ECOTOXICOLOGICAL SCREENING OF LJUBLJANA SURFACE WATERS WITH BIOLUMINESCENT BACTERIA VIBRIO FISCHERI (MICROTOX~(~R))

摘要

Ecotoxicology is a unique field of biological sciences devoted to issues surrounding the release of countless man-made chemicals into the biosphere and potentially harmful effects they can exert, alone or in combination, toward biota of receiving environments. Early studies of wastewater impact on the environment relied primarily on chemical analyses for identifying specific contaminants. The chemical data alone do not suffice for evaluation of global toxic effects because it is impossible to analyze all the relevant compounds including their degradation and transformation products. Biological systems may retain synergistic or antagonistic effects which are not easily assessed without biological tests. The aim of our study was to utilize an ecotoxicological method suitable for surface water toxicity screening of a large area in and around Slovenian capital Ljubljana. Due to a large number of water samples a simple, reliable, rapid and cost-effective method was required. Such qualities are characteristic for the so called microbiotests. Regarding similar investigations standardised Microtox microbiotest with luminescent bacteria Vibrio flscheri was a suitable assay for ecotoxicological screening. Ljubljana surface waters are represented by many streams and two larger rivers Ljubljanica and Sava. Outside the city, the streams flow in their natural riverbeds. In the city, they are mostly regulated with concrete channels. Many effluents of unknown and known origin are discharged into the streams of Ljubljana area. Irrespectively, until last year, official state monitoring of the surface waters was performed only at twelve sites.