Recent samples collected from 2012–2014 at Pigeon Spring had elevated uranium concentrations (73-92 micrograms per liter) compared to other springs from perched aquifers in the same drainage area (2.7–18 micrograms per liter)1.
To better understand the source of elevated uranium concentrations at Pigeon Spring, water from nine nearby springs, along with water that had been in contact with uranium-mining waste material, was studied. Statistical analyses of trace element concentrations (elements that are typically present in low concentrations in water such as arsenic and uranium) showed water from Pigeon Spring to be similar to water from other nearby springs and distinct from water in contact with uranium mining material. Water in contact with mining material from the Pigeon Mine contained elevated concentrations of several trace elements in addition to elevated uranium compared to the spring water.
Additionally, evidence from available groundwater-level measurements in the area indicate that groundwater is probably flowing towards the northwest, whereas Pigeon Spring is due east of Pigeon Mine, making groundwater effects from the mine on the spring unlikely.
Ongoing
Task 5c: Collect/analyze samples from biota with focus on trust resources Task 8a: Continue evaluation/analysis of Uranium Activity Ratio analysis
1 Beisner, K.R., Tillman, F.D., Anderson, J.R., Antweiler, R.C., and Bills, D.J., 2017, Geochemical characterization of groundwater discharging from springs north of the Grand Canyon, Arizona, 2009–2016: U.S. Geological Survey Scientific Investigations Report 2017–5068, 58 p., https://doi.org/10.3133/sir20175068
Kimberly Beisner
Hydrologist
Arizona and New Mexico Water Science Centers
505.830.7945
kbeisner@usgs.gov