Mirna Velki

The present study assessed the effect of agricultural practices on biomarker response in white stork (Ciconia ciconia) nestlings from continental Croatia. During the breeding season of 2022, blood was sampled (n = 54) from the landfill Jakuševec and the agricultural areas Baranja and Srijem. Different patterns of biomarker response in regard to the sampling site were detected. Results demonstrate the presence of inhibitory pollutants from the landfill Jakuševec and agricultural area Baranja, which is reflected in lower cholinesterase (ChE) activity. Oxidative stress biomarkers show different responses concerning study sites. Glutathione reductase (GR) activity was higher in Baranja and Srijem, suggesting a different mixture of pollutants inducing an antioxidative response. Leachate from the landfill Jakuševec is suspected to affect the white stork nestlings by elevating the concentrations of reactive oxygen species (ROS). An environmental combination of pollutants appears to induce oxidative stress in white stork nestlings. In addition to agricultural practices, white stork nestlings may also be under environmental pressure from the surrounding pollution. Further research is warranted to include additional chemical analysis to associate the environmental concentrations with the potential adverse effects in apex predators, such as the white stork.

Earthworms are key organisms of the soil ecosystem and bioindicators for soil quality. While pesticides are used for the improvement of crop yields, they also present a burden for soil organisms. To understand the complex effects of pesticides on soil organisms, it is important to test these effects in soil exposures to include influences of the soil matrix on the toxicity. Therefore, the aim of this study was the assessment of the effects pesticides on earthworm Eisenia andrei. In an initial screening, active ingredients and commercial preparations were tested for comparison. Since the commercial preparations showed a higher toxicity, all further investigations (biomarkers, multixenobiotic resistance (MXR) activity, and avoidance behavior) were performed using the commercial pesticide formulations only: Sumialfa (esfenvalerate), Calypso (thiacloprid), Frontier (dimethenamid-p), and Filon (prosulfocarb). Significant differences in avoidance behavior were observed for Filon and Frontier. All pesticides inhibited the MXR activity and affected oxidative stress-related markers. Frontier was the only pesticide that did not affect enzymatic biomarkers related to neurotransmission. The results show the potential hazards associated with the usage of the tested pesticides and the importance of evaluating the effects of commercial pesticide preparations for a more realistic insight into the adverse effects on the environment.