Version History for U.S. Geological Survey Scientific Investigations Report 2025-5095

Assessment of Treated Wastewater Infiltration in Bright Angel Wash and the Potential for Contaminants of Emerging Concern Influencing Spring Water Quality Along the South Rim of the Grand Canyon in Grand Canyon National Park, Arizona

By Nicholas V. Paretti, Kimberly R. Beisner, and Sarah J.R. Shepherd

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First posted online December 29, 2025

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Revised and reposted February 3, 2026 as version 1.1.

Suggested citation has been changed to the following:

Paretti, N.V., Beisner, K.R., and Shepherd, S.J.R., 2025, Assessment of treated wastewater infiltration in Bright Angel Wash and the potential for contaminants of emerging concern influencing spring water quality along the South Rim of the Grand Canyon in Grand Canyon National Park, Arizona (ver. 1.1, 2026): U.S. Geological Survey Scientific Investigations Report 2025-5095, 59 p., https://doi.org/10.3133/sir20255095.

Under "Abstract," third paragraph:

"The other detected pharmaceuticals included (in descending order of concentration) metformin (diabetes drug), sulfamethoxazole (antibiotic), fluconazole (antifungal), and venlafaxine (antidepressant and nerve pain medication)."

changed to:

"The other detected pharmaceuticals included (in descending order of concentration) fluconazole (antifungal), sulfamethoxazole (antibiotic), metformin (diabetes drug), tramadol (opioid analgesic), and venlafaxine (antidepressant and nerve pain medication)."

Under "Data Analysis," figure 5:

Added "Transcanyon Waterline" to the original figure. No other alterations were made.

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