MOLYBDENUM IN HUMAN HEALTH
URINE
Dietary intake and urinary metals among pregnant women in the Pacific Northwest
Pregnancy is a period when the mother and her offspring are susceptible to the toxic effects of metals. We investigated associations of intake of frequently consumed foods with urinary metals concentrations among pregnant women in the Pacific Northwest. We measured urinary cadmium (U-Cd), arsenic (U-As) and molybdenum (U-Mo) concentrations from spot urine samples in early pregnancy (15 weeks of gestation, on average) among 558 women from Seattle and Tacoma, Washington. We assessed periconceptional dietary intake using a semi-quantitative food frequency questionnaire (FFQ). We also determined early pregnancy zinc concentrations in serum. Statistical analyses involved multivariable linear regression models, adjusted for smoking status, age, race/ethnicity, multivitamin and supplement use, education, estimated total energy intake, and gravidity. The geometric mean and range in mug/g creatinine for U-Cd, U-As and U-Mo were 0.29 (0.1-8.2), 18.95 (3-550), and 72.1 (15-467), respectively. U-Cd was positively associated with dietary zinc intake (P-value=0.004) and serum zinc (P-value<0.001) while it was negatively associated with coffee intake (P-value=0.03). U-As was positively associated with dietary fish [(Lean fish, fatty fish, shellfish and non-fried fish) (P-values<0.01)], selenium (P-value=0.004), zinc (P-value=0.017), vegetables (P-value=0.004), and low-fat yogurt (P-value=0.03). Women who reported higher intake of dietary magnesium (Mg)(P-value=0.04), insoluble fiber (P-value=0.03), and low-fat yogurt (P-value=0.04) had higher U-Mo concentrations. Our study suggests that vegetables, fish, fiber and yogurt might be significant dietary sources of metals. Future studies aimed at investigating the risk of exposure to metals from other various food sources among reproductive-age and pregnant women are needed.
C. Osorio-Yanez, B. Gelaye, D. A. Enquobahrie, C. Qiu, and M. A. Williams,Dietary intake and urinary metals among pregnant women in the Pacific Northwest, Environmental pollution (Barking, Essex : 1987), 2018, 236, 680-688.
Molybdenum levels in humans
In considering physiological effects of molybdenum deficiency and excess, and possible toxic effects of molybdenum, it is important to know whether it accumulates in the body as a result of repeated exposure to low doses. The evidence obtained with experimental animals is that molybdenum is absorbed and excreted rapidly but the rate of excretion is less than the rate of absorption so there is some accumulation of molybdenum in the body (especially bones) and the amount stored increases with dose.
Molybdenum [Nutrition]
Molybdenum, a trace element essential for micro-organisms, plants, and animals, was discovered in 1778 by a Swedish chemist named Karl Scheele. Initially mistaken for lead, molybdenum was named after the Greek work molybdos, meaning lead-like. In the 1930s, it was recognized that ingestion of forage with high amounts of molybdenum by cattle caused a debilitating condition. In the 1950s, the essentiality of molybdenum was established with the discovery of the first molybdenum-containing enzymes. In humans, only 4 enzymes requiring molybdenum have been identified to date: sulfite oxidase, xanthine oxidase, aldehyde oxidase, and mitochondrial amidoxime-reducing component (mARC). Sulfite oxidase, an enzyme found in mitochondria, catalyzes oxidation of sulfite to sulfate, the final step in oxidation of sulfur amino acids (cysteine and methionine). Xanthine oxidase converts hypoxanthine to xanthine, and further converts xanthine to uric acid, preventing hypoxanthine, formed from spontaneous deamination of adenine, from leading to DNA mutations if paired with cytosine in place of thymine. Aldehyde oxidase is abundant in the liver and is an important enzyme in phase 1 drug metabolism. Finally, mARC, discovered less than a decade ago, works in concert with cytochrome b5 type B and NAD(H) cytochrome b5 reductase to reduce a variety of N-hydroxylated substrates, although the physiologic significance is still unclear. In the case of each of the molybdenum enzymes, activity is catalyzed via a tricyclic cofactor composed of a pterin, a dithiolene, and a pyran ring, called molybdenum cofactor (MoCo) (1).
J. A. Novotny, and C. A. Peterson,Molybdenum, Advances in nutrition, 2018, 9, 272-273.
Molybdenum Nutriture in Humans
Molybdenum is a trace element that functions as a cofactor for at least 4 enzymes: sulfite oxidase, xanthine oxidase, aldehyde oxidase, and mitochondrial amidoxime reducing component. In each case, molybdenum is bound to a complex, multiring organic component called molybdopterin, forming the entity molybdenum cofactor. The best sources of dietary molybdenum are legumes, grains, and nuts. Bioavailability of molybdenum is fairly high but depends on form, with molybdenum preparations having greater bioavailability than food-bound molybdenum. Molybdenum deficiency and toxicity are rare, possibly because of the body’s ability to adapt to a wide range of molybdenum intake levels. At low intakes of molybdenum, the fractional transfer of molybdenum from plasma to urine is lower and a greater fraction is deposited into tissues, and at high intakes of molybdenum, the opposite occurs. Molybdenum has proven to be an interesting trace mineral that is essential for life.
J. A. Novotny,Molybdenum Nutriture in Humans, Journal of Evidence-Based Complementary & Alternative Medicine, 2011, 16, 164-168.
Astrocyte dysfunction following molybdenum-associated purine loading could initiate Parkinson's disease with dementia
Sporadic or idiopathic Parkinson's disease is a movement disorder with a worldwide distribution, a long pre-clinical latent period and a frequent association with dementia. The combination of molybdenum deficiency and purine ingestion could explain the movement disorder, the distribution, the latent period and the dementia association. Recent studies in sheep have shown that molybdenum deficiency enables some dietary purines to accumulate in the central nervous system. This causes astrocyte dysfunction, altered neuromodulation and eventually irreversible central nervous system disease. Humans and sheep share the ability to salvage purines and this ability places humans at risk when they ingest xanthosine, inosine, adenosine and guanosine. Adenosine ingestion in molybdenum-deficient humans will lead to adenosine loading and potentially a disturbance to the A2a adenosine receptors in the nigro-striatum. This could result in Parkinson's disease. Guanosine ingestion in molybdenum-deficient humans will lead to guanosine loading and potentially a disturbance to the guanosine receptors in the hippocampus, amygdala and ventral striatum. This could result in dementia. The molybdenum content of the average daily diet in the United States is 0.07 ppm and in the United Kingdom 0.04 ppm. Central nervous system disease occurs in sheep at <0.04 ppm. Consistent with the role proposed for molybdenum deficiency in Parkinson's disease is the observation that affected individuals have elevated sulfur amino acid levels, depressed sulfate levels, and depressed uric acid levels. Likewise the geographical distribution of Parkinson's dementia complex on Guam corresponds with the distribution of molybdenum-deficient soils hence molybdenum-deficient food gardens on that island.
C. A. Bourke,Astrocyte dysfunction following molybdenum-associated purine loading could initiate Parkinson's disease with dementia, Npj Parkinsons Disease, 2018, 4.
HUMAN HEALTH
Serum reference values
27 Reference Values of 14 Serum Trace Elements for Pregnant Chinese Women: A Cross-Sectional Study in the China Nutrition and Health Survey 2010-2012
The development of reference values of trace elements is recognized as a fundamental prerequisite for the assessment of trace element nutritional status and health risks. In this study, a total of 1400 pregnant women aged 27.0 +/- 4.5 years were randomly selected from the China Nutrition and Health Survey 2010-2012 (CNHS 2010-2012). The concentrations of 14 serum trace elements were determined by high-resolution inductively coupled plasma mass spectrometry. Reference values were calculated covering the central 95% reference intervals (P2.5-P97.5) after excluding outliers by Dixon's test.
The overall reference values of serum trace elements were 131.5 (55.8-265.0 µg/dL for iron (Fe), 195.5 (107.0-362.4) µg/dL for copper (Cu), 74.0 (51.8-111.3) µg/dL for zinc (Zn), 22.3 (14.0-62.0) µg/dL for rubidium (Rb), 72.2 (39.9-111.6) µg/L for selenium (Se), 45.9 (23.8-104.3) µg/L for strontium (Sr), 1.8 (1.2-3.6) µg/L for molybdenum (Mo), 2.4 (1.2-8.4) µg/L for manganese (Mn), 1.9 (0.6-9.0) ng/L for lead (Pb), 1.1 (0.3-5.6) ng/L for arsenic (As), 835.6 (219.8-4287.7) ng/L for chromium (Cr), 337.9 (57.0-1130.0) ng/L for cobalt (Co), 193.2 (23.6-2323.1) ng/L for vanadium (V), and 133.7 (72.1-595.1) ng/L for cadmium (Cd). Furthermore, some significant differences in serum trace element reference values were observed between different groupings of age intervals, residences, anthropometric status, and duration of pregnancy. We found that serum Fe, Zn, and Se concentrations significantly decreased, whereas serum Cu, Sr, and Co concentrations elevated progressively compared with reference values of 14 serum trace elements in pregnant Chinese women. The reference values of serum trace elements established could play a key role in the following nutritional status and health risk assessment.
Liu, X., Zhang, Y., Piao, J., Mao, D., Li, Y., Li, W., Yang, L., and Yang, X.,Reference Values of 14 Serum Trace Elements for Pregnant Chinese Women: A Cross-Sectional Study in the China Nutrition and Health Survey 2010-2012, Nutrients, 2017, 9.
Trace elements and oral health: s systematic review
Background: The role of trace elements in the maintenance of oral health is a very debatable issue. With respect to dental caries, there are certain trace elements that may aid in the progression of dental caries, whereas there are some trace elements which may stop the development of dental caries. Irrespective of their role in oral health, these trace elements form an indispensable part of human growth and nutrition. They are required for performing certain essential physiologic functions in the human body. This systematic review was conducted with the aim to assess the role of trace elements on oral health particularly dental caries.
Materials and Methods: Appropriate guidelines determined for systematic reviews were followed. The time frame selected for the current systematic review was from the year 1952-2014. The studies were selected from various electronic databases on the basis of their title, study design, keywords, and their abstracts. A total of 128 citations were identified following initial searching, and after screening, and quality appraisal 28 studies were included.
Results: A reduction in the incidence of new carious lesions was associated with elements such as fluorides, molybdenum, strontium, lithium, and vanadium. On the other hand, caries-promoting agents were found to be elements such as selenium, cadmium, lead, copper, and others.
Conclusion: Trace elements are vital for the human body to maintain normal yet complex physiological functions related to body's growth and development. The trace elements important for good oral health are molybdenum, fluoride, vanadium, strontium, and lithium.
Pathak, M. U., Shetty, V., and Kalra, D.,Trace Elements and Oral Health: A Systematic Review
Absorption and excretion of molybdenum
Effect of pregnancy on the levels of urinary metals for females aged 17-39 years old: data from National Health and Nutrition Examination Survey 2003-2010
Data from National Health and Nutrition Examination survey for the years 2003-2010 were used (n=1565) to evaluate the effect of age, parity, body mass index (BMI), race/ethnicity, pregnancy, iron (Fe) storage status, smoking status, and fish/shellfish consumption on the levels of urine barium (Ba), cadmium (Cd), cesium (Cs), cobalt (Co), molybdenum (Mo), lead (Pb), antimony (Sb), thallium (TI), tungsten (W), uranium (U), and mercury (Hg) for females aged 1739 yr old. Regression analysis was used to fit models for each of the 11 metals.
For Cd, Cs, TI, and Hg, age was positively associated with levels of these metals. Body mass index was negatively associated with levels of Cs, Co, and TI. Levels of Co, Mo, and W increased over the period 20032010. Over the same period, levels of Pb, Sb, and Hg declined. Non-Hispanic blacks showed lower levels of almost all metals compared to either Mexican American or other unclassified race/ethnicities. Non-Hispanic whites displayed higher levels than non-Hispanic blacks for 9 of 11 metals. Smokers displayed significantly higher levels of Pb, Sb, W, and U than nonsmokers but significantly lower levels of Cd and Mo than nonsmokers.
Pregnancy was found to be associated with higher levels of Ba, Cs, Co, Mo, Pb, W, and Hg compared to nonpregnant females. Levels of Mo, Cs, and Cd declined significantly during the pregnancy period but levels of Co rose during the same period.
Jain, R. B., Effect of Pregnancy on the Levels of Urinary Metals for Females Aged 17-39 Years Old: Data From National Health and Nutrition Examination Survey 2003-2010, Journal of Toxicology and Environmental Health-Part A-Current Issues, 2013, 76, 86-97.
Molybdate diet polyphenol interaction
Trace elements are inorganic constituents of the human body present in concentrations less than 50mg/kg body weight. An exception is iron that is found in slightly higher amounts, 60mg/kg body weight, but it is classified within this category due to its physiological roles. Requirements of trace elements can vary according to age, gender, growth, body composition, genetics, pregnancy, lactation, wound healing and burns, alcohol abuse, infections, and diseases (anemia, coronary artery, Keshan, Kashin-Beck). Additionally, interactions may occur with dietary factors, such as other minerals (iron versus copper), phytates (zinc), oxalates (iron), fiber (manganese), and polyphenolic compounds (molybdenum). On a global basis, requirements can vary according to soil and geographical location, food preparation and processing, food accessibility, cultural practices (geophagia) and pollution. Furthermore, global differences exist in body composition, ethnicity, and age of menarche.
Freeland-Graves, J. H., Sanjeevi, N., and Lee, J. J.,Global perspectives on trace element requirements, J Trace Elem Med Biol, 2015, 31, 135.
Molbdate nutritional products
AOAC First Action Method 2011.19: Chromium, Selenium, and Molybdenum in Infant Formula and Adult Nutritional Products, was collaboratively studied. This method employs microwave digestion of samples with nitric acid, hydrogen peroxide, and internal standard followed by simultaneous detection of the elements by an inductively coupled plasma mass spectrometer (ICP-MS) instrument equipped with a collision/reaction cell. During this collaborative study, nine laboratories from four different countries, using seven different models of ICP-MS instruments, analyzed blind duplicates of seven infant, pediatric, and adult nutritional formulas. One laboratory's set of data was rejected in its entirety. The method demonstrated acceptable repeatability and reproducibility and met The Stakeholder Panel on Infant Formula and Adult Nutritionals (SPIFAN) standard method performance requirements (SMPR) for almost all of the matrices analyzed. The Cr, Mo, and Se SPIFAN requirement for repeatability was 5% RSD. The SMPR called for a reproducibility of 15% RSD in products for ultratrace element concentrations above the targeted limit of quantitation of 20 mug/kg Cr/Mo and 10 mug/kg Se (as ready-to-feed). During this collaborative study, repeatability relative standard deviation ranged from 1.0%-7.0% and reproducibility relative standard deviation ranged from 2.5-13.4% across all three ultratrace elements.,
Determination of Chromium, Selenium, and Molybdenum in Infant Formula and Adult Nutritional Products - Inductively Coupled Plasma-Mass Spectrometry: Collaborative Study, Final Action 2011.19, J AOAC Int, 2015.
Molybdenum intake from diet
The molybdenum intake by German and Mexican adults (21 test populations) aged 20 to 69 years with mixed and ovolactovegetarian diets was determined. Each test group consisted of at least 7 women and 7 men, which collected all consumed foodstuffs and beverages as visually estimated duplicates on 7 successive days.
The balance studies were carried out with 8 test populations (women and men) with mixed and ovolactovegetarian diets.
People with mixed diet in Germany consumed, on average, 89 (women) and 100 μg Mo/day (men), whereas in Mexico they took in 160 (women) and 210 (men) μg Mo/day. German ovolactovegetarians consumed approximately 175 μg Mo/day.
Male adults of Germany consumed 21% more molybdenum than women. This difference is the result of a 24% higher dry matter intake by males.
The residence place, its geological origin and time of examination influenced the molybdenum intake significantly (60-115 μg Mo/day). The normative molybdenum requirement of adults amounts to 25 μg/day, with women needing 20 and men 25 μ g/day.
As a rule approximately only one-third of the absorbed molybdenum is excreted renally, the rest faecally. Breast feeding mothers excreted 11% via milk, 56% faecally and 33% renally.
The apparent absorption rate of molybdenum amounted to 37% in humans with mixed and vegetarian diets, whereas it reached 44% in breast-feeding mothers.
The calculation of molybdenum consumption (basket method) overestimated the molybdenum intake by 50% in comparison to chemical determination by the duplicate portion method
Anke, M., Holzinger, S., Seifert, M., Muller, R., and Schafer, U., The Biological and Toxicological Importance of Molybdenum in the Environment and in the Nutrition of Plants, Animals and Man - Part Iv: the Molybdenum Intake of Adults with Mixed and Vegetarian Diets in Germany and Mexico, Acta Alimentaria, 2010, 39, 1-11.
Molybdate in human serum after exercise
The present study aims to examine how exercise performed until fatigue at night affects element distribution in the serum. The study examined 10 healthy sedentary males who were not actively engaged in any particular sport and whose mean age was 23.00 +/- 0.25 years, mean height 177.79 +/- 2.25 cm, and mean weight 70.70 +/- 1.63 kg. Blood samples were collected from the subjects at midnight twice: during rest before exercise and after exercise. Serum phosphorus, sodium, potassium, sulfur (mmol/L), cobalt, boron, cadmium, chrome, nickel, manganese, molybdenum, copper, iron, zinc and calcium levels (mg/L) were measured using atomic emission spectroscopy (ICP-AES).
Exhaustion exercise performed at night brought about a decrease in copper levels only (p< 0.05), while elevating levels of potassium, sodium, magnesium, calcium, iron, zinc, manganese, nickel, selenium, molybdenum, chrome, cobalt, lead and cadmium (p< 0.05).
The results of the study demonstrate that nighttime exercise until exhaustion significantly alters element metabolism
Patlar, S., Gulnar, U., Baltaci, A. K., and Mogulkoc, R., Effect of Nocturnal Exhaustion Exercise on the Metabolism of Selected Elements, Archives of Biological Sciences, 2014, 66, 1595-1601.
Molybdenum in human blood
Concentrations of molybdenum in whole blood (229 samples from 19 collection sites in the United States) have been determined [Roth, 1968]. The mean concentration ranged from 0.50 to 15.73 microg /100 ml. Similar findings were obtained by Morgan and Holmes in the normal population in England where the whole blood molybdenum concentration range in males was 0.8 ± 0.3 and in females 1.2 ± 0.5 ng/g, and by Nadkarni and Morisson (1976) who found the serum molybdenum concentration to range between 0.012 and 0.034 ng/g of molybdenum [Cilingarajan, 1965].
Roth, M., Arch. Environ. Health, 1968, 16, 340.
Schroeder, H. A., Balassa, J. J.and Tipton,I. H., J. Chronic Diseases, 1970, 23, 481.
Morgan, A.and Holmes, A., Radiochem. Radioanal. Letters, 1972, 9, 329.
Nadkarni, R. A. and Morrison, G. H., Radiochem. Radioanal. Letters, 1976, 24, 103.
Cilingarajan, A. G., Izv. Akad. Nauk Arm. SSR, 1965, 18, 29.
The trace element levels of hospital patients whose bone fractures had received osteosynthetic treatment or had required the use of artificial replacement joints is reported. For molybdenum the immediately preoperative blood plasma level of Mo (0.7 microg/l) was below the normal level (1.20 microg/l) and decreased postoperatively (0.5 microg/l. This marked reduction of the Mo content of the blood plasma is attributed to a shift of Mo into the affected tissue, since the enzymes xanthine oxidase and sulfite oxidase, which require Mo as a cofactor, are essential enzymes of bone and connective tissue metabolism, functioning as part of a detoxification mechanism for accumulated cell debris. The extent of the reduction of the plasma Mo level could be a measure of the wound healing process. A deficiency of Mo due to increased demand from the wound could cause interference in the healing process.
Keller, T, Gehring, L, Grafe, S, Hetzel, G, Loser, T, Electrolyte and trace element status following osteosynthetic Operations, Trace Elements And Electrolytes,1999,16, 4, 183-191.
Most people have whole blood concentrations
Reference ranges of the concentration of trace elements in human serum are established by inductively coupled plasma- mass spectrometry (ICP-MS). The range of Mo concentrations in sera collected from 110 healthy humans was 0.44 +/- 1.62 microg/l.
Forrer, R., Gautschi, K., and Lutz, H., Simultaneous measurement of the trace elements Al, As, B, Be, Cd, Co, Cu, Fe, Li, Mn, Mo, Ni, Rb, Se, Sr, and Zn in human serum and their reference ranges by ICP-MS, Biological Trace Element Research, 2001, 80, 77-93.
Whole blood and serum concentrations of metals in a Swedish population-based sample
Objective: While the potential toxicity of metals in humans is a well-established field of research, there are few studies that examine circulating concentrations of metals in large population-based samples. The aim of this study was to analyze levels of heavy metals and trace elements in both whole blood and serum in an elderly population, and to examine if gender, kidney function, haemoglobin or serum albumin could impact the distribution of metals between whole blood and serum.
Methods: Whole blood and serum samples from 1016 70-year-olds living in Uppsala, Sweden, were analyzed for aluminium, cadmium, cobalt, copper, chromium, mercury, manganese, molybdenum, nickel, lead, and zinc using inductively coupled plasma-sector field mass spectrometry (ICP-SFMS).
Distribution between whole blood and serum was evaluated by the ratio between whole blood and serum concentration (B/S-ratio).
Results: Concentrations differed significantly between whole blood and serum measurements for all 11 metals (p < 0.00001). The highest B/S-ratios were found for lead (27), zinc (9), manganese (6), and nickel (4).
Copper (0.86), cobalt (0.84), and molybdenum (0.86) showed B/S-ratios < 1.
Especially the B/S-ratios for chromium, mercury and nickel correlated with kidney function (GFR) (r = 0.21, - 0.21 and -0.36 respectively, p < 0.0001).
Conclusions: The distribution between whole blood and serum varied considerably for different metals. This distribution correlated with physiological factors, mainly with kidney function, for several of the metals
Schultze, B., Lind, P. M., Larsson, A., and Lind, L., Whole blood and serum concentrations of metals in a Swedish population-based sample, Scandinavian Journal of Clinical & Laboratory Investigation, 2014, 74, 143-148.
Molybdate levels in humans
Levels of trace elements, aluminium, arsenic, cobalt, copper, iron, lead, manganese, mercury, molybdenum, nickel, selenium and zinc, in whole blood, serum and urine of 61 non-smoking adults living on the west coast of Canada and their association with age, gender, diet, participation in certain hobby and/or occupational activities, and levels of other trace elements are reported.
Trace elements were measured using inductively-coupled plasma mass spectrometry.
Participants estimated their intake of shellfish (oysters, mussels, scallops), organ meats (beef and pork liver, chicken liver, beef kidney), leafy green vegetables (spinach, lettuce, seaweed; cooked and uncooked), potatoes (French fries, chips, boiled, mashed), carrots, and tomatoes (fresh, processed into sauce, ketchup, or juice) in the previous 12 months.
Geometric mean blood molybdenum level was 15.36 nmol l-1 and urine molybdenum was 58.41micromol
mol-1 cr-1.
Urine molybdenum levels were generally higher in this study than have previously been measured, possibly due to higher consumption of seafood in this sample.
Molybdenum in urine and blood decreased with increasing with consumption of mashed potatoes and scallops (negative correlation) possibly because potatoes and scallops have less molybdenum than plants growing above the ground, including legumes and leafy vegetables, and so provide less dietary molybdenum. (Barceloux, Barceloux, 1999).
Molybdenum in blood and molybdenum in urine correlated positively
(blood Mo) = 1.2892 + 0.3554 (urine Mo)
- expected as urine is the major excretory path for molybdenum in the body (Turnlund et al.,1995).
There was an inverse correlation of lead in blood with molybdenum in blood and urine. The plot below has been constructed from data in the paper.
Clark, N. A., Teschke, K., Rideout, K., and Copes, R., Trace element levels in adults from the west coast of Canada and associations with age, gender, diet, activities,. and levels of other trace elements, Chemosphere, 2007, 70, 155-164.
Japanese adults with and without liver dysfunction
The serum molybdenum (Mo) concentrations in 70 Japanese adults (35 males and 35 females) not receiving any medical care or treatment were determined by inductively coupled plasma-mass spectrometry.
Serum Mo concentration in the subjects ranged from < 0.1 to 9.11 ng/mL.
More than half (55.7%) of the subjects showed values of less than 1 ng/mL and only 6 (8.6%) subjects showed more than 2 ng/mL.
The mean +/- SD, geometrical mean (GM), range of GM geometrical SD (GSD) and median value were 1.21 +/- 1.34, 0.81, 0.30 to 2.16, and 0.90 ng/mL, respectively. 15 subjects suspected of having liver dysfunction showed significantly higher serum Mo than others.
Reference range of serum Mo in Japanese healthy adults without liver dysfunction: 0.10-4.73 ng/mL, estimated as a range of GM +/- 2GSD.
Yoshida, M., Ota, S., Fukunaga, K., and Nishiyama, T., Serum molybdenum concentration in healthy Japanese adults determined by inductively coupled plasma-mass spectrometry, Journal of Trace Elements in Medicine and Biology, 2006, 20, 19-23.
More than 90% of Mo contained in a routine dietary menu is absorbed, most of Mo absorbed is excreted in urine, and Mo balance is in equilibrium in the general Japanese population. (c) 2006 Elsevier GmbH. All rights reserved
Yoshida, M., Hattori, H., Ota, S., Yoshihara, K., Kodama, N., Yoshitake, Y., and Nishimuta, M., Molybdenum balance in healthy young Japanese women, Journal of Trace Elements in Medicine and Biology, 2006, 20, 245-252.
Molybdenum blood levels in mothers and newborns
The correlation of cord blood levels of molybdenum in newborns with maternal concentrations of molybdenum suggests that molybdenum compounds easily cross the placental barrier [Bougle et al.,1988, 1989].
Bougle, D., Bureau, F., Foucault, P.,. Molybdenum content of term and preterm human milk during the first two months of lactation, Am. J. Clin. Nutr., 1988, 48, 652-654.
Bougle, D., Voirin, J., Bureau, F., Molybdenum normal plasma values at delivery in mothers and newborns, Acta Paediatr. Scand., 1989, 78, 319-320.
Mean plasma level in 33 mothers 1.44 microg Mo/L with a range up to 3 microg Mo/L.
Mean concentration in breast milk in 6 mothers in France 10 microg Mo/L at birth decreasing to 1 microg/L 2 months post-delivery.
Bougle, D., Bureau, F., Foucault, P.,. Molybdenum content of term and preterm human milk during the first two months of lactation, Am. J. Clin. Nutr., 1988, 48, 652-654.
Bougle, D., Voirin, J., Bureau, F., Molybdenum normal plasma values at delivery in mothers and newborns, Acta Paediatr. Scand., 1989, 78, 319-320.
The concentration of molybdenum in the blood of women increased significantly during pregnancy (from 12.95 microg /100 ml after 12-19 weeks' pregnancy to 33.85 microg /100 ml at the time of labour) [Polonskaya, 1966]. The blood of non-pregnant controls contained 16.55 microg Mo/100 ml. For the pregnant women and the control group the daily molybdenum intake was 0.26 mg so the increase in blood molybdenum concentration was probably due to a mobilisation of tissue reserves.
Polonskaya, M. N., Gig. Pitan., 1966, 126.
Plasma studies were conducted in healthy breast-fed infants and in patients with phenylketonuria at the age of 4 weeks, and the plasma investigations were repeated at the ages of 4 and 12 months. Molybdenum concentrations in formulas exceed those in human milk. Molybdenum intake and retention in all infants with phenylketonuria were more than 18 times those of breast-fed infants.The plasma concentrations reflected these differences. A median of 0.04 mu g/l was assessed in breast-fed infants at 4 weeks and less than 0.02 mu g/l at 4 months of age. Comparative results of infants with phenylketonuria were 2.9 mu g/l and 2.5 mu g/l, respectively. There were no significant differences between the groups at 12 months of age. The phenylketonuria diets investigated showed excessive retention and plasma concentrations of the essential trace element molybdenum in early infancy. In view of these findings, the present practice of molybdenum fortification should be revised
Sievers, E., Arpe, T., Schleyerbach, U., and Schaub, J., Molybdenum supplementation in phenylketonuria diets: Adequate in early infancy?, Journal of Paediatric Gastroenterology and Nutrition, 2000, 31, 57-62.
Blood: Human biomonitoring for metals in Italian urban adolescents: Data from Latium Region
As a part of the activities of the first Italian human biomonitoring survey (PROBE - PROgramme for Biomonitoring general population Exposure), a reference population of adolescents, aged 13-15 years, was examined for their exposure to metals. The study included 252 adolescents living in urban areas, representative of Latium Region (Italy) and blood specimens were analyzed for metals (As, Be, Cd, Co, Cr, Hg, It, Mn, Mo, Ni, Pb, Pd, Pt, Rh, Sb, Sn, Tl, U, V and W) by sector field inductively coupled plasma mass spectrometry.
The results obtained will improve the knowledge about the body burden in adolescents and are tentative reference values for Italian young people as a basis for risk evaluation deriving from urban/environmental exposure to metals. (C) 2011 Elsevier GmbH. All rights reserved
Pino, Anna, Amato, Antonio, Alimonti, Alessandro, Mattei, Daniela, and Bocca, Beatrice, Human biomonitoring for metals in Italian urban adolescents: Data from Latium Region, International Journal of Hygiene and Environmental Health, 2012, 215, 185-190.
Blood: Serum metal ion levels after rotating-hinge knee arthroplasty: comparison between a standard device and a megaprosthesis
Purpose The effects of systemic metal ion exposure in patients with implants made of common prosthetic alloys continue to be a matter of concern. The aim of the study was to determine the measurement values of cobalt (Co), chromium (Cr) and molybdenum (Mo) in serum following rotating-hinge knee arthroplasty.
Methods Blood was taken from 25 patients [mean follow-up 35 (range nine to 67) months] treated with megaprostheses (n=17) or standard rotating-hinge devices (n=8) and analysed using electrothermal graphite furnace atomic absorption spectrometry (ET-ASS).
Results Determining the concentrations of metal ions following rotating-hinge knee arthroplasty revealed increments for Co and Cr but not Mo. Metal ion release was significantly higher in patients with megaprostheses compared to a standard rotating-hinge knee device (Co p=0,024; Cr p=0.025).
Conclusion The authors believe there might be an additional metal ion release from the surface of the prosthesis and not only from the articulating surfaces because, in cases of rotating-hinge knee prosthesis, there is a metal-on-polyethylene articulation and not a direct metal-on-metal junction. Nevertheless, long-term studies are required to determine adverse effects of Co, Cr and Mo following total hip replacement and total knee arthroplasty
Friesenbichler, Joerg, Maurer-Ertl, Werner, Sadoghi, Patrick, Lovse, Thomas, Windhager, Reinhard, and Leithner, Andreas, Serum metal ion levels after rotating-hinge knee arthroplasty: comparison between a standard device and a megaprosthesis, International Orthopaedics, 2012, 36, 539-544.
Simultaneous determination of 10 ultratrace elements in infant formula, adult nutritionals, and milk products by ICP/MS after pressure digestion: single-laboratory validation
A single-laboratory validation (SLV) is presented for the simultaneous determination of 10 ultratrace elements (UTEs) including aluminum (Al), arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), mercury (Hg), molybdenum (Mo), lead (Pb), selenium (Se), and tin (Sn) in infant formulas, adult nutritionals, and milk based products by inductively coupled plasma (ICP)/MS after acidic pressure digestion. This robust and routine multielemental method is based on several official methods with modifications of sample preparation using either microwave digestion or high pressure ashing and of analytical conditions using ICP/MS with collision cell technology. This SLV fulfills AOAC method performance criteria in terms of linearity, specificity, sensitivity, precision, and accuracy and fully answers most international regulation limits for trace contaminants and/or recommended nutrient levels established for 10 UTEs in targeted matrixes.
Dubascoux, S., Nicolas, M., Rime, C. F., Payot, J. R., and Poitevin, E.,Simultaneous Determination of 10 Ultratrace Elements in Infant Formula, Adult Nutritionals, and Milk Products by ICP/MS After Pressure Digestion: Single-Laboratory Validation, Journal of Aoac International, 2015, 98, 953-961.
Molybdenum in human milk
Molybdenum microg/l in term and preterm milk during 21 days of lactation
Molybdenum in human milk
| 2-6 d | 12-16 d | 21 d |
term milk |
6.82.5 |
5.72.3 |
3.61.4 |
preterm milk |
3.91.4 |
2.41.1 |
1.90.9 |
|
Blood content |
1 d |
21 |
|
term newborns |
4.70.3 |
4.20.3 |
|
preterm newborns |
1.80.5 |
1.50.3 |
|
Aquilio, E., Spagnoli, R., Seri, S. Bottone, G., Spennati, G., Trace-Element Content In Human-Milk During Lactation Of Preterm Newborns, Biological Trace Element Research, 1996, 51, 63-70.
Molybdenum in human milk from lactating mothers of premature and full-term living in Newfoundland, Canada, showed a definite decrease with time, suggesting that the Mo content in milk is homeostatically regulated. [Friel et al., 1999.]
Friel, J.K., Andrews, W.L., Jackson, S.E., Longerich, H.P., Mercer, C., McDonald, A., Dawson, B., Sutradhar, B., Elemental composition of human milk from mothers of premature and full-term infants during the first 3 months of lactation, Biological Trace Element Research, 1999, 67, 225-247.
19 mothers were assessed daily over 2 to 8 weeks.
Transfer factor: the element concentration in food (g/kg) divided by the element concentration in milk (g/l)
Elements in food and milk
La | Ce | Ti | Nb | Th | Cr | Mo | U | Ru | Co | Ag | Ga | Sb |
13.8 |
16.1 |
5.6 |
20.7 |
20.2 |
6.9 |
77.4 |
21.3 |
4.1 |
8.4 |
5.1 |
19.1 |
13.2 |
Factors differed across individuals, the result of individual differences in milk production and factors other than the amount of any particular element absorbed by the body.
Wappelhorst, O., Kuhn, I., Heidenreich, H., and Markert, B., Transfer of selected elements from food into human milk, Nutrition, 2002, 18, 316-322.
The molybdenum concentration in human mature milk from 241 subjects who resided in cities in state, former Uttar Pradesh, India. The overall mean value for the molybdenum content of mature human milk was 0.018 ppm Mo. Most of the individual values for molybdenum in human milk fell within the narrow range of 0.007 to 0.033 ppm Mo. A geographical variation was attributed to differences in the molybdenum content of food items consumed by the residents of different communities.
Pandey, R., Singh, U., and Singh, S. P., Geographical distribution of molybdenum in human milk, Journal of Advanced Zoology, 2003, 24, 8-10.
Molybdenum in the breast milk and plasma of lactating women
The trace element content of breast milk and plasma in 209 lactating women in the UAE was determined using ICP-MS. The concentrations of trace elements in blood and breast milk were little different between women from the UAE and those from elsewhere. Molybenum (and chromium and arsenic) increased with increasing age of the infant, while manganese, copper and zinc decreased. with increasing age of the infant. The trace element concentrations of breast milk and maternal blood were comparable to published values. Normal values for plasma and breast milk trace metal concentrations have been obtained for UAE women.
Molybdenum concentrations/microg L−1 were:
In plasma: range 0.001―2.05, mean 0.281, median 0.270;
In breast milk: range 0.001―1.9, mean 0.348, median 0.061
Abdulrazzaq, Y. M., Osman, N., Nagelkerke, N., Kosanovic, M., and Adem, A., Trace element composition of plasma and breast milk of well-nourished women, Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 2008, 43, 329-334.
Molybdate in breast milk from Japanese women
Molybdenum and chromium in 79 Japanese breast milk samples were measured by inductively coupled plasma-mass spectrometry. The molybdenum concentration in 51 samples (64.6%) was less than 5 nag/ml and in only 12 samples (15.2%) was more than 10ng/ml. The range was
Data on the secretion of trace elements in human milk is needed to estimate intake by breast-fed infants and to establish the recommended intake for infants. For some trace elements adequate intake (AI) levels for infants are in “Dietary Reference Intakes for Japanese, 2005” (DRI-J 2005) but not for molybdenum (or chromium) because of the lack of information of their concentrations in breast milk. The aim of the investigation was to obtain and estimate of AI levels of Mo and Cr in Japanese infants. The derived AI for Japanese infants (0 to 5 months) was 2.5 microg Mo/day. A detailed account of the statistical treatment of the measurements and the calculation of the AI is given in the paper.
Yoshida, M., Takada, A., Hirose, J., Endo, M., Fukuwatari, T., and Shibata, K., Molybdenum and chromium concentrations in breast milk from Japanese women, Bioscience Biotechnology and Biochemistry, 2008, 72, 2247-2250.
Human tissues and organs
In healthy individuals, the average molybdenum content in the liver and kidneys determined spectrographically was 1.0 and 0.3 mg/kg respectively [Tipton and Cook, 1963]. The molybdenum content in the cortex of suprarenals of males 51-62 years old was 0.20 microg/kg, in the liver 0.88 microg/kg and in the myocardium 0.022 microg/g [Plantin, 1972]. In a report from the former U.S.S.R., the molybdenum concentration in the liver of normal individuals 17-77 years old was found to range between 0.54 and 0.64 microg/g of which 0.22 and 0.24 microg/g was found in the kidneys [Pribluda, 1964]. It has been reported that the molybdenum content in the human embryonic membranes specifically the amnion contains on average 3.50 ± 0.27 microg/g and the chorion 0.60 ± 0.02 microg/g molybdenum in ash.
Tipton, I. H. and Cook, M. J., Health Phys., 1963, 9, 103.
Plantin, L. O., WHO/IAEA Progress Report, Stockholm ,1972.
Pribluda, L. A., Vest. Akad. Nauk BSSR, Serie, 1964, 4, 133.
Sievers, E., Arpe, T., Schleyerbach, U., and Schaub, J., Molybdenum supplementation in phenylketonuria diets: Adequate in early infancy?, Journal of Paediatric Gastroenterology and Nutrition, 2000, 31, 57-62. Molybdenum in human milk
Molybdenum concentrations in adult human organs
Molybdenum concentrations in adult hHuman organs
| Brain | Kidney | Liver | Lung | Muscle | Spleen |
Adult human |
0.14 |
1.6 |
3.2 |
0.15 |
0.14 |
0.20 |
Concentrations in ppm Mo on dry weight basis.
Tipton, I. H. and Cook, M. J., Trace Elements in Human Tissue. Part II Adult Subjects from U.S., Health Phys.,1963, 9,103.
Underwood, E. J., Trace Elements in Human and Animal Nutrition, 2nd Ed. 1962, 100. Academic Press, London.
Kolomiitseva, M. G., Polonskaya, M. N. and Osipov, G. K.,Mikroelem. Sel. Khoz. Med., 1968, 4, 183; Tipton, I. J., J. Chronic Dis., 1970, 23, 481.
Molybdenum concentrations in human tissues
Molybdenum concentrations in human tissues
| Concentration/microg (g ash)-1 |
Tissue | Fraction Observed | Median Concentration |
Adrenal |
10/13 |
15 |
Lung |
5/141 |
<4 |
Lung, S.F. |
23/27 |
2 |
Larynx |
1/50 |
<4 |
Trachea |
1/60 |
<4 |
Skin |
2/22 |
<4 |
Esophagus |
1/66 |
<4 |
Stomach |
11/130 |
<4 |
Duodenum |
6/67 |
<4 |
Jejunum |
7/102 |
<4 |
Ileum |
18/83 |
<4 |
Cecum |
6/31 |
<4 |
Sigmoid Colon |
4/108 |
<4 |
Rectum |
2/42 |
<4 |
Omentum |
12/75 |
<4 |
Bladder |
6/110 |
<4 |
Kidney |
140/144 |
31 |
Liver |
147/147 |
75 |
Pancreas |
12/139 |
<4 |
Spleen |
4/143 |
<4 |
Muscle |
2/136 |
<4 |
Diaphragm |
3/91 |
<4 |
Heart |
8/140 |
<4 |
Aorta |
3/104 |
<4 |
Uterus |
1/32 |
<4 |
Ovary |
0/16 |
- |
Postrate |
2/50 |
<4 |
Testis |
2/72 |
<4 |
Thyroid |
1/21 |
<4 |
Brain |
3/129 |
<4 |
Fat |
27/27 |
5 |
Bone |
1/91 |
<4 |
Tipton, I. H. and Cook, M. J., Trace Elements in Human Tissue. Part II Adult Subjects from U.S., Health Phys.,1963, 9,103.
Yoo, Y.C., Lee, S. K., Yang, J. Y., In, S. W., Kima, K. W., Chung, K. H., Chung, M. G., and Choung, S. Y., Organ distribution of heavy metals in autopsy material from normal Korean, Journal of Health Science, 2002, 48, 186-194.
Molybdenum in human cadavers
The concentrations of aluminum, arsenic, cadmium, chromium, copper, iron, lead, manganese, mercury, molybdenum, nickel, selenium, silicon, tin, vanadium and zinc were determined in 89 male and 61 female Korean cadavers of ages from 12 to 87 years. Mean Mo concentrations were:
Molybdenum in human cadavers
Tissue | Mean/microg Mo (g wet weight)-1 | Standard Deviation |
Liver |
0.73 |
0.37 |
Kidney |
0.27 |
0.14 |
Heart |
0.09 |
0.10 |
Lung |
0.10 |
0.11 |
Spleen |
0.08 |
0.10 |
0.06 |
0.09 |
0.10 |
Cerebmm |
0.05 |
0.07 |
Bone |
0.09 |
0.14 |
Hair |
0.25 |
0.28 |
Nail |
1.9 |
2.5 |
Prenatal molybdenum exposure and infant neurodevelopment in Mexican children
Objective:
To evaluate the association between prenatal exposure to molybdenum (Mo) and infant neurodevelopment during the first 30 months of life. Methods:
We selected a random sample of 147 children who participated in a prospective cohort study in four municipalities in the State of Morelos, Mexico. The children were the products of uncomplicated pregnancies with no perinatal asphyxia, with a weight of >= 2 kg at birth, and whose mothers had no history of chronic illnesses. These women were monitored before, during, and after the pregnancy.
For each of these children a maternal urine sample was available for at least one trimester of pregnancy, and urine Mo levels were determined by electrothermal atomic absorption spectrometry.
Neurodevelopment was evaluated using the psychomotor (PDI) and mental development indices (MDI) of the Bayley scale.
Association between prenatal exposure to Mo and infant neurodevelopment was estimated using generalized mixed effect models.
Results:
The average urinary concentrations of Mo adjusted for creatinine varied between 45.6 and 54.0 mu g/g of creatinine at first and third trimester, respectively. For each doubling increase of Mo (mu g/g creatinine) during the third trimester of pregnancy, we observed a significant reduction on PDI (beta = -0.57 points; P = 0.03), and no effect on MDI (beta = 0.07 points; P = 0.66).
Discussion:
As this is the first study that suggests a potential negative association between prenatal Mo exposure and infant neurodevelopment, these results require further confirmation
Vazquez-Salas, R. A., Lopez-Carrillo, L., Menezes, J. A., Rothenberg, S. J., Cebrian, M. E., Schnaas, L., Viana, G. F. D., and Torres-Sanchez, L., Prenatal molybdenum exposure and infant neurodevelopment in Mexican children, Nutritional Neuroscience, 2014, 17, 72-80.
Industrial and Environmental Exposure of Humans
Humans are exposed to molybdenum compounds in industrial operations and in the environment. As with other elements maximum exposure limits for molybdenum are laid down in government legislation and regulatory controls. The limits may vary from country to country and are not always consistent. The basis for the limits is not always clear. Here we list the regulatory limits, the natural levels of molybdenum and the levels derived from industrial activity including mining.
Mo uptake from industrial sources
Average daily intakes of Mo 0.1 – 0.5 mg Mo increasing to 1 mg if contamination from industrial sources
Friberg, L., Lener, J., Molybdenum, in Handbook on the Toxicology of Metals Vol II, Friberg, L., Nordberg, G.F., and Vouk, V.B., eds., Elsevier, 1986, 446 – 461.
56 adults in Germany 47 – 89 microg
Anke, M., Groppel, B., Krause, U., Arnhold, W., Langer, M., Trace element intake of humans , J. Trace Elemen. Electrolytes Health Dis., 1991, 5, 69 – 74.
Adults in Denver 120 – 240 microg Mo/d av 180
Tsongas, T.A., Meglen, R.R., Walravens, P.A., Chappell W.R., Molybdenum in the diet, Am. J. Clin. Nutr., 1980, 33, 1103 –1107.
NE US 74 – 126 microg Mo/d
Pennington, J.A.T., Young, B.E., Wilson, D., Nutritional elements in US diets, J. Am. Diet. Assoc., 1989, 89, 659 – 664.
For guinea pigs exposed to the dust or fumes of molybdenum trioxide (150-300 mg/m3) for 1 h per day, 5 times per week, for 5 weeks [Fairhall et al., 1945]. Low concentrations of molybdenum (20-270 microg/10g fresh tissue) were found in the lungs, liver, kidneys, spleen and bone. The molybdenum concentrations in these tissues decreased after exposure was stopped to 20% of the original level after 2 weeks. After an oral gavage dose of 50 mg molybdenum trioxide was administered to guinea pigs, molybdenum was distributed to the kidneys, spleen, blood, bile, liver, and lungs within 4 h. The concentrations of molybdenum in the organs decreased, whereas in the blood and bile molybdenum titres were higher at 48 h. Bone retained molybdenum longer than any other tissues [Fairhall et al., 1945]. Based on the amount recovered in faeces for up to 48 h, Fairhall et al. (1945) calculated that 85 % of the oral dose was absorbed. Excess hexavalent forms of molybdenum are excreted rapidly through the kidneys and the bile. Twice as much molybdenum is eliminated in urine as in the faeces. The urinary and faecal concentrations of molybdenum returned to normal after an oral dose of molybdenum trioxide was administered to guinea pigs [Fairhall et al., 1945]. The predominant urinary metabolite of molybdenum was in the form of molybdate complexes [Venugopal and Luckey, 1978].
Fairhall, L. T., Dunn, R. C., Sharpless, N. E. and Pritchard, E. A., U. S. Public Health Bull., 1945, 293, 1.
Venugopal, B. and Luckey, T. D., Metal Toxicity in Mammals, 1978, Vol. 2, Chemical Toxicity of Metals and Metalloids, Plenum Press, New York.
Regulatory controls and legislation
Threshold Limit Values of Some Common Metals
| TLV/mg Mo/m3 |
Metal | soluble | insoluble |
molybdenum |
5 |
10 |
tungsten |
1 |
5 |
iron oxide |
|
5 |
tantalum |
|
5 |
nickel |
0.1 |
1 |
copper dust |
1 |
1 |
copper fume |
|
0.2 |
chromium |
|
0.5 |
lead |
0.15 |
0.15 |
cobalt |
0.02 |
0.02 |
chromium(VI) |
0.05 |
0.01 |
cadmium |
0.01 |
0.01 |
arsenic |
0.01 |
0.01 |
TLV, threshold limit value
International Molybdenum Association (IMOA), Report 1995, p. 5
Molybdenum Regulatory Limits
Process or material | Limit | Units | Averaging period | Source of limit |
Air emission |
Dust collectors |
15 |
mg Mo dust/m3 |
|
Holland-permit |
Calciner dust collector |
0.126 |
kg Mo oxide/h |
|
Holland-permit |
Dryer dust collector |
0.024 |
kg ADM/h |
|
Holland-permit |
As dust |
10 |
mg/m3 |
|
NER (Dutch emission guidelines) |
Soluble compounds |
5 |
mg Mo/m3 |
|
UK Health and Safety Executive |
Insoluble compounds |
10 |
mg Mo/m3 |
|
UK Health and Safety Executive |
Exhaust air from production plants |
5 |
mg Mo/m3 |
0.5 - 3 h total |
Austria |
For non-ferrous metals after filter stations |
0.2 |
mg Mo/m3 |
0.5 - 3 h |
Austria-regional authority |
Soluble Mo TLV |
5 |
mg Mo/m3 |
0.5 - 3 h |
Austria |
Insoluble Mo TLV |
15 |
mg Mo/m3 |
0.5 - 3 h |
Austria |
Water quality |
Drinking |
0.07 |
mg/l |
|
Austria-WHO guideline |
|
0.01 |
mg/l |
|
Chile-N Ch 1333 - 1978 |
Industrial |
1 - 2 |
kg/day |
|
Holland-permit |
|
5 |
mg/l |
|
Austria-country |
|
5 |
mg/l |
2 h average |
Germany-municipal authorities |
Ground |
300 |
mg/l |
|
Holland-intervention values |
|
5 |
ppm |
|
Holland-authorisation |
|
none |
|
|
Belgium-80/68/EEC |
|
0.1 |
mg/l |
|
US EPA |
|
0.07 |
mg/l |
|
Japan |
target limit |
5 |
mg/l |
|
Belgium-MILBOWA (DBO 07494013) |
intervention limit |
300 |
mg/l |
|
Belgium-MILBOWA (DBO 07494013) |
Soil |
soil sanitation |
200 |
mg/kg |
|
Holland-intervention values |
arableland pastures |
10 |
mg/kg dry |
|
Austria-TLV |
|
30 |
kg/ha |
|
Austria-TLV |
|
3 |
g/m2 |
|
Austria-TLV |
target limit |
10 |
mg/kg dry |
|
Belgium-MILBOWA (DBO 0749013) |
intervention limit |
200 |
mg/kg dry |
|
Belgium-MILBOWA (DBO 0749013) |
emission limit |
150 |
mg/kg dry |
|
Belgium-MILBOWA (DBO 0749013) |
Solid waste |
waste |
5000 |
mg/kg |
|
Holland-(BAGA) |
to landfill |
50 |
mg/l |
|
Germany-approval DIN 38414 |
landfill leachate limit |
125 |
mg/kg dry |
|
OVAM proposals to Belgium Government |
leachate limit |
35 |
mg/m2 |
|
OVAM proposals to Belgium Government |
|
150 |
mg/m3/100y |
|
Belgium-NEM 7340 Decision 23/11/95 |
sludge from dredging |
10 |
mg/kg dry |
|
Belgium-Decision 25/11/93 |
fly ash leachate limit |
3 |
mg/kg |
|
Belgium- NEM 7343 Decision 20/1/93 |
Sewage sludge |
agricultural disposal |
20 |
mg/kg dry |
|
Austria |
|
0.5 |
mg/l |
|
Chile |
land application ceiling concentration |
75 |
mg/kg |
|
US EPA |
Milk |
|
0.2 |
mg/kg |
|
Austria |
Data assembled by IMOA Health and Safety Committee, 1999.
MAC Limits for Insoluble and Soluble Molybdenum Compounds
Country | MAC Limit (mg/m3) | |
Insoluble molybdenum compounds |
Holland |
10 (mean) |
|
Romania |
5 (mean) |
|
Germany |
15 (mean) |
|
Russia (USSR), Hungary, Bulgaria |
6 (peak) |
|
USA |
20 (peak) |
10 as TWA |
Soluble molybdenum compounds |
Holland |
5 (mean) |
|
Romania |
2 (mean) |
|
Germany, USA, Austria, Belgium, Italy |
5 (mean) |
|
Russia (USSR), Bulgaria, Poland |
4 (peak) |
|
Romania, USA |
10 (peak) |
5 as TWA |
ILO, Occupational Exposure Limits, 2nd (revised) Ed., Occupational Safety and Health Series, 1980, 37, ILO Geneva.
Workplace Exposure TLV USA
Material | TLV-TWA /mg m-3 |
Soluble Mo respirable particulate |
0.5 |
Insoluble Mo inhalable particulate respirable particulate |
10 3 |
Threshold Limit Values and Biological Exposure Indices for 2001: American Conference of Governmental Industrial Hygienists (ACGIH), Cincinatti, Ohio, 2001.
Notes
The number of workers in the United States potentially exposed to molybdenum trioxide during the years 1981 to 1983 was approximately 17,072
National Occupational Exposure Survey (NOES): National Institute for Occupational Safety and Health (NIOSH), 1995.
Occupational standards of exposure established by the Occupational Safety and Health Administration (OSHA) are 5 mg/m3 for soluble molybdenum compounds and 15 mg/m3 for insoluble molybdenum compounds
Hammond, P.B. and Beliles, R.P. Metals. In Casarett and Doull's Toxicology:The Basic Science of Poisons ,ed. Doull, J., Klaasen C. D. and Amdur, M. O., Macmillan, New York, 2nd Ed. 1980, 409.
The American Conference of Governmental Industrial Hygienists [ACGIH, 1995, 2001] recommends a threshold limit value-time-weighted average of 5 mg/m3 for soluble molybdenum compounds and 10 mg/m3 for insoluble molybdenum.
Toxicity of Molybdenum towards Humans
Data on the occurrence and toxicity of molybdenum are summarised in a very useful review article.
Barceloux, D.G., Molybdenum, Journal Of Toxicology-Clinical Toxicology, 1999, 37, 231-237.
See also
Gupta, U.C., Gupta,_S.C., Trace element toxicity relationships to crop production and livestock and human health: Implications for management, Communications In Soil Science And Plant Analysis, 1998, 29, 1491-1522.
We distinguish between acute toxicity and chronic, or long, term toxicity. The occurrence of acute poisoning is easy to detect since it produces obvious and often dramatic symptoms and ultimately death. Most experimental studies of molybdenum poisoning have been concerned with possible acute toxic effects. It is clear from the data summarised here that acute molybdenum poisoning in human beings is very unlikely: a massive dose would be required [National Research Council 9, 1980]. Compared with some metals used industrially (antimony, arsenic, beryllium, cadmium, chromium, lead, mercury) molybdenum is of very low toxicity [Saunders, 1956; Browning, 1969; Ashmead, 1972; Nguyen-Phu-Lieh, 1971]
National Research Council 9 1980, Molybdenum in: Mineral Tolerance of Domestic Animals, 328. National Academy of Sciences,
Saunders, W. B., Handbook of Toxicology, London, 1956.
Browning, E., Toxicity of Industrial Metals, 2nd edn., 1969, Butterworths, London.
Ashmead, H., J. Appl. Nutrition, 1972, 24, 8.
Nguyen-Phu-Lieh, Aliment. Vie, 1971, 59, 104.
There have been no reports of accidental deaths due to molybdenum poisoning in industry. More relevant in terms of environmental considerations are possible effects on human beings of long exposure to low concentrations of molybdenum compounds. Experience with workers exposed to molybdenum compounds indicates that molybdenum does not have long term chronic toxic effects. However, in making such assessments it would be helpful to know what to look for. Herein is the importance of a knowledge of the physiological and pathological effects of molybdenum compounds. Finally we have to assess the danger or otherwise of molybdenum as a general environmental pollutant. At current levels and in view of its low toxicity molybdenum is not a source of environmental pollution; but it should be noted that some animal species, especially cattle and sheep, are more susceptible to molybdenum poisoning than human beings. Chronic exposure defined as the administration of a total single dose of 2.365 to 24.497 microg of molybdenum results in a rise in the number of death rates from 14.2% to 57.2% in exposed animals the most common symptom of chronic exposure being acute anemia [Caujolle and Pham Hu Changh, 1967]. In chronically exposed cattle the addition of copper ions can result in a complete recovery from the signs of molybdenum intoxication.
Caujolle, F., Pham Hu Changh. (1967), Agressologie, 8, 265-273.
By extrapolation from animal experiments massive doses of molybdenum compounds would be required to produce acute molybdenum poisoning in human beings and so acute poisoning is unlikely. What is more important is the problem of whether continued exposure to low concentrations of molybdenum compounds causes subtle physiological changes. Such changes would be difficult to detect and we are not aware of any experimental investigations with human beings. Experience in the molybdenum mining and refining industries suggests that molybdenum compounds are not industrial health hazards [Saunders, 1956; Browning, 1969; Ashmead, 1072; Nguyen-Phu-Lieh, 1971].
Saunders, W. B., Handbook of Toxicology, London, 1956.
Browning, E., Toxicity of Industrial Metals, 2nd edn., 1969, Butterworths, London.
Ashmead, H., J. Appl. Nutrition, 1972, 24, 8.
Nguyen-Phu-Lieh, Aliment. Vie, 1971, 59, 104.
It is clear from animal experiments that molybdenum does have physiological effects and can affect the balance of other trace elements. In experimental animals the harmful effects of molybdenum are most apparent in the liver and kidneys. These organs in human beings as in various animals have consistently higher concentrations of molybdenum than other body organs [Underwood, 1962; Kolomiitseva et al., 1968; Schroeder et al., 1970]. So it is likely that harmful effects of exposure to molybdenum compounds will be most apparent in the liver and kidneys. Also molybdenum may have a harmful effect on bones.
Underwood, E. J., Trace Elements in Human and Animal Nutrition, 2nd Ed.,1962, Academic Press, London.
Kolomiitseva, M. G., Polonskaya, M. N. and Osipov, G. K., Mikroelem. Sel. Khoz. Med., 1968, 4, 183.
Schroeder, H. A., Balassa, J. J. and Tipton, I. H., J. Chronic Dis, 1970, 23, 481.
Dust and fumes of molybdenum trioxide and molybdates are likely to present a greater hazard than molybdenum disulfide. The observation that sulfide enhances the toxicity of soluble molybdenum compounds suggests the desirability of exercising care in handling and use of soluble molybdenum sulfur compounds.
Some studies of apparent effects of molybdenum on human beings are summarised below. The discussion in this and the following section is based on abstracts of Russian papers of which we have not been able to obtain the originals and so cannot assess the validity of the results. This work is widely quoted but its value and relevance is doubtful (see below). Thus we are unable to give the concentrations of molybdenum encountered; but they are presumably greater than the maximum permissible values subsequently adopted by Russia (U.S.S.R.): 4 mg/m3 for soluble compounds and 6 mg/m3 for insoluble compounds. It is also not certain that the effects were, in fact due to molybdenum.
Toxicity of Molybdenum Towards Human Beings
Tolerable daily intake
A tolerable daily intake (TDI) for molybdenum of 0.009 mg Mo /kg/ day for humans was calculated based on a toxicological risk analysis derived from a survey of the absorption, excretion, uptake, and physiological and toxic effects of molybdenum in humans and animals [Vyskocil and Viau, 1999]. The TDI was given a medium confidence rating. This TDI is more than double the upper limit of adequate intake for adolescents and adults that was derived from the Mo content of the average diet in the USA.
Vyskocil, A., Viau, C., Assessment of molybdenum toxicity in humans, Journal Of Applied Toxicology, 1999, 19, 185-192.
Absorption and excretion of molybdenum
In humans, absorption of molybdenum after oral intake is in the range of 28-77% and urinary excretion is 17-80% of the total dose. Molybdenum compounds have low toxicity towards humans but there are not enough data to calculate any dose-response or dose-effect relationships. Because molybdenum toxicity is associated with copper intake or depleted copper stores in the body, humans who have an inadequate intake of dietary copper or some dysfunction in their copper metabolism that makes them copper-deficient could be at greater risk of molybdenum toxicity.
However, in rats and mice molybdenum adversely affected reproduction and foetal development. were found to be critical effects observed. The 'no observed adverse effect' level was 0.9 and the 'lowest observed adverse effect' level 1.6 mg Mo/ kg/ day.
In studies with students the no observed adverse effect level for students was 8 microg/kg/d [EPA, 1979].
USEPA. Human Health Effects of Molybdenum in Drinking Water. Cincinnati, Ohio: US Environmental Protection Agency, EPA-600A-79-006, 1979.
Young girls aged 7-9 years given 75 microg Mo/d revealed elevated levels of molybdenum in the urine, but no specific adverse effects [Miller et al., 1959].
Miller, R.F., Price, N.O., Engel, R.W., The microelement (Al, Mn, Cu, Molybdenum, and Co) balance of 7-9-year-old girls, Fed. Proc. 1959, 18, 538.
Effect of molybdenum-containing dusts on the lungs
The effect on the lungs of 503 workers in a Russian powder metallurgy plant, of exposure to dusts containing molybdenum has been described [IOG, 1965]. The inspiratory, expiratory and vital capacities were determined. Reduced expiratory capacity was observed in 17.8% of molybdenum workers, 12.9% of sulphuric acid workers and 7.2% of sintered carbide workers. A pathological ratio of expiratory and inspiratory capacities, which may be an indication of bronchospasm, was encountered with a comparatively greater frequency among molybdenum workers than among those working in other departments. The nature of the molybdenum to which the workers were exposed was not clear but was probably molybdenum trioxide fume and molybdenum metal powder.
IOG, Referativny Zhurnal-Metallurgiya, 1965, IOG153, 154.