Geochemistry and hydrology of perched groundwater springs: assessing elevated uranium concentrations at Pigeon Spring relative to nearby Pigeon Mine, Arizona (USA)

Beisner, Kimberly R.; Paretti, Nicholas V.; Tillman, Fred D.; Naftz, David L.; Bills, Donald J.; Walton-Day, Katherine; Gallegos, Tanya J.

doi:10.1007/s10040-016-1494-8

Cited by 14 publications

(9 citation statements)

References 37 publications

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“…Pigeon Spring discharges from perched groundwater within the Toroweap Formation (Fig. 2 ), most likely after having moved down through the Kaibab and Toroweap Formations 62 . USGS has been monitoring water chemistry at Pigeon Spring since 2012, and uranium concentrations at the site are the highest observed in the study area north of Grand Canyon—as high as 104 µg/L on March 15, 2012 (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Temporal changes in uranium concentrations, which may be due to fluctuations in recharge amount and seasonality, are apparent in the dataset, with concentrations averaging 73 µg/L and varying from 56 to 104 µg/L between 2012 and 2020 63 . Beisner et al 62 published a detailed description of water chemistry at Pigeon Spring and nearby springs and investigated the likelihood that the source of elevated uranium concentrations at the site was Pigeon Mine. Based on estimated direction of groundwater flow inferred from spring elevations in the area and comparison of uranium concentrations at Pigeon Spring to leaching experiments involving Pigeon Mine waste rock, ore, and nearby soil, Beisner et al 62 concluded that current evidence indicate it is unlikely that elevated uranium at Pigeon Spring is coming from the former Pigeon Mine.…”

Section: Resultsmentioning

confidence: 99%

“…Beisner et al 62 published a detailed description of water chemistry at Pigeon Spring and nearby springs and investigated the likelihood that the source of elevated uranium concentrations at the site was Pigeon Mine. Based on estimated direction of groundwater flow inferred from spring elevations in the area and comparison of uranium concentrations at Pigeon Spring to leaching experiments involving Pigeon Mine waste rock, ore, and nearby soil, Beisner et al 62 concluded that current evidence indicate it is unlikely that elevated uranium at Pigeon Spring is coming from the former Pigeon Mine. This conclusion is important for establishing expectations of naturally occurring concentrations of uranium (and other associated trace elements) in groundwater in the region.…”

Section: Resultsmentioning

confidence: 99%

“…Ongoing monitoring at the site and samples from a planned nearby well will provide additional data on temporal changes in geochemistry in groundwater at the site and allow for further evaluation of the relationship between the mine and spring.

Figure 5 Map of Pigeon Spring and the former Pigeon Mine with uranium concentrations through time at the spring and inferred direction of groundwater flow from Beisner et al 62 . Created in Adobe Illustrator 25.4.1 ( https://www.adobe.com/products/illustrator.html ).…”

Section: Resultsmentioning

confidence: 99%

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An assessment of uranium in groundwater in the Grand Canyon region

Tillman

Beisner

Anderson

et al. 2021

Sci Rep

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The Grand Canyon region in northern Arizona is a home or sacred place of origin for many Native Americans and is visited by over 6 million tourists each year. Most communities in the area depend upon groundwater for all water uses. Some of the highest-grade uranium ore in the United States also is found in the Grand Canyon region. A withdrawal of over 4000 km2 of Federal land in the Grand Canyon region from new uranium mining activities for 20 years was instituted in 2012, owing in part to a lack of scientific data on potential effects from uranium mining on water resources in the area. The U.S. Geological Survey has collected groundwater chemistry samples since 1981 in the Grand Canyon region to better understand the current state of groundwater quality, to monitor for changes in groundwater quality that may be the result of mining activities, and to identify "hot spots" with elevated metal concentrations and investigate the causes. This manuscript presents results for the assessment of uranium in groundwater in the Grand Canyon region. Analytical results for uranium in groundwater in the Grand Canyon region were available for 573 samples collected from 180 spring sites and 26 wells from September 1, 1981 to October 7, 2020. Samples were collected from springs issuing from stratigraphic units above, within, and below the Permian strata that host uranium ore in breccia pipes in the area. Maximum uranium concentrations at groundwater sites in the region ranged from less than 1 µg/L at 23 sites (11%) to 100 µg/L or more at 4 sites (2%). Of the 206 groundwater sites sampled, 195 sites (95%) had maximum observed uranium concentrations less than the U.S. Environmental Protection Agency’s Maximum Contaminant Level of 30 µg/L for drinking water and 177 sites (86%) had uranium concentrations less than the 15 µg/L Canadian benchmark for protection of aquatic life in freshwater. The establishment of baseline groundwater quality is an important first step in monitoring for change in water chemistry throughout mining lifecycles and beyond to ensure the health of these critical groundwater resources.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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An assessment of uranium in groundwater in the Grand Canyon region

Tillman

Beisner

Anderson

et al. 2021

Sci Rep

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“…While several studies have been published on water quality of groundwater discharging from springs in the Grand Canyon region [e.g., 9 , 10 , 17 – 19 ], few published studies have focused on the concentration of metals in the Colorado River and major tributaries that are related to uranium mining in the area. Hopkins et al [ 20 ] collected water and stream sediment samples in March of 1982 in the Snake Gulch drainage of Kanab Creek as part of determining mineral resource potential in the area.…”

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confidence: 99%

Assessing uranium and select trace elements associated with breccia pipe uranium deposits in the Colorado River and main tributaries in Grand Canyon, USA

et al. 2020

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Assessing chemical loading from streams in remote, difficult-to-access watersheds is challenging. The Grand Canyon area in northern Arizona, an international tourist destination and sacred place for many Native Americans, is characterized by broad plateaus divided by canyons as much as two-thousand meters deep and hosts some of the highest-grade uranium deposits in the U.S. From 2015–2018 major surface waters in Grand Canyon were monitored for select elements associated with breccia-pipe uranium deposits in the area, including uranium, arsenic, cadmium, and lead. Dissolved constituents in the Colorado River were monitored upstream (Lees Ferry), in the middle (Phantom Ranch), and downstream (Diamond Creek) of uranium mining areas. Concentrations of uranium, arsenic, cadmium, and lead at these main-stem sites varied little during the study period and were all well below human health and aquatic life benchmark criteria (30, 10, 5, and 15 μg/L maximum contaminant levels and 15, 150, 0.8, and 3.1 μg/L aquatic life criteria, respectively). Additionally, dissolved and sediment-bound constituents were monitored during a wide range of streamflow conditions at Little Colorado River, Kanab Creek, and Havasu Creek tributaries, whose watersheds have experienced different levels of uranium mining activities over time. Samples from the tributary sites contained ≤3.8 μg/L of dissolved cadmium and lead, and ≤17 μg/L of dissolved uranium. Dissolved arsenic also was mostly below human and aquatic life criteria at Little Colorado River and Kanab Creek; however, 63% of water samples from Havasu Creek were above the maximum contaminant level for arsenic. Arsenic in suspended sediment was greater than sediment quality guidelines in 9%, 35%, and 35% of samples from Little Colorado River, Kanab Creek, and Havasu Creek, respectively. At the concentrations observed during this study, tributaries contributed on average only about 0.12 μg/L of arsenic and 0.03 μg/L of uranium to the main-stem river. This study demonstrates how chemical loading from mined watersheds may be reliably assessed across a wide range of flow conditions in challenging locations.

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Rethinking groundwater flow on the South Rim of the Grand Canyon, USA: characterizing recharge sources and flow paths with environmental tracers

et al. 2020

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In the arid landscape south of the Grand Canyon, natural springs and seeps are a critical resource for endemic species and Native American tribes. Groundwater is potentially threatened by expanding populations, tourism, and mineral extraction activities. Environmental tracers, including noble gases, stable isotopes of hydrogen and oxygen in water, tritium, and carbon-14, were used to characterize recharge sources and flow paths in South Rim aquifers. Results confirm the regional Redwall-Muav aquifer is the primary groundwater source to springs. However, a second local recharge source is required to explain the detection of tritium. Probable sources are: (1) low-elevation infiltration of surface run-off with warm recharge temperatures and high excess air determined from noble gas models, and relatively low fractions of winter recharge, and (2) high-elevation plateau recharge with cool recharge temperatures, low excess air, and fraction of winter recharge of approximately 1. Previous investigators have linked spring occurrence with regional faults and fractures. Such features also likely control the chemical mixing between the regional and local groundwater sources, the transport of deeply sourced and local recharge fluids, groundwater age, and thus the relative vulnerability of groundwater to depletion and contamination. The new conceptual model of groundwater sources and flow paths suggests that many South Rim springs may respond on the order of tens to hundreds of years to groundwater depletion and contamination, even though the majority of groundwater flow is along longer flow paths with longer lag times. The magnitude of response to short-term changes in the flow system remains unclear.

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Geochemistry and hydrology of perched groundwater springs: assessing elevated uranium concentrations at Pigeon Spring relative to nearby Pigeon Mine, Arizona (USA)

Cited by 14 publications

References 37 publications

An assessment of uranium in groundwater in the Grand Canyon region

An assessment of uranium in groundwater in the Grand Canyon region

Assessing uranium and select trace elements associated with breccia pipe uranium deposits in the Colorado River and main tributaries in Grand Canyon, USA

Rethinking groundwater flow on the South Rim of the Grand Canyon, USA: characterizing recharge sources and flow paths with environmental tracers

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