Removal of Chlorpyrifos Residue in Water and Pakchoi by Sodium Hypochlorite

The effect of sodium hypochlorite on degradation of chlorpyrifos in water and in the elimination of chlorpyrifos residue on pakchoi (a variety of Chinese cabbage) was studied.The results indicated that washing with sodium hypochlorite solutions at lower pH or higher concentration was more effective on degradation of chlorpyrifos residue in water.For instance,the percentage of degradation reached 97.4% and 100% by 20 and 500 mg/L sodium hypochlorite in 5 min at pH 5.0,respec-tively.Washing with sodium hypochlorite solutions was effective in the removal of chlorpyrifos residue in pakchoi,the removal rate was 34.4% ~70.6% at the concentration of 100 and 500 mg/L,respectively.