BBE Moldaenke, represented in Australia by Technical & Scientific Equipment , uses organisms such as daphnia, algae or zebra fish to check the health of water supplies. Sophisticated analysers can measure specific contaminants such as metals and organics in water, but they are relatively slow and it is difficult to cover a wide range of possible toxic materials in a real-time, online monitoring system.
The toximeters from bbe Moldaenke use a number of organisms including daphnia (water fleas), algae or small fish to detect the widest range of potential toxins in water supplies.
Water is pumped through a flow cell and the behaviour of the organisms is monitored by a video camera. A digital interpretation of the swimming patterns shows behaviour changes when toxins are introduced. Daphnia may swim in straight lines more often or for longer distances than normal well before the organisms start to die off. The behaviour of daphnia is classified using average speed, distribution of speed, average distances, altitude of swimming daphnia, fractal dimension (sum up of turns, curves and circle movements), number of active animals, and average growth. Parameters are compared to normal behaviour and alterations to the normal pattern trigger an automatic alarm.
Evaluation of the method using nerve agents, cyanide and other highly lethal contaminants, shows it can rapidly identify toxicity at levels less than 1/10th of those which are dangerous to humans. Potential risks can be identified and an automated warning sent out, well before any danger.