The association between the essential metal mixture and fasting plasma glucose in Chinese community-dwelling elderly people.

BACKGROUND: Epidemiological studies about the effect of essential metal mixture on fasting plasma glucose (FPG) levels among elderly people are sparse. The object of this study was to examine the associations of single essential metals and essential metal mixture with FPG levels in Chinese community-dwelling elderly people. METHODS: The study recruited 2348 community-dwelling elderly people in total. Inductively coupled plasma-mass spectrometry was adopted to detect the levels of vanadium (V), selenium (Se), magnesium (Mg), cobalt (Co), calcium (Ca), and molybdenum (Mo) in urine. The relationships between single essential metals and essential metal mixture and FPG levels were evaluated by linear regression and Bayesian kernel machine regression (BKMR) models, respectively. RESULTS: In multiple-metal linear regression models, urine V and Mg were negatively related to the FPG levels (ß = - 0.016, 95 % CI: - 0.030 to - 0.003 for V; ß = - 0.021, 95 % CI: - 0.033 to - 0.009 for Mg), and urine Se was positively related to the FPG levels (ß = 0.024, 95 % CI: 0.014-0.034). In BKMR model, the significant relationships of Se and Mg with the FPG levels were also found. The essential metal mixture was negatively associated with FPG levels in a dose-response pattern, and Mg had the maximum posterior inclusion probability (PIP) value (PIP = 1.0000), followed by Se (PIP = 0.9968). Besides, Co showed a significant association with decreased FPG levels in older adults without hyperlipemia and in women. CONCLUSIONS: Both Mg and Se were associated with FPG levels, individually and as a mixture. The essential metal mixture displayed a linear dose-response relationship with reduced FPG levels, with Mg having the largest contribution to FPG levels, followed by Se. Further prospective investigations are necessary to validate these exploratory findings.

Systemic exposure and urinary excretion of vanadium following perinatal subchronic exposure to vanadyl sulfate and sodium metavanadate via drinking water.

Vanadium is a ubiquitous environmental contaminant although there are limited data to assess potential adverse human health impact following oral exposure. In support of studies investigating the subchronic toxicity of vanadyl sulfate (V4+) and sodium metavanadate (V5+) following perinatal exposure via drinking water in male and female rats, we have determined the internal exposure and urinary excretion of total vanadium at the end of study. Water consumption decreased with increasing exposure concentration following exposure to both compounds. Plasma and urine vanadium concentration normalized to total vanadium consumed per day increased with the exposure concentration of vanadyl sulfate and sodium metavanadate suggesting absorption increased as the exposure concentration increased. Additionally, females had higher concentrations than males (in plasma only for vanadyl sulfate exposure). Animals exposed to sodium metavanadate had up to 3-fold higher vanadium concentration in plasma and urine compared to vanadyl sulfate exposed animals, when normalized to total vanadium consumed per day, demonstrating differential absorption, distribution, metabolism, and excretion properties between V5+ and V4+ compounds. These data will aid in the interpretation of animal toxicity data of V4+ and V5+ compounds and determine the relevance of animal toxicity findings to human exposures.

Concentrations of vanadium in urine with hypertension prevalence and blood pressure levels.

The associations of vanadium exposure with hypertension risk in animal studies are inconsistent. Furthermore, epidemiologic studies on this topic are scarce. We aimed to assess the associations of vanadium exposure with hypertension prevalence and blood pressure levels in a general Chinese population. We measured urinary vanadium concentrations in 1867 participants to evaluate their internal exposure levels. The associations of urinary vanadium concentrations, categorized into quartiles or treated as continuous variables by logarithm transformation (log2), with hypertension prevalence and blood pressure levels were assessed by the multivariable logistic and linear regression models, respectively. We used the restricted cubic spline model to evaluate the dose-response relationship. Compared with the bottom quartile of vanadium, participants in the third and fourth quartile had an adjusted odds ratio of 2.04 (95% CI:1.40, 2.96) and 2.08 (95% CI:1.42, 3.06) for hypertension, with a linear dose-response relationship. The corresponding number for a doubling of vanadium concentrations was 1.25 (95% CI:1.12, 1.39). Besides, a doubling of vanadium concentrations was associated with a 0.66 (95% CI: 0.01, 1.31) and 0.90 (95% CI: 0.50, 1.31) mm Hg increased systolic and diastolic blood pressure level, respectively. Vanadium exposure was associated with increased hypertension prevalence and blood pressure levels. Prospective studies are needed to confirm our findings in other populations.

Association between changes in gestational blood pressure and vanadium exposure in China.

OBJECTIVE: To investigate the association between urinary vanadium concentrations and blood pressure (BP) changes in Chinese pregnant women. METHODS: This longitudinal study included 716 pregnant women who visited our hospital in Wuhan, China, from 2014 to 2016. Urinary sample collection and BP measurements were performed at 9-15, 21-27, and 34-40 weeks of gestation. Outcomes were repeated BP measurements (systolic blood pressure [SBP], diastolic blood pressure [DBP], pulse pressure [PP], and mean arterial pressure [MAP]) during pregnancy. RESULTS: The geometric mean of urinary vanadium concentrations was 0.65 µg/g creatinine. After adjusting for potential confounders, each threefold increase in urinary vanadium concentration was observed to be associated with a 1.06 mmHg decrease in SBP (95 % confidence interval [CI]: -1.80, -0.32), a 0.68 mmHg decrease in DBP (95 % CI: -1.32, -0.04), and a 0.81 mmHg decrease in MAP (95 % CI: -1.42, -0.19). Cross-sectional analysis showed a negative association between urinary vanadium concentrations and BP in the third trimester. Specifically, each threefold increase in urinary vanadium concentration in the second trimester was associated with decreases in SBP, DBP, PP, and MAP by 2.72 mmHg (95 % CI: -4.02, -1.41), 1.57 mmHg (95 % CI: -2.72, -0.42), 1.14 mmHg (95 % CI: -2.15, -0.14), and 1.95 mmHg (95 % CI: -3.06, -0.85), respectively, in the third trimester. CONCLUSION: To the best of our knowledge, this is the first longitudinal study that suggests the negative association between vanadium exposure and BP among pregnant women in China.

Metal(loid)s urinary level among workers of gas refinery and petrochemical companies: Health risk assessment of metal(loid)s in drinking water and dust.

BACKGROUND: Asalouyeh (southern Iran) contains many pollution sources like petrochemical and gas refinery companies. Few studies were conducted on the body burden of metal(loid)s in occupationally exposed workers of the companies in this area. OBJECTIVES: The urine concentration of metal(loid)s in workers of gas refinery and petrochemical companies in Asalouyeh (who have been worked as "two weeks work-two weeks rest" schedule) was evaluated during a before-and-after observational study. The risks of metal(loid)s in drinking water and dust particles in the studied area were also assessed. METHODS: Urinary samples (n = 179) were gathered at the first day of two weeks of work (before) and at the end of two weeks of work (after). The concentration of V, Ni, Mn, Cd, and As was measured using a graphite furnace atomic absorption spectrometry. The health hazards of metal(loid)s in the air dust and drinking water of workers were also evaluated. RESULTS: The median concentration of metal(loid)s for workers of gas refinery and petrochemical companies for before and after two weeks of work was measured, respectively, as: As (11.44 and 9.31 µg/L), Ni (1.06 and 0.51 µg/L), Cd (0.36 and 0.31 µg/L), Mn (0.29 and 0.24 µg/L), and V (0.08 and 0.05 µg/L). After two weeks work, the median of all metal(loid)s in the urine of petrochemical and gas refinery workers was significantly increased. The non-cancer risk due to intake metal(loid)s from drinking water was more than the threshold value and the cancer risk from drinking water and inhaled air dust was less than the threshold. CONCLUSION: Our results revealed the effect of gas refinery and petrochemical activities on increasing the metal(loid)s concentration of the worker's body and the necessity to protect this group. Additionally, the metal(loid)s intake from drinking water and inhaled dust posed no cancer risk to the workers.

Maternal Heavy Metal Exposure, Thyroid Hormones, and Birth Outcomes: A Prospective Cohort Study.

CONTEXT: Maternal thyroid hormones during pregnancy play a critical role in fetal development. However, whether maternal heavy metal exposure affects their thyroid hormones and the effects on fetal growth are still unclear. OBJECTIVE: To explore the effect of heavy metal exposure on maternal thyroid hormones and the potential mediation role of thyroid hormones on birth outcomes. METHODS: Concentrations of heavy metals in urine samples and thyroid hormones in blood samples of 675 pregnant women were measured during early pregnancy in a cohort study conducted in China. Multivariable linear regressions were applied to explore the associations of maternal urinary heavy metal levels with both maternal thyroid hormones and birth outcomes. Mediation analyses were performed to assess the mediation role of thyroid hormones in these associations. RESULTS: Maternal urinary vanadium (V) exhibited an inverse association with free T3 (FT3) and FT3/free T4 (FT4) ratio levels. Urinary arsenic (As) and lead (Pb) had inverse relationships with FT3. We also observed the positive associations of maternal FT3 and FT3/FT4 ratio with birthweight. The mediation analyses suggested that 5.33% to 30.57% of the associations among V, As, and Pb levels and birth size might be mediated by maternal FT3 or FT3/FT4 ratio. CONCLUSIONS: We have shown that maternal exposures to V, As, and Pb at early pregnancy were associated with decreased maternal FT3 or FT3/FT4 ratio, which might contribute to reduced birthweight. Mediation analyses indicated that maternal thyroid hormone was a possible mediator of the association between urinary heavy metals and birth size.

Urinary vanadium concentration in relation to premature rupture of membranes: A birth cohort study.

Heavy metal exposure has been indicated to be linked with reproductive and developmental toxicity. However, human studies on the association between heavy metal exposure and premature rupture of membranes (PROM) are limited. Thus, we aimed to evaluate the associations between urinary metal concentrations in pregnant women and the risk of PROM. The study was conducted among 7290 pregnant women from an ongoing cohort study in China. Levels of urinary metals were determined using an inductively coupled plasma-mass spectrometry and adjusted by creatinine concentration (µg/g creatinine). Adjusted odds ratios (OR) and 95% confidence intervals (CI) for PROM and preterm PROM were estimated using logistic regression models. Among 12 urinary metals detected, vanadium (V) have shown stable positive associations with PROM and preterm PROM. With one unit increase in natural logarithmically transformed urinary V concentration, adjusted OR of 1.57 (95% CI: 1.47, 1.66) for PROM was observed. Compared with the lowest tertile of urinary V, we also observed positive associations between V levels and PROM (for the medium tertile, adjusted OR = 1.66, 95% CI: 1.34, 2.05; for the highest tertile, adjusted OR = 3.75, 95% CI: 3.09, 4.54). In addition, higher adjusted ORs for preterm PROM were observed (for the highest tertile, adjusted OR = 8.14, 95% CI: 4.55, 14.55). Further stratified analysis suggested the associations were more pronounced among women delivering male infants than those with female infants. Our present epidemiological study indicated that pregnant women exposure to higher level of V might lead to an increased risk of PROM.

Concentrations of vanadium in urine and seminal plasma in relation to semen quality parameters, spermatozoa DNA damage and serum hormone levels.

Widespread human exposure to vanadium has been well documented. Vanadium exposure was reported to induce male reproductive toxicity in toxicological studies, yet human epidemiologic studies are lacking. Here we determined the associations between environmental exposure to vanadium and semen quality, spermatozoa DNA damage and serum reproductive hormones. Concentrations of vanadium in seminal plasma and repeated urine samples were determined among 764 men recruited from a reproductive medicine centre. Associations of vanadium concentrations with semen quality parameters (n = 764), DNA integrity measures (n = 404) and serum reproductive hormones (n = 381) were assessed by logistic or linear regression models with adjustment for potential confounders. Significant positive dose-response relationships were observed between vanadium concentrations in seminal plasma and tail length and serum estradiol, as well as odds ratios for a below-reference-value sperm concentration; whereas inverse relationships between seminal plasma vanadium with total testosterone (T) and free T (all p values for trends <0.05) were observed. These relationships were maintained after adjusting for seminal plasma concentrations of other elements (i.e., arsenic, cadmium, copper, selenium, or tin). No significant associations was revealed between urinary vanadium concentrations and semen quality, spermatozoa DNA integrity and reproductive hormones. Our findings suggested that elevated vanadium exposure may be adversely associated with male reproductive health, and that seminal plasma vanadium may be a more direct exposure biomarker for the male reproductive system than urinary vanadium.

Urinary arsenic, cadmium, manganese, nickel, and vanadium levels of schoolchildren in the vicinity of the industrialised area of Asaluyeh, Iran.

Asaluyeh is one of the most heavily industrialised areas in the world where gas, petrochemical, and many downstream industries are located. This study aims to survey the biomonitoring of four metals and one metalloid in children living in the vicinity of Asaluyeh area. To do this, we analysed the creatinine-adjusted urinary levels of arsenic (As), cadmium (Cd), vanadium (V), manganese (Mn), and nickel (Ni) in 184 elementary schoolchildren (99 boys and 85 girls) living in Asaluyeh and compared them with a reference population. The comparisons were done for two seasons (spring and fall). The results showed that in the case area (Asaluyeh), the levels of As, V, Mn, and Ni were significantly higher and that of Cd was not significantly higher than the reference city for both seasons. The mean concentration of metal(loid)s in Asaluyeh (case) and Sadabad (reference) area as µg g-1 creatinine was As 2.90 and 2.24, V 0.06 and 0.03, Mn 0.28 and 0.25, Ni 0.54 and 0.29, and Cd 0.31 and 0.28 in spring and As 3.08 and 2.28, V 0.07 and 0.03, Mn 0.30 and 0.26, Ni 0.91 and 0.30, and Cd 0.36 and 0.31 in the fall. Seasonal variations played a key role in determining urinary metal(loid) concentration, as we saw the significant level of As, Cd, V, and Ni in fall than in spring. With regard to the impact of gender on the absorption and accumulation of urinary metal(loid)s, boys showed higher levels of the studied elements, especially for As, than girls as outdoor activities are more popular among boys. Due to the values being lower than those reported in literature, more research is needed on various population groups and other exposure sources in order to judge whether living in the vicinity of the gas and petrochemical industries in Asaluyeh is a threat to nearby residents.

Biological monitoring of welders' exposure to chromium, molybdenum, tungsten and vanadium.

BACKGROUND: Welders are exposed to a number of metallic elements during work. Bioaccessability, that is important for element uptake, has been little studied. This study addresses bioaccessability and uptake of chromium (Cr), molybdenum (Mo), tungsten (W) and vanadium (V) among welders. METHODS: Bioaccessability of Cr, Mo, V and W was studied in airborne particulate matter collected by personal sampling of the workroom air among shipyard welders by using the lung lining fluid simulant Hatch solution. Associations between concentrations of Hatch soluble and non-soluble elements (Hatchsol and Hatchnon-sol) and concentrations of the four elements in whole blood, serum, blood cells and urine were studied. RESULTS: Air concentrations of the four elements were low. Only a small fraction of Cr, V and W was Hatchsol, while similar amounts of Mo were Hatchsol and Hatchnon-sol. Welders (N=70) had statistically significantly higher concentrations of all four elements in urine and serum when compared to referents (N=74). Highly statistically significant associations were observed between urinary W and Hatchsol W (p<0.001) and serum V and Hatchsol V (p<0.001), in particular when air samples collected the day before collection of biological samples were considered. CONCLUSIONS: Associations between Hatchsol elements in air and their biological concentrations were higher than when Hatchnon-sol concentrations were considered. Associations were generally higher when air samples collected the day before biological sampling were considered as compared to air samples collected two days before.

A nested case-control study of prenatal vanadium exposure and low birthweight.

STUDY QUESTION: Is prenatal vanadium exposure associated with adverse birth outcomes? SUMMARY ANSWER: The odds of low birthweight (LBW) are increased 2.23-fold in mothers with a urinary vanadium of ≥2.91 µg/g creatinine compared with that in mothers with a urinary vanadium of ≤1.42 µg/g creatinine. WHAT IS KNOWN ALREADY: Human exposure to vanadium occurs through intake of food, water and polluted air. Vanadium has been suggested to have fetotoxicity and developmental toxicity in animal studies, and epidemiological studies have reported an association between a decrease in birthweight and vanadium exposure estimated from particulate matter. STUDY DESIGN, SIZE, DURATION: A nested case-control study involving 816 study participants (204 LBW cases and 612 matched controls) was conducted with data from the prospective Healthy Baby Cohort between 2012 and 2014 in the province of Hubei, China. PARTICIPANTS/MATERIALS, SETTING, METHODS: Vanadium concentrations in 816 maternal urine samples collected before delivery [the median gestational age was 39 weeks (range 27-42 weeks)] were measured by inductively coupled plasma mass spectrometry. Information on the infants' birth outcomes was obtained from medical records. Conditional logistic regression was used to calculate the odds ratios (ORs) and 95% confidence intervals (CIs). MAIN RESULTS AND THE ROLE OF CHANCE: The median urinary vanadium concentration of the cases was much higher than that of the controls (3.04 µg/g creatinine versus 1.93 µg/g creatinine). The results revealed a significant positive trend between the odds of LBW and level of maternal urinary vanadium [relative to the lowest tertile; adjusted OR = 1.69 (95% CI: 0.92, 3.10) for the medium tertile; adjusted OR = 2.23 (95% CI: 1.23, 4.05) for the highest tertile; P-trend = 0.02]. Additionally, the association was not modified by maternal age (P for heterogeneity = 0.70) or infant gender (P for heterogeneity = 0.21). LIMITATIONS, REASONS FOR CAUTION: The maternal urine sample was collected before labor, and the maternal urinary vanadium levels measured at one point in time may not accurately reflect the vanadium burden during the entire pregnancy. WIDER IMPLICATIONS OF THE FINDINGS: The results of this study can enrich the biological monitoring data on urinary vanadium in pregnant women; and may be evidence that vanadium may affect fetal development. STUDY FUNDING/COMPETING INTERESTS: This work was supported by the National Natural Science Foundation of China (21437002, 81372959 and 81402649), the R&D Special Fund for Public Welfare Industry (Environment) (201309048) and the Fundamental Research Funds for the Central Universities, HUST (2016YXZD043). The authors have no conflicts of interest to declare.

Automatic On-line Solid-phase Extraction-Electrothermal Atomic Absorption Spectrometry Exploiting Sequential Injection Analysis for Trace Vanadium, Cadmium and Lead Determination in Human Urine Samples.

A fully automated sequential injection column preconcentration method for the on-line determination of trace vanadium, cadmium and lead in urine samples was successfully developed, utilizing electrothermal atomic absorption spectrometry (ETAAS). Polyamino-polycarboxylic acid chelating resin (Nobias chelate PA-1) packed into a handmade minicolumn was used as a sorbent material. Effective on-line retention of chelate complexes of analytes was achieved at pH 6.0, while the highest elution effectiveness was observed with 1.0 mol L(-1) HNO3 in the reverse phase. Several analytical parameters, like the sample acidity, concentration and volume of the eluent as well as the loading/elution flow rates, have been studied, regarding the efficiency of the method, providing appropriate conditions for the analysis of real samples. For a 4.5 mL sample volume, the sampling frequency was 27 h(-1). The detection limits were found to be 3.0, 0.06 and 2.0 ng L(-1) for V(V), Cd(II) and Pb(II), respectively, with the relative standard deviations ranging between 1.9 - 3.7%. The accuracy of the proposed method was evaluated by analyzing a certified reference material (Seronorm(TM) trace elements urine) and spiked urine samples.

Urinary titanium and vanadium and breast cancer: a case-control study.

Titanium and vanadium are essential trace elements. This study examined the associations of urinary titanium and vanadium with breast cancer risk in a hospital-based case-control study comprising 240 women with incident breast cancer, and 246 cancer-free and age-matched controls who attended health screening assessments in 2 affiliated hospitals of Sun Yat-sen University in Guangzhou between October 2009 and July 2010. Survey data and urine specimens were collected before treatment for the patients and after interview for the controls. The urinary concentrations of titanium and vanadium were measured by inductively coupled plasma mass spectrometry. Women in the second and the highest tertile of vanadium showed 64% and 40% decreased risk of breast cancer, respectively, when compared with those in the lowest tertile after adjustment for established risk factors of breast cancer (ORs [95%CI]: 0.36 [0.21-0.60] and 0.60 [0.37-0.97], respectively). In contrast, urinary titanium was not significantly related to a decreased risk of breast cancer. These results have potentially significant implications on nutritional chemoprevention of breast cancer and the development of new anticancer drugs. Further replications of the study are recommended, and the biological mechanisms warrant clarification.

An investigation of aircraft worker anemia: medical surveillance interpretation in an aging workforce.

OBJECTIVE: To identify exposures possibly contributing to anemia cases among hexavalent chromium medical surveillance program enrollees. METHODS: An investigation encompassed metals surveillance programs, extensive workplace sampling and remediation, consultation, evaluation of laboratory accuracy, and follow-up of anemic individuals. RESULTS: Workers had underlying medical conditions that affected surveillance results. There was a systemic error in classification based on hematocrit value. The prevalence of anemia in a workforce averaging 52 years old was 16%. CONCLUSIONS: Anemia may be more prevalent in middle-aged workers than expected. Modern laboratories generally report a calculated hematocrit value, and using hemoglobin for most classification purposes is preferred. Characteristics of a specific workforce, including age, health, hobbies, and diet, should be taken into account when interpreting medical surveillance program findings. The value of a team approach in addressing occupational health problems was demonstrated.

High-resolution ICP-MS determination of Ti, V, Cr, Co, Ni, and Mo in human blood and urine of patients implanted with a hip or knee prosthesis.

The main components (Ti, V, Cr, Co, Ni, and Mo) of metallic alloys currently used in hip and knee articular prostheses have been simultaneously determined in human whole blood and urine of implanted people by a (HR)-ICP-MS method previously developed in our laboratory. The determination of those elements has been carried out in patients with knee and hip prosthesis and in a group of pre-operation patients without any metallic device in their bodies, used as controls, demonstrating the usefulness of this technique to perform multielement analysis at ppt levels in complex matrices. The concentrations of V, Cr, Co, Ni, and Mo in urine and blood of implanted people turned out to be very similar to those obtained in control patients. However, raised Ti levels could be found both in urine and blood of patients with articular prostheses made or coated with a titanium alloy (Ti(6)Al(4)V).

On-line preconcentration and speciation analysis of inorganic vanadium in urine using l-methionine immobilised on controlled pore glass.

A study was undertaken to ascertain the analytical capabilities of combined ICP-OES with ultrasonic nebulization to perform on-line preconcentration and speciation of inorganic V species in urine samples using a micro-column packed with l-methionine immobilized on controlled pore glass (CPG) as solid phase extractant. At pH 5.0, l-methionine is selective only towards V(V) while, total vanadium was quantitatively adsorbed by the solid phase at pH 9.0 [as V(V)] due to V(IV) oxidation in alkali media. Vanadium species retained by l-methionine were quantitatively eluted from the column with 10% HCl. Effects of acidity, sample flow rate, concentration of eluent and interfering ions on the recovery of the analytes have been systematically investigated. The detection limit (3sigma) of V is 0.008ngmL(-1) for USN-ICP-OES with an enhancement factor of 900 (10 for USN and 90 for l-methionine), and the relative standard deviation (R.S.D.) is better than 2%. The proposed method has been applied to the determination of inorganic V(V) and V(IV) in urine.

A novel capillary microextraction on ordered mesoporous titania coating combined with electrothermal vaporization inductively coupled plasma mass spectrometry for the determination of V, Cr and Cu in environmental and biological samples.

In this work, an ordered mesoporous titania film was introduced to coat a capillary by means of sol-gel technique. Sol-gel titania coating was developed for the preconcentration/separation of trace V, Cr and Cu by capillary microextraction (CME), and the adsorbed analytes were eluted for electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS) detection. By immobilizing sol-gel titania on the inner surface of a fused-silica microextraction capillary, the sol-gel titania coating was prepared easily. Its adsorption properties, stability and the factors affecting the adsorption behaviors of V, Cr and Cu were investigated in detail. At pH range of 7 to 9, the titania-coated capillary (50 cm x 0.25 mm) is selective towards V, Cr and Cu, and the target analytes could be desorbed quantitatively with 50 microl of 1.0 mol l(-1) HNO3 at the rate of 0.05 ml min(-1). With a consumption of 2 ml sample solution, an enrichment factor of 33.3, and a detection limit (3 s) of 1.1 pg ml(-1) (10.5 fg) for V; 3.3 pg ml(-1) (33.0 fg) for Cr and 6.3 pg ml(-1) (63.1 fg) for Cu respectively were obtained. The precisions Relative Standard Deviations (RSDs) for nine replicate measurements of 1 ng ml(-1) V, Cr and Cu were 3.4, 5.1 and 6.4%, respectively. The proposed method has been applied to the determination of V, Cr and Cu in human urine and lake water, and the recoveries for these elements were 89.2 approximately 105%. The developed method was also applied to the determination of the target elements in NIES No. 10-a (rice flour-unpolished) and NIES No. 9 (sargasso) certified reference materials, and the results found are in good agreement with the certified values.

Chronic vanadium poisoning in calves and its treatment with calcium disodium ethylenediaminetetraacetate.

Sixteen Friesland heifer calves aged between 96 and 157 days were removed from a dairy farm that had been polluted with vanadium and randomly allocated into two equal groups (n = 8). The objective of the trial was to determine whether calcium disodium ethylenediaminetetraacetate (CaNa(2)EDTA) could be used as a treatment for cattle running in environments high in background vanadium. The treatment group received 80 mg CaNa(2)EDTA per kg body weight intraperitonealy (i.p.) twice a week over a 10-week period. The control group received normal saline i.p. over the same period. During the trial calves were exposed to a daily intake of vanadium in the form of contaminated tef hay derived from the farm of origin. In addition, the total mixed ration was spiked with a further 20 mg V(2)O(5)/kg feed to compensate for possible on-farm inhalation exposure. A stochastic model was used to estimate daily intake of vanadium as a distribution function. The model estimated that the daily intake of vanadium varied between an absolute minimum of 33 mg/day to an absolute maximum of 124 mg/day. The average intake of vanadium was 71.8 mg per day per calf. Various chemical pathology parameters were measured throughout the trial as well as urine excretion rates of vanadium and lymphocyte stimulation counts. All calves were slaughtered and necropsied in cohorts of 4-6 animals at monthly intervals after completion of the trial and withdrawal of vanadium from the ration. Tissue concentrations of vanadium were determined and necropsy findings were noted. The study found that CaNa(2)EDTA appears to enhance the excretion of vanadium in calves, but could not prove that the treatment had a protective effect against vanadium exposure. Calves were able to tolerate the prolonged treatment with CaNa(2)EDTA without side-effects.

Vanadium complexes with mixed O,S anionic ligands derived from maltol: synthesis, characterization, and biological studies.

Four mixed O,S binding bidentate ligand precursors derived from maltol (3-hydroxy-2-methyl-4-pyrone) have been chelated to vanadium to yield new bis(ligand)oxovanadium(IV) and tris(ligand)vanadium(III) complexes. The four ligand precursors include two pyranthiones, 3-hydroxy-2-methyl-4-pyranthione, commonly known as thiomaltol (Htma), and 2-ethyl-3-hydroxy-4-pyranthione, commonly known as ethylthiomaltol (Hetma), as well as two pyridinethiones, 3-hydroxy-2-methyl-4(H)-pyridinethione (Hmppt) and 3-hydroxy-1,2-dimethyl-4-pyridinethione (Hdppt). Vanadium complex formation was confirmed by elemental analysis, mass spectrometry, and IR and EPR (where possible) spectroscopies. The X-ray structure of oxobis(thiomaltolato)vanadium(IV),VO(tma)(2), was also determined; both cis and trans isomers were isolated in the same asymmetric unit. In both isomers, the two thiomaltolato ligands are arranged around the base of the square pyramid with the V=O linkage perpendicular; the vanadium atom is slightly displaced from the basal plane [V(1) = 0.656(3) A, V(2) = 0.664(2) A]. All of the new complexes were screened for insulin-enhancing effectiveness in streptozotocin-induced diabetes in rats, and VO(tma)(2) was profiled metabolically for urinary vanadium and ligand clearance by GFAAS and ESIMS, respectively. The new vanadium complexes did not lower blood glucose levels acutely, possibly because of rapid dissociation and excretion.