Assessment of Different Sizes Silver Particles According to the Haplic Chernozem Biological Indicators

The ecotoxicity of Ag particles of different sizes was assessed by microbiological, biochemical and phytotoxic indicators of the upper layer (0-20 cm) of ordinary chernozem (Haplic Chernozem) in a laboratory model experiment. We studied the effect of nano- (10 and 100 nm) and microparticles (1000 nm) of Ag at concentrations of 1, 10 and 100 mg/kg on the biological parameters of ordinary chernozem 30 days after contamination: the activity of catalase, dehydrogenases, ferrireductase, urease, peroxidase, poliphenoloxidase, invertase, phosphatase, the total number of bacteria, the abundance of bacteria of the genus Azotobacter, the number of germinated seeds and the length of radish roots. It was found that the ecotoxicity of Ag particles depends on their size: in most cases, Ag particles 10 nm in size had a stronger ecotoxic effect on biological parameters than particles 100 and 1000 nm in size. There were no significant differences in the ecotoxicity of 100 and 1000 nm Ag particles. The difference in the effects of Ag particles of different sizes increased with increasing Ag concentration in the soil: the higher the Ag concentration in the soil (from 1 to 100 mg/kg), the more pronounced the difference in ecotoxicity between 10 nm Ag particles and 100 and 1000 nm Ag particles. Phytotoxic indicators are more sensitive to contamination by Ag nanoparticles at all concentrations studied (1, 10 and 100 mg/ kg); total number of bacteria, invertase and phosphatase activity – at 10 and 100 mg/kg; the abundance of bacteria of the genus Azotobacter and the activity of dehydrogenases – at 100 mg/kg. It is advisable to use these indicators in biodiagnostics of the ecotoxicity of Ag nanoparticles.