In aqueous oxidative processes with ozone (O3), chlorine, or chloramine, naturally occurring iodide (I-) can easily be oxidized to hypoiodous acid (HOI) which can react with natural organic matter (NOM) or be further oxidized to iodate (IO3-). Such processes can be of importance for the geochemistry of iodine and for the fate of iodine in industrial processes (drinking water treatment, aquacultures). Whereas IO3- is the desired sink for iodine in drinking waters, iodoorganic compounds (especially iodoform, CHI3) are problematic due to their taste and odor. To assess the sink for iodine during oxidation of natural waters, we determined the kinetics of several oxidation reactions of HOI. Ozone, chlorine, and chloramine have been tested as potential oxidants. Ozone oxidized both HOI and hypoiodite (OI-) (kO3+HOI = 3.6 × 104 M-1 s-1; kO3+OI− = 1.6 × 106 M-1 s-1) in a fast reaction. Chlorine species oxidized HOI by a combination of second- and third-order reactions (k‘ ‘HOCl+HOI = 8.2 M-1 s-1; k‘ ‘‘HOCl+HOI = ...

Oxidation of Iodide and Hypoiodous Acid in the Disinfection of Natural Waters

Types of Antimicrobial Agents

Due to their efficacy in deactivating a range of microbial pathogens, particularly amoebic cysts, iodine-based disinfectants have been a popular option for point-of-use (POU) drinking water disinfection by campers, the military, and rural consumers in developing countries. Recently, concerns regarding the formation of cytotoxic and genotoxic iodinated disinfection byproducts (I-DBPs) have arisen during chloramine disinfection of iodide-containing waters in the developed world; similar concerns should pertain to iodine-based POU disinfection. Because there are alternative POU disinfection techniques, including chlorine-based disinfectants, this paper compared disinfection byproduct formation from a range of iodine-based disinfectants at their recommended dosages to chlorination and chloramination under overdosing conditions. Just as chloroform was the predominant trihalomethane (THM) forme during chlorination or chloramination, iodoform was the predominant THM formed during iodination. Conditions fostering...

Comparison of Byproduct formation in Waters Treated with Chlorine and Iodine: Relevance to Point-of-Use Treatment

Chlorine dioxide and iodine inactivated poliovirus more efficiently at pH 10.0 than at pH 6.0. Sedimentation analyses of viruses inactivated by chlorine dioxide and iodine at pH 10.9 showed that viral RNA separated from the capsids, resulting in the conversion of virions from 156S structures to 80S particles. The RNAs release from both chlorine dioxide- and iodine-inactivated viruses cosedimented with intact 35S viral RNA. Both chlorine dioxide and iodine reacted with the capsid proteins of poliovirus and changed the pI from pH 7.0 to pH 5.8. However, the mechanisms of inactivation of poliovirus by chlorine dioxide and iodine were found to differ. Iodine inactivated viruses by impairing their ability to adsorb to HeLa cells, whereas chlorine dioxide-inactivated viruses showed a reduced incorporation of [14C]uridine into new viral RNA. We concluded, then, that chlorine dioxide inactivated poliovirus by reacting with the viral RNA and impairing the ability of the viral genome to act as a template for RNA synthesis.

Mechanisms of inactivation of poliovirus by chlorine dioxide and iodine.

Variability of chlorination by-product occurrence in water of indoor and outdoor swimming pools.

A paper presented on Jun. 5, 1967, at the Annual Conference, Atlantic City, N.J., by A. P. Black, Research Prof . Emeritus of Chemis ry and Bioenvironmental Eng., Univ. of Florida, and P oject Director , Iodine Demonstratio Gra t, Gainesville, Fla .; W. C. Thomas Jr., Pr f, of Medicine, J. HiUis Miller H alth Center ; W. P. Bonner and M. A. Keirn, PHS Trainees, and A. A. Jabero, Graduate Student, Dept. of Bioenvironmental Eng., all of Univ. of Florida ; J. J. Smith Jr., Research Assoc., Iodi e Demonstrati n Grant, Gainesville, Fla.; and R. N. Kin an, Asst. Chief, Div. of Rese rch & Training Grants , FWPCA, Washington, D.C.

M A Keirn

Papers

Iodine for the Disinfection of Water

The disinfection of swimming pool water. II. A field study of the disinfection of public swimming pools.

The disinfection of swimming pool waters. I. Comparison of iodine and chlorine as swimming pool disinfectants.