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Geology topics

M. J. Focazio

Publications and source records attributed to M. J. Focazio.

15 recordsLinked to original sources
USGS2011

Effects of human-induced alteration of groundwater flow on concentrations of naturally-occurring trace elements at water-supply wells

The effects of human-induced alteration of groundwater flow patterns on concentrations of naturally-occurring trace elements were examined in five hydrologically distinct aquifer systems in the USA. Although naturally occurring, these trace elements can exceed concentrations that are considered harmful to human health. The results show that pumping-induced hydraulic gradient changes and artificial connection of aquifers by well screens can mix chemically distinct groundwater. Chemical reactions between these mixed groundwaters and solid aquifer materials can result in the mobilization of trace elements such as U, As and Ra, with subsequent transport to water-supply wells. For example, in the High Plains aquifer near York, Nebraska, mixing of shallow, oxygenated, lower-pH water from an unconfined aquifer with deeper, confined, anoxic, higher-pH water is facilitated by wells screened across both aquifers. The resulting higher-O2, lower-pH mixed groundwater facilitated the mobilization of U from solid aquifer materials, and dissolved U concentrations were observed to increase significantly in nearby supply wells. Similar instances of trace element mobilization due to human-induced mixing of groundwaters were documented in: (1) the Floridan aquifer system near Tampa, Florida (As and U), (2) Paleozoic sedimentary aquifers in eastern Wisconsin (As), (3) the basin-fill aquifer underlying the California Central Valley near Modesto (U), and (4) Coastal Plain aquifers of New Jersey (Ra). Adverse water-quality impacts attributed to human activities are commonly assumed to be related solely to the release of the various anthropogenic contaminants to the environment. The results show that human activities including various land uses, well drilling, and pumping rates and volumes can adversely impact the quality of water in supply wells, when associated with naturally-occurring trace elements in aquifer materials. This occurs by causing subtle but significant changes in geochemistry and associated trace element mobilization as well as enhancing advective transport processes.

Applied Geochemistry↗
USGS2008

A national reconnaissance for pharmaceuticals and other organic wastewater contaminants in the United States - II) Untreated drinking water sources

Numerous studies have shown that a variety of manufactured and natural organic compounds such as pharmaceuticals, steroids, surfactants, flame retardants, fragrances, plasticizers and other chemicals often associated with wastewaters have been detected in the vicinity of municipal wastewater discharges and livestock agricultural facilities. To provide new data and insights about the environmental presence of some of these chemicals in untreated sources of drinking water in the United States targeted sites were sampled and analyzed for 100 analytes with sub-parts per billion detection capabilities. The sites included 25 ground- and 49 surface-water sources of drinking water serving populations ranging from one family to over 8 million people. Sixty-three of the 100 targeted chemicals were detected in at least one water sample. Interestingly, in spite of the low detection levels 60% of the 36 pharmaceuticals (including prescription drugs and antibiotics) analyzed were not detected in any water sample. The five most frequently detected chemicals targeted in surface water were: cholesterol (59%, natural sterol), metolachlor (53%, herbicide), cotinine (51%, nicotine metabolite), β-sitosterol (37%, natural plant sterol), and 1,7-dimethylxanthine (27%, caffeine metabolite); and in ground water: tetrachloroethylene (24%, solvent), carbamazepine (20%, pharmaceutical), bisphenol-A (20%, plasticizer), 1,7-dimethylxanthine (16%, caffeine metabolite), and tri (2-chloroethyl) phosphate (12%, fire retardant). A median of 4 compounds were detected per site indicating that the targeted chemicals generally occur in mixtures (commonly near detection levels) in the environment and likely originate from a variety of animal and human uses and waste sources. These data will help prioritize and determine the need, if any, for future occurrence, fate and transport, and health-effects research for subsets of these chemicals and their degradates most likely to be found in water resources used for drinking water in the United States.

Science of the Total Environment↗
USGS2004

Historical trends in occurrence and atmospheric inputs of halogenated volatile organic compounds in untreated ground water used as a source of drinking water

Analyses of samples of untreated ground water from 413 community-, non-community- (such as restaurants), and domestic-supply wells throughout the US were used to determine the frequency of detection of halogenated volatile organic compounds (VOCs) in drinking-water sources. The VOC data were compiled from archived chromatograms of samples analyzed originally for chlorofluorocarbons (CFCs) by purge-and-trap gas chromatography with an electron-capture detector (GC-ECD). Concentrations of the VOCs could not be ascertained because standards were not routinely analyzed for VOCs other than trichloromonofluoromethane (CFC-11), dichlorodifluoromethane (CFC-12) and 1,1,2-trichloro-1,2,2-trifluoroethane (CFC-113). Nevertheless, the peak areas associated with the elution times of other VOCs on the chromatograms can be classified qualitatively to assess concentrations at a detection limit on the order of parts per quadrillion. Three or more VOCs were detected in 100% (percent) of the chromatograms, and 77.2% of the samples contained 10 or more VOCs. The maximum number of VOCs detected in any sample was 24. Modeled ground-water residence times, determined from concentrations of CFC-12, were used to assess historical trends in the cumulative occurrence of all VOCs detected in this analysis, as well as the occurrence of individual VOCs, such as CFC-11, carbon tetrachloride (CCl 4 ), chloroform and tetrachloroethene (PCE). The detection frequency for all of the VOCs detected has remained relatively constant from approximately 1940 to 2000; however, the magnitude of the peak areas on the chromatograms for the VOCs in the water samples has increased from 1940 to 2000. For CFC-11, CCl 4 , chloroform and PCE, small peaks decrease from 1940 to 2000, and large peaks increase from 1940 to 2000. The increase in peak areas on the chromatograms from analyses of more recently recharged water is consistent with reported increases in atmospheric concentrations of the VOCs. Approximately 44% and 6.7% of the CCl 4 and PCE detections, respectively, in pre-1940 water, and 68% and 62% of the CCl 4 and PCE detections, respectively, in water recharged in 2000 exceed solubility equilibrium with average atmospheric concentrations. These exceedences can be attributed to local atmospheric enrichment or direct contaminant input to ground-water flow systems. The detection of VOCs at concentrations indicative of atmospheric sources in 100% of the samples indicates that untreated drinking water from ground-water sources in the US recharged within the past 60 years has been affected by anthropogenic activity. Additional inputs from a variety of sources such as spills, underground injections and leaking landfills or storage tanks increasingly are providing additional sources of contamination to ground water used as drinking-water sources.

Science of the Total Environment↗
USGS2004

Occurrence of human pharmaceuticals in water resources of the United States: A review

The widespread environmental presence of some pharmaceuticals and other organic wastewater compounds has been documented globally (e.g. Buser et al. 1998; Ternes 1998; Stumpf et al.1999; Heberer et al. 2001; Kümmerer 2001; Ternes et al. 2001; Scheytt et al. 2001; Golet et al. 2002; Kolpin et al. 2002; Boyd et al. 2003; Metcalf et al. 2003). Recently, there have been several literature reviews and summary studies of the occurrence, fate, transport, and treatment of targeted human pharmaceuticals in wastewater effluent and associated environmental waters across the globe (e.g. Daughton and Ternes 1999; Sedlak et al. 2000; Suter and Giger 2000; Daughton and Jones-Lepp 2001; Jones et al. 2001; Heberer 2002; and Drewes et al. 2002). The occurrence of pharmaceutical compounds in water resources is explained by their ubiquitous use, excretion of large percentages of the mass consumed, and incomplete removal during wastewater treatment (Stumpf et al.1999). The recent increase in detection of trace concentrations (typically less than a part per billion) of pharmaceuticals in water resources across the globe reflects improvements in laboratory analytical methods (Sedlak et al. 2000) and the associated increases in field surveys. The detection of pharmaceutical compounds in large rivers in Europe and in the North Sea (Buser et al. 1998; Ternes 1998; Stumpf et al. 1999) highlighted the fact that highly soluble, trace organic compounds, such as pharmaceuticals, may escape removal in wastewater treatment, and the mixing and concentration of wastewaters through conventional wastewater treatment processes could provide a means of delivering these chemicals to environmental waters in a manner that would contaminate water resources on a large scale at trace levels (Richardson and Bowron 1985). In the United States, some of the first detections of a limited number of pharmaceutically active compounds or their transformation products were found in waters associated with landfill leachates or sewage effluent (Tabak and Bunch 1970; Garrison et al. 1976; Hignite and Azarnoff 1977; Bouwer et al. 1982; Eckel et al. 1991) decades ago. At the time of these studies, other industrial contaminants were the focus of regulatory and scientific interest; therefore, further studies on the environmental occurrence and transport of pharmaceutical compounds were rare.

Book chapter↗
USGS2000

Contaminants and drinking-water sources in 2001; recent findings of the U. S. Geological Survey

As the Nation's principal earth-science agency, the U.S. Geological Survey (USGS) studies numerous issues related to contamination of drinking-water sources. The work includes monitoring to determine the spatial and temporal distribution of contaminants; research to determine sources, transport, transformations, and fate of contaminants, and assessments of vulnerability. Much of the work is conducted in cooperation with the U.S. Environmental Protection Agency and other Federal, State, Tribal, and local governments, to help provide a scientific basis for resource management and regulation. Examples of recent results are presented for two broad categories of drinking-water projects: occurrence studies, and source-water assessments.

Open-File Report↗
USGS1995

Selected characteristics of stormflow and base flow affected by land use and cover in the Chickahominy River basin, Virginia, 1989-91

The Chickahominy River is the principal source of raw-water supply managed by the Department of Public Utilities, City of Newport News. Selected characteristics of stormflow and base flow, and major land use and cover factors that affect the distribution, movement, and quality of water of the nontidal Chickahominy River were monitored at three continuous-record stations and two partial-record stations. The stations are located in areas that drain urban, residential, and rural land uses.

Water-Resources Investigations Report↗
USGS1994

Potentiometric surface of the Brightseat-upper Potomac Aquifer in Virginia, 1993

Ground-water level measurements from 30 wells in the Brightseat-upper Potomac aquifer in the Coastal Plain Physiographic Province of Virginia in 1993 were used to prepare a map of the potentiometric surface of the aquifer. The map shows the potentiometric surface of the Brightseat-upper Potomac aquifer indicating a regional trend toward the Chesapeake Bay and Atlantic Ocean. The potentiometric-surface data indicate that cones of depression are apparent around West Point and in southeastern Isle of Wight County near Franklin, Virginia. The highest ground-water-level measurement was 4 feet above sea level in northern Accomack County, and the lowest ground-water-level measurement was 117 feet below sea level in Franklin, Virginia.

Virginia↗
USGS1994

Potentiometric surface of the middle Potomac Aquifer in Virginia, 1993

Ground-water level measurements from 50 wells in the middle Potomac aquifer in the Coastal Plain Physiographic Province of Virginia in 1993 were used to prepare a map of the potentiometric surface of the aquifer. The map shows the potentiometric surface of the middle Potomac aquifer sharply declining eastward from nearly 100 feet above sear level near the western boundary of the aquifer to 20 feet below sea level, and continues declining gradually toward the Chesapeake Bay and Atlantic Ocean. A cone of depression is apparent around well fields in Franklin, Virginia. The potentiometric surface also appears to be affected by pumping in the area of Henrico County and Hanover County, Virginia. The highest ground-water-level measurement was 89 feet above sea level in Chesterfield County near Richmond, and the lowest ground-water-level measurement was 179 feet below sea level in southeastern Isle of Wight County, Virginia.

Virginia↗
USGS1994

Potentiometric surface of the lower Potomac Aquifer in Virginia, 1993

Ground-water level measurements from 17 wells in the lower Potomac aquifer in the Coastal Plain Physiographic Province of Virginia in 1993 were used to prepare a map of the potentiometric surface of the aquifer. The map shows the potentiometric surface of the lower Potomac aquifer indicating a regional trend toward the Chesapeake Bay and Atlantic Ocean. The potentiometric-surface data indicate that there are two cones of depression, one around well fields in Henrico County and the other around large well fields in Isle of Wight County and Franklin, Virginia. The highest ground-water-level measurement was 47 feet above sea level in southeast Southampton County, and the lowest ground-water-level measurement was 161 feet below sea level in the southeast area of Isle of Wight County near Franklin, Virginia.

Virginia↗
USGS1993

Estimating net drawdown resulting from episodic withdrawals at six well fields in the coastal plain physiographic province of Virginia

The groundwater-flow system of the Virginia Coastal Plain consists of areally extensive and interconnected aquifers. Large, regionally coalescing cones of depression that are caused by large withdrawals of water are found in these aquifers. Local groundwater systems are affected by regional pumping, because of the interactions within the system of aquifers. Accordingly, these local systems are affected by regional groundwater flow and by spatial and temporal differences in withdrawals by various users. A geographic- information system was used to refine a regional groundwater-flow model around selected withdrawal centers. A method was developed in which drawdown maps that were simulated by the regional groundwater-flow model and the principle of superposition could be used to estimate drawdown at local sites. The method was applied to create drawdown maps in the Brightseat/Upper Potomac Aquifer for periods of 3, 6, 9, and 12 months for Chesapeake, Newport News, Norfolk, Portsmouth, Suffolk, and Virginia Beach, Virginia. Withdrawal rates were supplied by the individual localities and remained constant for each simulation period. This provides an efficient method by which the individual local groundwater users can determine the amount of drawdown produced by their wells in a groundwater system that is a water source for multiple users and that is affected by regional-flow systems.

Water-Resources Investigations Report↗