This paper presents the results of spectral optical measurements of hydrochemical characteristics in the Angara/Yenisei river system (AYRS) extending from Lake Baikal to the estuary of the Yenisei River. For the first time. such large-scale observations were made as part of a joint American-Russian expedition in July and August of 1995. when concentrations of radionuclides. https://www.sunsetnoveltiers.shop/product-category/anal/