The Environmental Protection Agency (EPA) provides access to information on a variety of topics related to the environment and strives to inform citizens of health risks. The EPA also has an extensive library network that consists of 26 libraries throughout the United States, which provide access to a plethora of information to EPA employees, scientists, and researchers. The EPA implemented a reorganization project to digitize their materials so they would be more accessible to a wider range of users, but this plan was drastically accelerated when the EPA was threatened with a budget cut. It chose to close and reduce the hours and services of some of their libraries. As a result, the agency was accused of denying users the “right to know” by making information unavailable, not providing an adequate strategic plan, and discarding vital materials. This case study explores the background of the digitization project, the practices implemented, and the critiques of the project.

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The Environmental Protection Agency

Ozonation of drinking water: part I. Oxidation kinetics and product formation.

 Many atmospheric chemicals occur in the gas phase as well as in liquid cloud droplets and aerosol particles Therefore, it is necessary to understand the distribution between the phases According to Henry's law, the equilibrium ratio between the abundances in the gas phase and in the aqueous phase is constant for a dilute solution Henry's law constants of trace gases of potential importance in environmental chemistry have been collected and converted into a uniform format The compilation contains 17 350 values of Henry's law constants for 4632 species, collected from 689 references It is also available at http://wwwhenrys-laworg 

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Compilation of Henry's law constants (version 4.0) for water as solvent

The rapid rise of shale gas development through horizontal drilling and high volume hydraulic fracturing has expanded the extraction of hydrocarbon resources in the U.S. The rise of shale gas development has triggered an intense public debate regarding the potential environmental and human health effects from hydraulic fracturing. This paper provides a critical review of the potential risks that shale gas operations pose to water resources, with an emphasis on case studies mostly from the U.S. Four potential risks for water resources are identified: (1) the contamination of shallow aquifers with fugitive hydrocarbon gases (i.e., stray gas contamination), which can also potentially lead to the salinization of shallow groundwater through leaking natural gas wells and subsurface flow; (2) the contamination of surface water and shallow groundwater from spills, leaks, and/or the disposal of inadequately treated shale gas wastewater; (3) the accumulation of toxic and radioactive elements in soil or stream sediments near disposal or spill sites; and (4) the overextraction of water resources for high-volume hydraulic fracturing that could induce water shortages or conflicts with other water users, particularly in water-scarce areas. Analysis of published data (through January 2014) reveals evidence for stray gas contamination, surface water impacts in areas of intensive shale gas development, and the accumulation of radium isotopes in some disposal and spill sites. The direct contamination of shallow groundwater from hydraulic fracturing fluids and deep formation waters by hydraulic fracturing itself, however, remains controversial.

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A Critical Review of the Risks to Water Resources from Unconventional Shale Gas Development and Hydraulic Fracturing in the United States

Review of risk from potential emerging contaminants in UK groundwater.

Four chlorinated solvents-methylene chloride, perchloroethene (PCE), 1,1,1-trichloroethane, and trichloroethene (TCE)-were analyzed in samples of groundwater taken throughout the conterminous United States by the U.S. Geological Survey. The samples were collected between 1985 and 2002 from more than 5,000 wells. Of 55 volatile organic compounds (VOCs) analyzed in groundwater samples, solvents were among the most frequently detected. Mixtures of solvents in groundwater were common and may be the result of common usage of solvents or degradation of one solvent to another. Relative to other VOCs with Maximum Contaminant Levels (MCLs), PCE and TCE ranked high in terms of the frequencies of concentrations greater than or near MCLs. The probability of occurrence of solvents in groundwater was associated with dissolved oxygen content of groundwater, sources such as urban land use and population density, and hydraulic properties of the aquifer. The results reinforce the importance of understanding the redox conditions of aquifers and the hydraulic properties of the saturated and vadose zones in determining the intrinsic susceptibility of groundwater to contamination by solvents. The results also reinforce the importance of controlling sources of solvents to groundwater.

Chlorinated solvents in groundwater of the United States.

The 1990 Clean Air Act Amendments require fuel oxygenates to be added to gasoline used in some metropolitan areas to reduce atmospheric concentrations of carbon monoxide or ozone. Methyl tert-butyl ether (MTBE) is the most commonly used fuel oxygenate and is a relatively new gasoline additive. Nevertheless, out of 60 volatile organic chemicals analyzed, MTBE was the second most frequently detected chemical in samples of shallow ambient groundwater from urban areas that were collected during 1993-1994 as part of the U.S. Geological Survey's National Water-Quality Assessment program. Samples were collected from five drinking water wells, 12 springs, and 193 monitoring wells in urban areas. No MTBE was detected in drinking water wells. At a reporting level of 0.2 μg/L, MTBE was detected most frequently in shallow groundwater from urban areas (27% of 210 wells and springs sampled in eight areas) as compared to shallow groundwater from agricultural areas (1.3% of 549 wells sampled in 21 areas) or deeper groundwater from major aquifers (1.0% of 412 wells sampled in nine areas). Only 3% of the shallow wells sampled in urban areas had concentrations of MTBE that exceed 20 μg/L, which is the estimated lower limit of the United States Environmental Protection Agency draft drinking water health advisory. Because MTBE is persistent and mobile in groundwater, it can move from shallow to deeper aquifers with time. In shallow urban groundwater, MTBE generally was not found with benzene, toluene, ethylbenzene, or xylene (BTEX) compounds, which commonly are associated with gasoline spills. This disassociation causes uncertainty as to the source of MTBE. Possible sources of MTBE in groundwater include point sources, such as leaking storage tanks, and non-point sources, such as recharge of precipitation and stormwater runoff.

Preliminary assessment of the occurrence and possible sources of MTBE in groundwater in the United States, 1993-1994

RICHARD JOHNSON, JAMES PANKOW, DAVID BENDER, CURTIS PRICE, AND JOHN ZOGORSKI T he increasing frequency of detection of the widely used gasoline additive methyl tertbutyl ether (MTBE) in both groundand surface waters is receiving much attention from the media, environmental scientists, state environmental agencies, and federal agencies. At the national level, the September 15,1999, Report of the Blue Ribbon Panel on Oxygenates in Gasoline (i) )tates that between 5 and 10% of community drinking water supplies in high MTBE use areas show at least detectable concentrations of MTBE, and about 1% of those systems are characterized by levels of this compound that are above 20 pg/L. In Maine, a desire to determine the extent of MTBE contamination led to a 1998 study (2) that revealed that this compound is found at levels above 0.1 pg/L in 16% of 951 randomly selected household wells and in 16% of the 793 community water systems tested in that state (37 wells were not tested). The study also suggested that between 1400 and 5200 household wells may have levels above 35 pg/L, although no community water supplies were found to be above that concentration. For comparison, Maryland, New Hampshire, New York, and California have set MTBE remediation \"action levels\" at or below 20 pg/L, and EPA has set its advisory level for taste and odor at 20-40 pg/L (3). In California, concern regarding MTBE reached statewide levels in 1996 when seven wells supplying 50% of the water for the city of Santa Monica were removed from service because of MTBE at concentrations as high as 600 pg/L. For the city's Charnock well field, an initial review of known and suspected petroleum spill sites identified about 10 potential sources that lay within 1 km of the well field, lay above the hydrologic unit accessed by the well field, and were created after MTBE use began in the state (4). At the time that contamination of die wells was discovered, pumping of the Charnock well field was at 5 million gallons/day (mgd). This aggressive pumping was approximately twice the total natural flow of water moving into the aquifer. Despite the presence of a protective aquitard in the system, the pumping had dewatered a significant portion of the upper aquifer, caused water to flow toward the well field from all directions, and had greatly increased the likelihood that the community water supply (CWS) wells in Santa Monica would in fact become contaminated by one or more persistent organic pollutants such as MTBE. Besides leaking underground fuel tanks (LUFTs) and leaking pipelines, other sources of MTBE in groundwater include tank overfilling and faulty construction at gas stations, spillage from vehicle accidents, and homeowner releases. In Maine, it is pos-

Peer Reviewed: MTBE-To What Extent Will Past Releases Contaminate Community Water Supply Wells?

As part of the National Water-Quality Assessment Program of the US Geological Survey, an assessment of 60 volatile organic compounds (VOCs) in untreated, ambient groundwater of the conterminous US was conducted based on samples collected from 2,948 wells between 1985 and 1995. The samples represent urban and rural areas and drinking-water and nondrinking-water wells. A reporting level of 0.2 {micro}g/L was used with the exception of 1,2-dibromo-3-chloropropane, which had a reporting level of 1.0 {micro}g/L. Because ambient groundwater was targeted, areas of known point-source contamination were excluded from this assessment. VOC concentrations generally were low; 56% of the concentrations were less than 1 {micro}g/L. In urban areas, 47% of the sampled wells had at least one VOC, and 29% had two or more VOCs; furthermore, US Environmental Protection Agency drinking-water criteria were exceeded in 6.4% of all sampled wells and in 2.5% of the sampled drinking-water wells. In rural areas, 14% of the sampled wells had at least one VOC; furthermore, drinking-water criteria were exceeded in 1.5% of all sampled wells and in 1.3% of the sampled drinking-water wells. Solvent compounds and the fuel oxygenate methyl tert-butyl ether were among the most frequently detected VOCs in urban and rural areas.

http://lib3.dss.go.th/fulltext/Journal/Environ%20Sci.%20Technology1998-2001/1999/23,1999%20vol.33,p.4175-4187.pdf

Volatile Organic Compounds in Untreated Ambient Groundwater of the United States, 1985-1995

A review of pertinent equations and current research indicates that when gasoline oxygenated with methyl tert-butyl ether (MTBE) comes into contact with water, large amounts of MTBE can dissolve. At 25°C, the water solubility of MTBE is about 5,000 mg/L for a gasoline that is 10% MTBE by weight, whereas for a nonoxygenated gasoline, the total hydrocarbon solubility in water is typically about 120 mg/L. Methyl tert-butyl ether sorbs only weakly to subsurface solids; therefore, sorption does not substantially retard the transport of MTBE by ground water. In addition, MTBE generally resists biodegradation in ground water. The half-life of MTBE in the atmosphere can be as short as 3 d in a regional airshed. In the air, MTBE tends to partition into atmospheric water, including precipitation. However, the washing out of gas-phase MTBE by precipitation will not, by itself, greatly alter the gas-phase concentration of the compound in the air. The partitioning of MTBE to precipitation can nevertheless result in concentrations as high as 3 μg/L or more in urban precipitation and can contribute to the presence of MTBE in surface and ground water.

John S. Zogorski

Papers

Chlorinated solvents in groundwater of the United States.

Preliminary assessment of the occurrence and possible sources of MTBE in groundwater in the United States, 1993-1994

Peer Reviewed: MTBE-To What Extent Will Past Releases Contaminate Community Water Supply Wells?

Volatile Organic Compounds in Untreated Ambient Groundwater of the United States, 1985-1995

Review of the environmental behavior and fate of methyl tert-butyl ether