AWWA RSP64381

This slide presentation explores this question: given the week-to-week, day-to-day, and even hour-to-hour variation in disinfection byproduct (DBP) levels at the point-of-entry (POE) and in the distribution system, what is the meaning of a grab sample taken at 3- month intervals with respect to public health exposure, and why is this the basis for compliance monitoring? The presentation argues that, given this variability, our compliance monitoring paradigm must change. It presents information that supports the statement that spatial and temporal variability in DBP levels must be taken into consideration when developing a reliable compliance monitoring program. These spatial and temporal variations must also be taken into consideration when assessing exposure in epidemiological studies. The presentation also states that regulations should address individual DBP species. It outlines information which argues that a better assessment of public exposure to HAAs requires the measurement of all nine bromine- and chlorine-containing HAAs; better protection of public health requires the regulation of all 9 HAAs. Includes figures.