Spacecraft Water Exposure Guidelines for Selected Contaminants Volume 1 (2004) / Chapter Skim
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Appendix 9: Silver
Appendix 9: Silver
Pages 324-354
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From page 324... ...
Silver forms several inorganic and a few organic salts, including silver chloride, silver fluoride, silver iodide, silver nitrate, silver acetate, silver sulfide, silver perchiorate, silver benzoate, and silver diethy! dithiocarbamate (see Table 9-2~.
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From page 325... ...
CAS registry no. 7440-22-4 Molecular weight 107.87 Atomic number 47 Melting point 960.5°C Density 10.5 g/cm3 at 20°C Units 1 ppm in water = 1 mg/L in water Solubility Metallic silver is practically insoluble in hot and cold water; it is soluble in fused alkali hydroxides; most silver salts have limited solubility in water; low solu bility depends on pH and chloride concentrations (0.1 10 mg/L)
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From page 326... ...
, the fuel-cell water transferred from the shuttle was deiodinated and silver was added as silver salts to support the crew drinking water requirements. The residual iodine precipitated some of the silver, which caused very low silver concentrations in some samples.
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From page 327... ...
By extrapolating the parabolic relationship between body weights and estimated equilibrium factors from small animals to humans, the authors estimated 4°/O retention of silver in humans. A much higher level of silver retention was estimated from a case history study of silverpoisoning associated with antismoking lozenges (Respa
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From page 328... ...
reported the onset of discoloration after the use of 32 lozenges per day for 6 mot The woman was given an oral dose of silver acetate labeled with silver tracer Wag (4.4 Loci and 10 mg of ammonium chloride, as in the Respaton formulation)
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From page 329... ...
Distribution Reports strongly indicate that silver is distributed to almost all organs of the body after exposure. Rats given silver nitrate in drinking water (0.15% or 8.8 millimolar tmM]
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From page 330... ...
in drinking water, silver was found in the meduliary interstitial tissue and in the interstitial cells (which showed signs of degeneration) in both species.
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From page 331... ...
studied the distribution of silver after an intramuscular administration of radioactive metallic silver alone as a tracer dose and then coadministered with two doses of nickel nitrate (0.4 mg/kg/d and 4.0 mg/kg/~. They reported that when excretion in the feces was decreased, a corresponding increase was noted in the deposition of silver in the pancreas, gastrointestinal tract, and thyroid.
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From page 332... ...
that the deposition of silver in tissues is the result of precipitation of insoluble silver chlorides and silver phosphates and that those silver salts are transformed to silver sulfides by forming complexes with amino or carboxy! groups in proteins or are reduced to metallic silver by reduction with ascorbic acid (Danscher 1981~.
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From page 333... ...
Workers with elevated concentrations of silver in the urine and in the blood had corneal deposits of silver and complained of poor night vision. They had significantly increased urinary levels of N-acetyI-beta-c'7-glucosaminidase (NAG)
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From page 334... ...
A considerable amount of data is available from animal studies. Emphasis will be placed on oral bolus studies and drinking water studies with silver salts.
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From page 335... ...
were given silver acetate in drinking water at 7.6 mg/kg/d for 52 ~ while ingesting a diet that had the recom
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From page 336... ...
Neurotoxicity Deposition of silver in the brains of animals and humans after shortterm or long-term oral exposure through drinking water has been reported in several studies. In a 4-mo study (Rungby and Danscher 1984)
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From page 337... ...
in drinking water for a total of 81 wk. Silver deposits were found in the gIomerular basemen" membranes in the kidneys at4,6,8,10, 12,25, and 60 wk.
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From page 338... ...
When weanling Norwegian hooded rats fed a basal vitamin-E deficient diet were provided drinking water containing silver at 970 mg/L (as silver acetate) , all rats developed liver necrosis within 2-4 wk and died.
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From page 339... ...
Male rats given water containing silver chloride or silver nitrate (89 mg/kg/~) over a 2-y period did not show any change in the appearance or production of spermatozoa or any accumulation of silver.
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From page 341... ...
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From page 342... ...
assay in vitro, in vivo, and in the Ames/ microsome test. Silver iodide did not induce SCEs in cultured human lymphocytes (1 ~g/mL,72 h incubation)
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From page 343... ...
RATIONALE The following paragraphs provide a rationale for proposing spacecraft water exposure guidelines (SWEGs) for silver in spacecraft drinking water for 1, 10, 100, and 1,000 d.
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From page 344... ...
Abbreviations: ATSDR, Agency for Toxic Substances and Disease Registry; DWEL, drinking water equivalent level; EPA, U.S. Environmental Protection Agency; HA, health advisory; MCL, maximum contaminant level; MCLG, maximum contaminant level goal; MRL, minimal risk level; RfD, reference dose; SMCL, secondary maximum contaminant level.
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From page 345... ...
via drinking water showed decreases in water consumption for the first 3 4, water consumption returned to normal in the days following. The initial phenomenon may have been due to taste aversion.
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From page 346... ...
In OIcott's (1950) study, rats administered silver nitrate in drinking water for 21 ~ ~ at a dose of 89 mg/kg/d developed left ventricular hypertrophy.
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From page 347... ...
~ 1976) reported that water consumption dramatical ly dropped in mice administered silver nitrate at 130 mg/kg/d in drinking water.
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From page 348... ...
348 Cat v ¢ ¢I=IE-Z o At o v D Ct as ¢ to o 1 1 1 1 o 0 8 to Io ~ o Cat ¢ .
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From page 349... ...
and in human cases involving use of eye drops or make-up containing silver (Greene and Su 1987~. Workers exposed to silver for over 2 y had corneal deposits of silver, and some complained of poor night vision (Rosenman et al.
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From page 350... ...
ATSDRITP-90-24. Agency for Toxic Substances and Disease Registry, U.S.
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From page 351... ...
1980. Silver retention, total body silver and tissue silver concentrations in argyria associated with exposure to an anti-smoking remedy containing silver acetate.
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From page 352... ...
1983. Distribution of radioactive silver in the subcellular fractions of various tissues ofthe rat and its binding to low molecular weighs proteins.
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From page 353... ...
.1977. Drinking Water and Health.
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From page 354... ...
.1984.Pp.141-144inGuidelinesforDrinking Water Quality, Volume 2. Geneva: WHO.
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