CrVI

CrVI refers to chromium in the +6 oxidation state, a group of chemically related species including chromate (CrO4^2−), dichromate (Cr2O7^2−), chromium trioxide (CrO3), and chromic acid (H2CrO4) in solution. In aqueous environments, speciation depends on pH and concentration: chromate dominates at neutral to basic pH; dichromate forms under more acidic conditions; in very acidic solutions chromic acid is present.

Hexavalent chromium compounds have a long industrial history as pigments, oxidizing agents, and in electroplating and coating processes. They are used in chromium plating, corrosion-resistant coatings, wood preservation, and as constituents of pigments in paints and inks. The high solubility and mobility of Cr(VI) compounds contribute to their environmental behavior and exposure potential.

CrVI compounds are highly toxic and carcinogenic. Occupational inhalation exposure is a major concern, and Cr(VI) is classified as carcinogenic to humans by IARC. In biological systems, Cr(VI) can be transported into cells and is reduced to Cr(III), a process that can generate reactive species and damage DNA and proteins, leading to oxidative stress and cellular injury. Cr(VI) contamination presents environmental risks because it readily migrates in water.

Remediation strategies focus on reducing Cr(VI) to Cr(III) and then removing the insoluble Cr(III) species by precipitation or adsorption. Regulatory approaches aim to minimize occupational exposure and environmental release, enforce treatment of effluents, and promote safer alternatives where feasible.