[Examination and experiences with the fish-test according to the German Sewer Charge Law (AbwAG) (author's transl)].

Different domestic and industrial waste waters were tested by the fishtest with orfes (breeding form of Leuciscus idus melanotus) to determine their toxicity. There was no reaction of the test fishes in receiving waters. Domestic sewages from secondary treatment proved also nontoxic in 50% of the tested waste waters. Other sewages yielded very low toxicity concentrations (highest concentration: LD50 = 660 l/m3). The fishtest of industrial effluents resulted maximal LD50 concentrations of 62.5 l/m3. A comparison to the chemical analysis reveal no correlation between results of the fishtest and the pollution of sewage samples. Observations and experiences with the methods of the orfetest are critically discussed especially according to routine examinations.