Bromide levels in natural waters: its relationship to levels of both chloride and total dissolved solids and the implications for water treatment

South Australian freshwaters from a wide variety of environments were analysed for bromide and the results correlated with both chloride and total dissolved solids (TDS) concentrations. A linear relationship was obtained which allows chloride data to be successfully used to estimate bromide concentrations. Bromide displayed a slightly better correlation with TDS indicating that an improved estimate of bromide could be made by reference to TDS data which is more easily and commonly obtained, and generally available extensively as historical data. The bromide content in relation to its ratio with both chloride and TDS contents was around seventy percent of the corresponding ratios found in seawater, a finding reported in other published data. The ability to estimate bromide concentrations is a potentially useful tool in the drinking water industry as it enables the assessment of the extent of bromate formation (predicted through the use of mathematical models and other water quality data) which is an important factor when ozonation is being considered as a treatment option, particularly as many water industry regulatory bodies have imposed stringent limits on the levels of acceptable bromate.