Research on acute toxicity of nanodisperse manganese oxide aerosol for predicting health hazards for workers and population under inhalation exposure

Our research object was nanodisperse manganese oxide synthesized at Mn2+ and MnO4 ions interaction when nano-reactors, namely bromide cetyltrimethylammonium micelles, were present but they didn't become a part of an end product. We applied scanning electronic microscopy, X-ray phase analysis, dynamic laser light scattering, Brunauer, Emmeth, Taylor and Barret, and Joyner and Halenda techniques to confirm that the synthesized substance was a nanomaterial with particles sections having a needle form and being equal to mostly 13-29 nanometers (95.6 % of the total particles number). Acute inhalation toxicity was assessed in conformity with the procedures stated in “OECD Guidelines for the Testing of Chemicals, Section 4: Health Effects, Acute Inhalation Toxicity - Acute Toxic Class Method” (OECD, Test № 436:2008, IDT); it revealed that synthesized nanodisperse manganese oxide had acute toxicity when it was inhaled as an aerosol. CL50 under 4-hours exposure which male and female Wistar rats with body weight being equal to 190 ± 10 grams had to undergo was 120 mg/m3. Acute intoxication had the following clinical picture: irritating and neurotoxic effects, and respiratory depression. As per CL50 criterion (>50-500) mg/m3 the tested substance is of the 2nd hazard degree (in accordance with the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) and of the 1st hazard degree (according to the State Standard 12.1.007.76. Classification and general safety requirements). The obtained inhalation toxicity parameters which nanodisperse manganese oxide has prove the substance can exert hazardous impacts on workers' health when they are exposed to it at the work places or on population health; they also call for safety precautions development.