ACTI-BROM is an oxidizing biocide program that utilizes a chlorine source, either gas or sodium hypochlorite, to activate a bromide/biodispersant chemistry. On their own, the bromide salt and biodispersant present in ACTI-BROM are nonmolluscicidal; however, in the presence of chlorine gas or sodium hypochlorite in situ, ACTI-BROM=s bromine portion is activated to form hypobromous acid and hypobromite ion, depending on water pH (McCarthy and Trulear 1992). Both these forms of bromine are lethal to zebra mussels, destroying vital tissue. Hypochlorous acids are also formed, and the ratio of hypobromous to hypochlorous acid can be varied by altering the molar ratios between sodium bromide-surfactant and the chlorine source.
The oxyalkylate surfactant, present at 5 to 10 ppb, is not expected to contribute to toxicity, but may inhibit settling and attachment by acting as a biodispersant.