Automatic biodetector of water toxicity (ABTOW) as a tool for examination of phenol and cyanide contaminated water

We describe an automatic biodetector for continuous monitoring of water toxicity (ABTOW). Construction of the ABTOW is based on natural ability of the biofilm formation to immobilize consortia of nitrifying bacteria (the sensing element) on the open cellular polyurethane foam as the support. Change of rates of oxygen consumption is used as an indicator of biocatalytic activity (nitrification) of the bacteria in response to xenobiotics. Owing to this design the ABTOW features stability long-term use, is inexpensive and simple in operation. The dynamics of ABTOW response is studied in details for phenol and cyanide as model toxins. These data indicate that the sensitivity was 3.5 μM for phenol and 0.19 μM for cyanide, respectively. The magnitudes of toxic effect were proportional to concentration whereas kinetics of the response is an indicator for the mechanism of toxicity. Similar methodology is applied to quantify toxicity of a range of heavy metals, herbicides and oxidative chain inhibitors. One may conclude that the presented biodetector provides a good sensitivity for continuous on-line monitoring of toxicity in water.