University of Peshawar
Muhammad Ismail is an Assistant Professor in the Department of Civil and Environmental Engineering, at University of California, United States.
The analysis of 20 organochlorine pesticides has been carried out in surface water samples collected from Peshawar, KPK, Pakistan, using SPME-GC-ECD method. This method showed good liner response with R2 values in the range of 0.9933 to 0.9999 for all pesticides. Percent recoveries at 1 µg L-1 for all the pesticides ranged from 89.9 to 106.1%. A total of 59 surface water samples were tasted for 20 organochlorin pesticides residues, of which, 37 samples were found contaminated with γ-BHC, 12 samples with β-BHC, 25 samples with heptachlor and 25 samples with aldrin with a maximum concentration of 0.092, 0.053, 0.089 and 0.036 µg L-1, respectively. However other pesticides were found in lesser no. of water samples. The Gamma irradiation decomposition of monocrotophos aqueous solution at various concentrations (60-150 mg L-1) were carried out and their removal efficiency was investigated. Gamma irradiation showed 100% degradation for a 60 mg L-1 solution at an absorbed dose of 1200 Gy. The dose constants investigated in this study ranged from 1.4 10-3 to 3.0 10-3 Gy-1. The effect of saturated solutions of N2 and N2O, and radical scavengers such as tert-butanol, iso-propanol, H2O2, NO3- and NO2- on the degradation of monocrotophos were also studied. The results showed that degradation of monocrotophos mainly proceeded through oxidative •OH radical. The organic by-products were determined by UPLC/MS/MS and inorganic by-products NO3-, NH4+ and PO43- were quantitatively determined by ion chromatography. A detail mechanism pathway of monocrotophos degradation by irradition has been developed.