Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

It's only natural: Lawrence Livermore helps find link to arsenic-contaminated groundwater

05.03.2013
Human activities are not the primary cause of arsenic found in groundwater in Bangladesh.

Instead, a team of researchers from Lawrence Livermore National Laboratory, Barnard College, Columbia University, University of Dhaka, Desert Research Institute and University of Tennessee found that the arsenic in groundwater in the region is part of a natural process that predates any recent human activity, such as intensive pumping.

The results appear in the March 4 edition of the Proceedings of the National Academy of Sciences.

Millions of people in Bangladesh and neighboring countries are chronically exposed to arsenic-contaminated groundwater, which causes skin lesions and increases the risk of certain cancers. Bacterial respiration of organic carbon releases naturally-occurring arsenic from sediment into groundwater, but the source of this organic carbon remains unclear.

Brian Mailloux of Barnard College and his team isolated microbial DNA from several depth intervals in arsenic-contaminated aquifers in Bangladesh and analyzed the DNA's radiocarbon signature, which reflects whether the organic carbon used by the microbes derives primarily from younger, surface-derived sources that are transported by groundwater into the aquifers, or older, sediment-derived sources.

Using "bomb pulse" radiocarbon analysis, Lawrence Livermore scientist Bruce Buchholz dated the DNA of groundwater bacteria. He found that the DNA samples were consistently younger than the sediment, suggesting that the microbes favor using surface-derived carbon.

The surface-derived carbon has flowed into the aquifer over hundreds to thousands of years -- a rate that is approximately 100 times slower than groundwater flow. The results suggest that recent human activities, such as intensive groundwater pumping, have not yet significantly affected the release of arsenic into the groundwater at this site.

Above-ground testing of nuclear weapons during the Cold War (1955-1963) caused a surge in global levels of carbon-14 (14C), and remains in all living things. Carbon-14 or radiocarbon is naturally produced by cosmic ray interactions with air and is present at low levels in the atmosphere and food. Although nuclear weapon testing was conducted at only a few locations, excess levels of 14C in the atmosphere rapidly dispersed and equalized around the globe.

According to Buchholz, "The bomb curve forms a chronometer of the past 60 years."

The radiocarbon signature of DNA is a direct measure of the carbon used during microbial respiration and growth. In this study, the team developed a method to filter, extract and purify DNA from groundwater aquifers for radiocarbon analysis to determine the organic carbon pools fueling microbial reduction.

"We were able to separate the recent bomb pulse radiocarbon from the natural carbon signature and found the arsenic levels are now directly tied to a natural process as opposed to being driven by human activities," Buchholz said.

The results may help scientists understand the causes of arsenic contamination in the region, and the development of potential mitigation strategies.

More Information

"Cold cases heat up through Lawrence Livermore approach to identifying remains," LLNL news release, Oct. 10, 2012

"Putting teeth into forensic science," LLNL news release, May 19, 2010

"Date for a heart cell," Science & Technology Review, April/May 2010

"New technique determines that the number of fat cells remains constant in all body types," LLNL news release, May 5, 2008

Founded in 1952, Lawrence Livermore National Laboratory provides solutions to our nation's most important national security challenges through innovative science, engineering and technology. Lawrence Livermore National Laboratory is managed by Lawrence Livermore National Security, LLC for the U.S. Department of Energy's National Nuclear Security Administration.

Anne Stark | EurekAlert!
Further information:
http://www.llnl.gov

More articles from Ecology, The Environment and Conservation:

nachricht New approach for environmental test on livestock drugs
27.07.2016 | Universität Zürich

nachricht Managing an endangered river across the US-Mexico border
18.07.2016 | International Institute for Applied Systems Analysis (IIASA)

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: Streamlining accelerated computing for industry

PyFR code combines high accuracy with flexibility to resolve unsteady turbulence problems

Scientists and engineers striving to create the next machine-age marvel--whether it be a more aerodynamic rocket, a faster race car, or a higher-efficiency jet...

Im Focus: X-ray optics on a chip

Waveguides are widely used for filtering, confining, guiding, coupling or splitting beams of visible light. However, creating waveguides that could do the same for X-rays has posed tremendous challenges in fabrication, so they are still only in an early stage of development.

In the latest issue of Acta Crystallographica Section A: Foundations and Advances , Sarah Hoffmann-Urlaub and Tim Salditt report the fabrication and testing of...

Im Focus: Piggyback battery for microchips: TU Graz researchers develop new battery concept

Electrochemists at TU Graz have managed to use monocrystalline semiconductor silicon as an active storage electrode in lithium batteries. This enables an integrated power supply to be made for microchips with a rechargeable battery.

Small electrical gadgets, such as mobile phones, tablets or notebooks, are indispensable accompaniments of everyday life. Integrated circuits in the interiors...

Im Focus: UCI physicists confirm possible discovery of fifth force of nature

Light particle could be key to understanding dark matter in universe

Recent findings indicating the possible discovery of a previously unknown subatomic particle may be evidence of a fifth fundamental force of nature, according...

Im Focus: Wi-fi from lasers

White light from lasers demonstrates data speeds of up to 2 GB/s

A nanocrystalline material that rapidly makes white light out of blue light has been developed by KAUST researchers.

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

The energy transition is not possible without Geotechnics

25.08.2016 | Event News

New Ideas for the Shipping Industry

24.08.2016 | Event News

A week of excellence: 22 of the world’s best computer scientists and mathematicians in Heidelberg

12.08.2016 | Event News

 
Latest News

Designing ultrasound tools with Lego-like proteins

26.08.2016 | Life Sciences

Allergy Research: Response to House Dust Mites is Age-Dependent

26.08.2016 | Life Sciences

Spherical tokamak as model for next steps in fusion energy

25.08.2016 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>