[Use of bacterial toximeters with separate cell cultures for continuous water monitoring]

Two commercially available bacterial toxicity monitors are compared. As test organisms pure cultures of Pseudomonas putida are used in both systems. The bacteria are grown continuously in turbidostatic ("Toxalarm", LAR, Berlin, Germany) or chemostatic ("Stiptox-norm", Siepmann und Teutscher, Gross-Umstadt, Germany) regulated cultures in a selective culture medium in nonsterile devices. Toxic substances can be detected by continuously working bacterial respiration tests. Oxygen consumption is the measuring parameter. The bacterial test suspension is mixed continuously in a fixed proportion with air-saturated test water in a measuring cell. The separate culturing of the bacteria and the carrying out of the tests ensures that neither the bacterial culture is endangered by toxic substances nor the sensitivity can be changed by poison adaptation. Results of "Toxalarm"-tests with several chemicals (e.g. Atrazine, Lindane, 2-Nitro-phenol, Sodiumpentachlorophenolate) are presented. The registration of an alarm event (River Rhine) by "Stiptox-norm" is shown.