Occurrence, persistence and risk assessment of pesticide residues in European wheat fields: a continental scale approach

Pesticide residues in agricultural soils represent an environmental concern that requires special attention due to their potential ecological and public health risks. We analyzed 614 pesticides in 188 wheat fields across Europe subjected to both conventional and organic farming systems. At least one pesticide residue was detected in 141 soils. Seventy-eight pesticides or their metabolites were detected. The presence of pesticides was significantly higher in both number and concentration in conventional fileds (up to 0.98 mg kg−1) compared to organically managed sites (up to 0.40 mg kg−1). A total of 88 % of conventional fields and 63 % of organic fields contained two or more pesticides. Conversion from conventional to organic farming does not guarantee that soils will be pesticide-free in the short term. Fenbutatin oxide was the most frequently detected pesticide in both farming systems, followed by AMPA. Other substances, such as boscalid, epoxiconazole, diflufenican, tebuconazole, dinoterb, bixafen, and DEET, were found in ≥ 10 % of samples. Some Persistent Organic Pollutants, including dieldrin, endosulfan sulphate, and chlorpyrifos, were also detected. Ecological risks were higher in conventionally managed fields, with 46 % exhibiting high-risk levels, compared to just 1 % in organic fields. Epoxiconazole and boscalid were the substances with the highest risk levels.