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13 Arsenic, Boron, Nickel, Silicon, and Vanadium
Pages 502-553

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From page 502...
... There are also clearly clefineci, readily reproducible indicators in humans for these vitamins and other minerals that can be used to determine an EAR and calculate a Recommencleci Dietary Allowance, or to establish an AI. At present, such ciata do not exist for arsenic, boron, nickel, silicon, and vanadium.
From page 503...
... Estimates of Tolerable Upper Intake Levels (UL) were set for boron, nickel, and vanadium.
From page 504...
... The major contributors of inorganic arsenic are raw rice (74 ng/g) , flour (11 ng/g)
From page 505...
... , adverse effects of inorganic forms are clescribeci. It is unclear whether risk assessments should be clevelopeci for specific groups of inorganic arsenic compounds.
From page 506...
... Arsenicism Chronic intake of 10 ~g/kg/day or greater of inorganic arsenic produces arsenicism, a condition characterized by alteration of skin pigmentation and keratosis (NRC, 1999~. In some regions, an occlusive nerinheral vascular disease also occurs resulting in gangrene 1 1 lo, 1 , ·, · · 11 lo, 1 ~ , , 1 , 1 1 1 1 ~ , 1 ot the extremities, especially ot the teet, thus termed blacktoot d~sease (Engel and Recevour, 1993; Tseng, 1977~.
From page 507...
... Most studies of a positive association with cancer involve intake of inorganic arsenic in drinking water. A large-scale survey of 40,421 inhabitants (19,269 men and 21,152 women)
From page 508...
... ,~ Summary Clearly, high intakes of inorganic arsenic are associated with various toxicities, including increased risks of several cancers with chronic exposure to high levels in drinking water. There is no evidence linking organic arsenic in food to any adverse effect, including cancer.
From page 509...
... The average arsenic content of mineral drinking water in European countries is 21 ~g/L (Zielhuis and Wibomo, 1984~. Risk Characterization Although no UL was set for arsenic, there is no justification for Hilling arsenic to food and there may be a risk of adverse effects with consumption of organic arsenic in food or with intake of inorganic arsenic in water supplies at the current MCL of 50 ~g/L in the United States.
From page 510...
... . Physiological effects, including changes in blood glucose and triglyceride concentrations and abnormal calcitriol (1,25,0H2D3)
From page 511...
... The blood boron concentration is clepenclent on clietary intake as primarily shown by animal studies (Price et al., 1998; Samman et al., 1998~. This reflects the relatively
From page 512...
... boron consumption was assessed by use of the Boron Nutrient Data Base linked to 2-clay food records from respondents to the Third National Health and Nutrition Examination Survey (NHANES III) Appendix Table C-12)
From page 513...
... Although members of the general population should be aciviseci not to routinely exceed the UL, intake above the UL may be appropriate for investigation within wellcontrolleci clinical trials. Clinical trials of closes above the UL should not be cliscourageci, as long as subjects participating in these trials have signed informed consent documents regarding possible toxicity and as long as these trials employ appropriate safety monitoring of trial subjects.
From page 514...
... . Effects on the testis have been observed in three speciesrats, mice, and clogs after supplementation with boric acid or berates in feeci or drinking water (Fail et al., 1990, 1991; Green et al., 1973; Ku et al., 1993; Lee et al., 1978; Weir and Fisher, 1972)
From page 515...
... Although methodological clifferences between studies preclude a clear-cut, cross-species comparison of blood boron concentrations in animals and humans at similar closes, IPCS (1998) reported a preliminary comparison between humans and rats after oral intakes of boron from cliet or drinking water.
From page 516...
... NOAEL/LOAEL for decreased fetal body weight, increased fetal cardiovascular malformations and maternal toxicity Heindel et CD-1 mouse/ 43 NOAEL for mouse al., 1992 gd 0-17 79 developmental toxicity LOAEL for decreased fetal body weight Ku et al., Male SD rat/ 1993 63 days 52 LOAEL for testicular atrophy a Administered as boric acid. b SD = Sprague-Dawley rats, gd = gestational days, NZ = New Zealand.
From page 517...
... Because no ciata are available on adverse reproductive effects in humans from the consumption of large amounts of boron from food and water, animal ciata were utilized to estimate the UL. The following factors support the use of the laboratory animal studies listed in Table 13-1 to assess the clevelopmental and reproductive risks from boron exposure in humans: (1)
From page 518...
... The UL for boron is calculated by dividing the NOAEL of 9.6 mg/kg/day by the UF of 30, resulting in an UL of 0.3 mg/kg/day. This value was multiplied by the average of the reference body weights for adult women, 61 kg, from Chapter 1 (Table 1-1~.
From page 519...
... Thus, the adult UL of 20 mg/ciay of boron was acljusteci for children and adolescents on the basis of relative body weight as clescribeci in Chapter 2 using reference weights from Chapter 1 (Table 1-1~. Values have been rouncleci.
From page 520...
... The average intake of supplemental boron at the ninety-fifth percentile is approximately 0.4 mg/day for adults (Appendix Table C-13. A consumption of 1 L/ciay of municipal drinking water in the United States contributes 0.005 to 2 mg/ciay (mean of 0.2 mg/ciay)
From page 521...
... Nickel is an essential trace element in animals, as clemonstrateci by deficiency signs reported in several species. Rats clepriveci of nickel exhibit retarcleci growth, low hemoglobin concentrations (Schnegg and Kirchgessner, 1975)
From page 522...
... Therefore, neither an Estimated Average Requirement, Recommencleci Dietary Allowance, nor Acloquate Intake was established for nickel. INTAKE OF NICKEL Food Sources Major contributors to nickel intake are mixed dishes and soups (19 to 30 percent)
From page 523...
... Cooking foocis in stainless steel utensils can increase the nickel content if the foocis are acidic (Christensen and Molter, 1978~. Dietary Intake Baseci on the Food and Drug Administration Total Diet Study of 1984, the mean nickel consumption of infants and young children was 69 to 90 ~g/ciay (Pennington and Jones, 1987~.
From page 524...
... Hazard Identification Adverse Effects There is no evidence in humans of adverse effects associated with exposure to nickel through consumption of a normal cliet. The UL cleriveci here applies to excess nickel intake as soluble nickel salts.
From page 525...
... Although the study was suitable in design and conduct for use in establishing a UL for human dietary exposure to soluble nickel salts, poor survivorship in controls does raise some concern about its interpretability. The results of three reproductive studies, one three-generation study (Schroeder and Mitchener, 1971)
From page 526...
... , was associated with increased neonatal cleath; however, these conclusions were baseci on the results of only five nonranclomizeci matings and therefore were not consiclereci valid for use in determining a LOAEL for human clietary exposure to soluble nickel salts. In fact, all of the reproduction studies either were flawoci or their interpretation was hampered by their statistical design and methodological and ciata-reporting limitations, as well as by inconsistencies in the reported close-response relationships.
From page 527...
... Thus, the adult UL of 1.0 mg/ciay of soluble nickel salts was acljusteci for children and adolescents on the basis of relative body weight as clescribeci in Chapter 2 using reference weights from Chapter 1 (Table 1-1~. Pregnancy and Lactation.
From page 528...
... These inclivicluals may not be protected by the UL for nickel intake for the general population. DIETARY REFERENCE INTAKES 0.2 mg/day of soluble nickel salts 0.3 mg/day of soluble nickel salts 0.6 mg/day of soluble nickel salts 1.0 mg/day of soluble nickel salts 1.0 mg/day of soluble nickel salts 1.0 mg/day of soluble nickel salts 1.0 mg/day of soluble nickel salts 1.0 mg/day of soluble nickel salts Intake Assessment Baseci on the Food and Drug Administration Total Diet Study (Appendix Table E-7)
From page 529...
... Rats deprived of silicon showed decreased bone hydroxyproline and alkaline and acid phosphatases (Seaborn and Nielsen, 1993, 1994~. Silicon has been suggested to have a preventive role in atherogenesis (Mancinella, 1991~.
From page 530...
... Silicate aciclitives that have been increasingly used as antifoaming and anticaking agents can raise the silicon content in foocis; however, the bioavailability of these aciclitives is low. Dietary Intake Baseci on the Total Diet Study, the mean intakes of silicon in adult men and women were 40 and 19 mg/ciay, respectively (Pennington, 1991~.
From page 531...
... Although members of the general population should be aciviseci not to routinely exceed the UL, intake above the UL may be appropriate for investigation within wellcontrolleci clinical trials. Clinical trials of closes above the UL should not be cliscourageci, as long as subjects participating in these trials have signed informed consent documents regarding possible toxicitv and as long as these trials employ appropriate safety monitoring of trial subjects.
From page 532...
... Although insulin requirements were decreased in patients with Type I diabetes, the doses of vanadium used in the supplements were about 100 times the usual intakes (Pennington and Jones, 1987) , and they greatly exceed the Tolerable Upper Intake Level (UL)
From page 533...
... Commodity groups highest in vanadium are grains and grain products, sweeteners, and infant cereals. Analysis of ciata from the 1984 Food and Drug Administration Total Diet Study (Pennington and Jones, 1987)
From page 534...
... Although members of the general population should be aciviseci not to routinely exceed the UL, intake above the UL may be appropriate for investigation within wellcontrolleci clinical trials. Clinical trials of closes above the UL should not be cliscourageci, as long as subjects participating in these trials have signed informed consent documents regarding possible toxicity and as long as these trials employ appropriate safety monitoring of trial subjects.
From page 535...
... Domingo and coworkers (1985) found histopathological lesions of the kidney and increased plasma urea and uric acid concentrations in rats exposed to 50 fig/ mL in drinking water for 3 months.
From page 536...
... The effect of supplemental vanadium intake on renal function neecis further careful study. Gastrointestinal Effects.
From page 537...
... Effects on kidney morphology No effects Vanadium detected in kidneys Increased uric acid and urea; vanadium detected in kidneys Increased serum urea and creatinine Increased serum urea, but not creatinine Increased serum urea and creatinine average drinking water consumption of 42 mL/day. 50 1lg/mL x 42 me/d x 1/0.27/kg body weight x 1 mg/1,000 fig = 7.7 mg/kg/day.
From page 538...
... Other adverse effects associated with vanadium intake in humans include green tongue, fatigue, lethargy, and focal neurological lesions (Barceloux, 1999~. These effects, however, have not been consistently observed or close-relateci.
From page 539...
... = 52 mg/d. c Body weight used was the average of the reference weights for adult men and women (76 and 61 kg, respectively)
From page 540...
... A NOAEL of 0.8 mg/kg body weight/day and a LOAEL of 7.7 mg/kg body weight/day were determineci on the basis of the results of Domingo and coworkers (1985~. Vanadium could not be cletecteci in the kidneys of animals receiving ~ ~g/mL (or 0.8 mg/kg/day)
From page 541...
... The LOAEL of 7.7 mg/kg/day was divided by a UF of 300 to obtain a UL of 0.026 mg/kg/day or 26 ~g/kg/day for adult humans. This value was rouncleci and multiplied by the average of the reference body weights for adult men and women, 68.5 kg, from Chapter 1 (Table 1-1~.
From page 542...
... The average intake of supplemental vanadium at the ninety-ninth percentile by adults was 20 ~g/ciay, which is significantly lower than the adult UL for vanadium. Risk Characterization The risk of adverse effects resulting from excess intake of vanadium from food is very unlikely.
From page 543...
... 1992. Comparison of trace elements in milk of four species.
From page 544...
... environmental health criteria on boron human health risk assessment. Biol Trace Elem Res 66:439-452.
From page 545...
... Biol Trace Elem Res 66:453-463. Eckhert CD.
From page 546...
... Biol Trace Elem Res 66:237-259. Fort Dl, Stover EL, Strong PL, Murray Fl, Keen CL.
From page 547...
... One possible role of dietary boron in higher animals and humans. Biol Trace Elem Res 66:205-225.
From page 548...
... Biol Trace Elem Res 66:271-298. Lanoue L, Strong PL, Keen CL.
From page 549...
... Biol Trace Elem Res 66:319-330. Nielsen FH, Flyvholm M
From page 550...
... Biol Trace Elem Res 66:227-235. Schnegg A, Kirchgessner M
From page 551...
... Biol Trace Elem Res 66: 193-204. Tabata M, Sarkar B
From page 552...
... Biol Trace Elem Res 66:101-109. Yamamoto S
From page 553...
... ARSENIC, BORON, NICKEL, SILICON, AND VANADIUM 553 Zielhuis RL, Wibomo AA.


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