AWWA WQTC60769

In addition to many other halogenated disinfection byproducts (DBPs), a numberof halonitromethanes including chlorinated, brominated, and mixed bromochlorinatednitromethanes, have been identified in drinking water. These halonitromethanes,especially the brominated ones, are more cytotoxic and mutagenic than most of theDBPs that are currently regulated in drinking water. In this work, gas chromatography-mass spectronomy (GC/MS) was used tostudy the formation of halonitromethanes during the chlorination of laboratory preparedwater. The effect of preozonation and elevated bromide concentration onhalonitromethane formation was investigated.Experiments were conducted in the laboratory using model compound precursorsspiked into deionized water to determine the source of the nitrogen in the nitro group ofthe halonitromethanes. Precursors studied included humic and fulvic acid (SuwanneeRiver Standard), amino acids, 2,4- and 2,5-dichlorophenol, and chlorophyll b, whichwere reacted with chlorine (0.4 mM-2.5 mM) in the presence and the absence of nitrite(0 mM-1.0 mM). For most halonitromethane formation study, the solution of 100 mg/Lhumic acid containing 1 mM nitrite and 0.02-0.8 mM bromide was chlorinated (2.5 mMHOCl) for 24 hours. For the preozonation, 10.5 mg/L ozone was added into the solutionand reacted 10 minutes before chlorine addition. The pH was adjusted to 7.5 using 2mM bicarbonate buffer. ¹⁵N labeled nitrite (<sup>15</sip>NO₂^-) was also reacted, and the massspectra of the halonitromethanes were examined. SPE polymeric sorbent cartridges(100mg/6mL, Strata-X) were used for extraction. Gas chromatography (GC) withelectron ionization mass spectrometry (MS) was used to measure thehalonitromethanes. Includes 3 references, figures.

Product Details

Edition:

Vol. - No.

Published:

11/15/2004

Number of Pages:

5

File Size:

1 file , 290 KB