Degradation kinetics of Ivermectin in tropical soils: the role of pH variability

Ivermectin is a widely used antiparasitic medication essential for controlling parasitic infections in agricultural and veterinary applications. However, its environmental use is limited by its potential ecological impacts on non-target organisms. This study investigates the degradation kinetics of ivermectin under varying soil pH conditions to better understand its environmental persistence and bioavailability, particularly in tropical soils. The results demonstrate a strong dependence of ivermectin degradation rates on soil pH, with distinct trends observed in acidic and basic conditions. In alkaline soils (pH > 7), ivermectin undergoes accelerated degradation, driven by increased hydrolysis and oxidation reactions. This rapid breakdown is attributed to the enhanced chemical reactivity of ivermectin in high pH environments, where alkaline hydrolysis dominates. Conversely, in acidic soils (pH < 7), degradation rates are significantly reduced, as the chemical stability of ivermectin is preserved under low pH conditions. Acidic environments inhibit hydrolysis while stabilizing the molecular structure of ivermectin, leading to its prolonged persistence in the soil matrix. Furthermore, pH influences ivermectin solubility and microbial activity: in acidic soils, increased solubility enhances microbial access, promoting biotic degradation, although at a slower chemical degradation rate. In contrast, basic conditions decrease solubility, limiting microbial involvement and favoring abiotic pathways. The interplay between pH-dependent chemical and microbial degradation processes highlights the complex dynamics governing ivermectin’s environmental fate. These findings provide critical insights into the role of soil pH in shaping ivermectin’s persistence, bioavailability, and ecological impact. Understanding these trends is crucial for predicting the environmental behavior of ivermectin, especially in agricultural settings, where soil pH management can serve as a mitigation strategy. By optimizing soil pH, the ecological risks associated with ivermectin use can be minimized, reducing potential harm to non-target organisms and mitigating environmental contamination. This study underscores the need for integrating soil chemistry into sustainable agricultural practices to ensure the responsible use of ivermectin.