COMPARATIVE TOXICOLOGICAL AND HYGIENE ASSESSMENT OF NEW TIO2 AND TIO2-AG NANOPOWDERS

Abstract

Abstract. Nanoparticles, particularly titanium dioxide, have a wide range of applications in various fields, such as medicine, electronics, construction, cosmetics, and other industries. Electron microscopy reveals that TiO2 nanopowder contains aggregates and nanoparticles predominantly ranging in size from 20 nm to 30 nm. For the TiO2-Ag nanocomposite, it has been determined that silver is localized on the surface of titanium dioxide, with average nanoparticle sizes of TiO2 ranging from 13 nm to 20 nm and Ag ranging from 35 nm to 40 nm. The lethal dose of TiO2 and TiO2-Ag nanopowders administered intraperitoneally in laboratory animals varies, with higher lethality observed in animals receiving the nano-TiO2-Ag composite compared to nano-TiO2 alone. The LD50 for TiO2 nanopowder is 4783,30 mg/kg, and the LD50 for TiO2-Ag nanopowder is 724,44 mg/kg, placing them in hazard class 3 (moderately hazardous) according to GOST 12.1.007-76. Native TiO2 and TiO2-Ag nanopowders cause temporary, mildly expressed inflammation of the mucous membrane of the eye. No irritation was observed after single or repeated application of nano-TiO2 and nano-TiO2-Ag ointments to the skin. TiO2 and TiO2-Ag nanopowders accumulate in the livers of laboratory animals following intraperitoneal administration. The accumulation of titanium (with nano-TiO2 treatment) and titanium and silver (with nano-TiO2-Ag treatment) in the liver tissue of laboratory mice increases with the administered dose (from 4000 mg/kg to 10000 mg/kg). The characteristic microscopic signs of the toxic effects of TiO2 and TiO2-Ag nanopowders following intraperitoneal administration to laboratory mice are dystrophic changes in hepatocytes and necrosis of the liver parenchyma, while inflammatory reactions are less common. In conditions in vitro, it has been shown that nanomaterials at concentrations of 30 μg/mL of nano-TiO2-Ag can increase the functional activity of peripheral blood mononuclear cells by producing pro-inflammatory cytokines IL-1, IL-6, TNF-α, and IL-4 in donors (p<0.05), indicating a potential impact on the formation of chronic inflammation and allergic reactions in the corresponding category of nanotechnology workers. When studying the effect of nanomaterials on the germ cells of male rats, it was shown that the most sensitive marker was the sperm survival rate, which significantly decreased under the action of TiO2 nanoparticles at a dose of 1/10 LD50, which is a consequence of impaired activity of mitochondrial enzymes and, accordingly, ATP resynthesis. OELs were calculated using mathematical equations, taking into account the nanosafety coefficients and margins at the level of 0,3 mg/m3 for nano-TiO2 and 0,2 mg/m3 for nano-TiO2-Ag.