engleski

Potential impacts of plant protection products on earthworms, carabid beetles and vertebrates on agricultural fields

The productivity and sustainability of agricultural fields depend on the maintenance of relevant ecosystem functions as well as on the existence of a sufficiently complex species diversity. In this context, earthworms play a prominent role for soil ecosystem by influencing organic and inorganic matter breakdown, and carabid beetles are one of the most important arthropod predators on soil surface. So far, the environmental risk assessment of potential impacts of plant protection products on earthworms (EFSA 2017) and ground beetles (ESCORT 2000) is based on single compounds and does not take into account that organisms within and above the soil are exposed to a mixture of active ingredients from different plant protection products within one season and partly over successive seasons. In addition, the potential for secondary poisoning, as assessed in EFSA (2009), may increase if contaminated earthworms and carabid beetles are combined in the diet of a mixed-diet feeding bird or mammal. In this study, earthworms and carabid beetles were sampled at two seasons from eight fields in Croatia and analysed for up to 300 active ingredients. Based on publicly available draft assessment reports from EC and EFSA, degradation parameters (DT50, DT90) were used to calculate degradation curves and the current soil concentration at the date of earthworm sampling as well as the current residue concentration on soil surface at the date of carabid sampling. Subsequently, bioaccumulation factors were calculated by dividing the analysed pesticide residues in earthworms and carabid beetles by the calculated concentrations in soil and on soil, respectively. The aim of this survey was to check the applicability and reliability of this method and to examine (i) whether the re-calculated soil concentrations of individual active ingredients and mixtures of active ingredients with the same mode of action do pose a potential risk to earthworms and carabid beetles ; (ii) whether a potential of secondary poisoning has to take into account when a bird or mammal feed both on contaminated earthworms and carabid beetles.

Environmental risk assessment, earthworms, bioaccumulation factor, carabid beetles, pesticide residues, secondary poisoning

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