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This work utilized Information Collection Rule (ICR) data to compare the percent halogen asbromine observed in four classes of disinfection byproducts (DBPs) for which a full spectra of brominated and chlorinatedspecies were available: dihaloacetic acids (DHAAs), trihaloacetic acids (THAAs), trihalomethanes(THMs), and dihaloacetonitriles (DHANs). As expected, the extent of bromine substitution withineach of the four DBP compound classes ranged widely for the data set overall. However, a stronginterdependence between the extents of bromine substitution in the four DBP classes wasdemonstrated such that, for a given water sample, the value in any one of the four classes could bewell predicted by that for any of the other classes. The extent of bromine substitution in DHAAsclosely mirrored that in THMs on a sample-by-sample basis. In contrast, the extent of brominesubstitution in THAAs was approximately 20% lower than that in THMs and the extent of brominesubstitution in DHANs was approximately 30% higher than that in THMs. Four bromineincorporation measures corresponding to the four DBP classes were treated as a multivariateresponse on individual water samples and observations with anomalous interclass brominesubstitution patterns were identified using a multivariate outlier detection method. This method wassuccessful at capturing samples that appeared discordant with respect to bromine incorporation upongraphic inspection. Only a small fraction (less than 1%) of the ICR samples were identified asoutliers in this manner. In about half of these cases, the reported species concentration data werelikely a result of data entry error. These results suggest a simple approach for augmenting routineDBP data quality assurance protocols. Includes 12 references, tables, figures.

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Edition: Vol. - No. Published: 11/02/2003 Number of Pages: 19 File Size: 1 file , 720 KB