The containment pond at Plain Mine (formerly Canyon Mine) has a mixture of metals and other inorganic contaminants that are of concern for wildlife utilizing the pond as a water source. For example, arsenic and selenium may be of concern for birds and tadpoles1; however, the toxicity risks of the aquatic pathways at breccia pipe mines remain largely unknown. Water in the containment pond comes from; 1) water pumped from the mine shaft, and 2) precipitation events and associated water runoff from the mine property. Runoff can contain metals leached from the ore pile (once the mine is operational), waste rock piles, and dust from the mine surface. Sediments in the containment pond are likely surficial dirt and dust transported by the wind that then settle onto the top of the pond liner. Aquatic invertebrates, which may serve as food sources for birds, bats, and other species, inhabit the sediment; a wide array of species, including fly and dragonfly larvae, beetles, and backswimmers are commonly present in collected samples. Vegetation, primarily cattails, also grows in the sediment.
Concentrations of constituents vary as water levels change seasonally (e.g., monsoon inputs) and with mining company management activities, including reduction of water levels by transport of water and sediments offsite.2-6 Concentrations will likely vary further once active mining begins. We aim to follow the mine throughout the entire lifecycle to evaluate risks from the mine containment pond.
Objectives
Sample the Plain Mine (formerly Canyon Mine) containment pond on a quarterly basis (winter, spring, summer, and fall beginning in 2017) to characterize seasonal concentrations of inorganic constituents in water, bulk sediment, vegetation, and invertebrates.
Collect additional water samples for environmental DNA analysis to identify vertebrate and invertebrate species that inhabit or utilize the pond.
Collect additional volumes of water and bulk sediment once per year for bioassay testing to evaluate the potential for toxicity of inorganic constituents in these ponds to aquatic invertebrates and other wildlife.
Ongoing
Task 5a: Compile/evaluate existing and newly collected monitoring data from various agencies/sources Task 7b: Collect/analyze water and sediment samples Task 7c: Collect/analyze samples from biota with focus on trust resources
1 Hinck, J.E., Cleveland, D., Brumbaugh, W.G., Linder, G., and Lankton, J., 2017, Pre-mining trace element and radiation exposure to biota from a breccia pipe uranium mine in the Grand Canyon (Arizona, USA) watershed: Environmental Monitoring and Assessment, February 2017
2 Chemistry data for assessment of the containment pond at Canyon Mine, Arizona 2017: U.S. Geological Survey data release, https://doi.org/10.5066/P9X3C9HL.
3 Data for assessment of the containment pond at Canyon Mine 2017-2018: U.S. Geological Survey data release, https://doi.org/10.5066/P9GD4MV2
4 Data for the assessment of the containment pond at Canyon Mine, Arizona, 2019: U.S. Geological Survey data release, https://doi.org/10.5066/P9AU43GI.
5 Chemistry data for assessment of the containment pond at Pinyon Plain Mine, 2020: U.S. Geological Survey data release, https://doi.org/10.5066/P93K2SOI.
6 Cleveland, D., and Hinck, J.E., 2022, Chemistry data for assessment of the containment pond at Pinyon Plain Mine, 2021: U.S. Geological Survey data release, https://doi.org/10.5066/P9V79QMG.
Danielle Cleveland
Supervisory Research Chemist
Columbia Environmental Research Center
573.876.1858
dcleveland@usgs.gov
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U.S. Forest Service (USFS) |
