Effect of pH on the degradation dynamics of deltamethrin insecticide in water

The degradation dynamics of deltamethrin 25% wettable dispersible granules (WDG) insecticide were studied in different pH water under laboratory-controlled conditions using a gas chromatography-mass spectrometry (GC-MS) based analytical method. The analytical method used for the analysis was validated to quantify the deltamethrin residues in the samples. The study found that dissipation of deltamethrin followed a first-order kinetics and the half-life depends upon the pH conditions. More specifically we observed that the half-life values ranges from 0.62 to 0.84 days depending upon the pH conditions and the number of treatments. Furthermore, the degradation was slower at pH 4.0 in comparison to pH 7.0 and pH 9.2, with notable persistence of deltamethrin residues up to the fifth day, suggesting that acidic conditions may prolong its stability in aquatic environments.