Lack of Promoting Effect of Sodium Chlorate and Potassium Chlorate in Two-Stage Rat Renal Carcinogenesis

Final Report on the Safety Assessment of Potassium Chlorate

Potassium Chlorate is an inorganic salt that is intended for use in cosmetic ingredients as an oxidizing agent, but there are no current uses reported. Oral administration of Potassium Chlorate with 36C label to rats produced elimination of the label as chloride, chlorate, and chlorite, in descending order of percentage. Potassium Chlorate causes mechanical fragility in erythrocytes and is a catalase inhibitor. In animals dosed orally with Potassium Chlorate, renal tubular necrosis has been seen. Only one mutagenicity study was available, the results of which were negative. A 6-month study in male rats of the tumor promotion potential of Potassium Chlorate caused no effect. Chlorate salts are considered toxic to humans with the lethal ingested dose estimated at 15 to 35 g. Toxic effects of lower doses in humans are seen in the kidneys, gastrointestinal tract, and blood (erythrocytes). Toxic effects in humans appear to be cumulative. The available data were insufficient to support the safety of this ingredient in cosmetic formulations. Additional data are considered necessary to evaluate the safety of this ingredient, including purpose of use and likely concentration of use in cosmetics, 28-day dermal toxicity data, ocular irritation data (if intended for use on or near the eye), two mutagenicity studies (if results are positive, carcinogenicity data are needed), human irritation data as a function of dose, and human sensitization data. It cannot be concluded that this ingredient is safe for use in cosmetic products until the listed safety data have been obtained and evaluated.

The effects of subchronic chlorate exposure in Sprague-Dawley rats

Male and female Sprague-Dawley rats were exposed to drinking water containing 3.0, 12.0 or 48.0 mM sodium chlorate. The mean drinking water consumption varied between exposure groups from 100-200 ml/kg/day. Female exposure groups consistently drank more water (23-42%) than male exposure groups thereby receiving more chlorate/kg/day at every exposure level. There were no compound related deaths; however, both males and females in the high exposure groups had significant weight loss during the 90-day exposure period. Also, in these same groups females had mild but significant decreases in the following relative organ weights; adrenals, thymus and spleen, while the relative brain weight was increased. In males, the heart, kidneys and liver were mildly decreased while the brain and testes were mildly increased. Red blood cell counts and percent hematocrit were decreased in both sexes in the high dose group. Pituitary gland (pars distalis) vacuolization and thyroid gland colloid depletion were prominent in both sexes in mid and/or high dose animals. A NOAEL of 0.36 mM chlorate/kg b.w./day in males and 0.50 mM chlorate/kg b.w./day in females were established.

Effect of chlorine dioxide water disinfection on hematologic and serum parameters of renal dialysis patients

A study of the blood chemistry parameters of 20 renal dialysis patients was undertaken when a local water district introduced chlorine dioxide (CIO2) as a disinfectant at the filtration plant headworks for 12 months without informing the renal dialysis clinic in the area of this potentially adverse change. Due to data limitations, including changes in clinical laboratories and lack of pre-exposure data for some patients, the analysis was focused on 17 patients for whom data was produced by the same clinical laboratory, for 3 months of pre-exposure and 1 month of exposure. Least-squares means of each parameter by CIO2 levels of 0.0 and 1.0 mg/L at the treatment plant were adjusted for age, sex, and creatinine. Water purification at the clinic included passing the water through granular activated carbon, filtration by 5-mu filters, and the use of reverse osmosis. Chlorination products measured at the clinic after this purification and prior to preparation of the dialysate consisted only of chlorite at the 0.02-0.08 mg/L level. No evidence of CIO2-induced anemia was found, nor were any other biologically significant responses observed. Study limitations include several potentially important hematologic parameters which were not measured, the small sample size, and three clinical laboratory changes.