doi: http://dx.doi.org/10.1038/nclimate1413

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A controversial method of drilling for natural gas, called fracking, has boomed in recent years—as have concerns over its potential to cause environmental contamination and harm human health. But a major review of the practice, released today, uncovered no signs that it is causing trouble below ground. “We found no direct evidence that fracking itself has contaminated groundwater,” said Charles Groat of the University of Texas (UT), Austin, who led the study.The report, released here at the annual meeting of the American Association for the Advancement of Science (which publishes ScienceNOW), doesn’t give this form of natural gas extraction a clean bill of health. Rather, it suggests that problems aren’t directly caused by fracking, a process in which water, sand, and chemicals are pumped into wells to break up deep layers of shale and release natural gas. Instead, the report concludes, contamination tends to happen closer to the surface when gas and drilling fluid escapes from poorly lined wells or storage ponds.

Mixed Verdict on Fracking – ScienceNOW

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On 28 October, China’s State Council unveiled a $5.5 billion initiative over 10 years to prevent and treat groundwater contamination. The plan will bolster monitoring and push development of groundwater cleanup technologies. The project is long overdue, hydrologists say. Water is scarce in China, which ekes by with only one-quarter of the global average for water per capita. Roughly 70% of Chinese get their drinking water from underground-and the economic boom of the past few decades has tainted much of that supply, hydrologists say. Disasters like the petrochemical plant explosions in 2005 that spilled 100 tons of benzene and other chemicals into the Songhua River near the Russian border have exacerbated China’s woes.

DOI:  http://dx.doi.org/10.1126/science.334.6057.745

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1. Tainted nuke plant water reaches major NJ aquifer
2. Global depletion of groundwater resources

Secondary treated wastewater was infiltrated through a 9 m-thick calcareous vadose zone during a 39 month managed aquifer recharge (MAR) field trial to determine potential improvements in the recycled water quality. The water quality improvements of the recycled water were based on changes in the chemistry and microbiology of (i) the recycled water prior to infiltration relative to (ii) groundwater immediately down-gradient from the infiltration gallery. Changes in the average concentrations of several constituents in the recycled water were identified with reductions of 30% for phosphorous, 66% for fluoride, 62% for iron and 51% for total organic carbon when the secondary treated wastewater was infiltrated at an applied rate of 17.5 L per minute with a residence time of approximately four days in the vadose zone and less than two days in the aquifer. Reductions were also noted for oxazepam and temazepam among the pharmaceuticals tested and for a range of microbial pathogens, but reductions were harder to quantify as their magnitudes varied over time. Total nitrogen and carbamazepine persisted in groundwater down-gradient from the infiltration galleries. Infiltration does potentially offer a range of water quality improvements over direct injection to the water table without passage through the unsaturated zone; however, additional treatment options for the non-potable water may still need to be considered, depending on the receiving environment or the end use of the recovered water.

doi:10.1016/j.watres.2011.08.058

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2. Quantification of pathogenic microorganisms and microbial indicators in three wastewater reclamation and managed aquifer recharge facilities in Europe

Sewage-contaminated shallow groundwater is a potential cause of beach closures and water quality impairment in marine coastal communities. In this study we set out to evaluate the feasibility of several strategies for disinfecting sewage-contaminated shallow groundwater before it reaches the coastline. The disinfection rates of Escherichia coli (EC) and enterococci bacteria (ENT) were measured in mixtures of raw sewage and brackish shallow groundwater collected from a coastal community in southern California. Different disinfection strategies were explored, ranging from benign (aeration alone, and aeration with addition of brine) to aggressive (chemical disinfectants peracetic acid (PAA) or peroxymonosulfate (Oxone)). Aeration alone and aeration with brine did not significantly reduce the concentration of EC and ENT after 6 h of exposure, while 4–5 mg L−1 of PAA or Oxone achieved >3 log reduction after 15 min of exposure. Oxone disinfection was more rapid at higher salinities, most likely due to the formation of secondary oxidants (e.g., bromine and chlorine) that make this disinfectant inappropriate for marine applications. Using a Lagrangian modeling framework, we identify several factors that could influence the performance of in-situ disinfection with PAA, including the potential for bacterial regrowth, and the non-linear dependence of disinfection rate upon the residence time of water in the shallow groundwater. The data and analysis presented in this paper provide a framework for evaluating the feasibility of in-situ disinfection of shallow groundwater, and elucidate several topics that warrant further investigation.

doi:10.1016/j.watres.2011.08.020

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1. Removal of petroleum hydrocarbons from contaminated groundwater using an electrocoagulation process: Batch and continuous experiments
2. Nitrate leaching to shallow groundwater systems from agricultural fields with different management practices

Removal of water from terrestrial subsurface storage is a natural consequence of groundwater withdrawals, but global depletion is not well characterized. Cumulative groundwater depletion represents a transfer of mass from land to the oceans that contributes to sea-level rise. Depletion is directly calculated using calibrated groundwater models, analytical approaches, or volumetric budget analyses for multiple aquifer systems. Estimated global groundwater depletion during 1900–2008 totals ∼4,500 km3, equivalent to a sea-level rise of 12.6 mm (>6% of the total). Furthermore, the rate of groundwater depletion has increased markedly since about 1950, with maximum rates occurring during the most recent period (2000–2008), when it averaged ∼145 km3/yr (equivalent to 0.40 mm/yr of sea-level rise, or 13% of the reported rate of 3.1 mm/yr during this recent period).

doi: http://dx.doi.org/10.1029/2011GL048604

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1. Global depletion of groundwater resources
2. Accelerated Melting Of Continental Icepacks Is Major Reason For Rise In Sea Level Between 2003 And 2008