<p>This study investigates particulate matter (PM) associated with aquatic moss as a monitor of the transfer of artificial radionuclides in the Yenisei River, which receives authorized releases of liquid radioactive wastes. Samples of aquatic moss and bottom sediments (BS) were collected in the Yenisei in September 2019–2023 close to the radioactive discharge site. PM associated with moss was recovered from samples of fresh moss in laboratory. Samples of unwashed moss, washed moss, PM retained by the moss, and BS were analyzed for contents of radionuclides using HPGe-gamma-spectrometry and alpha-spectrometry; for mineral composition – by X-ray diffraction analysis; for elemental composition – by SEM–EDS analyses. PM retained by aquatic moss constituted 13.5–43% of dry biomass of moss samples. Mineral matter constituted 89.4 ± 5.5% of the dry mass of that PM and consisted mainly of rock-forming minerals and a considerable proportion, up to 25%, of X-ray amorphous phase, represented mainly by frustules of epiphytic diatoms. Considerable proportions of artificial radionuclides were associated with PM of moss: 12–67% for ⁶⁰Co; 38–81% for ¹³⁷Cs; 20–66% for ²⁴¹Am; 25–78% for ¹⁵²Eu; 55% for ¹⁵⁴Eu; 2.5–48% for ²³⁸Pu; and 3.8–41% for ^239,240Pu. Principal Component Analysis revealed the greatest similarity between PM retained by aquatic moss and BS in contents of radionuclides, minerals, and organic matter. The results allowed us to conclude that PM associated with aquatic moss could be considered as a representative component of the ecosystem that makes it possible to monitor the transfer of artificial radionuclides in water current of the Yenisei River.</p> Graphical Abstract <p></p>