Contaminant Minimization for Safer Drinking Water

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The ultimate objective of the proposed research program is to improve the provision of safe drinking water to all, particularly in regards to minimizing chemical contaminants that are of potential human health concern.           Generally, the HQP involved in this research will discover and report on factors which improve the removal of trace contaminants from water and/or minimize byproducts formed from the disinfection or oxidative treatment of water when using conventional and/or innovative treatment processes. Even at trace levels, several contaminants in drinking water have known or suspected adverse human health effects. Nitrosamines, for example, can exert carcinogenic effects at ng/L (parts-per-trillion) concentrations and can be present either in the raw water or are formed as byproducts of disinfection. Certain pharmaceuticals can also find their way into our drinking water treatment plant intakes, usually as a result of upstream wastewater discharges and can be a significant fraction of a drinking water treatment plant's influent water, especially in heavily urbanized areas. They are not readily removed by conventional treatment processes, and while their direct effects are thought to be minimal some of them can be transformed during treatment into the nitrosamines mentioned above.           In addition, the list of `emerging contaminants' like nitrosamines and pharmaceuticals continues to grow as analytical methods and toxicological testing protocols evolve. Some trace contaminants are even `re-emerging'. For example, the compound known as `mutagen X', discovered as a chlorination byproduct more than 20 years ago, is currently being re-examined for its potential health impacts and treatability.  Of particular interest has been the recent discovery of microscopic plastic particles (micron-sized or nanometer-sized plastics) that have been shown to be incorporated into organs and tissues and either cause health effects directly or be vectors for the transmission of some of the abovenamed contaminants into tissues where they may have effects. Materials adsorbed to them may also react with disinfectants during treatment and form byproducts such as those named above.           Through the carefully planned and executed research that is proposed, it is hoped that means to reduce the occurrence and impact of these and other chemical contaminants in our drinking water may be discovered and employed.