Mobile Measurement Laboratory: Maximum Pesticide Contamination Values ​​in Water That Are Too High – News

A new measurement method shows that pesticide concentrations in water are many times higher than previously measured.

Using a new measurement method, scientists from the ETH Eawag domain water research institute have shown that peak concentrations are in some cases up to 170 times higher than those shown in conventional measurements. Therefore, the limit values ​​are greatly exceeded.

This has an impact on humans and animals, says SRF scientific editor Christian von Burg: “It is primarily living things in the water that are directly affected.” The number and biodiversity of small creatures in streams in intensive agricultural areas are significantly lower than in other areas. “This will also have an impact on fish that feed on smaller aquatic organisms.”

The consequences of pesticide contamination are not as direct for people because most of the drinking water comes from groundwater. “By the time heavily polluted water from streams and rivers has seeped into groundwater, the pollutants have been greatly diluted,” explains von Burg.

Eawag’s refined measurement method

Until now, pesticide contamination has been measured using water samples that were collected over an average of three days and then mixed. Peak concentrations are not recorded in this way, or only rarely.

A new fully automated mobile measurement laboratory developed by Eawag in a trailer called MS2Field takes a water sample every twenty minutes, prepares it, and analyzes the cocktail. Data can be accessed online in real time.

During a measurement in a stream in an agricultural area, many pesticides exceeded the mean concentration values ​​of mixed samples taken at the same time for 3.5 days up to 170 times, as shown by the results of an investigation published in the specialized journal “Aqua & Gas”.

Eawag is surprised at how high these peak loads are thanks to the new accurate measurement results. The condition is not acceptable. “We measure values ​​that are exceeded and that should never happen. And that shows that action is needed and that small organisms can be harmed, ”says Christian Stamm of the Eawag water research institute.

Particularly damaging frequent spikes

The example of the insecticide thiacloprid shows that short-term concentration peaks have an impact: the quality criterion established in the Water Protection Ordinance, which aims to prevent acute damage to aquatic organisms, has been exceeded several times and even 30 times, Eawag writes.

“Recording peak concentrations is extremely important for the ecotoxicological assessment of water contamination,” said environmental chemist Stamm. Successive peaks are particularly harmful to organisms, as they no longer recover in the medium.

Political measures

In Switzerland, the problem of pesticide pollution in streams and rivers is a serious problem and has been known for a long time. On Wednesday, the National Council opposed a bill passed by the Council of States that aims to reduce the risks of pesticides for drinking water.

The bill is not an indirect formal counterproposal to the drinking water initiative and the pesticide ban initiative. But it should take the popular initiative at full speed.