Drinking Water and Health, Volume 5 (1983) / Chapter Skim
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Uranium
Uranium
Pages 90-117
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From page 90... ...
The older animals and females appeared to be more susceptible. The cancer risk estimate for vinyl chloride can be found in Volume 1 of Drinking Water and Health.
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From page 91... ...
The radioactivity of the three isotopes in natural uranium averages approximately 7.35 x 105 disintegrations per minute per gram, almost all of which is from uranium-238 (National Council on Radiation Protection and Measurements, 1975~. Uranium-238 is generally found to be in equilibrium with thorium-234, palladium-234, and uranium-234, so that a gram of natural uranium would contain 0.33 psi of each of the four nuclides.
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From page 92... ...
METAB O LI S M The data indicate that approximately 1 psi (~ 1 Age of uranium is consumed daily and that from 2 % to 3 % of that amount is derived from drinking water (National Council on Radiation Protection and Measurements, 1975~. To a large extent, the uptake and fate of ingested uranium are controlled by the total quantity ingested and, to a lesser extent, on the particular chemical form.
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From page 93... ...
HEALTH ASPECTS Observations in Humans The committee found no reports of radiological toxicity in humans exposed to natural uranium by ingestion. Furthermore, as Hursh and Spoor (1973)
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From page 94... ...
Maynard and Hodge (1949) also studied the acquired uranium tolerance in rats and concluded that "prolonged exposure to uranium may produce conditions under which injection of an ordinary damaging dose of uranium results in no appreciable renal tubular necrosis." Chronic Effects Many studies have been conducted to compare the toxicity of natural uranium and some of its isotopes after continuous ingestion.
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From page 95... ...
There have been no reports of cancers resulting from the ingestion of natural uranium in laboratory animals.
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From page 96... ...
Furthermore, the fact that drinking water rarely contributes more than 2~o to 5~o of the total uranium ingested daily leads to the conclusion that a radiation risk model for natural uranium is inappropriate and unjustified on the basis of present knowledge. When natural uranium is subjected to an enrichment process resulting in specific activity exceeding 106 disintegrations per minute per gram, it is possible that a radiotoxicity model could be developed (U.S.
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From page 97... ...
Assessment of uranium toxicity in drinking water should be based on its chemical toxicity and not on radiation toxicity. However, when the specific activity of uranium in drinking water has been altered so that it is greater than that of natural uranium, potential radiotoxicity should be given attention equal to that of the chemical toxicity.
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From page 98... ...
. dNeither a SNARL nor a cancer risk estimate has been calculated by the committee pending the outcome of an ongoing study being conducted by the National Toxicology Program (1982d)
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From page 99... ...
1980. The mechanism of chloroform and carbon monoxide formation from carbon tetrachloride by microsomal cytoebrome P-450.
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From page 100... ...
1977. Dominant lethal studies with the halogenated olefins vinyl chloride and vinylidene dichloride in male CD-1 mice.
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From page 101... ...
1980. Vinyl chloride: An e~cample for evaluating mutagenic effects in mammals in vivo after exposure to inhalation.
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From page 102... ...
1975. Chemical reactivity, metabolic oxirane formation and biological reactivity of chlorinated ethylenes in the isolated perfused rat liver preparation.
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From page 103... ...
1979. Mutagenicity of vinyl chloride, vinylidene chloride and chloroprene in V79 Chinese hamster cells.
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From page 104... ...
dames. 1978 Congenital ~nlral ne~ous system malfo~ations and vinyl chloride monomer exposure: A community study.
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From page 105... ...
I Activation of vinyl chloride, 2-aminoanthracene and benzolaipyrene as measured by mutagenic effects in Salmonella typhimurium.
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From page 106... ...
1981. Cancer induction following single and multiple exposures to a constant amount of vinyl chloride monomer.
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From page 107... ...
1981. Vinyl chloride: Inhalation teratology study in mice, rats and rabbits.
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From page 108... ...
1974. Teratogenicity and dominant lethal studies on hexachlorobenzene in rats.
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From page 109... ...
1981. Rapid depression of rat liver microsomal calcium pump activity after administration of carbon tetrachloride or bromotrichloromethane and lack of effect after ethanol.
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From page 110... ...
1979. Embryotoxicity and fetoto~cicity of inhaled or ingested vinylidene chloride in rats and rabbits.
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From page 111... ...
1982b. NTP Technical Report on the Carcinogenesis Bioassay of Vinylidene Chloride in F344/N Rats and B6C3F ~ /N Mice.
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From page 112... ...
1979a. Formation and inactivation of a chemically reactive metabolite of vinyl chloride.
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From page 113... ...
1977. Uptake and rate of metabolism of vinyl chloride by the isolated perfused rat liver preparation.
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From page 114... ...
1977. A dominant lethal study in male rats after repeated exposure to vinyl chloride or vinylidene chloride.
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From page 115... ...
1978. Effects of vinyl chloride exposure alone and in combination with trypan blue—applied systematically dunng all thirds of pregnancg on the fetuses of CFY rats.
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From page 116... ...
Pate of TIC] vinyl chloride following inhalation exposure in rats.
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From page 117... ...
1972. inhibition of acetylcholinesterase from mammals and insects by carbofuran and its related compounds and their toxicities toward these animals.
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