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PubMed2001

Collaborative study of EPA Method 317.0 for the determination of inorganic oxyhalide disinfection by-products in drinking water using ion chromatography with the addition of a postcolumn reagent for trace bromate analysis.

The development of the U.S. Environmental Protection Agency (EPA) Method 317.0 is initiated to provide a sufficiently sensitive and fundamental technique for the compliance monitoring of trace levels of bromate in drinking water. After a comparative evaluation of Method 317.0 and elimination of a chlorite interference, this method is tested by a collaborative study in order to determine the precision and bias of the method and evaluate its potential role as a future compliance-monitoring method for inorganic disinfection by-products (DBPs) and trace bromate. This technique provides a practical method for future compliance monitoring for all of the inorganic oxyhalide DBPs including trace concentrations of bromate.

Bromates↗
PubMed1991

Structure of hexaaquacopper(II) bromate.

[Cu(H2O)6](BrO3)2, Mr = 427.44, cubic, Pa3, a = 10.3240 (6) A, V = 1100.38 (4) A3, Z = 4, Dx = 2.580 g cm-3, lambda (Mo K alpha) = 0.71073 A, mu = 92.32 cm-1, F(000) = 828, T = 296 K, R = 0.038 for 336 unique reflections having I greater than sigma I. The single type of copper ion (site symmetry 3) is coordinated by six water-molecule O atoms, each at an observed distance of 2.079 (4) A, in an array which is virtually regular octahedral, the nominal 90 degree angles measuring 89.95 (15) and 90.05 (15) degrees. Thus, this is not a typical CuII complex in which (consistent with a static Jahn-Teller effect) a distorted octahedral array displays '(2 + 2 + 2)' coordination; rather, it is the sixth strict example of a CuII static structure inconsistent with the Jahn-Teller theorem. The presence of a dynamic Jahn-Teller effect is supported by the data. The single type of bromate ion has an observed Br-O bond length 1.649 (3) A and O-Br-O bond angle 104.17 (15) degrees. The bromate ion was found to manifest rigid-body behavior but, consistent with a dynamic Jahn-Teller effect, the copper-oxygen complex did not. The Br-O bond length corrected for rigid-body motion is 1.663 A. Refinement of the positional parameters of the two inequivalent H atoms permitted a detailed analysis of hydrogen bonding, which occurs principally between the oxygen octahedra and the bromate groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Bromates↗
PubMed1992

The structure of hexaaquaaluminium(III) bromate trihydrate, [Al(H2O)6](BrO3)3.3H2O.

Hexaaquaaluminium(III) bromate trihydrate, [Al(H2O)6](BrO3)3.3H2O, M(r) = 572.84, triclinic, P1, a = 9.536 (2), b = 11.095 (4), c = 9.291 (2) A, alpha = 106.58 (2), beta = 100.42 (2), gamma = 113.01 (2) degrees, V = 818.1 (4) A3, Z = 2, Dx = 2.33 g cm-3, lambda(Mo K alpha) = 0.71073 A, mu = 74.58 cm-1, F(000) = 560, T = 296 K, R = 0.050 for 3777 unique reflections having I greater than sigma 1. The single type of Al ion is coordinated by six inequivalent water O atoms which form a slightly distorted octahedron. The average Al--O distance within the octahedron is 1.872 (11) A. Each of the three inequivalent bromate groups has three inequivalent O atoms. The average Br--O distances and O--Br--O angles for these ions are: 1.652 (25) A and 104.1 (17) degrees for Br(1)O3; 1.650 (9) A and 104.4 (18) degrees for Br(2)O3; 1.643 (9) A and 103.6 (14) degrees for Br(3)O3. The aluminium-oxygen complex conformed to rigid-body behavior but the bromate groups did not. Corrected for rigid-body motion, the average Al--O distance becomes 1.880 (10) A. Least-squares refinement of the positional parameters of the 18 inequivalent H atoms permitted a detailed analysis of the hydrogen bonding.

Aluminum↗
PubMed1992

Polarized dispersion, glide-rule-forbidden reflections and phase determination in barium bromate monohydrate.

Reflections forbidden by a glide-plane rule are observed in diffraction experiments with a crystal of barium bromate monohydrate using linearly polarized synchrotron radiation with wavelength near the bromine K-absorption edge. Their intensities change with azimuth in agreement with equations derived using a tensor model of the anomalous scattering of the bromate ion and are consistent in scale with earlier measurements of that tensor in sodium bromate. The intensity of each forbidden h0l reflection gives the magnitude and phase of the bromine part of the structure factor of the allowed 2h,0,2l reflection. The x and z coordinates of the Br atom determined from such data for 11 reflections are within 0.02 A of those from two crystal structure determinations.

Barium↗
PubMed1990

Structure of hexaaquacobalt(II) bromate.

[Co(H2O)6](BrO3)2, Mr = 422.83, cubic, Pa-3, a = 10.3505 (7) A, V = 1108.88 (8) A3, Z = 4, Dx = 2.53 g cm-3, lambda(Mo K-alpha) = 0.71069 A, mu = 87.31 cm-1, F(000) = 820, T = 296 K, R = 0.027 for 365 unique reflections having I greater than sigma I. The single type of Co ion is coordinated by six water-molecule O atoms, each at an observed distance 2.095 (2) A, in an array which is regular octahedral within the estimated standard deviations of the relevant angles. The single type of bromate ion has a Br-O bond length 1.653 (2) A and O-Br-O bond angle 104.07 (9) degrees. The cobalt-oxygen complex manifested rigid-body behavior, but the bromate ion did not. The cobalt-oxygen distance corrected for rigid-body motion is 2.099 A. Location and refinement of the two inequivalent H atoms permitted detailed analysis of the hydrogen bonding, which occurs principally between the oxygen octahedra and the bromate groups. This structure is isomorphic to that of hexa-aquanickel(II) chlorate recently reported from this laboratory.

Bromates↗
PubMed2006

An ensemble of crystallographic models enables the description of novel bromate-oxoanion species trapped within a protein crystal.

Only a few protein-oxoanion crystal complexes have been described to date. Here, the structure of a protein soaked in a bromate solution has been determined to a resolution of 1.25 A and refined to final overall R/R(free) values of 18.04/21.3 (isotropic) and 11.25/14.67 (anisotropic). In contrast to the single-model approach, refinement of an ensemble of ten models enabled us to determine variances and statistically evaluate bond-length distances and angles in the oxoanions. In total, nine bromate positions, including two BrO(3)(-) x HBrO(3) dimer species, have been identified on the basis of the anomalous signal of the Br atoms. For all bromate ions, the main-chain amide atoms of the protein were identified as the dominant binding positions, a useful property in any experimental phase-determination experiment.

Amides↗
PubMedDate not supplied

Origin and distribution of potassium bromate-induced testicular and peritoneal mesotheliomas in rats.

Tissue sections were examined from a 2-year bioassay of male Fischer 344 rats treated with potassium bromate administered in drinking water. All animals exhibiting peritoneal mesotheliomas also had mesotheliomas of the tunica vaginalis testis mesorchium (the reverse was not true), and the correlation of these 2 types of mesotheliomas was highly significant (r2 = 0.98). Mapping of the tunica vaginalis tumors at all time points and at all bromate concentrations revealed a pattern of increasing incidence of tumor formation on the mesothelium of the tunica vaginalis testis as a function of proximity to the mesorchial ligament. Thus, the mesorchium appears to be the major mesothelial target site for potassium bromate-mediated carcinogenesis. The frequency of occurrence of mesotheliomas by location was tunica vaginalis testis (25%), mesosplenium (20%), mesentery (10%), mesojejunum/mesocolon (8%), bladder (6.5%), mesogastrium (13%), liver serosa (5%), and kidney, small intestine, and rectum (1% each). A complete cross-section of the rat testis was prepared and used to construct a complete map of the mesothelium. Any attempt to determine the role of local dose and tissue susceptibility for the purpose of interspecies risk extrapolation must take into account the complex anatomy and physiology of this region of the visceral and testicular suspensory apparatus. Improved histologic approaches are needed for adequate assessment of this delicate suspensory system.

Animals↗
PubMed2002

Acute renal failure and hearing loss due to sodium bromate poisoning: a case report and review of the literature.

Acute renal failure with hearing loss due to sodium bromate intoxication is described. A 48-year-old woman who ingested permanent wave neutralizer in a suicide attempt and developed anuria was admitted to our hospital for hemodialysis. Bromate intoxication was suspected and hemodialysis was carried out; she required maintenance dialysis 3 times a week. Irreversible severe sensorineural hearing loss continued and peripheral polyneuropathy developed in the lower limbs. We measured the concentration of bromine in the serum before and after the first hemodialysis and found its removal rate to be 61.3%. This is the first report that proved the utility of hemodialysis for bromate intoxication in a clinical setting.

Acute Kidney Injury↗
PubMed2000

The detrimental effects of potassium bromate and thioglycolate on auditory brainstem response of guinea pigs.

Potassium bromate (KBrO3) is known to be an oxidizing agent that is used not only as a food additive, mainly in the bread-making process, but also as a neutralizer in thioglycolate containing hair curling set. Although it has been shown that bromate poisoning could cause severe and irreversible sensorineural hearing loss as well as renal failure, the action mechanism of bromate-induced otoneurotoxicity especially its combination with thioglycolate remains to be studied. In this study, we attempted to investigate the toxic effects of KBrO3 in combination with or without thioglycolate on the auditory brainstem response (ABR) system in the guinea-pigs which was claimed to be very susceptible to the xenobiotics. In a preliminary test, we have found that after consecutive 2 weeks administration, KBrO3 caused a significant prolongation of wave I-III and the interwave latencies of ABR as well as significantly elevated the threshold of hearing, suggesting that the conduction velocity of the peripheral auditory nerve was delayed. By contrast, the absolute latency of wave IV/V and the interwave latency of wave III-V were not significantly prolonged, suggesting that KBrO3 had no effect on the brainstem. This oto-neurotoxic effect of KBrO3 was markedly enhanced by combining with thioglycolate. Our data also indicated that KBrO3 combined with thioglycolate but not KBrO3 alone prominantly caused a decrease of body weight. However, enzymatic activities (including Na+/K+-ATPase and Ca2+-ATPase) and the level of nitric oxide (NO) was significantly affected in the brainstem. Based on these findings, we tentatively conclude that whether KBrO3 alone or KBrO3 combined with thioglycolate induced oto-neurotoxicity majorly through the peripheral auditory nerve rather than via the central brainstem intoxication.

Animals↗
PubMed2004

Germanium dioxide as internal standard for simplified trace determination of bromate, bromide, iodate and iodide by on-line coupling ion chromatography-inductively coupled plasma mass spectrometry.

The use of elemental mass spectrometry as detection for ion chromatography allows sensitive determination of several bromine and iodine species at a reasonable time scale. Lowest concentrations observable are 66 ng L(-1) for bromate, 45 ng L(-1) for iodate, 74 ng L(-1) for bromide and 151 ng L(-1) for iodide. A major drawback of previous IC-ICP-MS applications is the high consumption of time and thus the running costs. The use of GeO2 as internal standard not only allows improved external calibration, but also semiquantitative determination of bromate, bromide, iodate and iodide without any calibration procedure. Furthermore, GeO2 can be used for all known types of anion exchange columns regardless of their construction principles. It is shown, that the analyte-to-GeO2 ratio of four bromine and iodine species was nearly constant over 4 months and almost independent from the ICP-MS instrumental settings. The quantification by means of the analyte-to-GeO2 ratio for samples taken from a bromate round robin test shows that the values obtained are in excellent agreement with calibration curve and isotope dilution results.

Bromates↗
PubMed1983

Carcinogenicity of potassium bromate administered orally to F344 rats.

The carcinogenicity of potassium bromate, a food additive and a neutralizer in permanent waving, was tested by adding it to the drinking water of F344 rats for 110 weeks. Groups of 53 males and 53 females, each, were given solutions of 500 or 250 ppm of potassium bromate or distilled water. A concentration of 500 ppm markedly inhibited an increase of body weight of male rats. The mean survival time was shortest for males given 500 ppm (88.1 +/- 18.1 wk); the survival times of other groups were 101-104 weeks. The percentage survival in week 104 was relatively high in all groups, and it was 77.4% for males and 66.0% for females in the control group. High incidences of renal cell tumors (in males and females given 500 or 250 ppm) and mesotheliomas of the peritoneum (in males given 500 ppm) were observed. The incidences of these tumors in test groups were significantly higher than those in controls (P less than .001). It was concluded that, when orally administered under the conditions of this experiment, potassium bromate was carcinogenic to F344 rats.

Adenocarcinoma↗
PubMed1983

Enhancement by potassium bromate of renal tumorigenesis initiated by N-ethyl-N-hydroxyethylnitrosamine in F-344 rats.

The effect of potassium bromate, a food additive, was examined in male F-344 rats based on two-stage renal carcinogenesis with N-ethyl-N-hydroxyethylnitrosamine (EHEN) as an initiator. Average numbers of dysplastic foci and renal cell tumors were significantly increased in rats given potassium bromate after initiation with EHEN. It was concluded that potassium bromate has an enhancing effect on renal tumorigenesis.

Animals↗
PubMed1993

[A case of sodium bromate intoxication with cerebral lesion].

We confirmed a cerebral lesion due to sodium bromate intoxication on MRI, SPECT, auditory brainstem response (ABR) and sensory evoked potential (SEP). The patient was 34 years old, and ingested sodium bromate (14 g) to commit suicide. Vomiting, epigastralgia, watery diarrhea and anuria appeared after 30 minutes and he became deaf within 12 hours. Renal function recovered after hemodialysis. Renal biopsy revealed acute renal tubular necrosis. After one month, burning pain appeared in bilateral lower extremities. Sporadic, clear and small high intensity spots were observed in the deep white matter of the right occipitotemporal border zone and bilateral centrum semiovale on T2 and proton weighted images of brain MRI. IMP-SPECT disclosed partial low perfusion in the left parietal gray matter. Central conduction time was delayed on ABR and SEP. The clinical symptoms and course together with laboratory studies suggest that the cerebral lesion was due to direct sodium bromate intoxication.

Adult↗
PubMed2003

Crystal structures and vibrational and solution and solid-state (CPMAS) NMR spectroscopic studies in triphenyl phosphine, arsine, and stibine silver(I) bromate systems, (R3E)xAgBrO3 (E = P, As, Sb; x = 1-4).

Adducts of triphenyl phosphine, triphenyl arsine, and triphenyl stibine with silver(I) bromate have been synthesized and characterized both in solution ((1)H and ESI MS spectroscopy) and in the solid state (IR, single-crystal X-ray structure analysis). The triphenyl phosphine complexes have been also investigated by (31)P[(1)H] solution and (31)P cross-polarization magic-angle-spinning (CPMAS) NMR spectroscopy. The topology of the structures in the solid state was found to depend on the nature of EPh(3) and on the stoichiometric ratio AgBrO(3)/EPh(3). In AgBrO(3)/PPh(3) (1:1)(4) (1) and AgBrO(3)/PPh(3) (1:2) (2), the bromate is in the unfamiliar and hitherto structurally uncharacterized role of coordinating ligand, the complex having a mononuclear form in 2 and a less familiar tetrameric form in 1. In AgBrO(3)/AsPh(3) (1:4).CH(3)OH (7) and AgBrO(3)/SbPh(3) (1:4).C(2)H(5)OH (11), the cations are the familiar homoleptic [Ag(EPh(3))(4)](+) array with the bromate role simply that of counterion. The AgBrO(3)/AsPh(3) (1:2)(2).0.7"H(2)O" derivative (6) is binuclear L(2)Ag(mu-BrO(3))(2)AgL(2) with a four-membered ring core (L = AsPh(3)).

Journal Article↗
PubMed2004

Kinetics and mechanism of bromate-bromide reaction catalyzed by acetate.

The initial rate of the bromate-bromide reaction, BrO3- + 5Br- + 6H+ --> 3Br2 + 3H2O, has been measured at constant ionic strength, I = 3.0 mol L(-1), and at several initial concentrations of acetate, bromate, bromide, and perchloric acid. The reaction was followed at the Br2/Br3- isosbestic point (lambda = 446 nm) by the stopped-flow technique. A very complex behavior was found such that the results could be fitted only by a six term rate law, nu = k1[BrO3-][Br-][H+]2 + k2[BrO3-][Br-]2[H+]2 + k3[BrO3-][H+]2[acetate]2 + k4[BrO3-][Br-]2[H+]2[acetate] + k5[BrO3-][Br-][H+]3[acetate]2 + k6[BrO3-][Br-][H+]2[acetate], where k1 = 4.12 L3 mol(-3) s(-1), k2 = 0.810 L4 mol(-4) s(-1), k3 = 2.80 x 10(3) L4 mol(-4) s(-1), k4 = 278 L5 mol(-5) s(-1), k5 = 5.45 x 10(7) L6 mol(-6) s(-1), and k6 = 850 L4 mol(-4) s(-1). A mechanism, based on elementary steps, is proposed to explain each term of the rate law. This mechanism considers that when acetate binds to bromate it facilitates its second protonation.

Journal Article↗
PubMed2002

Survey of bottled drinking waters sold in Canada for chlorate, bromide, bromate, lead, cadmium and other trace elements.

Mineral, spring and other bottled drinking waters sold in Canada in the winter of 1995-96 were surveyed for chlorate, bromide, bromate, Cr(VI), Li, B, Al, Mn, Cu, Zn, Sr, Ba, Be, V, Cr, Co, Ni, As, Se, Mo, Ag, Cd, Sb, Tl, Pb, Na, K, Ca and Mg. Chlorate and bromide were determined by ion chromatography (IC) with conductivity detection, Cr(VI) by IC with colorimetric detection, bromate by solvent extraction and gas chromatography (GC), trace elements by inductively coupled plasma mass spectrometry (ICPMS), and Na, K, Ca and Mg by flame atomic absorption spectrometry (FAA). Most chemicals in the 199 samples analysed were well within national and international drinking water guidelines. World Health Organization and/or Canadian drinking water guidelines were exceeded for B (22 samples), Al (9), Cr (1), Mn (5), Ni (1), As (10), Se (24) and Pb (1). Bromate levels are reported for information purposes and are considered as the maximum concentrations in the samples. In three distilled water products, unexpectedly high concentrations of Cu (88-147 micro g l(-1)) and Ni (16-35 micro g l(-1)) were found, and a comparison of distilled and non-distilled waters from two of the brands suggested the likely cause to be contamination during the distillation process. Li concentration in one sample was at a therapeutic dose and could pose an overdose risk to individuals on Li medication.

Canada↗
PubMed2001

Toxic effects of potassium bromate and thioglycolate on vestibuloocular reflex systems of Guinea pigs and humans.

Potassium bromate (KBrO(3)) and thioglycolate are two components of hair curling solution. The neurotoxic effects of KBrO(3) and thioglycolate on the vestibuloocular reflex (VOR) system have not been elucidated. In this paper, we report the adverse effects of KBrO(3) and thioglycolate on the VOR system of Hartley-strain guinea pigs. The function of the VOR system was evaluated by caloric test coupled with the electronystagmographic recordings after subcutaneous injection of 20 or 50 mg/kg KBrO(3) or 15 mg/kg thioglycolate, either alone or in combination once daily for 14 consecutive days. The results showed that KBrO(3) produced abnormal caloric responses in a concentration-dependent manner and thioglycolate enhanced this abnormality. Our clinical patients, 10 female hairdressers exposed to the hair curling solution for 10-30 years revealed a similar dysfunction in the caloric test. The possible mechanism of this adverse effect was studied: the cerebellar-regulated functions such as motor equilibrium performance and spontaneous locomotor activity of guinea pigs were reduced, the enzymatic Na(+)/K(+)-ATPase and Ca(2+)-ATPase activities of cerebellar tissues were significantly decreased, and the loss of Purkinje cells as well as the derangement of the granular cell layer of the cerebellar cortex was revealed after treatment with KBrO(3) plus thioglycolate. These findings imply that KBrO(3) plus thioglycolate is toxic to the VOR system, mediated by, at least in part, the dysfunction of a higher cerebellar regulatory mechanism. We suggest that the caloric test is a noninvasive method for monitoring the consequences of hazardous exposure of hair curling solution in humans. Our clinical findings together with the animal study imply that clinicians should be alert to the risk of bromate exposure in hairdressers, especially those with vertigo, tinnitus, or hearing loss.

Adenosine Triphosphatases↗
PubMed1991

Substitute anions and the chloride conductance of frog muscle: effects of chlorate and bromate on steady-state values and kinetics.

Voltage-clamp experiments have been used to study the effects of external nitrate, chlorate and bromate on the chloride conductance of sarcolemma of Xenopus laevis. Nitrate reduces inward current (chloride efflux), but less potently than does thiocyanate [Vaughan (1987) Pflügers Arch 410:153-158] and does not affect conductance kinetics. As its concentration is increased the blocking effect of nitrate saturates; at a nitrate mole fraction of 0.6 the anion conductance is reduced to about 50% and further increases in nitrate concentration are without significant effect. Nitrate's influences are not voltage-dependent. Chlorate is a much less potent blocker than is nitrate, and its effects are voltage-dependent. With small hyperpolarizations, currents are sometimes seen to be larger than the control, but the degree of block (or the conversion of augmentation to reduction) increases with the size of the voltage step. Anomalous mole-fraction effects are observed in the range 0.4-0.6 mol/mol, in that in some cells the reduction of conductance is noticeably greater in the lower than in the higher concentration of the replacement ion. In the presence of chlorate, relaxation rates are significantly increased, and this influence is not anomalously dependent on the mole fraction. Similar effects are observed in bromate. The effect on kinetics is not pH-dependent. The main series of experiments was conducted at pH 5, but the same influence on kinetics was observed at pH 9. Using point voltage-clamp experiments, chlorate and thiocyanate were both seen to lower the contraction threshold voltage, but thiocyanate has no influence on conductance kinetics.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗