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The occurrence of N-nitrosodimethylamine (NDMA) and its precursors on ozonationand chloramination of water were investigated. A national survey of NDMA confirmedthe frequent presence of NDMA in water sources of the Yodo and Tone River basins, thefirst and second largest basins on a population basis in Japan, at the level of severalng/L. Relatively high concentrations of NDMA were also shown to be formed byozonation, especially in the Yodo River basin. In sewage treatment plants (STPs)located in the Yodo River basin, NDMA concentrations before and after ozonation were16 - 290 ng/L and 14 - 440 ng/L, respectively. At one STP in the area, an extremelyhigh concentration of NDMA formation (10000 ng/L) was found after ozonation in oneinfluent water sample. NDMA precursors on ozonation in the influent at the STP werepartly identified as anti-yellowing agents. In the middle Tone River basin, NDMA and itsprecursors were frequently detected on chloramination regardless of the season. In theupper Tone River basin, the STP effluents were shown to contribute to the sources ofNDMA precursors in the downstream water. NDMA concentrations afterchloramination of the STP effluents ranged from 140 to 240 ng/L. NDMA itself wasshown to be contained at high levels ( 30000 ng/L) in industrial discharge from alivestock animal treatment facility. Includes 14 references, tables, figures.

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Edition: Vol. - No. Published: 11/01/2009 Number of Pages: 23File Size: 1 file , 1.3 MB