Reduction of U(VI) to U(IV) occurs naturally through a variety of means, including through the actions of microorganisms.

This synthetic addition of sulfuric acid unnaturally raises the abundance of uranium sulfate complexes at the site.

Oxidation states for uranium range from U3+ to U6+, U(III) and U(V) are rarely found, while U(VI) and U(IV) predominate.

Preventing the spread of toxic uranium compounds from mining sites often involves reduction of U(VI) to the far less soluble U(IV).

The presence of sulfuric acid and sulfates prevents this sequestration, however, by both lowering the pH and through the formation of uranium salts.

Bacteria which are able to reduce uranium have been proposed as a means of eliminating U(VI) from contaminated areas, such as mine tailings and nuclear weapons manufacture sites.

The ability to clear the environment of both sulfate (which solubilizes reduced uranium) and mobile U(VI) makes bioremediation of ISL mining sites a possibility.