Featured Research

from universities, journals, and other organizations

Model shows how façade pollutants make it into the environment

Date:
December 9, 2011
Source:
Ecole Polytechnique Fédérale de Lausanne
Summary:
Anti-fungal and anti-bacterial additives in house paint are present in dangerous quantities in the Vauchère river basin in the city of Lausanne, says a new study. Chemicals engineered to kill microorganisms, called biocides, are added to exterior paints in order to prevent molding and plant growth and are washed off of building facades during heavy rains.

Peak concentrations of biocides from house paint prove prevalent in urban river basins.

Related Articles


Anti-fungal and anti-bacterial additives in house paint are present in dangerous quantities in the Vauchère river basin in the city of Lausanne, says a study to be presented the 9th of December, at the American Geophysical Union (AGU) conference in San Francisco. Chemicals engineered to kill microorganisms, called biocides, are added to exterior paints in order to prevent molding and plant growth. Washed off of building facades during heavy rains, however, these chemicals can be wind up in soil, groundwater and river basins where they attack bacteria, fungi and algae at the bottom of the food chain. Researchers at EPFL's Ecological Engineering Laboratory have now modeled the flow of biocides from building façades into river basins with surprising accuracy, which could lead to stricter regulations for Switzerland and abroad.

In Switzerland, biocides are present in exterior paint on some 60% of buildings and they are common worldwide. The global demand on all biocides for use in industrial and consumer goods was estimated at US$6.4 billion in 2008. Certain antifouling biocides have been phased out of use on boat hulls after being proven toxic to marine life.

The mathematical tool developed by Sylvain Coutu at EPFL accurately predicts peak concentration levels in a local river of three biocides commonly found in industrial paint: DCMU, Terbutryn and Carbendazim. Coutu predicted the concentration of these biocides after four rainstorms during the spring of 2011 and compared the numbers to actual measurements taken from the river. The model proved accurate up to a couple of nanograms per liter, an impressive feat considering the variety and complexity of variables. The model's strength comes from its delicate balance between the simplification of urban surface hydraulic behaviors -- how water is channeled down streets and gutters compared to lawns and gardens -- and the necessity for extreme accuracy.

"A true toxicology report should include these peaks, and we have created the first model that takes them into account over a period of time," says Coutu.

Establishing a working model has the advantage of reproducibility as well as reducing dependency on expensive testing. Once a reliable model has been created it can be used in other regions, although the model needs to be adapted to the specific geography, for example the surface area of contaminated façades as well as the quick water drainage of urban surfaces. Once the input is determined and the dynamics of the hazardous substances reacting to rainfall are worked out, it is possible to estimate the concentrations of these substances to see if they exceed acceptable levels.

The biocides that reached the river basin in Switzerland did so in extremely small concentrations -- 30 nanograms per liter, or 30 parts per trillion, of the chemical DCMU were present after heavy rains. DCMU is a common herbicide and algicide developed in the 1950s in Germany and the threshold concentration after which this substance is considered a threat for the environment is 20 nanograms per liter. DCMU is considered harmful and can potentially kill algae and other plantlife by inhibiting photosynthesis and thus depriving the organisms of energy. Biocides in general do not degrade easily, thus increasing their risk of moving up the food chain and making their way, in higher and higher concentrations, throughout the environment.

"While it may seem like a very small concentration, 20 nanograms is all that is needed to have an impact on the ecosystem since these chemicals are engineered to kill at very low doses," explains Coutu. Furthermore, the study also proves that water behavior in urban environments can be accurately modeled, opening the door to further toxicology studies for city ecosystems.


Story Source:

The above story is based on materials provided by Ecole Polytechnique Fédérale de Lausanne. Note: Materials may be edited for content and length.


Cite This Page:

Ecole Polytechnique Fédérale de Lausanne. "Model shows how façade pollutants make it into the environment." ScienceDaily. ScienceDaily, 9 December 2011. <www.sciencedaily.com/releases/2011/12/111209150150.htm>.
Ecole Polytechnique Fédérale de Lausanne. (2011, December 9). Model shows how façade pollutants make it into the environment. ScienceDaily. Retrieved January 31, 2015 from www.sciencedaily.com/releases/2011/12/111209150150.htm
Ecole Polytechnique Fédérale de Lausanne. "Model shows how façade pollutants make it into the environment." ScienceDaily. www.sciencedaily.com/releases/2011/12/111209150150.htm (accessed January 31, 2015).

Share This


More From ScienceDaily



More Earth & Climate News

Saturday, January 31, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Rare Clouds Fill Grand Canyon

Raw: Rare Clouds Fill Grand Canyon

AP (Jan. 29, 2015) — For the second time in two months, a rare weather phenomenon filled the Grand Canyon with thick clouds just below the rim on Wednesday. (Jan. 29) Video provided by AP
Powered by NewsLook.com
Senate Passes Bill for Keystone XL Pipeline

Senate Passes Bill for Keystone XL Pipeline

AP (Jan. 29, 2015) — The Republican-controlled Senate has passed a bipartisan bill approving construction of the Keystone XL oil pipeline. (Jan. 29) Video provided by AP
Powered by NewsLook.com
"Cloud Inversion" In Grand Canyon

"Cloud Inversion" In Grand Canyon

Reuters - US Online Video (Jan. 29, 2015) — Time lapse video captures a blanket of clouds amassing in the Grand Canyon -- the result of a rare meteorological process called "cloud inversion." Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Why Researchers Say We Should Cut Back On Biofuels

Why Researchers Say We Should Cut Back On Biofuels

Newsy (Jan. 29, 2015) — Biofuels aren&apos;t the best alternative to fossil fuels, according to a new report. In fact, they&apos;re quite a bad one. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins