ORIGINAL ABSTRACT

The intensive and recurring use of pesticides in agriculture has raised environmental concerns and impacts on ecosystem biodiversity. Glyphosate and 2,4-D are among the most widely used herbicides worldwide for weed control. Continuous and prolonged exposure of the soil to these compounds can compromise natural biogeochemical processes, affecting the structure and functioning of the edaphic microbiota, which plays a crucial role in nutrient cycling and bioremediation processes. In this study, biodegradation of these pesticides was investigated by the Bartha and Pramer spirometry technique, which estimates the heterotrophic microbial activity by the quantification of carbon dioxide released. Experimental data obtained were analyzed via the Ford-Walford model, which enabled the description of the behavior of the microbial degradation of pesticides in soil, estimating the asymptotic limit of stabilization of the CO2 generation. Results indicated that glyphosate shows a more accelerated biodegradation rate, with less environmental persistence and, potentially, less risk of accumulation in the soil, compared to 2,4-D, which showed more environmental persistence. These findings highlight the need for continuous monitoring of pesticide residues in soil and the adoption of sustainable agricultural practices. The integration of microbiological assays and mathematical modeling also provides valuable insights into xenobiotic degradation mechanisms, supporting strategies to mitigate the environmental impacts of persistent agrochemicals.