Drinking Water and Health, Volume 4 (1982) / Chapter Skim
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VI Toxicity of Selected Inorganic Contaminants in Drinking Water
VI Toxicity of Selected Inorganic Contaminants in Drinking Water
Pages 152-201
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From page 152... ...
. The health effects of the organic and inorganic contaminants evaluated in Chapters VI and VII of this volume were selected for one or more of the following reasons: · They are contaminants that have been identified in drinking water since the previous studies were conducted by the Safe Drinking Water Committee.
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From page 153... ...
factor of 10 was used when data on both human exposure and extensive chronic exposures of animals were available. · A factor of 100 was used when chronic and acute toxicity data were available for one or more species.
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From page 154... ...
7 Cadmium 0.15 0.021 0.005 Chlorate 0.125 0.125 Chlorite 0.125 0.125 Chlorine dioxide 1.2 0.125 Chloramine 1.2 0.125 Strontium 8.4 aSee text for details on individual compounds. during a major portion of the lifetime of the laboratory animals.
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From page 155... ...
For some of the contaminants reviewed here, appropriate parts of the criteria documents were condensed and included in the final report. The committee commends the EPA for making this valuable material available for study and evaluation.
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From page 156... ...
Aluminum compounds such as aluminum sulfate and potash aluminum and certain aluminum-bearing minerals are commonly used as major coagulants in the treatment of drinking water supplies. The principal coagulants are aluminum sulfate and potash aluminum.
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From page 157... ...
(1976) studied the absorption of aluminum in both normal patients and patients suffering from chronic renal failure.
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From page 158... ...
This transfer can occur even if the levels of aluminum in plasma are much higher than the levels of aluminum in the dialysate solution. Thus, aluminum has been shown to accumulate in the serum and in the tissues of chronic renal failure patients either after absorption from the gastrointestinal tract or from parenteral administration during dialysis with a solution that contains aluminum.
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From page 159... ...
Following large oral doses of aluminum, toxic syndromes involve gastrointestinal tract irritation and, eventually, interference with phosphate absorption, which results in rickets (Casarett and Doull, 19771. Industrial exposure to high concentrations of aluminum-containing airborne dusts has resulted in a number of cases of occupational pneumoconiosis (Norseth, 1979; Sorenson et al., 19741.
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From page 160... ...
In more recent studies, aluminum deposition in the brain has been implicated as an etiologic factor in two necrologic disorders: Alzheimer's disease and chronic renal failure accompanied by senile dementia (Alfrey et al., 1976; Crapper et al., 1973~. Nonetheless, the importance of aluminum as a pathogenic factor in human disease has not yet been established (Crapper and DeBoni, 1980~.
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From page 161... ...
The possible hazard of aluminum intoxication in dialysis patients was first described by Berlyne et al.
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From page 162... ...
= new cases of dialysis The major etiologic factor associated with this syndrome is untreated aluminum-rich tap water that is used to prepare the dialysis fluid. Aluminum is known to accumulate in the serum and tissues of chronic renal failure patients either after it is absorbed from the gastrointestinal tract (Alfrey et al., 1976)
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From page 163... ...
(1977a,b, 1978) indicated that PTH may also play an important role in this syndrome because of its ability to increase the absorption of aluminum in the gastrointestinal tract and because elevated levels of serum PTH have been found in most dialysis patients (Kleeman and Better, 1973~.
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From page 164... ...
, the aluminum hydroxide model provides one of the most promising approaches for studying processes underlying the epileptic focus. There have been few subacute or chronic studies of animals exposed to aluminum.
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From page 165... ...
Teratogenicity In one study, concentrations of aluminum ranging from 500 to 1,000 ,`4g/g body weight were added to the diets of pregnant rats from day 6 to day 19 of gestation, when the fetuses were removed by Caesarean section. Aluminum in the diet did not affect embryo or fetal mortality rate, litter size, fetal body weight, or length (McCormack et al., TABLE VI-3 Subchronic or Chronic Toxicity of Aluminum Chloride Species Route Dose Duration Effects References Mice Oral 100 mg/kg Rat Oral 150 mg/kg Rat Oral 1 g/kg/day Ondreicka et al., 1966 Ondreicka et al., 1966 6-12 mot No change in growth or reproduction Negative phosphorus balance; decreased incorporation of 32p into phospholipids; decrease in ATP 18 days Decrease in liver Kortus, 1967 glycogen and coenzyme A
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From page 166... ...
Using this value, applying a safety factor of 1,000, and assuming that a 70-kg human consumes 2 liters of drinking water daily and that 100% of exposure is from water during this period, one may calculate the 24-hour SNARL as: l.OOOmg/kg X 70 kg = 3s.0m /liter 1,000 x 2 liters g This value exceeds the solubility of aluminum in nonacidic solutions. Thus, it has only limited usefulness.
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From page 167... ...
Environmental Protection Agency, 1977~. Although there is no reliable evidence that arsenic compounds produce tumors in laboratory animals, epidemiological studies show that the incidence of epidermoid carcinomas of the skin and lungs and precancerous dermal keratoses may be increased in humans who have been chronically exposed to arsenic compounds by oral or respiratory routes (Leonard and Lauwerys, 19801.
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From page 168... ...
Calculations for the former oral intake limit were based on the original acceptable daily intake value of 3.75 mg derived from the 0.5 mg/m3 TLV by Stokinger and Woodward (1958) , 90~o gastrointestinal absorption, the consumption of 2 liters of water daily, and an additional safety factor of 2: 3 75mg = 4 17mg; 2 mg/liter 2 = 1 mg/liter 4.17mg 2 lit = 2 mg/liter; Substituting the gastrointestinal absorption value of 20~o, one may calculate the oral intake limit as follows: 0 2 g = 18.75 ma; 9.375 mg/liter = 4 7 mg/liter.
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From page 169... ...
(1981) also studied the effects of barium in public water supplies on blood pressure.
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19791. Based on a safety factor of 10 and the assumption that 100870 of the exposure during this period comes from a 2-liter daily intake of drinking water, the SNARL would be: 120 mg = 6 0 mg/liter.
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From page 171... ...
, but it is not considered here since it goes beyond a general toxicological review. HEALTH ASPECTS Observations in Humans In humans, acute oral doses of cadmium usually result from the ingestion of food or beverages that have been contaminated during storage in cadmium-plated containers.
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(1958~. After administering drinking water containing cadmium concentrations of 250 mg/liter to male rats for periods of 2 or 8 weeks, Hietanen (1978)
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From page 173... ...
Using these data, applying a safety factor of 10, and assuming 100% intake from 2 liters of drinking water daily by a 70-kg human, one may calculate the 7-day SNARL's as: and 6.7pg/kg X 70 kg = 0.o23smg/liter 8.3 ,ug/kg X 70 kg _ 0 0291 /lit Thus, the 7-day SNARL's calculated on the basis of either human or animal data are in rather good agreement. Chronic Exposure These calculations are based on the data of Decker et al.
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From page 174... ...
, adult male volunteers were given water containing chlorine dioxide, chloramine, chlorite, or chlorate. The study was carefully controlled, and subjects were monitored by physical examination, measurement of vital signs, assessment of side-effects, and an extensive battery of clinical laboratory tests.
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From page 175... ...
Accumulated data, averaged for all dose ranges in the study, revealed no striking, clinically relevant changes among these groups. In a subsequent study, groups of healthy adult males were given a 500-ml solution containing chlorine dioxide, chlorite, chlorate, chlorine, or chloramine in concentrations of 5 mg/liter.
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From page 176... ...
conducted similar studies over a 12month period in male rats given chlorine dioxide, chlorate, and chlorite, and in male mice given chlorine dioxide. Their data suggest oxidative stress to erythrocytes.
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From page 177... ...
Concentrations of chlorite identical to those for chlorate were also well tolerated in the two studies: 5 mg/liter X 0.5 liter 10 X 2 liters = 0.125 mg/liter. In the rising-dose tolerance study, subjects consumed two 500-ml bolus doses, each containing chlorine dioxide in concentrations up to 24 mg/liter without ill effect.
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From page 178... ...
However' it would be premature to project this value for chronic exposure. CONCLUSIONS AND RECOMMENDATIONS In light of the evidence that both chlorate and chlorite appear in animals given chlorine dioxide in their drinking water, additional studies are needed to evaluate the effects of lifetime exposure to these agents and to determine no-effect levels.
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From page 179... ...
Specific, leadinduced biochemical or functional disorders are commonly associated with specific ranges of lead concentrations in blood. The concentrations of free erythrocyte porphyrin is becoming widely accepted as a vety sensitive indicator of lead exposure and is currently used in many urban screening programs to detect excessive lead intake (Hammond and Beliles, 1980~.
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From page 180... ...
In a rural setting (Bennington, Vermont) , they found no correlation between blood lead and lead concentrations in the water.
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From page 181... ...
Subchronic and Chronic Effects Free erythrocyte porphyrin was measured in adult male and female and suckling rats after oral dosing with lead in drinking water. Young rats were more susceptible than adult females, which were more susceptible than adult males to elevated free erythrocyte porphyrin (Buchet et al., 1978~.
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From page 182... ...
Evidence from such studies clearly indicates that pre- and perinatal exposure to lead may alter neurological development, behavior, and learning ability in laboratory animals. At present, however, there is insufficient evidence to characterize the doseeffect relationship between lead intake or lead concentrations in tissue with nervous system impairment (Bornschein et al..
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From page 183... ...
The ~x ~, ~. .· r c~ ~ ~ ~- ~^ If ~ v ~ low ~ , ~ ne committee recommends that the following actions be taken: · Studies relating lead concentrations in drinking water to those In blood must be conducted in a way that permits accurate determination of lead ingested in the water consumed.
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From page 184... ...
Concentrations exceeding 150 ,ug/liter have been used to purify swimming pools, but because of the cost and the opalescence caused by colloidal silver chloride, the method is not practical nor is it recommended for public water supplies (National Academy of Sciences, 1977~. Natural freshwaters contain an average silver concentration of 0.2 ,ug/liter, and seawater contains an average of 0.24 ,ug/liter (Boyle, 1968~.
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From page 185... ...
, who fed some rabbits food containing 4.2 mg/kg of silver iodide and others a diet containing 10 mg/kg of silver nitrate. They found that 99% of the silver was eliminated in 3 days and essentially all of it in 6.3 days.
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From page 186... ...
They observed no effects on body weight, fluid intake, food consumption, or measures of forelimb or hindlimb strength, but water consumption was reduced by approximately 25~o. Mutagenicity Silver has not been found to be mutagenic in the Salmonella Ames test (McCoy and Rosenkrantz, 1978~; in the "rec-assay," in which differential sensitivities to killing by chemicals are observed in wild-type and recombination-deficient strains of Bacillus subtilis (Nishioka, 1975~; or in mutation tests in Micrococcus aureus (Clark, 1953)
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From page 187... ...
, who stated on page 292: There seem to be no pressing research needs with regard to silver in drinking water. There seems to be little possibility that the addition of oligodynamic silver will have any place in public water supplies, and natural concentrations are so low that consideration should be given to taking silver off the list of substances included in primary drinking-water standards.
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From page 188... ...
The skeleton contains more than 99% of the strontium. The rest is distributed among soft tissues, the largest concentrations residing in the aorta, larnyx, trachea, and lower gastrointestinal tract (Beliles, 1979; Schroeder et al., 19721.
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From page 189... ...
Acute poisoning in laboratory animals leads to excess salivation, vomiting, colic, and diarrhea. In rats, death is due to respiratory failure; in cats, it is due to cardiac arrest (Browning, 1969; Venugopal and
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From page 190... ...
has found that the bones of weanling male and female rats fed a diet high in strontium content (0.2~o) for 8 weeks will generally exhibit severe aberrations.
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From page 191... ...
fed adult male and weanling male and female rats strontium in the diet at levels of 10, 30, 100, and 1,000 mg/kg for 8 weeks. They found no differences in food intake, weight gain, total bone ash, calcium and phosphorus composition of the bone ash, or other signs of toxicity in the strontium-fed rats.
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From page 192... ...
0 mg/kg after 90 days of exposure in the diet, and assuming that the rats consumed 20 g of food daily and that their average weight was 250 g, one may calculate the daily exposure level as: 300 mg/kg/day X 0.02 kg/day = 24 mucky 0 25 k -~ ~~~-~ ~~-~ O O Using a safety factor of 100 and assuming that a 70-kg human consumes 2 liters of water per day, and that 100% of exposure is from water during this period, one may calculate the 7-day SNARL as: 24mg/kg X70 kg 84 /li tion. Chronic Exposure There are no data from which to make this calcula Sulfate (S04)
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From page 193... ...
1980. The safety study of chlorine dioxide and its metabolites in man.
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From page 194... ...
1979. Effect of chlorine dioxide and metabolites on glutathione dependent system in rat, mouse and chicken blood.
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1962. Public Water Supplies of the 100 Largest Cities in the United States, 1962.
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From page 196... ...
1979a. Oxidative damage to the erythrocyte induced by sodium chlorite.
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1968. Arterial calcification after vitamin-D therapy in hyperphosphataemic renal failure.
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1978. Potential health effects of chlorine dioxide as a disinfectant in potable water supplies.
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From page 199... ...
1978. Dialysis dementia' osteomalacic fractures and myopath`: A syndrome due to chronic aluminum intoxication.
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1979c. Silver: Ambient Water Quality Criteria.
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1973. Health Aspects Relating to the Use of Polyelectrolytes in Water Treatment for Community Water Supply.
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