A new study has revealed that pesticide residues are present in 70% of European soils, where they contribute towards soil biodiversity loss and disrupt critical ecosystem functions.
The research, the first comprehensive continent-wide analysis of its kind, indicates that current pesticide regulations fail to protect the hidden life essential for food production and environmental health.
An international team, co-led by researchers from the University of Zurich and the University of Vigo, analysed 373 soil samples from woodlands, grasslands and croplands across 26 European countries. They tested for 63 common pesticide active ingredients and measured the biodiversity of key soil organisms, from bacteria and fungi to nematodes and arthropods.
They found pesticide residues were the second strongest factor – after inherent soil properties – shaping soil biodiversity. Fungicides were the most frequently detected (54%), followed by herbicides (35%) and insecticides (11%). While concentrations were highest on farmland, residues were also found in forests and meadows, presumably due to the spray drifting.
Co-lead author Professor Marcel van der Heijden of the University of Zurich and Agroscope said: ‘We now have quantitative evidence that this contamination has a major impact on various beneficial soil organisms, impairing their biodiversity.’
The study documented widespread non-target effects. Pesticides suppressed beneficial groups like arbuscular mycorrhizal fungi – which form symbiotic partnerships with plant roots to aid nutrient and water uptake – and bacterivore nematodes that contribute to nutrient cycling. Conversely, certain bacteria thrived, possibly because of due to reduced competition.
Critically, the analysis of functional genes showed pesticides alter microbial processes involved in nitrogen and phosphorus cycling.
As van der Heijden explained: ‘This suggests the natural function of the affected soil is reduced, and additional fertilization may be necessary to maintain yields.’
The researchers warn that persistent pesticide residues can impact soils for years. They argue that current risk assessments, which often rely on single-species tests, are inadequate.
Co-lead author Professor Maria J. I. Briones said: ‘Our study shows that pesticides represent a very significant human environmental impact on our soils. Often, people don’t even consider the extent of the effects of pesticides on non-target organisms. To protect soil ecosystems, these community-level and functional effects must be urgently integrated into pesticide regulation.’
Photo: wuzefe
Leave a Reply