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Here, the Swiss groundwater is the most polluted

Groundwater in Switzerland is polluted, especially due to foreign substances from agriculture. That is the conclusion of the report of the Federal Environment Office (Bafu), which was presented today. The timing of the announcement is explosive: Next year, the population votes on the Drinking Water Initiative, which wants to grant subsidies only to those farmers who give up their use of pesticides and antibiotics.

The extent to which farmers pollute groundwater has not yet been fully elucidated. Bafu has now examined the state of groundwater throughout the area. To Switzerland 524 seats made measurements. According to the latest 2017 data, two-thirds of the samples were pesticide-free (not shown on the map). in 170 seats However, residues of pesticide active substances have been reported. in 8 cases even the limit was exceeded.

The biggest burden is in Mittelland, which is heavily populated and intensively farmed. Industrial and commercial sites, urban drainage and traffic areas also increase groundwater. Since this has been in the underground for a long time and there is almost no degradation of artificial substances, it is difficult to solve problematic substances.

In addition to the active ingredients of pesticides and degradation products, so-called metabolites have been discovered. They are more mobile and durable compared to the active ingredients. In addition, they occur more frequently, more regularly and at higher concentrations. Metabolites were detected at 265, more than half the site.

There are no maximum values ​​for most metabolites. As of 2017, however, for a few minerals like pesticides, the limit of 0.1 microgram price per liter. So, the places where this value is exceeded are colored pink on the map.

According to Bafu, such residues are "potentially critical" and must be "prevented or reduced". Wherever above the limits, the Chloridazon and Metolachlor herbicides were used in many cases. These are crop protection products used in the cultivation of beets and maize.

"Groundwater is Switzerland's most important source of drinking water – and it is under a lot of pressure."Bafu

Bafu also noted a high concentration of nitrate. It accumulates in the soil as Swiss farmers fertilize more than the plants can absorb and then penetrate the groundwater. At more than 15 to 20 percent of the measurement points, more nitrates were detected than allowed. In agricultural fields, values ​​were sometimes as high as 40 percent above the border. In 2 to 4 percent of cases, the maximum permissible value for drinking water is exceeded.

According to the report, groundwater is by far the most important drinking water resource in Switzerland. Do the Swiss have to worry now? Not yet, says Bafu. Impeccable drinking water is still available "in sufficient quantity". However, groundwater quality is "widespread and sustainable" impaired. Therefore, the most important drinking water resource comes under increasing pressure.

Created: 15.08.2019, 11:25 hour