Anglers demand measures to save Ticino’s lakes

Ticino's mountain lakes and streams are threatened by acid rain Keystone Archive

Acid rain is threatening to destroy the fragile ecological balance of dozens of mountain lakes in canton Ticino.

Local fishermen want to neutralise the acidity by a process called liming which involves pouring tons of calcium carbonate into the affected water.

“We have to act as soon as possible,” Urs Lüchinger, president of the Ticino Angler’s Federation told swissinfo. “Otherwise the fish are going to be wiped out.”

The worst affected region is the northern part of Lake Maggiore’s catchment area which includes more than 150 small Alpine lakes in Switzerland and Italy. The pollution is coming from the industrialised Po Valley in northern Italy.

Extreme measure

Alberto Barbieri, head of the laboratory of environmental studies for canton Ticino, has been monitoring 20 lakes since 1999 to assess their neutralisation capacity.

“Two lakes are acid, 11 are sensitive to acidification and there could be a similar situation in neighbouring cantons like Valais and Uri because of the strong acidity coming mainly from the south.”

He said rivers, lakes and streams were threatened and that fish survival was seriously endangered.

Barbieri said reducing atmospheric emissions in the Po valley would be the best solution and that liming was a more extreme measure, which would have to be carefully considered.

Test project

Lüchinger wants to test the liming process in three lakes in Valle Leventina, Valle Maggia and Val Verzasca. The cantonal government is expected to finance the project.

Scandinavian countries have been using calcium carbonate to neutralise the acidity in lakes since the 1980s, and Lake Darengo in Como province in Italy has recently undergone similar treatment.

Calcium carbonate, after neutralising the affected water, sinks to the bottom of the lake and is reactivated when acidity levels rise.

by Vincent Landon