No abstract

In order to assist drinking water utilities with identifying the possible sources and causes of taste-and-odor conditions associated with materials used in distribution systems, we evaluated information from case studies and a database from the National Sanitation Foundation (NSF), International. This database identified chemicals that had leached from drinking water system components during testing of materials under ANSI/NSF Standard 61, which provides information to water utilities on potential taste-and-odor and health concerns from the use of new materials. The data were arranged to provide a process for locating the potential source of a taste-and-odor event. After a sensory analysis is conducted on the drinking water samples, the descriptor can be matched with categories on the "Drinking Water Taste and Odor Wheel 2000" in order to suggest the candidate material.

Until recently, the dissolved organic matter (DOM) of pore waters was an overlooked pool of organic matter important to the fate and transport of hydrophobic organic chemicals (HOCs). The aqueous solubility enhancement and the porewater DOM partition coefficient (K PWDOM) of 2,2‘,4,4‘-tetrachlorobiphenyl (TeCB) were compared in samples of anoxic porewater and that same porewater after aeration. Aeration of anoxic porewater increased TeCB partitioning by porewater DOM. Despite a decrease in DOM concentration (coagulated by precipitated iron(III) oxidized during porewater aeration), oxic (aerated) porewaters had greater solubility enhancement and up to an order of magnitude larger K PWDOM than anoxic (unaltered) porewaters. Anoxic porewaters with no detectable dissolved oxygen and 45 mg/L dissolved iron(II) had the smallest TeCB solubility enhancement and K PWDOM. Using experimentally determined K PWDOM values, a three-phase equilibrium-partitioning model predicts the following:  (1) the distribution of HOC freely dissolved and associated with porewater DOM will change when anoxic sediments are aerated; (2) HOC mobility will increase with anoxic sediment aeration because HOC concentration in the aquatic phase will increase; and (3) HOC bioavailability will be less in anoxic porewaters as compared to oxic systems because a smaller concentration of HOC will be freely dissolved.

No abstract

Reports by different scientific groups indicate concern about traces of drugs that could make their way into tap water. Studies indicate that activated carbon and ozone are promising treatment methods to remove traces of pharmaceuticals and pesticides. The Windsor Utilities Commission (WUC), Windsor, Ontario, Canada, evaluated the occurrence of pharmaceuticals and endocrine disrupting chemicals in its raw water supply, and the effectiveness of ozone in removing these compounds. The analysis indicated that trace levels of compounds such as carbamazepine, caffeine, cotinine, and atrazine were detected in raw water and that treatment with ozone resulted in a greater removal versus conventional treatment.