Poison in German lake targeted local drinking supplies

German authorities were searching Western Europe's second largest lake with underwater cameras yesterday after discovering two sunken canisters of herbicide apparently planted to poison water supplies.

The containers were found on Wednesday, three weeks after the local water supply company received an anonymous letter threatening to contaminate Lake Constance, but the discovery was made public only on Sunday.

The company, Bodensee-Wasserversorgung, supplies water to some four million people in the German state of Baden-Wuerttemberg. It said tests had shown barely detectable levels of herbicide in the water and there was no risk to the public.

A police spokesman in the lakeside town of Friedrichshafen said the authorities had yet to find more herbicide containers.

"The search is taking place initially with underwater cameras because the water is 70 to 75 metres deep. If something is found, divers will be sent down to recover it," he said.

He said the motive behind the incident was unclear, but police were not treating it as terrorist-related.

They were in touch with colleagues in Switzerland and Austria, which also border the 67 km-long Lake Constance.

However, the other countries were not directly affected at this point because the canisters were found far from either of them in the lake's northwestern corner near a pumping station at Sipplingen, which had been mentioned in the threat letter.