Chromium

Chromium compounds find their way to the environment mainly through tanning and electroplating industries. Chromium, essentially exists in two forms namely Cr(VI) and Cr(III). Cr(III) is proved to be biologically essential  to mammals as it maintains an effective glucose, lipid and protein metabolism. In contrast, Cr(VI) is highly toxic as it can diffuse as CrO₄^2- or HCrO₄^- through cell membranes. Major toxic effects of Cr(VI) are chronic ulcers, dermatitis, corrosive reaction in nasal septum and local effects in lungs. In view of the toxic effects, BIS maximum permissible level of Cr(VI) in drinking water is 0.05 mg/l.