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"
Chlorine Dioxide, EPA Guidance Manual -Alternative Disinfectants and Oxidants 1999
********* {Includes graph comparing contact time effects for differing dosages.} {Includes chart of level testing methods} {Includes comparison chart of commercial chlorine dioxide generator equipment} "...it is stable in dilute solution in a closed container in the absence of light. " "In drinking water, chlorite (ClO2-) is the predominant reaction endproduct, with approximately 50 to70 percent of the chlorine dioxide converted to chlorite and 30 percent to chlorate (ClO3-) and chloride (Cl-)" "educing the temperature from 20°C to10°C reduced the disinfection effectiveness of chlorine dioxide on Cryptosporidium by 40 percent,which is similar to previous results for Giardia and viruses." "At neutral pH levels, the required doses may be morethan 20 mg/L." "mostly viral aggregates took 2.7 times longer to inactivate with chlorine dioxide than single state viruses" "clumps of... cysts were more resistant to chlorine dioxide" " CT required for 2-log inactivation [of Naegleriagruberi cysts] was much higher than normally employed for water treatment" "In water treatment processes that require high pH, such as softening, chlorine dioxide should beadded after the pH has been lowered" "The occurrence of photochemical decomposition of chlorine dioxide can affect the ultimateconcentrations of chlorine dioxide, chlorite, and chlorate in water treated with chlorine dioxide" "[Sodium chlorite] 25 percent solution [as formulated commercially] may not require any special protection except in cold climates" "The reactions produce chlorite and chlorate as endproducts (compoundsthat are suspected of causing hemolytic anemia and other health effects)" "chlorinedioxide dosage cannot exceed 1.4 mg/L to limit the total combined concentration ofClO2, ClO2-, ClO3-, to a maximum of 1.0 mg/L. Under the proposed DBP regulations,the MRDL for chlorine dioxide is 0.8 mg/L and the MCL for chlorite is 1.0 mg/L"
Alternative Disinfectants and Oxidants Guidance Manual ~Office of Water, EPA
1999. Chapter 4--Chlorine Dioxide. "The MRDL for chlorine dioxide is 0.8 mg/L and the MCL for chlorite is 1.0 mg/L per the D/DBP rule. This means that if the oxidant demand is greater than about 1.4 mg/L, chlorine dioxide may not be used as a disinfectant because the chlorite/chlorate ions byproduct, might exceed the maximum level allowed, unless inorganic byproducts (e.g., chlorite) are subsequently removed. There are numerous means to reduce excessive chlorite levels..."
WHO~ Chlorine Dioxide, Chlorite and Chlorate in Drinking Water--Background document for development of WHO Guidelines for Drinking Water Quality ~WHO
**** 2017 Jan. "Any chlorine dioxide remaining at the consumer’s tap will be reduced to chlorite and chloride upon ingestion. *** Consequently, a guideline value for chlorine dioxide has not been established."..."For chlorite, JECFA established an ADIof 0–0.03mg/kg bw on the basis of the NOAEL of 3mg/kg bw per day...Using the upper bound of the chlorite ADI of 30 μg/kg bw, a typical human body weight of 60 kg, the assumption that drinking-water contributes80% of the total exposure and a typical consumption of 2 L of water per day, the provisional guideline value is calculated to be 0.7mg/L (rounded figure). This guideline value is designated as provisional because use of chlorine dioxide as a disinfectantmay result in the chlorite guideline value being exceeded, " "JECFA therefore established an ADIof 0–0.01 mg/kg bw for chlorate" "[Page 1] Conversion factor in air: 1 part per million (ppm) = 2.8 mg/m3"
