Inhaltszusammenfassung:
Pesticides are widely used in modern agriculture and are frequently detected in aquatic environments. However, ecotoxicological risk assessments are commonly performed under standardized laboratory conditions that do not adequately reflect environmentally relevant variations. This thesis investigates how temperature and pH influence the toxicity of two widely used pesticides, nicosulfuron (an herbicide) and azoxystrobin (a fungicide), on the early life stages of zebrafish (Danio rerio).
To achieve this purpose, I used zebrafish in their early life stages as experimental subjects to test the developmental toxicity, proteotoxicity and behavior toxicity of nicosulfuron and azoxystrobin at different pH and temperature. The results demonstrated that nicosulfuron exhibits relatively low toxicity to zebrafish embryos under optimal conditions; however, sub-organismic responses, particularly stress protein (Hsp70) expression, revealed the changes in sensitivity under environmentally stressful conditions.
Azoxystrobin induces developmental abnormalities, delayed development, and altered physiological responses at higher concentrations. The results further demonstrated that environmental factors significantly modulate the toxicity of azoxystrobin, with complex interactions between chemical exposure and abiotic stressors influencing survival, hatching, heart rate, and stress protein expression.
In the final part of this thesis, the findings revealed that environmental factors strongly influence pesticide-induced behavioral responses. Nicouslfuron has a neuroexcitotoxic effect that enhances swimming activity in zebrafish larvae, while azoxystrobin inhibits swimming activity. Furthermore, pesticide effects were shown to be context-dependent. Light conditions significantly altered locomotor activity and enhanced the detection of behavioral toxicity. In contrast, azoxystrobin elicited detectable behavioral toxicity only under acidic conditions in darkness
Overall, abiotic environmental factors such as temperature, pH, and light play a crucial role in shaping toxicological responses during early developmental stages. These findings highlight the importance of incorporating environmentally relevant conditions into ecotoxicological risk assessments to improve the ecological relevance and predictive power of pesticide hazard evaluation.
