Abstract
Pollutants in water environment are briefly reviewed concerning the water quality standard, especially the new items listed in the standard. They are disinfection byproducts, organohalogen compounds, and agrochemicals. Effects of chlorination and ozonation in the water treatment process on these contaminants and the contribution of the free radical to their toxicity are also discussed. Chlorination and ozonation in the water treatment process are believed to produce various active oxygen species, which seem to participate in the reaction with fumic acid, pollutants and bacteria. Main active oxygen species generated during the water treatment was a hydroxy radical, because DMPO-OH adduct was detected by the spin-trapping electron spin resonance (ESR) technique using 5, 5-dimethyl-1-pyrroline-N-oxide (DMPO) as a spin-trapping reagent. Besides DMPO-OH, several DMPO adducts detected in both treatments were also described.
