International Programme on Chemical Safety


IPCS Environmental Health Criteria 216: Disinfectants and disinfectant by-products

IPCS Environmental Health Criteria 216: Disinfectants and disinfectant by-products

Please note that these corrigenda have been incorporated in the electronic versions of the document.

Page 3, 4th paragraph, 3rd line:

"tens of milligrams" should read "tens of micrograms"

Section 4.5.1, page 237, 2nd paragraph: The last four lines should read:

[Rats] tolerated doses of 200 mg/kg of body weight administered by gavage but displayed severe symptoms including dyspnoea, laborious breathing, depressed motor activity and cyanosis at higher doses (Komulainen et al., 1994). At necropsy, gastrointestinal inflammation was observed, and oedema was noted in the lungs and kidneys. An LD50 of 230 mg/kg in 48 hours was identified in this study.

Page 276, add after the section 4.9:

After the printing of the document, Dr James Huff kindly brought to the attention of the Secretariat that a study on the carcinogenicity of sodium hypochlorite, and another on the carcinogenicity of bromodichloromethane, chlorodibromomethane, bromoform, chlorine, and chloramine, were not cited in the document. The authors' abstracts of these studies are given below.

- Soffritti M, Belpoggi F, Lenzi A, Maltoni C (1997) Results of long-term carcinogenicity studies of chlorine in rats.Ann NY Acad Sci, 837: 189-208.

Four groups, each of 50 male and 50 female Sprague-Dawley rats, of the colony used in the Cancer Research Center of Bentivoglio of the Ramazzini Foundation, 12 weeks old at the start of the study, received drinking water containing sodium hypochlorite, resulting in concentrations of active chlorine of 750, 500, and 100 mg/l (treated groups), and tap water (active chlorine < 0.2 mg/l) (control group), respectively, for 104 weeks. Among the female rats of the treated groups, an increased incidence of lymphomas and leukemias has been observed, although this is not clearly dose related. Moreover, sporadic cases of some tumors, the occurrence of which is extremely unusual among the untreated rats of the colony used (historical controls), were detected in chlorine-exposed animals. The results of this study confirm the results of the experiment of the United States National Toxicology Program (1991), which showed an increase of leukemia among female Fischer 344/N rats following the administration of chlorine (in the form of sodium hypochlorite and chloramine) in their drinking water. The data here presented call for further research aimed at quantifying the oncogenic risks related to the chlorination of drinking water, to be used as a basis for consequent public health measures.

- Dunnick JK, Melnick RL (1993) Assessment of the carcinogenic potential of chlorinated water: experimental studies of chlorine, chloramine, and trihalomethanes. J Natl Cancer Inst, 85: 817-822.

BACKGROUND: Water chlorination has been one of the major disease prevention treatments of this century. While epidemiologic studies suggest an association between cancer in humans and consumption of chlorination byproducts in drinking water, these studies have not been adequate to draw definite conclusions about the carcinogenic potential of the individual byproducts.

PURPOSE: The purpose of this study was to investigate the carcinogenic potential of chlorinated or chloraminated drinking water and of four organic trihalomethane byproducts of chlorination (chloroform, bromodichloromethane, chlorodibromomethane, and bromoform) in rats and mice.

METHODS: Bromodichloromethane, chlorodibromomethane, bromoform, chlorine, or chloramine was administered to both sexes of F344/N rats and (C57BL/6 x C3H)F1 mice (hereafter called B6C3F1 mice). Chloroform was given to both sexes of Osborne-Mendel rats and B6C3F1 mice. Chlorine or chloramine was administered daily in the drinking water for 2 years at doses ranging from 0.05 to 0.3 mmol/kg per day. The trihalomethanes were administered by gavage in corn oil at doses ranging from 0.15 to 4.0 mmol/kg per day for 2 years, with the exception of chloroform, which was given for 78 weeks.

RESULTS: The trihalomethanes were carcinogenic in the liver, kidney, and/or intestine of rodents. There was equivocal evidence for carcinogenicity in female rats that received chlorinated or chloraminated drinking water; this evidence was based on a marginal increase in the incidence of mononuclear cell leukemia. Rodents were generally exposed to lower doses of chlorine and chloramine than to the trihalomethanes, but the doses in these studies were the maximum that the animals would consume in the drinking water. The highest doses used in the chlorine and chloramine studies were equivalent to a daily gavage dose of bromodichloromethane that induced neoplasms of the large intestine in rats. In contrast to the results with the trihalomethanes, administration of chlorine or chloramine did not cause a clear carcinogenic response in rats or mice after long-term exposure.

CONCLUSION: These results suggest that organic byproducts of chlorination are the chemicals of greatest concern in assessment of the carcinogenic potential of chlorinated drinking water.

Page 382, The page heading:

- Delete: EHC 213: Carbon monoxide

- Insert: EHC 216: Disinfectants and Disinfectant By-products.