Featured Research

from universities, journals, and other organizations

Biological Selenium Removal: Solution To Pollution?

Date:
September 16, 2008
Source:
Soil Science Society of America
Summary:
Unsafe levels of selenium, sometimes referred to as an "essential toxin," can be reduced by a microbiological treatment. With this method, microorganisms reduce selenate to the less-toxic elemental selenium, which can potentially be recovered from the process. An estimated 0.5 to 1 billion people worldwide suffer from selenium deficiency, even though many live near areas where levels of selenium have reached toxic levels.

Selenium has been referred to as an “essential toxin” due to the fact that it shows only a marginal line between the nutritious requirement and toxic effects upon exposure. The steep dose response curve due to bioaccumulation effects have lead to the characterization of selenium as a “time bomb” that can be fused by exceeding a narrow threshold concentration in ecosystems through anthropogenic activities.

Ironically, an estimated 0.5 to 1 billion people worldwide suffer from selenium deficiency, whereas areas of toxicity can be separated from selenium deficient areas by only 20 km.

The microbiological treatment of selenium - so called "dissimilatory metal reduction" - could supersede this problem, as selenium-reducing microorganisms are highly selective for selenate, reducing it to insoluble, less-toxic elemental selenium that can potentially be recovered from the process.

A study funded by the European Union, published in the September-October issue of the Journal of Environmental Quality, demonstrates that the biological treatment is indeed efficient for selenate reduction, and substantial amounts of selenate are converted to methylated selenium species or nano-sized elemental selenium particles. The emission of nano-sized selenium particles is problematic, as these can become bioavailable by direct assimilation or reoxidize to selenite and selenate.

Dimethlyselenide and dimethyldiselenide, two species with unknown ecotoxicological long-term effects, contributed substantially to selenium dissolved in the effluent. Their formation was induced by minor temperature changes during biological reduction, thus a careful process control might drastically increase removal success of existing biotreatment systems for selenium and is a prerequisite for successful removal in full scale applications.

Consequently, remediative systems aiming at minimizing ecotoxicological risks on the one hand and selenium recovery and reuse on the other hand should be implemented. Due to the "high volume - low concentration" character, no sustainable solution has been found yet to treat selenium-contaminated drainage waters originating from the San Joachin Valley, one of the agriculturally most productive areas of the US (a comprehensive report by the USGS is available at http://pubs.usgs.gov/pp/p1646/pdf/pp1646.pdf).


Story Source:

The above story is based on materials provided by Soil Science Society of America. Note: Materials may be edited for content and length.


Journal Reference:

  1. Lenz et al. Biological Alkylation and Colloid Formation of Selenium in Methanogenic UASB Reactors. Journal of Environmental Quality, 2008; 37 (5): 1691 DOI: 10.2134/jeq2007.0630

Cite This Page:

Soil Science Society of America. "Biological Selenium Removal: Solution To Pollution?." ScienceDaily. ScienceDaily, 16 September 2008. <www.sciencedaily.com/releases/2008/09/080915121321.htm>.
Soil Science Society of America. (2008, September 16). Biological Selenium Removal: Solution To Pollution?. ScienceDaily. Retrieved August 1, 2014 from www.sciencedaily.com/releases/2008/09/080915121321.htm
Soil Science Society of America. "Biological Selenium Removal: Solution To Pollution?." ScienceDaily. www.sciencedaily.com/releases/2008/09/080915121321.htm (accessed August 1, 2014).

Share This




More Health & Medicine News

Friday, August 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Texas Quintuplets Head Home

Texas Quintuplets Head Home

Reuters - US Online Video (Aug. 1, 2014) After four months in the hospital, the first quintuplets to be born at Baylor University Medical Center head home. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Ebola Patient Coming to U.S. for Treatment

Ebola Patient Coming to U.S. for Treatment

Reuters - US Online Video (Aug. 1, 2014) A U.S. aid worker infected with Ebola while working in West Africa will be treated in a high security ward at Emory University in Atlanta. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Ebola Vaccine Might Be Coming, But Where's It Been?

Ebola Vaccine Might Be Coming, But Where's It Been?

Newsy (Aug. 1, 2014) Health officials are working to fast-track a vaccine — the West-African Ebola outbreak has killed more than 700. But why didn't we already have one? Video provided by Newsy
Powered by NewsLook.com
Study Links Certain Birth Control Pills To Breast Cancer

Study Links Certain Birth Control Pills To Breast Cancer

Newsy (Aug. 1, 2014) Previous studies have made the link between birth control and breast cancer, but the latest makes the link to high-estrogen oral contraceptives. 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:
from the past week

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