Br^-. An inorganic bromide anion. Also used to describe any compound (usually a bromide salt) that contains the Br^- ion, such as sodium bromide (NaBr).
Inorganic bromide is widely distributed in the environment. It is commonly found in natural waters, that is, streams, lakes and reservoirs. Br- comes from wastewater discharges, agricultural run-off (mainly from soil fumigation) and run-off from roads. The bromide ion is a precursor to water disinfectant by products when ozone or possibly hypochlorite (bleach) are used as disinfectants, and therefore needs to be controlled. The bromide ion itself is sometimes used as a water disinfectant because, in water it forms hypobromous acid (HOBr) considered as a strong disinfectant.