Limits RegistryPUBLIC RECORD
Limits RegistryAcid mine waters in the Richmond Mine at Iron Mountain, near Redding, California, were measured at pH values as low as −3.6 by USGS geochemist D. Kirk Nordstrom and colleagues — the most acidic waters known. Formed by oxidation of pyrite and concentrated by evaporation, they carry up to 200 g/L of dissolved metals and 760 g/L of sulfate.
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Acid mine waters in the Richmond Mine at Iron Mountain, near Redding, California, were measured at pH values as low as −3.6 by USGS geochemist D. Kirk Nordstrom and colleagues — the most acidic waters known. Formed by oxidation of pyrite and concentrated by evaporation, they carry up to 200 g/L of dissolved metals and 760 g/L of sulfate.
The lowest pH ever measured in water occurring in the environment (not prepared in a laboratory).
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Permanent ID limitsregistry.com/limits/LR-MOST-ACIDIC-NATURAL-WATER
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Limits Registry. LR-MOST-ACIDIC-NATURAL-WATER. Most acidic water ever measured in the environment. 2026.