Which term describes the residual bromine measurement used in water testing?

• A. Total Bromine Residual
• B. Free Bromine Residual
• C. Bromine Vapor Residual
• D. Total Bromide Residual

Answer: (A)

Residual bromine measurement in water testing reflects all bromine species present after disinfection. The term that captures this total amount is total bromine residual, because it includes both the free, active bromine species and the bromine that has formed combined compounds. This differs from the free bromine residual, which only accounts for the active disinfectant portion and misses the bromine bound in combined forms. The other options aren’t standard metrics for this purpose—bromine vapor residual isn’t used in routine water testing, and total bromide residual measures bromide ion, not the disinfection-capable bromine. So, total bromine residual is the correct description.