More than 2,000 pesticides are used for agricultural production in Europe, yet knowledge about the effects of pesticide residue mixtures on ecosystems and human health is scarce and scattered. The SPRINT project investigates the occurrence and resulting impact of these mixtures on ecosystems and humans.
“In our extensive field campaign across Europe and Argentina, we analysed more than 200 pesticides. We found that mixtures of pesticide residues are common in the environment, as well as in humans,” says professor of Soil Degradation and Land Management Violette Geissen of Wageningen University & Research and affiliated with the Wageningen Institute for Environment and Climate Research (WIMEK). She is the coordinator of SPRINT, a large-scale European project on current concentrations of crop protection agents in the environment, humans and animals. Geissen recently communicated the interim results with stakeholders.
Mixtures of remnants of pesticides can be found almost everywhere in the environment, as well as in animals and humans. Of the ten European countries that participate in the study, the amount of pesticides in the environment and indoor dust were relatively the highest in the Netherlands. Especially household dust is full of residues, often from more than a hundred different products. “Across Europe, we detected 144 types of pesticide residue in indoor dust – glyphosate, a herbicide, was found most frequently.” Around three quarters of the pesticides found by the researchers are approved for sale; around a quarter are banned.
The team compiled the hazard properties, which showed that more than 50% of the residues detected in the environment were harmful for soil or water organisms. Likewise, 60% were described to have a possible effect on reproductive development, and 30% were considered to be possibly carcinogenic.
However, the effects of the mixtures of these harmful substances are not studied sufficiently, says Geissen: “Environmental and human health are discussed, but it is difficult to show a cause-and-effect relationshop since both the variability and number of mixtures are high. So what are we going to do about that?”
The European Union wants to cut the use of chemical crop protection agents by 50% by 2030. What is more, they can reduce use of half of the most harmful products by promoting other products. The findings from SPRINT (Sustainable Plant Protection In Transition) will give the EU supporting arguments for possible reduction of pesticides.
Geissen is incredibly passionate about her research. “When I was young, I worked on farms that used pesticides. I always wondered what effect they had on humans and the environment. The story then was that crop protection products couldn’t do any damage. Later, I carried out studies in non-European countries that showed the products did in fact have harmful effects. Since my return to Europe, I’ve delved into the directives and discovered they mainly offer a false sense of security.”
For years, attempts have been made to estimate the transport routes and fate of crop protection agents in the environment. According to Geissen, these models cover important transport routes, yet wind transporting pesticides that are bound to soil particles is not taken into consideration sufficiently. There was no large-scale monitoring. “Data on residues in the ‘real world’ were missing. Furthermore, EFSA tests are only taking the effects of single pesticides into consideration, as tests of mixtures are still under development.”
Photo left: Insect trap to measure insect biodiversity in conventional and organic potato crops. Photo: Paula Harkes. Photo right: Mole cricket, an example of crawling insects in the field.
This is not the only problem she encounters, as Geissen sketches another problem in the approval of pesticides. “When we assess the safety of a crop protection product for the soil, we currently carry out tests on just five soil organisms,” explains Geissen. “But the soil houses millions of different species of insects, bacteria and fungi, so testing on just five of them does not capture the impact of the product on other forms of soil life. We try to address these urgent questions in the SPRINT project.”
Additionally, there isn’t much known about the consequences of using combinations of products. “By now, such combinations are widely present in the environment and in groups of living organisms, which is why the current tests and models don’t give a good indication of the actual situation.”
The first step taken in SPRINT was to determine which pesticides should be addressed in the project: “We focus on more than 200 herbicides, fungicides and insecticides, and their metabolites,” says Geissen. They studied 207 products, 151 of which have been approved for sale and 56 of which have been banned. However, traces can still be found years later.
The second step entailed a sampling campaign across ten European case study sites and Argentina to analyse pesticide residues in the respective ecosystems, animals, and humans. Geissen: “Based on the outcomes of this field work, we select certain residue mixtures that will then be tested in the laboratory.”
More than 700 people participated in the SPRINT sampling campaign, ranging from farmers and their neighbours to consumers. The team also took hundreds of samples from the terrestrial and aquatic environment. Argentina was included in the project because it produces a lot of soya for animal feed in Europe, so the pesticides used in the cultivation of the soya can end up in Europe. The European regions include all main European cropping systems and cover a wide range of different climate zones. Sampling in the Netherlands focused on potato production in Groningen and Frisia.
The next two years will be spent investigating the risks of the measured concentrations of residues for the ecosystem and humans. To do this, the scientists are working with toxicological institutes across Europe. SPRINT will develop innovative ecotoxicological and toxicological tests that can contribute to a new generation of EFSA tests.
SPRINT creates a toolbox that will integrated new data sets on risk assessment, new model components and pesticide application and risk maps across Europe as a base for risk reduction scenarios in Europe.
According to Geissen, SPRINT has a vibrant stakeholder network on national and international level. “The idea is to develop transition pathways that take the whole food chain into consideration on national and European level. SPRINT can play a key role here too.”