AWWA WQTC54998

With the objective of accurately characterizing DBP exposure, this study focused on different aspects related to sample collection, including the use of appropriate quenching agents and development of a sampling strategy to determine the best distribution system locations at which samples should be collected. A quenching agent study was undertaken where the performance of different quenching agents and preservatives (sodium sulfite, ascorbic acid, sulfuric acid, acetic acid and ammonium sulfate) was compared. For this study a large amount of chloraminated water was collected from the treatment plant, at the point of entry to the distribution system, and separated into three groups of samples: for immediate extraction without quenching agent addition; for immediate quenching but extraction after 48h; and, for immediate quenching with extraction after 7 days. For the second and third group, the quenched samples were stored at 4 degrees C until extraction. For the several quenching agents studied, we found that sodium sulfite was the most effective agent for THM and TOX analysis, while ammonium sulfate proved to be the most effective agent for the preservation of samples for HAA analysis. Includes 3 references, figures.