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METHODS FOR THE ANALYSIS OF PRIORITY DBPS IN RO-CONCENTRATED DRINKING WATER
Citation:
BODIN, N., H. WEINBERG, S. KRASNER, S. D. RICHARDSON, J. G. PRESSMAN, T. F. SPETH, R. J. MILTNER, AND J. E. SIMMONS. METHODS FOR THE ANALYSIS OF PRIORITY DBPS IN RO-CONCENTRATED DRINKING WATER. Presented at 2007 WATER QUALITY AND TECHNOLOGY CONFERENCE, CHARLOTTE, NC, November 15 - 18, 2007.
Description:
The ability to understand mechanisms of formation and occurrence of disinfection by-products (DBPs) resulting from treatment of natural waters has been limited to those formed at µg/L levels. Toxicological evaluations suggest that many of the DBPs missing from current regulation may be of greater concern to public health, but because of their sub-µg/L levels and resulting challenges to analytical methods, we have little occurrence data for them. “Scaling-up” drinking water DBPs by concentrating (˜130-fold with RO) the total organic carbon from a treated surface water and subjecting the concentrate to chlorination generated higher levels of all DBPs that could then be detectable using currently available methods. Moreover, such a water was used in toxicological evaluations, so characterization of the DBPs formed was critical. Our laboratories have previously developed methods for the analysis of over 50 priority DBPs in treatment plant drinking waters. These methods use a variety of techniques, including micro- or macro-scale liquid-liquid and solid-phase extraction, and subsequent analysis by gas chromatography with electron capture or mass spectrometric detectors. However, when handling chlorinated RO concentrates, the organic-rich matrix presented challenges to existing protocols, including the generation of emulsions and the clogging of extraction columns. This presentation will discuss approaches that have been used to adapt the methods used in our laboratories for the accurate quantitation of many of the priority DBPs in the chlorinated RO concentrates of natural water. The targeted DBPs included, among others, expanded numbers of chlorine- and bromine-containing haloketones, haloacetaldehydes, haloacetonitriles, halonitromethanes, haloacetamides, and halofuranones, as well as iodinated trihalomethanes. Different dilutions were prepared, standard additions used where appropriate, and recovery of analytes calculated. Methods were generated that balanced accuracy with quantifiable detection and subsequently revealed whether priority DBPs might be formed during drinking water treatment.