The dissipation kinetics of malathion in aqueous extracts of different fruits and vegetables

摘要

The dissipation of malathion in 5 % aqueous extracts of some fruits and vegetables including bell pepper, tomato, cucumber, cantaloupe, carrot, and also buffer (control) was investigated at 37 degrees C for 4 h. The dissipation trend of malathion in the fruit/vegetable samples and buffer followed first-order double-exponential decay (FODED) and simple first-order kinetic (SFOK) models, respectively. The initial dissipation rate of malathion in tomato (DT10 = 0.05 h), bell pepper (DT10 = 0.06 h), and carrot (DT10 = 0.07 h) was faster compared to the other samples. The slowest rate of pesticide decline belonged to cantaloupe (DT50 = 1.92 h) with a significant difference from the other samples (p = 0.01), whereas tomato (DT50 = 0.43 h) and carrot (DT50 = 0.53 h) showed the fastest dissipation rate. DT90 values derived from the models revealed no significant difference between the samples except for cantaloupe which had the slowest rate of dissipation (DT90 = 8.27 h) with a significant difference compared to others (p = 0.01). A direct correlation was observed between protein content of the samples and the rate of malathion decline which indicates the role of plant enzymes in degrading malathion residues.