Degradation of chlorpyrifos, an organophosphorus insecticide in aqueous solution with gamma irradiation and natural sunlight

The radiation induced degradation of chlorpyrifos, an organophosphorus insecticide, was studied using gamma irradiation and sunlight. Chlorpyrifos was analysed by High Performance Liquid Chromatography (HPLC) with Photo Diode Array (PDA) detector. The effect of various doses (1–10 kGy) of gamma irradiation on the degradation of different concentrations (5, 10 and 20 mg/l) of chlorpyrifos insecticide in distilled water was investigated. The lowest tested concentration (5 mg/l) indicated higher removal compare to higher concentration (10–20 mg/l) and irrespective of the absorbed doses (1–10 kGy) and the study revealed a direct relation between absorbed dose and percent of pesticides removal. The degradation of chlorpyrifos by sunlight in distilled water was 39.5% in 12 days, whereas 51.95% was degraded in lake water under same period and same light intensity. The highest degradation rate was recorded in distilled water in 9 days (4.2% per day) at the light intensity of 43,400 lx and in lake water highest degradation was found in 1st day (7.4% per day) at the light intensity of 42,200 lx. Chlorpyrifos degradation using gamma irradiation had the potential to clean up environmental samples contaminated with the organophosphate pesticide, chlorpyrifos.