Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Toxic flood lifts lid on common urban pollution problem

20.09.2005


Broken sewers, flooded industrial plants and dead bodies are all likely to blame for poisoning the waters being drained from New Orleans.



But the water – and the muck it is leaving behind — also owes its contamination to a source as mundane as it is unexpected: Toxins common in most urban environments that made their way en masse into the water as it stagnated atop the city.

So says a University of Florida professor who has spent years studying the harmful contaminants that turn up in urban runoff, or rainwater that washes across streets and other hard surfaces in cities. Environmental engineering professor John Sansalone’s perspective is especially relevant because it is based on field research in New Orleans and Baton Rouge, where he was a professor at Louisiana State University before taking a job at UF this summer.


“What we see in New Orleans is that when you put a lot of water in contact with the urban environment, all the potential contaminants that stayed around in that environment are now back in the water – definitely, to our horror,” Sansalone said.

Federal and Louisiana officials continue to sound alarms about the contaminated waters and scum left behind by the retreating flood. Early September test results released late last week showed high levels of bacteria, lead and harmful levels of chemicals including arsenic, according to the Environmental Protection Agency.

While the sources of these and other contaminants remain under investigation, public scrutiny has focused on broken sewer pipes and other major failures in the city’s infrastructure attributed to Hurricane Katrina. Though these are certainly real problems, it’s also highly likely that the stagnant waters are contaminated because they’ve soaked up “legacy” pollutants that accumulated during normal conditions on the city’s streets, sidewalks, roofs and other impermeable surfaces, Sansalone said.

These pollutants, which normally appear in urban runoff, are more toxic than commonly understood, he said. In a study published last month in Water Environment Research, Sansalone and three co-authors report that runoff from an elevated section of Interstate 10 in Baton Rouge contained some contaminants at levels “greater than those found in untreated municipal wastewater from the same service area,” according to the study.

The findings were based on periodic analysis of runoff that drains off Interstate 10 into Baton Rouge’s City Park Lake just below the highway. Based on data first gathered in 1999, they revealed high levels of particulates, or microscopic- to millimeter-sized particles of material, as well as high chemical oxygen demand, an indicator of the presence of organic chemicals in oil, gas, grease, cigarette filters and other pollution.

Other research on urban runoff, meanwhile, has detected high levels of toxic metals and nutrients including phosphorus thought to leach from building materials, Sansalone said.

Organic chemicals are particularly dangerous to fish and other aquatic life because they reduce the levels of oxygen in the water, impinging on its ability to support life. Particulates cloud water, reducing sunlight penetration and plant growth. Once they cross a certain threshold, organic chemicals and metals also can be harmful to people.

New Orleans officials remain extremely concerned about bacterial contamination in the flood waters. Typically the result of contamination from untreated sewage, bacteria also can come from urban runoff, Sansalone said. Although it was not measured as part of his published study, other studies have found that such runoff contains heightened levels of bacteria stemming from bird and animal droppings, among other sources.

Sansalone said based on his studies of urban runoff alone, it’s critical that environmental officials scour the city of flood residue. “How we clean up this residual matter – which will not be easy – will be a chronic issue to the health of the city,” he said.

He said the contamination in New Orleans also highlights the need for other cities nationwide to do more to remove the toxins in urban runoff before, rather than after, it gets washed into waterways. There are several good strategies, he said. Increasingly affordable “permeable pavements” allow runoff to be stored, evaporate or percolate through pavement and into the ground, where soil and microorganisms can help filter the contaminants. Planting vegetation and especially trees also creates aesthetically pleasing buffer zones, providing storm water flooding control and other benefits. Finally, cities can use high-tech street sweeping equipment that is very effective at capturing pavement contaminants.

“If you pick up this potentially toxic material before it gets into the hydrological cycle, it is far more economical than if you try to take it out of the water after the fact,” he said.

John Sansalone | EurekAlert!
Further information:
http://www.ufl.edu

More articles from Ecology, The Environment and Conservation:

nachricht Joint research project on wastewater for reuse examines pond system in Namibia
19.12.2016 | Technische Universität Darmstadt

nachricht Scientists produce a new roadmap for guiding development & conservation in the Amazon
09.12.2016 | Wildlife Conservation Society

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: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

Im Focus: Newly proposed reference datasets improve weather satellite data quality

UMD, NOAA collaboration demonstrates suitability of in-orbit datasets for weather satellite calibration

"Traffic and weather, together on the hour!" blasts your local radio station, while your smartphone knows the weather halfway across the world. A network of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Water - as the underlying driver of the Earth’s carbon cycle

17.01.2017 | Earth Sciences

Satellite-based Laser Measurement Technology against Climate Change

17.01.2017 | Machine Engineering

Studying fundamental particles in materials

17.01.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>