The inspection found the cause of mass death of fish in the Nikolaev reservoirs
From 11 to 19 June this year, the State ecological inspection in the Nikolaev area repeatedly documented fish kills in the rivers the southern bug, Ingul and the Bugsky estuary. In this regard, we selected 22 samples of water and held control for the major pollutants.
As reported in a press-state ecoinspection service in the Nikolaev area, in the surface layer recorded water dissolved oxygen for the entire period from 0.9 to 10.5 mg/DM 3. The ratio — during the summer, the oxygen content in all water bodies should be not less than 6,0 mg/dm3 .
The oxygen is released into the water column as a result of processes of photosynthesis, which better takes place in the daytime. At night there is a reverse process. Therefore, the minimum content of oxygen is observed at dawn, which was recorded on June 19, in 6 hours (the water temperature was 25 0 C). The concentration of dissolved oxygen ranged from 4.0 mg/DM 3 the water surface to 0.2 mg/dm3 in the bottom horizon. This fact is due to the hydrometeorological conditions prevailing in the present time, what is the likely cause of the phenomena zamorny.
The concentrations of major pollutants are within the limits of observation, which are characteristic for the summer period in the conditions of intensivnostei water, namely ammonium salt 0,22-1,00 mg/dm3 (the maximum excess of maximum permissible concentration for water bodies of fishery (hereinafter MPC) in 2 times), nitrates 0,5-3,5 mg/dm3 (no exceedance), nitrite 0,030-0,081 mg/DM 3 (no exceedance), phosphates 0,137 – 0,497 mg/dm3 (the maximum excess of MPC by 3 times), the total iron 0,22-0,43 mg/dm3 (the maximum excess of MPC in 4.3 times), no hydrogen sulphide (no exceedance). The exceedance is recorded continuously on the ammonium salt, phosphate, total iron and indicate water pollution due to discharges of insufficiently treated domestic sewage and a gradual decrease in the ability of water bodies to cleanse itself. In recent years, such maximum permissible concentration recorded constantly, and especially in the summer.