Organic complex compounds of iron and chromium and their chemical nature in the Dnieper reservoirs

The distribution of iron and chromium among complexes with dissolved organic compounds varying in chemical nature (anionic, cationic, and neutral) and in molecular weight was analyzed in the Dnieper reservoirs. Iron and chromium formed complexes with humic compounds, protein-like compounds, and carbohydrates. Humic compounds (fulvic acids predominantly) played the major role in binding both metals in all Dnieper reservoirs. The spatial and temporal variations in the distribution of iron and chromium complexes varying in chemical nature was studied in the Kiev reservoir. The major proportions of iron and chromium formed complexes with humic compounds in spring, with protein-like compounds in summer, and with carbohydrates in winter.