Journal of Pollution

Prediction of Adsorption Capacity, Degradation and Leaching Potential of Metolachlor in Selected Agricultural Soils of Ethiopia

Abstract

Bereket Ayenew Alemu* and Endalkachew Getu*

The adsorption, degradation and leaching of metolachlor in soil samples from 10 locations, is covered in this paper. The batch equilibrium technique was used to conduct the adsorption experiments. Solid-phase extraction and HPLC chromatography were used to evaluate pesticides. The Langmuir and Freundlich models were used to analyze the equilibrium adsorption data. Adsorption and degradation rate are investigated employing kinetic models. According to the findings, the Freundlich (R2 ≥ 0.99) and pseudo second order (R2 ≥ 0.99) models offer the most accurate correlation between the experimental data. The investigated soils showed modest adsorption of metolachlor, with adsorption coefficients ranging from 2.27-6.75 μg1-nmLng-1 and GUS index of 2.70-4.21. This suggests that the chemical may be able to travel downward with percolating water. Metalochlor had the maximum adsorption and persistence among the soils under study (Kf=6.75 μg1-nmLng-1; DT50 117.07 days) in SC1 soil, followed by SD10 (Kf=2.27 μg1-nmLng-1; DT50 33.25 days). Multiple linear regression analysis revealed that the GUS index depends on the combination of DT50 and Kf. The pesticide's poor adsorption on the 10 soils under study, as evidenced by KOC values in the range of 80.13-134.26, also indicates a high risk of contamination to the region's water sources.