video transcript

The Achatina snail is usually found in sub-Saharan Africa - but this one is at work in Russia. Its task is to sample the atmosphere at a water treatment plant in St Petersburg - monitoring air pollution produced by incinerated sewage residue. The living sensor reacts to harmful gases in the air, according to environmental researcher, Vassily Lyubimtsev. (SOUNDBITE) (Russian) VASSILY LYUBIMTSEV, SENIOR ENVIRONMENTAL RESEARCHER SAYING: "When the gas concentration changes drastically, the mollusc gets disturbed. It can change it's relatively calm behaviour to an active one. At the same time the frequency of its heart rate increases and as a matter of fact this reaction is a test for air pollution." Scientists are able to monitor changes in the snail's heartbeat and behaviour by watching it in real time on a computer screen.. This kind of snail can live for up to ten years and grow to 20cm in length - they were chosen for the task because they have lungs and breathe in a similar way to humans. The snails are not being exposed to dangerous levels of gas, says lead researcher, Sergei Kholodkevich. (SOUNDBITE) (Russian) SERGEI KHOLODKEVICH, HEAD OF BIOELECTRONICS MONITORING LABORATORY SAYING: "The snails are not breathing the smoke, but a gas with a thousand-times lower concentration of the smoke. Why? Because people are concerned about quality of air outside of the plants restricted zone." Animals have been involved in environmental monitoring in St Petersburg before, with crayfish tasting water quality in the Neva river - now this not so little snail is joining the effort to clean up the atmosphere. Stuart McDill, Reuters