06.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>