Development of a New, Simple, Innovative Procedure for the Analysis of Bromate and Other Oxy-Halides at Sub-ppb Levels in Drinking WaterEPA Grant Number: R825952
Title: Development of a New, Simple, Innovative Procedure for the Analysis of Bromate and Other Oxy-Halides at Sub-ppb Levels in Drinking Water
Investigators: Weinberg, Howard S. , Singer, Philip C.
Institution: University of North Carolina at Chapel Hill
EPA Project Officer: Nolt-Helms, Cynthia
Project Period: September 1, 1997 through August 31, 1999 (Extended to December 31, 2000)
Project Amount: $198,460
RFA: Drinking Water (1997) RFA Text | Recipients Lists
Research Category: Water , Drinking Water
This proposal presents an innovative approach to oxyhalide analysis that permits bromate and other oxyhalide detection at 0.5ug/L or lower from a single injection of aqueous sample that has undergone no special pre-treatment other than filtration to remove suspended material. This method utilizes anion chromatographic resolution of the oxyhalides iodate, chlorite, and bromate and the subsequent generation of the tribromide ion which is detected at 267nm in a UV spectrophotometer. The regulation of bromate in drinking water is being proposed at a PQL (practical quantitation level) of 10ug/L, despite animal studies that suggest a 10-5 cancer risk level of 0.5ug/L. Accurate, sensitive detection methods for bromate are needed to determine the levels of bromate in finished drinking water and to assess the exposure of the public to this drinking water contaminant and to other oxyhalide species, such as iodate. It is well-known that ozonation of bromide-containing water leads to the formation of bromate, but a lack of sensitivity in the past has prevented successful monitoring of oxyhalide species generated from other disinfection processes, including chlorination.
An ion chromatographic system will resolve the oxyhalides which will combine with a post-column reagent generating the tribromide ion which will be detected in a UVspectrophotometer. The operating parameters of each segment of this process will be optimized for maximum sensitivity towards all known oxyhalides in synthetic solutions with a controlled ionic strength and organic carbon background. Following evaluation of appropriate quenching procedures, the method will be applied to a wide variety of drinking waters derived from different treatment processes. In addition to waters from municipal treatment plants, bottled waters, filtered waters, and boiled waters will be assessed.
This project will answer a specific call by EPA to provide a "user-friendly" sensitive analytical method for the detection of bromate in drinking waters at the 0.5ug/L level. This method will not require sophisticated sample handling or analytical equipment and will have the added bonus of permitting simultaneous, sub-ppb analysis of other oxyhalides. Accordingly, this project will allow for the first assessment of the presence of iodate in drinking waters. It is expected that this project will provide the tools that have been sought for several years to allow successful assessment of oxyhalide levels in finished drinking water which in turn will determine the future efficacy of the alternative treatment processes which generate them and the operating conditions under which their formation can be controlled.