At present, chromium oxide is commonly produced by thermolysis of sodium bichromate, ammonium sulfate and chromic anhydride, and there is serious pollution of Cr~(6+) in the production.

Apparent digestibility coefficients(AD)(%) of sludge worm Perinereis aibuhitensis fed commercial Japanese flounder diet for dry matter,energy,protein and organic carbon were determined at water temperature of 16,20 and 24 ℃ using chromic oxide(Cr2O3) as a marker.