Carcinogenicity of by-products of disinfection in mouse and rat liver
By-products of disinfection were tested for initiating and/or promoting activity in rat liver by using the rat liver foci bioassay. The assay uses an increased incidence of ..gamma..-glutamyltranspeptidase-positive foci (GGT foci) as an indicator of carcinogenicity. The by-products of disinfection, including chloramine, halogenated humic acids, halogenated ethanes, halogenated acetonitriles, halogenated methanes, halogenated ethylene, and N-Cl piperidine, did not initiate GGT foci, which would indicate that they are not capable of initiating carcinogenesis. Chloroform and halogenated benzenes were tested in this assay for their ability to promote the occurrence of GGT foci and tumors initiated by diethylnitrosamine (DENA). Chloroform either had no effect or inhibited the occurrence of GGT foci when administered subsequent to a single dose of DENA. However, when the chloroform was administered in drinking water concurrently with weekly doses of DENA, it enhanced the formation of liver tumors. Of 20 halogenated benzenes tested, only 1,2,4,5-tetrachlorobenzene and hexachlorobenzene promoted the occurrence of DENA-initiated GGT foci. Thus in rat liver, the tested by-products of drinking water disinfection did not demonstrate tumor-initiating activity, although a few appeared to possess tumor-promoting activity. Chloroform was also tested for tumor-promoting activity in 15-days-old Swiss mice initiated with ethylnitrosourea (ENU). ENU at 5 and 20 ..mu..g/g caused a dose-dependent increase in liver tumors. In male mice, chloroform inhibited both spontaneous and ENU-induced liver tumors. When administered in the drinking water, chloroform inhibited, whereas phenobarbital promoted, hepatocarcinogenesis in mice.
- Research Organization:
- Environmental Protection Agency, Cincinnati, OH
- OSTI ID:
- 5554975
- Journal Information:
- Environ. Health Perspect.; (United States), Vol. 69
- Country of Publication:
- United States
- Language:
- English
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CHLORINATED AROMATIC HYDROCARBONS
BIOLOGICAL EFFECTS
CHLOROFORM
DRINKING WATER
WATER TREATMENT
ACETONITRILE
BY-PRODUCTS
CHLORAMINES
DISINFECTANTS
HALOGENATED ALIPHATIC HYDROCARBONS
HUMIC ACIDS
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MICE
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NITROSOUREAS
PEPTIDE HYDROLASES
RATS
TUMOR PROMOTERS
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ANIMALS
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CHLORINATED ALIPHATIC HYDROCARBONS
DIGESTIVE SYSTEM
ENZYMES
GERMICIDES
GLANDS
HALOGENATED AROMATIC HYDROCARBONS
HYDROGEN COMPOUNDS
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NITRILES
NITROSO COMPOUNDS
ORGANIC ACIDS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
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560300* - Chemicals Metabolism & Toxicology