Origin of natural organic matters in drinking water reservoir and relationship with trihalomethane formation potential

1. Establishment of method to characterize natural organic matter (NOM)A method was established tocharacterize NOM by Pyrolysis-GC/MS，GPC和UF fractionation. and a method to concentrate diluted samples such as water in drinkingwater reservoir was also established by utilizing reverse osmosis and freeze-dry. by这些方法，我们可以evaluate NOM from its pyrogram， molecular weight distribution分离的组织材料concentration (DOC)，trihalomethane formation potential (THMFP) and UV absorbance both in raw sample and fractionatedone.2. Seasonal change of NOM in drinking water reservoir, Lake TsukuiIn Tsukui Lake，DOC and THMFP was higher in summer than in winter. Molecular weight fraction between 1,000 to 10,000dalton had higher specific THMFP =THMFP/DOC than fraction less than 1,OOO dalton。Characterization of released NOM from sediment of drinking water reservoirSediment released tests与sediment and bottom layer水in Tsukui Lake. THMFP rose up to 300μg/L underaerobic环境and 764μg/L under anaerobic环境in 21 days. anaerobic environmentDOC release and increased THMFP more than aerobic one. Specific THMFP showed少差异between这两个条件和rather stable in time (34μg/mg on average) From the viewpoint ofmolecular weight distribution by GPCNOM released under anaerobic condition had three peaks in its chromatogram at 10d1510 D13 D1 and 10 D12 D1 ~ 10 D13 D1 dalton，althose in aerobic condition had an additional and large peak at D12 ddalton . As theseresults,we could evaluated the difference between released NOM under anaerobic and aerobic condition by数量重量分布while specific THMFP showed little difference。

1. Establishment of method to characterize natural organic matter (NOM)A method was established to characterize NOM by Pyrolysis-GC/MS, GPC and UF fractionation. And a method to concentrate diluted samples such as water in drinking water reservoir was also established by utilizing reverse osmosis and freeze-dry. By these methods, we can evaluate NOM from its pyrogram, molecular weight distribution, dissolved organic matter concentration (DOC), trihalomethane formation potential (THMFP) and UV absorbance both in raw sample and fractionated one.2. Seasonal change of NOM in drinking water reservoir, Lake TsukuiIn Tsukui Lake, DOC and THMFP was higher in summer than in winter. Molecular weight fraction between 1,000 to 10,000 dalton had higher specific THMFP (=THMFP/DOC) than fraction less than 1,OOO dalton.3. Characterization of released NOM from sediment of drinking water reservoirSediment released tests were conducted with sediment and bottom layer water in Tsukui Lake. THMFP rose up to 300μg/L under aerobic condition and 764μg/L under anaerobic condition in 21 days. Anaerobic environment enhanced DOC release and increased THMFP more than aerobic one. Specific THMFP showed less difference between these two DO condition and rather stable in time (34μg/mg on average). From the viewpoint of molecular weight distribution by GPC, NOM released under anaerobic condition had three peaks in its chromatogram at 10ィイD15ィエD1, 10ィイD13ィエD1 and 10ィイD12ィエD1〜10ィイD13ィエD1 dalton, although those in aerobic condition had an additional and large peak at 10ィイD12ィエD1 dalton. As these results, we could evaluated the difference between released NOM under anaerobic and aerobic condition by molecular weight distribution while specific THMFP showed little difference.