WARSAW The state waterworks in Poznan have started using freshwater mussels to monitor the quality of drinking water in the city. The degree to which the molluscs have opened their shells provides an early-warning system for the waterworks, reports Polish news agency PAP. The mussels react to any increase in the level of poisonous substances in the water by closing their shells.

When they do this, a computer-controlled alarm system is triggered, says the report. Polish scientists recommended the use of mussels to the waterworks four years ago, when a blackmailer threatened to pollute drinking water with potassium cyanide. After being in the water for six months, the mussels were set free in a lake and replaced by new ones. According to the management in Poznan, a city of 800,000 people, the drinking water it provides to the city and surroundings is very good.

(DPA)