Dissipation behavior and risk assessment of acephate in brinjal using GLC with FPD.

A study was conducted to observe the persistence, dissipation behavior, and risk assessment of acephate on brinjal fruit. Brinjal crop was sprayed with acephate 75 SP at 560 and 1120 g a.i. ha(-1) at fruiting stage followed by another application at 10-day interval. After sampling, the samples were extracted and cleaned up using quick, easy, cheap, effective, rugged, and safe (QuEChERS) technique, and the residues of acephate were analyzed with gas chromatography using flame photometric detector (FPD). The average initial deposits of acephate on brinjal fruits were found to be 2.54 and 4.07 mg kg(-1) following application of insecticide at 560 and 1120 g a.i. ha(-1), respectively. Residues of acephate reached below determination level of 0.10 mg kg(-1) after 7 days at recommended dosages and after 10 days at double the recommended dosages. The half-life of acephate was found to be 1.55 and 1.52 days, respectively, at 560 and 1120 g a.i. ha(-1). For risk assessment studies, theoretical maximum residue contributions (TMRC) were calculated and compared with maximum permissible intake (MPI). It was observed that TMRC values reached below MPI in 0-day samples at both recommended and double the recommended dosages. Therefore, it was concluded that if waiting period of 1 day is observed, there will be much reduced risk to consumers and the insecticide could be safely used for the protection of brinjal crop from insect pests.

Persistence of fipronil and its risk assessment on cabbage, Brassica oleracea var. capitata L.

Persistence of fipronil in cabbage was studied following three applications of Jump 80 WG at 75 and 150 g a.i. ha(-1) at 7 day interval. The average initial deposits of total fipronil (fipronil and its metabolites) were 1.226 and 2.704 mg kg(-1) on the heads following 3rd application of fipronil at single and double the dosages, respectively. Desulfinyl was found to be the main metabolite followed by sulfone and sulfide. Metabolite amide was not detected in cabbage samples. Half-life periods for fipronil were found to be 3.43 and 3.21 day at single and double the application rates, respectively. Risk assessment of fipronil to the consumers was calculated on the basis of per capita 80 g consumption of cabbage and comparing it to its ADI for an adult of 55 kg which was found to be less than its ADI on 10th day at both the dosages.