Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Katrina floodwaters not as toxic to humans as previously thought, study says

12.10.2005


The floodwaters that inundated New Orleans immediately following Hurricane Katrina were similar in content to the city’s normal storm water and were not as toxic as previously thought, according to a study by researchers at Louisiana State University. Their study, the first peer-reviewed scientific assessment of the water quality of the Katrina floodwaters, is good news for those who’ve been exposed directly to the floodwaters, the scientists say.



But the LSU researchers caution that the same floodwaters that were pumped back into Lake Pontchartrain contain high levels of some toxic metals, especially copper and zinc, and could pose a long-term danger to the area’s aquatic life, which are more sensitive to the metals than humans. Their findings will appear in the Oct. 11 online issue of the American Chemical Society’s journal Environmental Science & Technology.

"What we had in New Orleans was basically a year’s worth of storm water flowing through the city in only a few days," says study leader John Pardue, Ph.D., an environmental engineer and director of the Louisiana Water Resources Research Institute at LSU in Baton Rouge. "We still don’t think the floodwaters were safe, but it could have been a lot worse. It was not the chemical catastrophe some had expected."


Some experts had predicted that the floodwaters from Katrina could potentially destroy chemical plants and refineries in the area, releasing a deadly brew containing toxic levels of benzene, hydrochloric acid and chlorine. Instead, high levels of bacteria and viruses were the biggest human threat, not exposure to chemicals, Pardue and his associates say.

The researchers obtained 38 floodwater samples from widespread sections of New Orleans, primarily in the area of the city known as the "East Bank," where the main human contact with the floodwaters occurred. The samples, which included both surface waters and bottom samples, were taken within five to nine days after flooding occurred. Additional samples were also obtained from the 17th Street drainage canal, after pumping of the floodwater began, to evaluate the flood’s impact on Lake Pontchartrain, the receiving body for the pumped floodwaters.

The researchers found high levels of bacteria, most likely from fecal contamination resulting from sewage. Levels were within the range of typical storm-water runoff in the city, the scientists say. They also detected high levels of lead, arsenic and chromium and noted that levels of these toxic metals were also similar to those typically found in the area’s stormwater. In general, these particular findings were similar to those obtained by the Environmental Protection Agency in their initial assessment of the floodwaters, the researchers say.

Gasoline was also a significant component of the floodwaters, as measured by elevated levels of three of its components: benzene, toluene and ethylbenzene. These compounds were somewhat elevated in comparison to typical stormwater runoff, the researchers say. The chemicals most likely came from cars and storage tanks submerged in the floodwaters, they add.

Compounds found in common household chemicals were also detected in the floodwaters, Pardue says. The waters contained chemical compounds from aerosol paints, insecticides, caulking compounds, rubber adhesives and other common substances, they say, but at levels that typically do not create concern for human health.

If the floodwaters had occurred in another location near more industrial sites in the city and if the wind damage or water surge had been more severe, then the resultant floodwaters could have been a more serious toxic threat, Pardue says. "Instead, the city filled slowly, like a bathtub, and the water velocities and forces on the buildings, including chemical storage facilities, were relatively benign," he says. The large volume of floodwater also diluted the potency of many of the chemicals, he adds.

While serious toxicity to human life was largely avoided, the floodwater may pose a chemical risk to aquatic life in the area, Pardue says. He believes that low oxygen levels in the water that is being pumped back into Lake Pontchartrain could result in fish kills. He also says that heavy metals being discharged into the lake, particularly copper and zinc, can be toxic to fish and other marine life and may bioaccumulate and contaminate seafood collected from the region. More studies are needed to assess the long-term impact of the flood on aquatic life, Pardue says.

Funding for this study was provided by the Louisiana Water Resources Research Institute and the LSU Center for the Study of Public Health Impacts of Hurricanes.

The American Chemical Society is a nonprofit organization, chartered by the U.S. Congress, with a multidisciplinary membership of more than 158,000 chemists and chemical engineers. It publishes numerous scientific journals and databases, convenes major research conferences and provides educational, science policy and career programs in chemistry. Its main offices are in Washington, D.C., and Columbus, Ohio.

Michael Bernstein | EurekAlert!
Further information:
http://www.acs.org

More articles from Ecology, The Environment and Conservation:

nachricht Scientists team up on study to save endangered African penguins
16.11.2017 | Florida Atlantic University

nachricht Climate change: Urban trees are growing faster worldwide
13.11.2017 | Technische Universität München

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: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

NASA detects solar flare pulses at Sun and Earth

17.11.2017 | Physics and Astronomy

NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures

17.11.2017 | Health and Medicine

The importance of biodiversity in forests could increase due to climate change

17.11.2017 | Studies and Analyses

VideoLinks
B2B-VideoLinks
More VideoLinks >>>