| Abstract: | To protect a water for the purpose of local recreation – inclusive of bathing – the effluent of an upstream clarification plant was chlorinated. Due to poorly controlled dosing, residual chlorine quantities exceeding the permissible level entered the receiving stream, its biocenosis having been considerably endangered. Detrimental effects on the chemical composition are graphically represented by the measured results for some waters – partly criteria of quality. There is explained that the self-purification capacity of the water decreased by about 30 % and that the hydrobiological species composition of periphyton was reduced by about 80 %. Finally, advice is given concerning the prevention of such damages to waters. |
