Abstract
The contamination of drinking water resources with micropollutants, such as pesticides, is of great concern nowadays. This work was to investigate the reactivity of eight classes of 26 extensively used pesticides listed in Table 1, with three common disinfectants including UV(254) (average intensity of 10.8mW-cm(-2)), ozone (dosage of 4.1 similar to 6.2 mg center dot L(-1)) and permanganate (dosage of 15.8 mg center dot L(-1)). The reactions were allowed to proceed for 30min at pH 7.0 and ambient temperature (25 +/- 3 degrees C). As shown in Table 1, results indicate that under the applied experimental conditions, more than 95% of chlorobenzilate, etridiazole, alachlor, butachlor, metolachlor, propachlor, atrazine, simazine, aldicarb, oxamyl and methiocarb could be effectively removed by UV(254); and the removal efficiencies of other pesticides were over a range of 12.9% similar to 77.7%. Ozone could completely degrade chloroneb, dichlorvos, bromacil, aldicarb, carbaryl, carbofuran, oxamyl and methiocarb; prometon and aldicarb sulfone were resistant to ozonation; and the removal efficiencies of other pesticides varied from 19.0% to 93. 1 %. Permanganate could fully degrade dichlorvos, aldicarb and methiocarb; organochlorines, dinitroanaline, anilinopyrimidine, acetamides and other carbamates were resistant to permanganate oxidation; and the removal efficiencies of other pesticides ranged from 16.0% to 88.2%. If the practical disinfectant dosage applied in drinking water treatment is considered, it is expected that most of the pesticides will be completely degraded by ozone, a few by permanganate, but probably none by UV(254).