The first precise census of contaminated sites in Switzerland shows they cover a surface of 225 square kilometres, but their number is still more than 20 per cent lower than earlier estimates.
The Federal Environment Office said on Thursday that it had compiled and analysed data from all available federal and cantonal registers. The 38,000 polluted sites would cover 80 per cent of canton Geneva or all of canton Zug.
Nearly half of those sites are industrial areas, 40 per cent former dumps, ten per cent shooting ranges and just one per cent accident sites.
Nearly two thirds of the contaminated zones are in the most densely populated and most industrialised part of the country between the Jura mountains and the Alps, where most of the country’s water reserves are also to be found.
Given that nearly 60 per cent of the sites are near exploitable underground water supplies, the office said special care should be taken to protect this resource from pollution.
Around two thirds of the sites, however, do not require any particular intervention. For half of them, the authorities say there is no danger for the environment, while for one in ten, investigations have shown that no monitoring or cleaning up was required.
Another 10,000 sites are either being investigated or will be in the near future. Results so far have led to five per cent of those sites being put under surveillance and three per cent requiring a clean-up.
The environment office expects that around 4,000 sites will eventually need some form of intervention, adding that 700 have already undergone pollution abatement measures.
The office warned that while the results were satisfactory, the cost of cleaning up the sites would be high. Parliament is expected to vote in favour of taking some of the burden off the cantons and communes.
A proposal by the Senate’s environment commission would allow local authorities to demand upfront financial guarantees from the companies responsible for the costs generated for testing, monitoring and cleaning up sites.
Currently, those authorities carry the financial burden if those responsible for the pollution cannot be identified or are bankrupt. In some cases, the final bill can total hundreds of millions of francs.
swissinfo.ch and agencies