Analysis of dissolved light hydrocarbon gas concentrations (primarily methane and ethane) in water supply wells is commonly used to establish conditions before after drilling areas shale oil extraction. Several methods are currently collect samples for analysis from wells; however, the reliability results obtained these has not been quantified. This study compares ethane measured groundwater collected using three sampling employed pre- post-drill programs Appalachian Basin. These include an...

Abstract The recent boom in shale gas development the Marcellus Shale has increased interest methods to distinguish between naturally occurring methane groundwater and stray associated with drilling production operations. This study evaluates relationship natural occurrence three principal environmental factors (groundwater redox state, water type, topography) using two pre‐drill datasets of 132 samples from western Pennsylvania, Ohio, West Virginia 1417 northeastern Pennsylvania. Higher...

The use of measured volatile organic chemical (VOC) concentrations in indoor air to evaluate vapor intrusion is complicated by (i) sources the same VOCs and (ii) temporal variability intrusion. This study evaluated efficacy utilizing induced negative positive building pressure conditions during a investigation program provide an improved understanding potential for Pressure control was achieved five six buildings where tested. For these buildings, differences were sufficient flow soil gas...

At buildings with potential for vapor intrusion of volatile organic chemicals (VOCs) from the subsurface, ability to accurately distinguish between and indoor sources VOCs is needed support accurate efficient investigations. We have developed a method application compound-specific stable isotope analysis (CSIA) this purpose that uses an adsorbent sampler obtain sufficient sample mass air analysis. Application five residences near Hill Air Force Base in Utah indicates subsurface...

Abstract A landmark National Research Council report from 2013 emphasized the need to transition passive or less resource‐intensive management strategies like monitored natural attenuation (MNA) at sites where pump‐and‐treat and active remedies are providing diminishing returns. While this is now more than a decade old, process for implementing type of assessment still not well understood by practitioners. The objective study was help address gap developing software tool (TA 2 Tool) that...

In this study, the headspace vapor compositions of 37 unreleased petroleum products and field-collected non-aqueous phase liquid (NAPL) samples including crude oil, gasoline, diesel, kerosene, jet fuel, naphtha, tar, lubricating field NAPL were measured using an innovative high-resolution analytical method. Gasoline some oils are highly volatile while fuel have much lower volatility. gasoline light distillates, benzene, toluene, ethylbenzene, xylenes (BTEX) constitute majority aromatic...

Abstract While petroleum plumes and even many chlorinated solvent stabilize in size on a time scale of few to several years, perfluoroalkyl polyfluoroalkyl substances, particularly acids (PFAAs), groundwater pose specific challenge for site investigation remediation due their recalcitrance, which creates potential much longer‐term plume expansion. Understanding the stability condition (i.e., is expanding, stable, or shrinking) essential management remedy selection, but resolving this trend...

Our understanding of vapor intrusion has evolved rapidly since the discovery first high profile sites in late 1990s and early 2000s. Research efforts field investigations have improved our processes including role preferential pathways natural barriers to intrusion. This review paper addresses recent developments regulatory framework conceptual model for In addition, a number innovative investigation methods are discussed.

Abstract Quantifying the overall progress in remediation of contaminated groundwater has been a significant challenge. We utilized GeoTracker database to evaluate from 2001 2011 at over 12,000 sites California with groundwater. This paper presents an analysis analytical results 2.1 million samples representing least $100 laboratory costs. Overall, evaluation monitoring data shows large decrease concentrations gasoline constituents. For benzene, half showed concentration 85% or more. methyl...

Distinguishing between vapor intrusion and indoor sources of volatile organic compounds (VOCs) is a significant challenge in conventional assessments. For this research project, the authors developed step-by-step protocol to streamline building-specific investigations by using on-site gas chromatography/mass spectrometry (GC/MS) analysis building pressure manipulation determine source VOCs air during 1-day field investigation. Protocol validation included implementation industrial buildings...

US EPA and many state regulatory agency guidance documents recommend below-foundation vapor sampling as a key element of site investigations to determine if migration from underlying soil into buildings is completed exposure pathway (USEPA, 2002 (U.S. Environmental Protection Agency). Draft Guidance for Evaluating the Vapor Intrusion Indoor Air Pathway Groundwater Soils (Subsurface Guidance). November2002. [Google Scholar]; WIDHFS, 2003 WIDHFS (Wisconsin Department Health Family Services)....

Long-term groundwater monitoring data for 48 retail gasoline sites were analyzed to define the characteristics of affected plumes containing benzene, methyl tert-butyl ether (MTBE), and alcohol (TBA). Results this analysis used determine observed range statistical distribution current plume lengths, stability conditions, constituent concentration trends attenuation rates, remediation timeframe population sites. The goal evaluation was characterize behavior as across a variety hydrogeologic...

Vapor intrusion is associated with subsurface sources of both chlorinated VOCs and petroleum VOCs; however, vapor has been reported to occur under a narrower range hydrogeologic settings. Research conducted over the last several years including field studies, evaluation large datasets, modeling provided an improved understanding differences in VOCs. When oxygen present vadose zone, aerobic biodegradation typically results rapid attenuation diffusing upwards from deeper sources. At many...

Abstract A large number of states have issued guidance addressing the vapor intrusion pathway making it difficult to keep up with various policies and requirements. We compiled reviewed from 35 states, half which documents within last three years. comparison among shows reasonable consistency in some areas—for example, 20 23 that provide an exclusion distance for subsurface sources chlorinated volatile organic compounds (VOCs) use a 100 feet. However, more commonly, policy decisions vary...

The reduction of the tetrazolium salt 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl bromide (MTT) to a blue formazan product is widely used for assaying cell survival and proliferation. reaction catalyzed by dehydrogenases localized in mitochondria viable cells. As part an analysis ability glutathione S-transferase (GST) enzymes protect cells from electrophilic compounds, we found extremely high background levels produced that overexpressed mouse GST P1-1 enzyme. Further with purified confirmed...

Abstract To further our understanding of the groundwater-to-indoor-air exposure pathway, a database 270 paired groundwater and indoor air measurements volatile organic compounds (VOCs) from 31 sites has been compiled analyzed. Using regression analyses, these data have analyzed to (1) detect evidence impacts dissolved petroleum hydrocarbons or chlorinated solvents in underlying groundwater, (2) estimate true attenuation factor for volatilization air, (3) assess utility popular transport...

This paper explores the application of natural resource assessment and valuation procedures as a tool for developing groundwater remediation strategies that achieve objectives health environmental protection, in balance with considerations economic viability conservation resources. The process, applied under U.S. international guidelines, entails characterization contamination terms pre-existing beneficial services impacted resource, loss these caused by contamination, measures associated...