Plant protection products raise concerns because their software can affect certain soil organisms considered as non-target species and which could be very sensitive to certain pesticides. The European Food Safety Authority (EFSA, which regulates agricultural practices, uses of plant protection products, and so on. at European level) has developed an information and software tool called Persistence in Soil Analytical Model (PERSAM) to perform soil exposure assessments.
Until now, the PERSAM program “made it possible to calculate the focus that could be anticipated from ‘a given software for phytosanitary products’, explains Manu Soto, UPV/EHU lecturer. “We have now succeeded in extrapolating the potential risks of these concentrations and the factors influencing this risk, taking into account not only soil conditions, but also the type of lifestyle and the type of pesticide used.”
Soil characteristics and environmental variables vary along the extent of the latitudinal axis across the European continent, which influences predicted environmental concentrations, degree of toxicity to soil biota and thus characterization of risk. “If the toxicity varies according to the characteristics of the soil, the logic of applying a special dose across Europe cannot be followed, because or truck a dose may have no effect in Sweden, but may exert an effect in Spain or France, for example. EFSA wanted to make this differentiation, and contacted our group because it was essential to develop a landscape assessment method that takes regional variability into account,” explains Erik Urionabarrenetxea, UPV/EHU researcher.
Soil and interstitial water
Thus, members of the Department of Zoology and Animal Cell Biology studied the effect of four pesticides on two different types of organisms in different parts of northern, central and southern Europe. The study was carried out with earthworms and springtails or springtails, since earthworms are affected by soil contamination and springtails by contamination present in the aquatic pores of the soil. “Depending on the diet and needs of each organism, some are more vulnerable than others to contamination present in one soil compartment or another.” The research team believes that many factors should be taken into account when calculating the risk.
In the study performed, the team found that the risks associated with concentrations vary greatly from one soil compartment to another. They underlined that, within the framework of the adaptation of the regulations, this concern should be taken into account in addition to the possible landscape variabilities between the different Euroregions. “There is great variability between northern and southern Europe, but also within each region,” they pointed out. Regarding the type of pesticide, they also noted that “the characteristics of the pesticides greatly influence their distribution in each of the compartments”.
“It is a question of better calculating the risk, and not just to stick to the concentrations, as they can vary widely. It is vital to look at the toxic effects induced by these concentrations, their potential effects and the risks incurred, when it comes down to then applying them to agricultural practices”, explain the researchers. The need to take into account the characteristics of the ground is a major advance, because it was not taken into account until now. The team continues to work in this area: “We are now looking at the impact this would have from an environmental point of view.”