AWWA WQTC59001

AWWA WQTC59001 Application of a Consolidated Method (LLE-GC/ECD) for the Determination of Halogenated Acetaldehydes (HA) in Canadian Drinking Water
Conference Proceeding by American Water Works Association, 11/02/2003

Koudjonou, Boniface; LeBel, Guy L.

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Chloral hydrate (CH), a chlorinated acetaldehyde, has been found in chlorinated drinking water.In addition, other related haloacetaldehydes (HAs), have been tentatively identified in drinkingwater samples. However, authentic standards required for quantification of these HAs have onlyrecently been available commercially. Dichloroacetaldehyde (DCA), bromochloroacetaldehyde(BCA), dibromoacetaldehyde (DBA), bromodichloroacetaldehyde (BDCA), chlorodibromoacetaldehyde(CDBA), and tribomoacetaldehyde (TBA) were purchased and verified for purityand stability using a dual-column GC-ECD system. Several commercial standards containedother target HAs. The stability of the HAs stock solutions was solvent dependent. When preparedin acetone, several HAs, particularly the brominated species partially degraded and bromoacetonewas formed. However, the target HAs were all stable in methyl-tert-butyl-ether (MTBE)+ for up to 8 months. The analyticalparameters, required for the quantification of HAs in water, were determined and used to evaluatethe stability of the HAs in water. All the target HAs were stable in water for up to 14 days usingconsolidated method sampling protocol conditions (field pH adjustment [pH 4.2] and storage at4C). However, at typical drinking water pH and temperature conditions, the stability varied withthe HA species, pH, temperature and storage period. The trihalogenated acetaldehydes degraded,in part, to their corresponding trihalomethanes (THMs) at increasing pH and temperature. Mosttarget HAs were detected in Canadian drinking water samples and the speciation was dependenton water quality (e.g. bromide concentration) and treatment processes. Also, the pattern for thedi- and tri- halogenated species varied within the distribution system. For selected water samples,the contribution of CH to the total HAs ranged from 7% to 51% and the total HAs represented10% to 46% of the total THMs. Includes 19 references, tables, figures.