De Flora, S; Coppola, R; Camoirano, A; Battaglia, MA; Bennicelli, C
Chromyl chloride (CC) (Cl2CrO2) is a liquid volatile Cr6+ compound prepared from CrO3, HCl and H2SO4. Due to its corrosive, explosive and toxic properties, CC is very difficult and dangerous to handle. At sub-lethal concentrations, the liquid phase of CC was mutagenic for S. typhimurium (TA100), both in the spot test and in the plate test. Toxic effects were generally prevailing on mutagenic effects in CC vapours, as tested by a variety of methods. In all cases S9 mix (Aroclor) decreased both toxic and mutagenic effects. On the whole, we have so far tested 18 Cr compounds in our lab. With the exception of Cr carbonyl and Cr yellow (both water-insoluble), all Cr6+ compounds (Na dichromate, chromic acid, Ca chromate, K chromate, NH4 chromate, Cr orange, Mo orange, Zn yellow and CC) were mutagenic in the Ames test. However, their mutagenicity was decreased by S9 mix and other metabolic systems. Conversely, with the exception of chromite (contaminated with Cr6+) all Cr3+ compounds (Cr-K sulfate, Cr nitrate, Cr chloride, Cr acetate, neochromium and Cr alum) were negative. Therefore, the mutagenic activity of Cr appears to depend on availability of Cr6+ ion to bacterial cells.