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New threat to water purity

Effluents are purified before being returned to the waterways. www.sensetal.ch

Switzerland's rivers and lakes have become much cleaner since the 1960s thanks to an active water purification policy.

This content was published on March 18, 2003 - 13:21

But these natural water resources are being threatened with new types of pollution - residues from medication and pesticides.

A recent Unesco survey ranked Switzerland 16th in the world for water management and reserved particular praise for the efforts the country has made to stop industrial contamination.

"Some important industrial waste treatment plants have been built in the past 20 years, especially round Basel, which meant the quality improved a lot," Bruno Schädler, head of the water management division at the Federal Office of Water and Geology, told swissinfo.

New dangers

Millions of francs have been pumped into cleaning up water in Switzerland and into the installation of a national water purification programme, which can deal with biodegradable organic matter, most phosphates and many other organic substances.

Phosphates have been banned in the production of washing powder in Switzerland since 1986. But even water treatment plants have their limits.

“For example, they can’t treat remnants of certain types of medication,” said Edwin Müller, head of water hygiene at the environment ministry.

“We are at the moment studying what possible consequences there might be for both humans and wildlife of having these substances in water,” he added.

Müller says residues from medication get into the water system via showers, sinks and WCs.

“Today, for example, we are even able to measure micro pollution. In this way, we have ascertained the presence in water of certain anti-rheumatic substances,” Müller told swissinfo.

“What we don’t yet know is if this very low amount constitutes an environmental problem,” added the chemist.

Antibiotics

But there are signs that such pollution has already affected the environment. Last year, the Association of Swiss Cantonal Chemists said it was alarmed to find that one in every six fish bred in the country contained significant levels of medication or banned substances.

A study by the Federal Institute for Environmental Science and Technology in Dübendorf also found that fields were being contaminated with antibiotics used to treat animals - placing drinking water at risk.

"The use of antibiotics in livestock production induces antibiotic resistance in bacteria that can enter the food chain. If you apply manure to agricultural fields, it's possible humans could be contaminated," warned Stephan Müller, head of the water and agricultural division at the institute.

The results were even more surprising in light of Switzerland's ban on the use of antibiotics as growth promoters in animal feed. But the benefits of the ban are being compromised by a rise in the therapeutic use of antibiotics to treat sick animals, said Müller.

Pesticides

Pesticides, especially nitrates, which seep into the soil after rain, are also causing concern.

A ban on using sludge as fertiliser will come into force in 2003, as it is often contaminated by heavy metals that could be washed back into the ground water.

In 2001, the Worldwide Fund for Nature (WWF) issued warnings that the presence of hormones and other chemical substances from fertilisers, antibiotics and perfumes in Switzerland could pose a potential threat to human health.

Another problem is that about 90 per cent of Switzerland's rivers and streams have been dammed, canalised and channelled underground, impairing the natural functions of watercourses.

There are moves to counter this by moving waterways back into rivers and lakes. But Müller says that this is only happening on an ad hoc local level and that there is often not enough space - or funds - available.

swissinfo, Fabio Mariani and Isobel Johnson

In brief

Switzerland has spent millions of francs in cleaning up its water over the last few decades, creating a national water system.

But new pollution risks have appeared in the form of medication and hormones.

Studying the consequences and returning water to rivers are two points in the national water programme.

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water summary

95% of the Swiss domestic economy is linked to water processing plants; in Europe, it's less than 60%, in the US, just over 70%
Switzerland uses 5% of its water resources compared to 11% in Europe and almost 20% in the US.
Water use per capita in Switzerland is less than 400m³, in Europe it is more than 900m³ and the US rates 1800m³.

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