Chronic effects of commercial pesticide preparations on biomarkers and reproductive success in earthworm Eisenia andrei

Chemical pollution resulting from pesticide usage has been a continuous issue since the 1960s, despite comprehensive European Union legislation designed to safeguard human health and the environment from the adverse effects of pesticides. While regulatory risk assessments primarily focus on the active ingredients, recent research indicates ecotoxicological impacts of commercial preparations on non-target organisms, particularly within the soil ecosystem where key species such as earthworms play a vital role in maintaining soil quality and fertility. Therefore, the aim of this study was the assessment of the long-term effects of the following respective commercial preparations: the insecticides Sumialfa (esfenvalerate) and Calypso (thiacloprid), as well as the herbicides Frontier (dimethenamid-p) and Filon (prosulfocarb) on the earthworm Eisenia andrei in standardized soil during long-term exposures of 7, 14, and 28 days. To study the possible effects on different levels of biological organization, enzymatic biomarkers: acetylcholinesterase (AChE), carboxylesterase (CES) glutathione S-transferase (GST), glutathione reductase (GR), glutathione peroxidase (GPx); non-enzymatic biomarkers: multixenobiotic resistance activity (MXR), levels of glutathione (GSH), and reactive oxygen species (ROS) as well as reproductive success were investigated. While Calypso appeared to be the least toxic substance, all pesticides showed significant effect on multiobiomarker response in E. fetida. That being said, the response of MXR activity was significantly altered by all tested pesticides indicating MXR being the most sensitive endpoint of the present research. Recovery of MXR was observed after 28 days, however, only in case of exposure to Filon, while the recovery of CAT activity was recorded after 28 days as well, subsequent to Sumialfa exposure. Reproductive success was negatively impacted regarding the Frontier and Sumialfa exposure at the highest concentration (100 mg/kg) reflected in reduced number of cocoons, while only the exposure to Frontier (100 mg/kg) reduced the number of juveniles. Based on the results, it is important to include commercial pesticide formulations in pesticide risk assessments. The toxicity classifications of the studied pesticides suggest the potential detrimental consequences to the key soil species in terrestrial ecosystems at various concentrations. Future studies should include other soil species as well as investigation of higher levels of biological organization, i.e., behavioral endpoints, to determine the potential risks to terrestrial ecosystems.