(Press-News.org) DURHAM, N.C. -- A new study by scientists at Duke University and the U.S. Geological Survey (USGS) finds no evidence of groundwater contamination from shale gas production in Arkansas.
"Our results show no discernible impairment of groundwater quality in areas associated with natural gas drilling and hydraulic fracturing in this region," said Avner Vengosh, professor of geochemistry and water quality at Duke's Nicholas School of the Environment.
The scientists sampled 127 shallow drinking water wells in areas overlying Fayetteville Shale gas production in north-central Arkansas. They analyzed the samples for major and trace elements and hydrocarbons, and used isotopic tracers to identify the sources of possible contaminants. The researchers compared the chemical composition of the contaminants to those found in water and gas samples from nearby shale gas drilling sites.
"Only a fraction of the groundwater samples we collected contained dissolved methane, mostly in low concentrations, and the isotopic fingerprint of the carbon in the methane in our samples was different from the carbon in deep shale gas in all but two cases," Vengosh said. This indicates that the methane was produced primarily by biological activity in the region's shallow aquifers and not from shale gas contamination, he said.
"These findings demonstrate that shale gas development, at least in this area, has been done without negatively impacting drinking water resources," said Nathaniel R. Warner, a PhD student at Duke and lead author of the study.
Robert Jackson, a professor of environmental sciences at Duke, added, "Overall, homeowners typically had good water quality, regardless of whether they were near shale gas development."
Vengosh, Warner, Jackson and their colleagues published their peer-reviewed findings in the online edition of the journal Applied Geochemistry.
Hydraulic fracturing, also called hydrofracking or fracking, involves pumping water, sand and chemicals deep underground into horizontal gas wells at high pressure to crack open hydrocarbon-rich shale and extract natural gas. Accelerated shale gas drilling and hydrofracking in recent years has fueled concerns about water contamination by methane, fracking fluids and wastewater from the operations.
Previous peer-reviewed studies by Duke scientists found direct evidence of methane contamination in drinking water wells near shale-gas drilling sites in the Marcellus Shale basin of northeastern Pennsylvania, as well as possible connectivity between deep brines and shallow aquifers, but no evidence of contamination from fracking fluids.
"The hydrogeology of Arkansas's Fayetteville Shale basin is very different from Pennsylvania's Marcellus Shale," Vengosh noted. Far from contradicting the earlier studies, the Arkansas study "suggests that variations in local and regional geology play major roles in determining the possible risk of groundwater impacts from shale gas development. As such, they must be taken into consideration before drilling begins."
Human factors -- such as the drilling techniques used and the integrity of the wellbores – also likely play a role in preventing, or allowing, gas leakage from drilling sites to shallow aquifers, Vengosh said.
"The take-home message is that regardless of the location, systematic monitoring of geochemical and isotopic tracers is necessary for assessing possible groundwater contamination," he said. "Our findings in Arkansas are important, but we are still only beginning to evaluate and understand the environmental risks of shale gas development. Much more research is needed."
###
Vengosh, Warner and Jackson's coauthors on the new study were Timothy M. Kresse and Phillip D. Hays of the USGS, and Adrian Down and Jonathan D. Karr of Duke.
Funding for the study was provided by Duke's Nicholas School of the Environment and the Duke Center on Global Change. Field sampling activities were funded by Shirley Community Development Corporation; Faulkner County, Ark.; the University of Arkansas; the Arkansas Water Resource Center; and the USGS Arkansas Water Science Center.
CITATION: "Geochemical and Isotopic Variations in Shallow Groundwater in Areas of the Fayetteville Shale Development, North-Central Arkansas," Nathaniel R. Warner, Timothy M. Kresse, Phillip D. Hays, Adrian Down, Jonathan D. Karr, Robert B. Jackson, Avner Vengosh. Applied Geochemistry, May 15, 2013.
DOI: 10.1016/j.apgeochem.2013.04.013
Groundwater unaffected by shale gas production in Arkansas
2013-05-15
ELSE PRESS RELEASES FROM THIS DATE:
Keeping fruit, vegetables and cut flowers fresh longer
2013-05-15
New technology offers the promise of reducing billions of dollars of losses that occur each year from the silent, invisible killer of fruits, vegetables and cut flowers — a gas whose effects are familiar to everyone who has seen bananas and other fruit ripen too quickly and rot. That's the conclusion of an article in the ACS journal Chemical Reviews.
Nicolas Keller, Marie-Noëlle Ducamp, Didier Robert and Valérie Keller explain that fruits, vegetables and flowers are still alive after harvest. They produce and release into the air ethylene gas, which fosters ripening ...
Making frequency-hopping radios practical
2013-05-15
CAMBRIDGE, MA -- The way in which radio spectrum is currently allocated to different wireless technologies can lead to gross inefficiencies. In some regions, for instance, the frequencies used by cellphones can be desperately congested, while large swaths of the broadcast-television spectrum stand idle.
One solution to that problem is the 15-year-old idea of "cognitive radio," in which wireless devices would scan their environments for vacant frequencies and use these for transmissions. Different proposals for cognitive radio place different emphases on hardware and software, ...
Safer, more environmentally friendly flame retardant with first-of-its-kind dual effects
2013-05-15
Amid concerns over the potential health effects of existing flame retardants for home furniture, fabrics and other material, scientists are reporting development of an "exceptionally" effective new retardant that appears safer and more environmentally friendly. Their report on the first-of-its-kind coating, ideal for the polyurethane foam in couches and bedding that causes many fire deaths, appears in ACS Macro Letters.
Jaime Grunlan and colleagues explain that upholstery furniture and mattresses are the items that ignite in about 17,000 fires each year, causing more ...
Maps developed to help forest industry outwit climate change
2013-05-15
University of Alberta researchers have developed guidelines being used by foresters and the timber industry to get a jump on climate change when planting trees.
Maps developed by Laura Gray, a post-doctoral fellow in the Department of Renewable Resources, provide projections of climatically suitable habitat for tree species based on climate predictions for the 2020s, 2050s and 2080s.
The work, published recently in the journal Climatic Change, is the first of its kind to tackle multiple potential climate scenarios for a large number of tree species across Western North ...
Terracotta and cement roofs vulnerable in wildfires, NIST study finds
2013-05-15
VIDEO:
The NIST Dragon firebrand generator in action.
Click here for more information.
Although made of fire-resistant materials, terracotta and cement roof tiles are vulnerable to penetration by windblown embers generated in wildfires, according to new research findings* from the National Institute of Standards and Technology (NIST).
In scoping experiments conducted in the Fire Research Wind Tunnel Facility at Japan's Building Research Institute, NIST fire scientist Samuel Manzello ...
Squishy hydrogels may be the ticket for studying biological effects of nanoparticles
2013-05-15
A class of water-loving, jelly-like materials with uses ranges ranging from the mundane, such as superabsorbent diaper liners, to the sophisticated, such as soft contact lenses, could be tapped for a new line of serious work: testing the biological effects of nanoparticles now being eyed for a large variety of uses.
New research* by scientists at the National Institute of Standards and Technology (NIST) demonstrates that three-dimensional scaffolds made with cells and supporting materials known as hydrogels can serve as life-like measurement platforms for evaluating how ...
NIST demonstrates significant improvement in the performance of solar-powered hydrogen generation
2013-05-15
Using a powerful combination of microanalytic techniques that simultaneously image photoelectric current and chemical reaction rates across a surface on a micrometer scale, researchers at the National Institute of Standards and Technology (NIST) have shed new light on what may become a cost-effective way to generate hydrogen gas directly from water and sunlight.*
Their quarry is a potentially efficient, cost-effective, photoelectrochemical (PEC) cell—essentially a solar cell that produces hydrogen gas instead of electric current. "A major challenge with solar energy is ...
NASA sees activity continue on the sun
2013-05-15
Solar activity continued on May 14, 2013, as the sun emitted a fourth X-class flare from its upper left limb, peaking at 9:48 p.m. EDT.
This flare is classified as an X1.2 flare and it is the 18th X-class flare of the current solar cycle. The flare caused a radio blackout – categorized as an R3, or strong, on NOAA's space weather scales from R1 to R5 -- which has since subsided.
The flare was also associated with a non-Earth-directed CME. CMEs and flares are separate but related solar phenomena: solar flares are powerful bursts that send light and radiation into space; ...
Despite new recommendations, women in 40s continue to get routine mammograms at same rate
2013-05-15
Women in their 40s continue to undergo routine breast cancer screenings despite national guidelines recommending otherwise, according to new Johns Hopkins research.
In 2009, the U.S. Preventive Services Task Force (USPSTF) sifted through the evidence and recommended that while women ages 50-74 should continue to undergo mammograms every two years, those between the ages of 40 and 49 without a family history of breast cancer should discuss the risks and benefits of routine screening mammography with their physicians to make individual decisions.
As a result of the altered ...
Scientists develop 'green' pretreatment of Miscanthus for biofuels
2013-05-15
URBANA –Two University of Illinois scientists have developed an environmentally friendly and more economical way of pretreating Miscanthus in the biofuel production process.
"We pretreat the biomass with switchable butadiene sulfone in the presence of water to break down the plant cell wall, which consists of cellulose, hemicellulose, and lignin, the source of biofuels and value-added products," said Hao Feng, a U of I professor of food science and human nutrition who also has extensive research experience with biofuels.
The new technique is a green alternative to current ...