NEW INVESTIGATIONS ON ACUTE TOXICITIES OF VANADIUM-OXIDES

The ''in-vivo''-toxicity of the Vanadium-oxides V2O5 and V2O3 (adminis tered orally, dermally and by inhalation) has been reinvestigated with particular emphasis on the safety and handleability of vanadium-oxide s in the vanadium processing industry. Chemical-thermodynamic properti es of vanadium-oxides make it likely that some earlier results on vana dium-toxicities have introduced artefacts as a consequence of the admi nistration-techniques used. Special precautions have therefore been ta ken to avoid any chemical changes or artificial interactions during sa mple-preparation to ensure that the results significantly reflect the toxicities of the vanadium-compounds as exposure to them might occur. The LD50(14d)-values indicate, that V2O5 should be classified as ''ham ful'' (V2O5 techn. grade fused oral LD50 (14d): 716 mg/kg b.w. (rats m .) resp. 658 mg/kg b.w. (rats f.); inhal. LC50 16.2 mg/l (rats m.) res p. 4.0 mg/l (rats f.) for a 4-hour exposure), while V2O3 should be cla ssified as ''relatively non toxic'' (V2O3 tech. grade powder oral: LD5 0(14d): 5639 mg/kg b.w. (rats f.) resp. 8713 mg/kg b.w. (rats m.)) acc ording to the EEC-commission directive of July 29, 1983 (83/467/EEC). Based on interaction-studies and considering new results reported in l iterature, a 3-level-model of the mechanism of vanadium-toxicity via o xygen-radicals is suggested.