The Microtox biological test: Application in toxicity evaluation of surface waters and sediments in Poland

Research into the suitability of Microtox for the evaluation of toxicity of surface waters and bottom sediments in Poland was conducted. Water bodies of various pollution levels were tested, including the Odra River and its tributaries, the Lower Vistula River, the Kashubian Lake District and the Gulf of Gdańsk, using a Microtox Model 500 analyser (Microbics Corporation, USA). The majority of tested surface water samples were found to be apparently non-toxic. However, 75% of the bottom sediment samples were found to be highly toxic (EC50>2%). These results indicate that the Microtox test is suitable for evaluating the toxicity of bottom sediments, in which pollutants tend to accumulate. It seems, however, that Microtox lacks the sensitivity to be of use in analyzing water quality. The relationship between the toxicity of analysed sediments and their organic content was examined.