15 February 2023

Pesticide impact on plants and soil grows in Germany

Over the past 25 years, pesticide total toxicity in Germany has increased for fish, land plants and soil organisms, a research from the Technical University of Kaiserslautern-Landau has found. EU wants to cut use of chemicals in half by 2030 but its metrics are not convincing

by Matteo Cavallito


Over the past 25 years, risks associated with pesticide use in Germany have decreased for terrestrial vertebrates but increased for fish, plants and soil organisms. This is supported by a study from the Technical University of Kaiserslautern-Landau published in the journal Environmental Science & Technology.

The issue is highly critical as EU has committed to halving the fallout associated with pesticides by the end of the decade, the researchers point out. “TTo reduce pesticide risks at a national or continental scale, you can, for instance, use fewer amounts of pesticides or you can substitute some pesticides by the same amount of less toxic ones,” explained Sascha Bub, lead author of the study.

Pesticide impact is increasing

Landau researchers have developed a simple method for risk assessment. “IIf you multiply amounts and toxicities of all pesticides used in a country in a year, and then sum up the multiplication products, you get a rough indicator of how risks develop. We call this indicator the total applied toxicity (TAT),” the authors explain. The numbers highlight how the impact of substances turns out to be very different depending on the organisms involved. Some pesticides, for example, are particularly toxic to pollinators, while others are toxic to soil organisms or plants.

By calculating the total applied toxicity for eight organism groups and 292 pesticides used in Germany between 1995 and 2019 and using 1,889 values of the different officially recognized toxicity thresholds, the researchers were able to draw important conclusions.

Over the past 25 years, total applied toxicity has decreased only for terrestrial vertebrates. For fish, terrestrial plants and soil organisms, however, the overall figure has increased. “The increase we see for soil organisms is worrisome, because they are of high importance for soil health. Increased risks for soil organisms might eventually affect agricultural productivity,” Bub explained.

Risk for soil has doubled

Total toxicity “for terrestrial vertebrates decreased over time by about 20%,” the research states. The figure, however, “increased by a factor of three for fishes, largely due to insecticides, by a factor of two for soil organisms, largely due to fungicides and insecticides, and, to a lower extent, for terrestrial plants, solely due to herbicides.”

Other species observed “showed no trends in total applied toxicity, which for pollinators likely results from use restrictions of neonicotinoids,” chemically related nicotine insecticides that are particularly toxic to bees.

EU indicators are not convincing

The study also questions the EU Regulation on the Sustainable Use of Pesticides, which aims to reduce pesticide risks by 50 percent by 2030. The study’s findings implicitly highlight the limitations of the risk indicators developed by the EU, which do not distinguish between different groups of organisms.

The European parameters, in other words, place pesticides in fixed risk categories without taking into account species-specific toxicity.

In Brussels’ crosshairs are 54 particularly hazardous substances that are classified as “candidates for substitution” because of their potential impact on health, soil and the environment. Under the current Regulation, member states are required to replace these compounds with safer alternatives.

Contamination cases rise in Europe.

The picture is still worrying. Last year, a report by Pesticide Action Network (PAN), a federation of hundreds of NGOs in 60 different countries, showed a 53 percent increase in cases of fruit and vegetable contamination in Europe between 2011 and 2019.

In 2011, the study recalls, only 4 percent of kiwifruit sold in Europe had traces of pesticides. By 2019, the share of contaminated specimens had risen to 32 percent. During the same period, the incidence on cherries more than doubled from 22 percent to 50 percent. Moreover, in 2019, contamination was detected on 87 percent of pears produced in Belgium, 74 percent of cherries grown in Spain, and 85 percent of celery from Italy.