[The luminescent bacteria test for clean water legislation]

Luminescent bacteria (Photobacterium phosphoreum) may be used, on the one hand, for classical toxicity tests based on the inhibition of respiration or growth and, on the other hand, their luminescence itself may become the test criterion. Such a luminescence inhibition test is commonly called a luminescent bacteria test. It may be conducted with fresh bacteria or with conserved ones. The luminescence parameter is, just like the parameter oxygen consumption, a summative parameter for undisturbed metabolic processes. Dilution series are prepared to determine the concentration level at which no inhibition of the luminous intensity is detectable in comparison with reference samples. This paper highlights the necessity of standardizing the test methods (the influence of toxic substances depends on test duration and temperature) and describes the standardized procedure established by the DIN-Arbeitskreis "Leuchtbakterientest" (Working Group of the German Institute for Standardization for the luminescent bacteria test) using freeze-dried, liquid-dried, and fresh bacteria (DIN 38,412, part 34). Results of wastewater analyses are presented and the wide range of applications is described. The choice of biotests for applications under the Federal Water Resources Management Act (Wasserhaushaltsgesetz--WHG) and the Wastewater Charges Act (Abwasserabgabengesetz--AbwAG) is discussed and the reasons for the selection of the luminescent bacteria test are explained. Within the framework of a test battery of bioassays, this test shall be used according to section 7a WHG both for evaluating the technological level of wastewater treatment and for routine monitoring of wastewater discharges. In March 1992, this test (DIN 38,412, part 34, edition March 1991) became part of the general administrative regulations for wastewater (Rahmen-Abwasser-Verwaltungsvorschrift-RAV).