|
(W/EH073) Pollution of fresh water reservoirs in conditions of. Thseglnic, L.I.1, Dvoretsky, A.I.1, Belocon, A.S.1, Murzina, T.A.1, Novitskaya, O.A.1, 1 ABSTRACT- In Dniprovske reservoir's water having good (for fish-farming purposes) natural composition the organic substance content exceeds the standard values for fish-farming reservoirs by 1,5-2,5 times. Decrease to 46% of water saturation with oxygen in the most urbanized part of the reservoirs is connected with fact mentioned above. Here oil-products level in water sometimes exceeded the fish-farming standards by an order, surfactants content in water reached 65 mkg/l, content of iron reached 205 mkg/l, cadmium - 0,4 mkg/l, chrome - 7,7 mkg/l, zink - 11,3 mkg/l, lead - 8 mkg/l. Content of herbicides was: triazin - 36 mkg/l, DDE - 8 mkg/l. Radionuclide contents such as Sr-90 and Cs-137 reached 2,5.10-12 Ku/l and 1,3.10-12 Ku/l, respectively. By means of two test-objects as Daphnia and Paramecium it has been determined that under the biotic substance circulation seasonal slowing down of water toxicity indices increased and in the anthropogenically loaded parts they were high all the year round. Significant part of toxicants is sorbed with bottom sediments, particularly with black sludge, removing them from the circulation for a long time. Maximum total content of chlororganic pesticides in bottom deposits of the lower part of Dniprovske reservoir reached 1,1 mg/kg, total radioactivity - 27,7 Bk/kg, content of Mn - 1947, Zn - 258, Pb - 56, Cu - 19, Co - 19, Ni - 4,1, Cd - 1,2 mg/kg of dry weight. It has been shown that toxicity of water extracts of bottom sediments appears while decreasing concentration of organic substance by means of extracts dilution with the control water. Key words: n/a, n/a, n/a, n/a |
