The paper assessed the phytotoxicity of the most frequently used ice-melter reagents in Moscow (sand and salt mixture, anti-freeze reagent based on a composition of calcium and sodium chloride, technical salt), snow with varying degrees of contamination of the remnants of ice-melter reagents, as well as soil after the snow cover melting. The toxicity assessment was carried out in the samples taken on the lawns along the roads in nine administrative districts of the city in places with the same anthropogenic load. The test object is oat seeds (Avena sativa), as a sensitive biotest showing the most stable and reproducible data compared to seeds from other crops. Salt solutions of reagents with dilution rates of 1, 2, 4, 6, 8 and 10, melted snow and soil extracts were used for biotesting. The phytotoxic effect was determined by comparing the average root length of control and prototype seeds. It was found that all studied ice-melter reagents have a pronounced toxic effect on oat plants even at tenfold dilution. The phytotoxic effect of snow and soil polluted with ice-melter substances, which in turn inherits the chemical composition of snow cover after its melting, was shown. © The Authors, published by EDP Sciences, 2020.