Free Newsletters - Space News - Defense Alert - Environment Report - Energy Monitor
. Earth Science News .




WATER WORLD
It's only natural: Lawrence Livermore helps find link to arsenic-contaminated groundwater
Anne M Stark
Livermore CA (SPX) Mar 12, 2013


Sampling site in Bangladesh where thousands of liters of ground water were passed through filters to collect bacteria for DNA dating.

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.

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.

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

.


Related Links
Lawrence Livermore National Laboratory,
Water News - Science, Technology and Politics






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





WATER WORLD
Herbal defluoridation of drinking water
London, UK (SPX) Mar 07, 2013
Researchers in India have developed a filter system based on a medicinal herb, which they say can quickly and easily remove "fluoride" from drinking water. The technology described in the March issue of the International Journal of Environmental Engineering uses parts of the plant Tridax procumbens as a biocarbon filter for the ion. Drinking water can contain natural fluoride or fluoride m ... read more


WATER WORLD
Fukushima status little improved

Fukushima victims sue Japan government, TEPCO

British business backs PM's foreign aid pledge

NASA Wallops Recovery Continues from Hurricane Sandy

WATER WORLD
Russian satellite hit by remnants of destroyed Chinese spacecraft

NUS graphene researchers create 'superheated' water that can corrode diamonds

Activists fault WHO report on Fukushima radiation

SimCity climbing from launch wreckage

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

Four shark species win international trade protection

Tracking sediments' fate in largest-ever dam removal

Sharks, manta rays win global trade protection

WATER WORLD
Rivers flowing under Greenland ice traced

The making of Antarctica's hidden fjords

Global warming will open unexpected new shipping routes in Arctic, UCLA researchers find

Glaciers will melt faster than ever and loss could be irreversible warn scientists

WATER WORLD
Argentina's potash dream at risk from Vale

Thousands of dead pigs found in Shanghai river

Delayed EU phosphorus plans coming soon

Tokyo's sale of Japan Tobacco stake worth $7.8 bn: company

WATER WORLD
Japan marks second tsunami anniversary

California quake revives Big One jitters

Breaking the rules for how tsunamis work

Floating tsunami trash to be a decades-long headache

WATER WORLD
China congratulates Kenyatta over election win

Poll leaves Kenya still bitterly divided

South Sudan, Sudan say pulling troops from tense border

China's Xi to visit S.Africa this month

WATER WORLD
New study validates longevity pathway

Siberian fossil revealed to be one of the oldest known domestic dogs

Kirk, Spock together: Putting emotion, logic into computational words

After the human genome project: The human microbiome project




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement