David L. Naftz's research while affiliated with United States Geological Survey and other places

Publications (80)

Article
Growing worldwide concern over uranium contamination of groundwater resources has placed an emphasis on understanding uranium transport dynamics and potential toxicity in groundwater-surface water systems. In this study, we utilized novel in-situ sampling methods to establish the location and magnitude of contaminated groundwater entry into a recei...
Article
Radon (Rnair) was monitored in open air in publicly accessible areas surrounding the Pinenut uranium (U) mine during mining and reclamation activities in 2015–16 to address concerns about mining related effects to areas surrounding Grand Canyon National Park (GCNP) in Arizona, USA. During July 2015, Rnair concentrations associated with the ore stor...
Article
Full-text available
The enrichment factor (EF) is a widely used metric for determining how much the presence of an element in a sampling media has increased relative to average natural abundance because of human activity. Calculation of an EF requires the selection of both a background composition and a reference element, choices that can strongly influence the result...
Article
Full-text available
Nitrogen inputs to Great Salt Lake (GSL), located in the western USA, were quantified relative to the resident nitrogen mass in order to better determine numeric nutrient criteria that may be considered at some point in the future. Total dissolved nitrogen inputs from four surface-water sources entering GSL were modeled during the 5-year study peri...
Article
Surface water and biota from Great Salt Lake (GSL) contain some of the highest documented concentrations of total mercury (THg) and methylmercury (MeHg) in the United States. In order to identify potential biological sources of MeHg and controls on its production in this ecosystem, THg and MeHg concentrations, rates of Hg(II)-methylation and MeHg d...
Article
Full-text available
The processes that affect water chemistry as the water flows from recharge areas through breccia-pipe uranium deposits in the Grand Canyon region of the southwestern United States are not well understood. Pigeon Spring had elevated uranium in 1982 (44 μg/L), compared to other perched springs (2.7–18 μg/L), prior to mining operations at the nearby P...
Article
During 2012, approximately 404,000 ha of Federal Land in northern Arizona was withdrawn from consideration of mineral extraction for a 20-year period to protect the Grand Canyon watershed from potentially adverse effects of U mineral exploration and development. The development, operation, and reclamation of the Canyon Mine during the withdrawal pe...
Article
Density stratification in saline and hypersaline water bodies from throughout the world can have large impacts on the internal cycling and loading of salinity, nutrients, and trace elements. High temporal resolution hydroacoustic and physical/chemical data were collected at two sites in Great Salt Lake (GSL), a saline lake in the western USA, to un...
Article
Geophysical and geochemical surveys were conducted to understand groundwater discharge to Great Salt Lake (GSL) and assess the potential significance of groundwater discharge as a source of selenium (Se). Continuous resistivity profiling (CRP) focusing below the sediment/water interface and fiber-optic distributed temperature sensing (FO-DTS) surve...
Article
Great Salt Lake is the largest hypersaline lake in the Western Hemisphere and the fourth largest terminal lake in the world (Figure 1). The open water and adjacent wetlands of the Great Salt Lake ecosystem support millions of migratory waterfowl and shorebirds from throughout the Western Hemisphere [Aldrich and Paul, 2002]. In addition, the area is...
Article
[1] Seepage at the sediment-water interface in several lakes, a large river, and an estuary exhibits substantial temporal variability when measured with temporal resolution of 1 min or less. Already substantial seepage rates changed by 7% and 16% in response to relatively small rain events at two lakes in the northeastern USA, but did not change in...
Technical Report
During August of 2008, 35 solid-phase samples were collected from abandoned uranium waste dumps, undisturbed geologic background sites, and adjacent streambeds in Browns Hole in southeastern Utah. The objectives of this sampling program were (1) to assess impacts on human health due to exposure to radium, uranium, and thorium during recreational ac...
Article
Full-text available
Great Salt Lake (GSL) is one of the largest and most saline lakes in the world. In order to accurately model limnological processes in GSL, hydrodynamic calculations require the precise estimation of water density (ρ) under a variety of environmental conditions. An equation of state was developed with water samples collected from GSL to estimate de...
Article
A 24-h field experiment was conducted during July 2008 at a wetland on the eastern shore of Great Salt Lake (GSL) to assess the diurnal cycling of methylmercury (MeHg). Dissolved (< 0.45 μm) MeHg showed a strong diurnal variation with consistently decreasing concentrations during daylight periods and increasing concentrations during non-daylight pe...
Data
Supporting data. Isotopic and anion data used in the study
Article
Full-text available
Great Salt Lake (Utah, USA) is one of the world's largest hypersaline lakes, supporting many of the western U.S.'s migratory waterbirds. This unique ecosystem is threatened, but it and other large hypersaline lakes are not well understood. The ecosystem consists of two weakly linked food webs: one phytoplankton-based, the other organic particle/ben...
Article
Full-text available
Ice-core samples from Upper Fremont Glacier (UFG), Wyoming, were used as proxy records for the chemical composition of atmospheric deposition. Results of analysis of the ice-core samples for stable isotopes of nitrogen (δ15N, ) and sulfur (δ34S, ), as well as and deposition rates from the late-1940s thru the early-1990s, were used to enhance and ex...
Article
Diel (24-h) changes in Se and As concentrations in a freshwater wetland pond bordering the Great Salt Lake (GSL) were examined. Selenium concentrations (filtered and unfiltered) changed on a diel basis, i.e., were depleted during early morning and enriched during daytime over August 17-18. During the May 24-25, 2006 and September 29-30 diel studies...
Article
Direct measurement of exchange between groundwater and surface water with the use of standard seepage meters involves integration of seepage rates over the duration of the measurement. Measurement duration usually depends on the seepage rate; very slow seepage requires measurement periods of hours to days and very fast seepage can require measureme...
Technical Report
Full-text available
During May, June, and July 2007, 58 solid-phase samples were collected from abandoned uranium mine waste dumps, background sites, and adjacent streambeds in Red, White, and Fry Canyons in southeastern Utah. The objectives of this sampling program were to (1) assess the nonpoint-source chemical loading potential to ephemeral and perennial drainage b...
Article
Development of effective remediation techniques for protecting existing drinking water supplies and for mitigating existing contamination problems requires evaluating both the contaminant sequestration processes and the secondary reactions affecting the long term stability of contaminant attenuation. Permeable reactive barriers (PRB) provide a mean...
Article
The characterization of trace elements in terms of their apportionment among dissolved, macromolecular, nano- and micro-particulate phases in the water column of the Great Salt Lake carries implications for the potential entry of toxins into the food web of the lake. Samples from the anoxic deep and oxic shallow brine layers of the lake were fracti...
Article
The Great Salt Lake (GSL) is a unique ecosystem in which trace element activity cannot be characterized by standard geochemical parameters due to the high salinity. Movement of selenium and other trace elements present in the lake bed sediments of GSL may occur due to periodic stratification displacement events or lake bed exposure. The water colum...
Article
The mass of Se deposited annually to sediment in the Great Salt Lake (GSL) was estimated to determine the significance of sedimentation as a permanent Se removal mechanism. Lake sediment cores were used to qualitatively delineate sedimentation regions (very high to very low), estimate mass accumulation rates (MARs) and determine sediment Se concent...
Article
A mass balance for Se in the south arm of the Great Salt Lake was developed for September 2006 to August 2007 of monitoring for Se loads and removal flows. The combined removal flows (sedimentation and volatilization) totaled to a geometric mean value of 2079 kg Se/yr, with the estimated low value being 1255 kg Se/yr, and an estimated high value of...
Article
The Great Salt Lake (GSL) of Utah, USA, is the largest saline lake in North America, and its brines are some of the most concentrated anywhere in the world. The lake occupies a closed basin system whose chemistry reflects solute inputs from the weathering of a diverse suite of rocks in its drainage basin. GSL is the remnant of a much larger lacustr...
Article
In response to increasing public concern regarding mercury (Hg) cycling in Great Salt Lake (GSL) ecosystem, a series of studies were initiated to differentiate between the mass of Hg from riverine versus atmospheric sources to GSL. Cumulative riverine Hg load to GSL during a 1 year time period (April 1, 2007 to March 31, 2008) was 6 kg, with almost...
Technical Report
Discharge and water-quality data collected from six streamflow-gaging stations were used in combination with the LOADEST software to provide an estimate of total (dissolved + particulate) selenium (Se) load to the south arm of Great Salt Lake (GSL) from May 2006 through March 2008. Total estimated Se load to GSL during this time period was 2,370 ki...
Article
The removal mechanisms that govern Se concentrations in the Great Salt Lake are unknown despite this terminal lake being an avian habitat of hemispheric importance. However, the volatilization flux of Se from the Great Salt Lake has not been previously measured due to challenges of analysis in this hypersaline environment This paper presents result...
Conference Paper
Permeable reactive barriers (PRBs) represent a viable tool for remediation of metal-contaminated groundwater associated with abandoned mine lands (AML) on private, State, and Federal properties. Because many AML sites throughout the world are in remote areas, low-maintenance remediation technologies, such as PRBs, are especially relevant to current...
Conference Paper
A uranium mill, located on the White Mesa in San Juan County, Utah, began operating in 1980 to extract yellowcake (U3O8) and vanadium from uranium ores. Potential air and ground-water exposure pathways of uranium and other metals to tribal members include (1) airborne dust from ore storage pads, from trucks delivering ore to the mill, and from the...
Article
a b s t r a c t Despite the ecological and economic importance of Great Salt Lake (GSL), little is known about the input and biogeochemical cycling of nutrients and trace elements in the lake. In response to increasing public concern regarding anthropogenic inputs to the GSL ecosys-tem, the US Geological Survey (USGS) and US Fish and Wildlife Servi...
Article
Stream discharge and geochemical data were collected at two sites along lower Ashley Creek, Utah, from 1999 to 2003, to assess the success of a site specific salinity and Se remediation project. The remediation project involved the replacement of a leaking sewage lagoon system that was interacting with Mancos Shale and increasing the dissolved sali...
Conference Paper
In order to develop a selenium budget for the Great Salt Lake, the movement of selenium in the water column must be understood. Sediment flux in the water column includes deposition of transported sediment and re-suspension of deposited sediment. The water column of the Great Salt Lake is complicated by the presence of a chemocline that is persiste...
Conference Paper
Gas generation from groundwater interaction with a field-scale zero-valent iron permeable reactive barrier (ZVI PRB) was measured and simulated with the geochemical reaction path model PHREEQC. Due to anaerobic corrosion of Fe (0) within the ZVI PRB, measured total dissolved gas (TDG) pressure exceeded hydrostatic pressure resulting in ebullition a...
Article
Using a geographic information system, a regression model has been developed to identify and to assess potential sources of selenium in the Kendrick Reclamation Project Area, Wyoming. A variety of spatially distributed factors was examined to determine which factors are most likely to affect selenium discharge in tributaries to the North Platte Riv...
Article
Salinity increases in water in some parts of the Nava-jo aquifer in southeastern Utah have been documented previously. The purpose of this paper is to use bromide, iodide, and chloride concentrations and del oxygen-18 and deuterium values in water from the study area to determine if oil-field brines (OFB) could be the source of increased salinity....
Article
At the Naturita site in Colorado, USA, groundwaters were sampled and analyzed for chemical composition and by culture and culture-independent microbiological techniques. In addition, sediments were extracted with a dilute sodium carbonate solution to determine quantities of labile uranium within the sediments. Samples from the upgradient portion of...
Conference Paper
In order to develop a selenium budget for the Great Salt Lake, the movement of selenium in the water column must be understood. Sediment flux in the water column includes deposition of transported sediment and re- suspension of sediment. The water column of the Great Salt Lake is complicated by the presence of a deep brine layer more saline than th...
Article
Great Salt Lake (GSL), in the Western United States, is a terminal lake with a highly variable surface area that can exceed 5,100 km2. The open water and adjacent wetlands of the GSL ecosystem support millions of migratory waterfowl and shorebirds from throughout the Western Hemisphere, as well as a brine shrimp industry with annual revenues exceed...
Conference Paper
WEST (Water, the Environment, Science and Teaching) is an NSF-funded GK-12 program at the University of Utah. WEST partners graduate students in the sciences with K-12 teachers to enhance inquiry and place- based science teaching in the Salt Lake City urban area. This region is unique in that habitats relating to the entire local hydrologic cycle a...
Conference Paper
Full-text available
The Great Salt Lake is a large hypersaline, terminal water body in northern Utah, USA. The lake has both a significant economic importance to the local community as a source of brine shrimp and mineral resources, as well as, an ecological importance to large numbers of migratory waterfowl. Due to nutrient input from sewage treatment plants, section...
Article
Full-text available
1] The reactive transport of U(VI) in a shallow alluvial aquifer beneath a former U(VI) mill located near Naturita, CO, was simulated using a surface complexation model (SCM) to describe U(VI) adsorption. The groundwater had variable U(VI) concentrations (0.01–20 mM), variable alkalinity (2.5–18 meq/L), and a nearly constant pH equal to 7.1. U(VI)...
Article
Constructed and natural wetlands can accumulate elevated levels of Se; however, few data are available on cost-effective methods for remobilization and removal of Se from these areas. A field experiment was conducted to assess the effectiveness of flooding on the removal of Se from dry surface sediments. The 83-m2 flood-experiment plot contained 10...
Chapter
This chapter presents an introduction to the field installations of permeable reactive barriers (PRB) for metals, radionuclides, and nutrients. A permeable reactive barrier (PRB) is an engineered zone of reactive material placed in an aquifer that removes contamination from groundwater flowing through it. PRBs have been used with varying degrees of...
Chapter
This chapter focuses on deep aquifer remediation tools (DARTs), which have been developed for the emplacement of permeable reactive barriers (PRB) through arrays of non-pumping wells and which offer a number of advantages compared to classic trench installation methods, including easy replacement of spent reactive material and deeper installation d...
Chapter
This chapter reports on the laboratory and field testing of engineered solid mixtures for use with deep aquifer remediation tool (DART) technology for the removal of groundwater metal contamination resulting from mining and ore processing. In laboratory testing mixtures of pelletized bone charcoal (bone char apatite) and hematite pellets coated wit...
Chapter
This chapter presents the findings of the field demonstration of three permeable reactive barriers (PRB) to control uranium contamination in groundwater, in Fry Canyon, Utah in 1997. For this, a funnel-and-gate design was used to construct three PRBs consisting of bone char pellets (PO4), zero valent iron (ZVI) pellets, and amorphous ferric oxyhydr...
Article
Constructed and natural wetlands can accumulate elevated levels of selenium (Se); however, few data are available on cost-effective methods for remobilization and removal of Se from these areas. The experiment was conducted at Stewart Lake Waterfowl Management Area (SLWMA), a Se-contaminated wetland in northeastern Utah. The purpose of the experime...
Article
Full-text available
[1] Site-specific transfer functions relating delta oxygen 18 (δ18O) values in snow to the average air temperature (TA) during storms on Upper Fremont Glacier (UFG) were used in conjunction with δ18O records from UFG ice cores to reconstruct long-term trends in air temperature from alpine areas in the Wind River Range, Wyoming. Transfer functions w...
Article
Mercury (Hg) contamination of aquatic ecosystems and subsequent methylmercury bioaccumulation are significant environmental problems of global extent. At regional to global scales, the primary mechanism of Hg contamination is atmospheric Hg transport. Thus, a better understanding of the long-term history of atmospheric Hg cycling and quantification...
Article
Many published studies have used visual comparison of the timing of peak breakthrough of colloids versus conservative dissolved tracers (hereafter referred to as dissolved tracers or tracers) in subsurface media to determine whether they are advected differently, and to elucidate the mechanisms of differential advection. This purely visual approach...
Article
Chlorine-36 (36Cl) concentrations, 36Cl/Cl ratios, and 36Cl fluxes in ice-core samples collected from the Upper Fremont Glacier (UFG) in the Wind River Mountain Range, Wyoming, United States, and the Nangpai Gosum Glacier (NGG) in the Himalayan Mountains, Nepal, were determined and compared with published results from the Dye-3 ice-core drilling si...
Article
The potential to use ice cores from alpine glaciers in the midlatitudes to reconstruct paleoclimatic records has not been widely recognized. Although excellent paleoclimatic records exist for the polar regions, paleoclimatic ice core records are not common from midlatitude locations. An ice core removed from the Upper Fremont Glacier in Wyoming pro...
Article
Permeable Reactive Barriers show promise as an inexpensive and effective remediation technology alternative to Pump and Treat for removal of a wide range of contaminants including radionuclides from groundwater. Reactions within a reactive barrier either degrade contaminants to non -toxic forms or transfer contaminants to an immobile phase. Three p...
Article
Full-text available
Pump-and-treat methods are costly and often ineffective in meeting long-term protection standards for contaminated ground water. Permeable reactive barriers (PRBs) may offer a cost-effective alternative to other ground-water remediation methods. A PRB functions as a passive in-situ treatment zone that degrades or immobilizes contaminants. A demonst...
Chapter
Full-text available
In addition to providing an understanding of processes within a catchment system, isotopic techniques have been instrumental in providing reconstructions of catchment climate and other environmental indicators at various time scales. Many recent changes are a direct consequence of anthropogenic activities. Isotopic analysis serves as a valuable too...
Article
Salinity increases in water from the freshwater Navajo aquifer in the Aneth area have been documented in recent years. Previous studies during the 1980s in the Aneth area suggested that brines associated with oil production and their subsequent re-injection were the probable source of salinity in the Navajo aquifer. Differences in the delta stronti...
Article
In the past, ice-core records from mid-latitude glaciers in alpine areas of the continental United States were considered to be poor candidates for paleoclimate records because of the influence of meltwater on isotopic stratigraphy. To evaluate the existence of reliable paleoclimatic records, a 160-m ice core, containing about 250 yr of record was...
Article
One hundred samples were collected from the surface of the Upper Fremont Glacier at equally spaced intervals defined by an 8,100 m2 snow grid to assess the significance of lateral variability in major-ion concentrations and del oxygen-18 values. For the major ions, the largest concentration range within the snow grid was sodium (0.5056 mg/l) and th...
Article
Glaciological investigations of the Upper Fremont Glacier in the Wind River Range of Wyoming were conducted during 1990-1991. The glaciological data will provide baseline information for monitoring future changes to the glacier and support ongoing research utilizing glacial-ice-core composition to reconstruct paleoenvironmental records. Ice thickne...
Article
The major tributaries draining the Kendrick Reclamation Project (KRP) account for an average of 52% of the total Se load measured in the North Platte River downstream from Casper, Wyoming. The Casper Creek drainage basin contributed the largest Se load of the five tributary sites to the North Platte River. The 4-d average Se concentration in water...
Article
Snow and ice samples were collected from Gannett, Upper Fremont, and Knife Point Glaciers in the Wind River Range of Wyoming during 1989-90 and analyzed to evaluate the quality of climatic record present in the Wind River Range Glaciers. Seasonal δ18O signals are present in snowpits from Upper Fremont and Knife Point Glaciers and varied by as much...
Article
Using a geographic information system, a regression model has been developed to identify and to assess potential sources of selenium in the Kendrick Reclamation Project Area, Wyoming. A variety of spatially distributed factors was examined to determine which factors are most likely to affect selenium discharge in tributaries to the North Platte Riv...
Article
On August 24, 1991, a U.S. Geological Survey study team from Wyoming completed a core hole to bedrock underlying Upper Fremont Glacier in the Wind River Range of central Wyoming. During the month of core drilling, the team collected a 160-m ice core from the glacier at an elevation of 4000 m above sea level using a solar-powered thermal drill (See...
Article
Full-text available
During a reconnaissance study, ice samples were collected from Knife Point glacier to determine if glaciers in the Wind River Range could provide a long-term record of the chemical composition of wet deposition. Eight annual ice layers comprising the years 1980-1987 were identified. The concentration of calcium, chloride, and sulfate in the annual-...
Article
Geochemical data for samples of overburden from three mines in the Powder River Basin indicate a statistically significant (0.01 confidence level) positive correlation (r = 0.74) between Se and organic C. Results of factor analysis with varimax rotation on the major and trace element data from the rock samples indicate large (>50) varimax loadings...