Anwendung von biologischen Testverfahren an Abwässern der Textilindustrie

Testing Effluents of the Textile Refining Industry with Biological Methods The environmental problems caused by the manufacture of finished textiles involve a long chain of individual processes. This “textile chain” includes very diverse enterprises of varied size and structure. The textile refiners occupy a key position in the “textile chain”. On the one hand, this is due to their use of an obscurely large number of chemicals which can end up in the wastewater as well as in the textile products. On the other hand, this key role of the textile refining industry is based on their central position between the preproduction stage and the consumers. This study dealt with the textile refining industry's wastewater. As measured by volume and contents of its wastewater, this industry can be counted among the major industrial plants which discharge into municipal wastewater treatment plants. German wastewater legislation includes the provision that substances which are toxic, persistent, capable of accumulating, carcinogenic, fetotoxic or mutagenic be kept out of natural waters as well as technically possible (Wasserhaushaltsgesetz WHG). Several biotest methods for examining the effect of the substances contained in the wastewater were incorporated into the appendix of the German wastewater regulation (Rahmenabwasser-Verwaltungsvorschrift based on § 7a WHG). The aim of this study was to show, with the aid of biotest methods, how strongly the wastewater of textile refining companies is polluted as compared to other known industrial branches and to what degree the pollution of these wastewaters is eliminated by the treatment in wastewater treatment plants. Finally, we experimented to find out which biotest methods were suited for the examination of these wastewaters. The study's results show that the ecotoxicity of the textile refining industry's wastewater was only extraordinary high in isolated cases as compared to other examined branches of industry. The textile wastewaters exhibit values of G_L = 3 to G_L = 96 in the luminescent bacteria test, G_D = 1 to G_D = 192 (with one exception of G_D > 30000) in the daphnia test and G_F < = 2 to G_F = 32 in the fish test. It turned out though, that a large number of the samples from the textile refining companies (27%) reacted mutagenically in the Ames test in their native state. Consecutive tests for chromosomal aberrations (V79 hamster cell test) also showed mutagenic potential in five out of nine native samples. The employed testing methods with fish, daphnia and luminescent bacteria demonstrate a higher sensitivity of the luminescent bacteria and/or the daphnia as opposed to the fish in most cases. As the fish test is controversial anyway on the grounds of animal protection, a replacement of the fish test by these other tests should be aimed at: on account of the different end points of the luminescent bacteria and the daphnia test, a combination of these tests appears most sensible.