Pesticides pollute 50% of Swiss groundwater

Crop pesticides are contaminating groundwater Keystone

Agricultural pesticides are contaminating much of Switzerland's groundwater sources, according to study by the Swiss environment agency.

A survey of 390 monitoring stations found traces of pesticides and weed killer at more than half of them.

Priority was given to analysing data from farming areas, and pollution levels exceeding the permitted norms were recorded at several sites.

Some 80 per cent of Switzerland’s drinking water is taken from the ground, but experts denied there was any immediate health risk.

“We can safely say that Swiss people can continue in good confidence to drink water from the tap,” Daniel Hartmann, head of groundwater protection, told swissinfo.

“There is no problem as far as health is concerned – that is if we are talking about acute toxicity.”

Contamination fears

Hartmann said the biggest cause for concern was the potential long-term effect of pesticide contamination.

According to the agency, certain substances take a long time to break down and can pollute groundwater sources for years.

Some scientific studies claim to have established a link between deformities in frogs and tadpoles and the presence of pesticides in surface water.

While none of the research has so far proved conclusive, Hartmann insisted the findings could not be ignored.

“We simply do not yet know in any detail what the long-term effect could be,” said Hartmann.

“We have to be careful. It is no excuse to say that at the moment we cannot prove it. We should make every reasonable effort to minimise contamination.”

Progress

The agency says a great deal of progress has already been made to reduce the use of pesticides.

Farmers have been told to stop using them in the vicinity of groundwater sources and to only apply pesticides when insects are present and not as a preventative measure.

The most common toxic substances found were weed killers. The highest concentration of pesticides was 1.87 micrograms per litre.

But officials were only able to test for 88 of the 350 chemicals authorised for use as pesticides in Switzerland due to budgetary restraints.

The agency said it would publish recommendations next year for protecting the country’s water resources from pesticides and other persistent pollutants.

swissinfo, Billi Bierling and Adam Beaumont

pollution

There are 3,000 water monitoring stations across Switzerland.
80% of drinking water comes from underground sources.
The federal authorities have been monitoring water quality nationwide since 1976.