Chlorine dioxide, chlorite and chlorate History of Guideline Development ~WHO
****!!!!**** "guidelinevalue for chlorine dioxide was not needed as chlorine dioxide is reduced primarily to chlorite, chlorate and chloride in drinking-water, and to chlorite and chloride upon ingestion"
Chemistry and Toxicity of Selected Disinfectants and By-Products
Volume 3 of the Drinking Water and Health series examined the toxicity of several major disinfectants and many of the by-products formed during drinking water disinfection.
Chlorine Dioxide (Includes Sodium chlorite) Amended Final Work Plan Registration Review Case 4023 ~Regulations.gov
(2017 Sept.)
Situations that resulted in excessive concentrations: "product was added to chiller water used to process poultry carcasses. The application rate was too high given that no carcasses were being processed and the excess chlorine dioxide was released into the workroom air" "steam arose from the surfaces" "Product reacted with biofilm in water system resulting in
release of gas." {Also, malfunctions of generation, sensing and/or dosing in systems}
" residential RfC of 0.05 ppm" "maximum value of 13 ppm measured at one foot from the source exceeds the NIOSH IDLH of 5 pm and the AEGL-3 value of 3 ppm... risks will be severe or even life threatening if they are within one foot of the source"
Chlorine is a toxic gas with corrosive properties. It is widely used as bleach in the manufacture of paper and cloth and in manufacturing solvents, pesticides, synthetic rubber, and refrigerants.
****!!!!****!!!! "Chlorine dioxide is used directly as a bleaching agent for cellulose, textiles, flour, leather, oils, and beeswax. It is also used in the purification of water and as a bactericide and antiseptic." "The annual statewide industrial emissions ... were estimated to be 1136 pounds of chlorine dioxide" "Case reports of human occupational exposure to chlorine dioxide have shown that 19 ppm was fatal to one worker and 5 ppm was definitely irritating. Seven out of 12 workers exposed regularly to chlorine dioxide at levels generally below 0.1 ppm (0.28 mg/m3) reported symptoms of ocular and respiratory irritation leading to slight bronchitis. However, the authors ascribed the bronchitis to occasional acute excursions of chlorine dioxide levels"
"Acidified sodium chlorite: Mixing sodium chlorite solution with a weak food-grade acid solution (commonly citric acid), both stable, produces short-lived acidified sodium chlorite (ASC) which has potent decontaminating properties. Upon mixing the main active ingredient, chlorous acid is produced in equilibrium with chlorite anion. The proportion varies with pH, temperature, and other factors, ranging from approximately 5–35% chlorous acid with 65–95% chlorite; more acidic solutions result in a higher proportion of chlorous acid. Chlorous acid breaks down to chlorine dioxide which in turn breaks down to chlorite anion and ultimately chloride anion" "Sodium chlorite is derived indirectly from sodium chlorate, NaClO3. First, sodium chlorate is reduced to chlorine dioxide, typically in a strong acid solution using reducing agents such as sodium sulfite, sulfur dioxide, or hydrochloric acid. This intermediate is then absorbed into a solution of aqueous sodium hydroxide where another reducing agent converts it to sodium chlorite. Even hydrogen peroxide can be used as the reducing agent, giving oxygen gas as its byproduct rather than other inorganic salts or materials that could contaminate the desired product."
