Dissipation Pattern of Five Pesticides in Vegetable Samples

Abstract

Pesticides are frequently used in agricultural fields in Bangladesh. Residual pesticides in vegetable samples above maximum residue limits (MRL) are illegal use of pesticides and absence of Good Agricultural Practice (GAP). The Government made Safe Food Law to ensure safe food for all citizens of the country. To assess the dissipation of pesticides in vegetable samples for consumer safety, five locally banded pesticides i.e., Vitaban (chlorpyrifos), Double (mixture of imidacloprid and cypermethrin), Nitro (mixture of chlorpyrifos and cypermethrin), Acephate and Reeva (lambda cyhalothrin) were applied to eight different vegetables at the dose which farmers apply in their field in a large vegetable cultivation area. Samples were harvested from the farmer’s fields at 2h (0 day) after application of pesticides and analyzed at 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12 days keeping them at ambient temperature. Samples were extracted following Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method and cleaned up using primary secondary amine (PSA), and finally analysed by Gas Chromatograph Electron Captured Detector (GC-ECD. Limit of detection (LOD) and limit of quantification (LOQ) of chlorpyrifos, cypermethrin, imidacloprid, acephate and lambda cyhalothrin were 0.019 and 0.057, 0.019 and 0.057, 0.009 and 0.027, 0.019 and 0.057, and 0.009 and 0.057 µg/mL, respectively. Recoveries of these pesticides in these vegetables samples were within acceptable range of 74–110%. Level below MRL value of cypermethrin was found to be 2–5 days while chlorpyrifos, imidacloprid, acephate and lambda cyhalothrin treated vegetables were varied 3–8 days and considered to consume after these days, respectively.