engleski

Toxicity evaluation of the active ingredient azoxystrobin and a commercial product (Quadris®) on the non-target soil organism Enchytraeus albidus

Strobilurin fungicides (SFs) are a group of new fungicides produced by strobilurin A as a lead compound. Azoxystrobin, best-selling SF, is a highly efficient broad-spectrum fungicide with relatively high-water solubility, which may lead to accumulation in water, sediments, and soil. Due to its wide application and impact on non-target soil organisms azoxystrobin have attracted attention. Soil dwelling organisms are among the first in line of exposure to pesticides, however their risks are often based on the pure active ingredient (AI) and not on the commercial products (CPs) actually applied in the field. Enchytraeus albidus is a model species in soil ecotoxicology used for environmental risk assessment. Due to their important role in proper soil functioning, it is essential to investigate the toxicity and adverse effects of fungicides used in agriculture on enchytraeids. Previous research has demonstrated a negative impact of azoxystrobin on the reproduction and oxidative status of earthworms, and survival, reproduction, and hatching success in enchytraeids. However, most studies have assessed the effect of AI, while only a few used a CP. Therefore, we investigated the effects of pure AI, azoxystrobin, and CP Quadris on the survival, reproduction, oxidative stress biomarkers, energy metabolism, and MXR activity in E. albidus. Results showed that CP exhibited higher toxicity in terms of survival (LC50= 16.7 mg CP/kg soil, LC50= 15.3 mg AI/kg soil), while reproduction was affected only by CP (EC50= 3 mg CP/kg soil). Furthermore, although both tested substances caused oxidative stress, the toxicity of the CP was higher. Exposure to CP and AI affected energy metabolism, causing changes in lipid and carbohydrate content. Moreover, while AI caused induction of the multixenobiotic resistance system, CP caused inhibition. These results suggest the importance of evaluating the effect of AI and CP. Furthermore, to obtain more accurate information on the mode of action, access through different endpoints is required. These findings highlight the need to further explore the toxicity of CPs compared to AIs, aiming to predict a more ealistic environmental hazard of fungicides.

ecotoxicology ; enchytraeids ; fungicides ; azoxystrobin ; biomarkers.

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