The water is a part of the natural medium that supports big changes under the influence of urbanization, first of all being affected its quality. Different chemical substances from the aquatic environment combine between each other and give a more toxic effect than the action of individual substances. Therefore their detection in water through chemical analysis still do not reflect fairly what causes damage to living organisms, and if it can be used in various economic activities. In this context, for ecotoxicological assessment of the water of river Bîc within Chisinau municipality and identification of pollution sources, it was performed a biological testing of river water - a method that does not require material expenses, is not complicated, being an operative and objective method. Based on the above mentioned, our studies were designed to determine the water quality of the river Bîc within Chisinau municipality through biological assessment using gammarus species of amphipods - organisms susceptible to pollution, used as test-object for water toxicity detection.