Science for Decision Making on Uranium Mining in Arizona

Total concentrations of trace elements in soils can assist in understanding their sources and spatial distributions. The total concentration of an element in soil is usually much greater than the amount of that element that is able to move around in the soil in the presence of water (element mobility), or the amount that is physically and biochemically available for uptake by plants or animals (bioavailability). Soil samples can be leached with artificial rainwater or river water in the laboratory to help determine how mobile an element will be in the environment. More specialized chemical leaches help determine how available an element is for uptake by plants and animals. These solubility tests (called extractions) approximate the mobility and bioavailability of individual chemical elements present in soil samples.

Questions this study could help answer

• How much of an element present in soil will move in the presence of water?
• How much of an element present in soil may be taken up by plants and animals?
• Which elements present in soil are mobile or bioavailable?
• Is there a geographic difference (within and around a mine site) in element mobility and bioavailability?

Objectives

Submit soil samples for solubility tests

Compare solubility test results to samples collected from other mine sites before and during mining to compare and contrast amounts of mobile elements and relate them to the stage of the mining process, or other factors.

Pinyon Plain (formerly Canyon) Mine Activities

A subset of soil samples collected at the Pinyon Plain (formerly Canyon) mine in 2013 and 2015 was submitted for solubility tests. The results from these tests will be compared to samples collected from other mine sites before and after mining to compare and contrast amounts of mobile elements and relate them to the stage of the mining process, or other factors.

Status

Ongoing

Specific Tasks

Task 7b: Collect/analyze water and sediment samples
Task 7c: Collect/analyze samples from biota with focus on trust resources
Task 7d: Collect/analyze soils including deeper horizons to characterize vertical distributions
Task 11: Characterize the wind dispersion characteristics of uranium and trace elements associated with uranium mining and the subsequent risk to biota.
Task 17: Determine biological effects of uranium + trace element mixtures

Principal Investigators

Katie Walton-Day
Hydrologist
Colorado Water Science Center
303.236.6930
kwaltond@usgs.gov

Carleton Bern
Research Soil Scientist
Colorado Water Science Center
303.236.6915
cbern@usgs.gov

Photo Gallery

Pinyon Plain (formerly Canyon) Mine Gallery

Sites with Related Activities

Arizona 1 || EZ || Pinenut