Molybdenum in the Environment
Molybdenum in the Geosphere
Molybdenum in soil and rocks
The Mo concentration in soil of the Pamperan region of Argentina was <0.01 mg/kg.
Lavado, R.S., Porcelli, C.A., Alvarez, R., Concentration and distribution of extractable elements in a soil as affected by tillage systems and fertilization, Science Of The Total Environment, 1999, 232, 3, 185-191.
Average and "normal" concentration levels for various metals including molybdenum have been proposed in order to establish a base line from which to assess contamination and pollution of the environment. Suggested levels are based on experience in Canada, Great Britain and two small areas in Wisconsin, U.S.A., but the general applicability of these levels especially in the U.S.A., remains to be established. For soils an average molybdenum concentration of 1.5 ppm is suggested with a normal range of 0.2-5 ppm. Similarly, average trace element contents of some vegetables have been suggested.
Warren, H . V., Delavault, R. E., Fletcher, K. W., Geology Environ. Contr. Bull., 1971, 6, 34.
Molybdate and soil
Soil-to-plant transfer of elements is not linear
Element-specific concentration ratios (CRs) assuming that plant uptake of elements is linear are commonly used in radioecological modelling to describe the soil-to-plant transfer of elements. The goal of this study was to investigate the validity of the linearity assumption in boreal forest plants, for which only limited relevant data are available. The soil-to-plant transfer of three essential (Mo, Ni, Zn) and two non-essential (Pb, U) elements relevant to the safety of radioactive waste disposal was studied. Three understory species (blueberry, narrow buckler fern and May lily) and two tree species (Norway spruce and rowan) were included. Examining CRs as a function of soil concentration showed that CR was not constant but decreased with increasing soil concentrations for all elements and plant species. A non-linear equation fitted fairly well with the empirical data; the R(2)-values for this equation were constantly higher than those for the linear fit. The difference between the two fits was most evident at low soil concentrations where the use of constant CRs underestimated transfer from soil to plants. Site-specific factors affected the transfer of Mo and Ni. The results suggested that systematic variation with soil concentrations explains a part of the large variation of empirically determined CRs, and the accuracy of modelling the soil-to-plant transfer might be improved by using non-linear methods. Non-linearity of soil-to-plant transfer has been previously reported for a few different species, elements and environments. The present study systematically tested the linearity assumption for five elements (both essential and non-essential) and in five boreal forest species representing different growth traits and phylogenies. The data supported non-linearity in all cases.
Tuovinen, Tiina S.; Roivainen, Paivi; Makkonen, Sari; Kolehmainen, Mikko; Holopainen, Toini; Juutilainen, Jukka. Soil-to-plant transfer of elements is not linear: Results for five elements relevant to radioactive waste in five boreal forest species. Science of the Total Environment, 2011, 410,191-197.
Metals in industrially contaminated soil
The concentrations of heavy metals (As, Ba, Co, Cr, Cu, Ni, Mo, Pb, Sr, V and Zn) were studied in soils to understand metal contamination due to industrialization and urbanization around Manali industrial area in Chennai, Southern India. This area is affected by the industrial activity and saturated by industries like petrochemicals, refineries, and fertilizers generating hazardous wastes. The data revealed elevated concentrations of chromium (149.8-418.0 mg/kg), copper (22.4-372.0 mg/kg), nickel (11.8-78.8 mg/kg), zinc (63.5-213.6 mg/kg) and molybdenum (2.3-15.3 mg/kg).
Krishna, A.K. and Govil, P. K., Assessment of heavy metal contamination in soils around Manali industrial area, Chennai, Southern India, Environmental Geology, 2008, 54, 1465-1472.
Argentinean Pampas
Mo content of soil in a cropland area of northern Buenos Aires province was 1.80 mg kg-1.
Lavado, R.S. and Porcelli, C. A., Contents and main fractions of trace elements in Typic Argiudolls of the Argentinean Pampas, Chemical Speciation and Bioavailability, 2000, 12, 67-70.
Molybdenum in herbage decreased by Sulfur fertilizer
Application of sulphur fertilizer increased herbage sulfur content and reduced the contents of boron, chromium, molybdenum and nickel. Cows grazing pasture that had received sodium fertilizer had increased milk yields and the content of lactose in milk, whereas those grazing pasture that had received sulfur fertilizer application had reduced milk yields and the content of milk fat
Chiy, P.C., Avezinius, J. A., and Phillips, C. J. C., Sodium fertilizer application to pasture. 9. The effects of combined or separate applications of sodium and sulphur fertilizers on herbage composition and dairy cow production, Grass and Forage Science, 1999, 54, 312-321.
Molybdenum availability in forest soils
The oxalate-extractable Mo concentrations of acid forest soils, the Mo, nitrate, phosphate, and sulfate fluxes from the organic forest floor into the mineral soil using resin tubes and the Mo concentrations of the Norway spruce tree needles were measured. The supply of oxalate-extractable Mo varied from 51 to 3400 g.ha- 1, with the lowest values occurring in sandstone-derived soils (370 +/- 212 g.ha- 1; mean +/- SD). Molybdenum concentrations of current-year needles were in the range of 5 to 48 ng.g- 1. The Mo needle concentrations and oxalate-extractable Mo of soils did not correlate. Mo fluxes (6-60 g.ha- 1.a- 1from the organic forest floor into the mineral soils were correlated to needle concentrations and to the NO3 fluxes. Mo turnover within forest ecosystems is governed by Mo plant availability of mineral soils as well as by plant Mo uptake. In addition, Mo cycling strongly affects Mo distribution within soil profiles and Mo fluxes out of the organic layer
Lang, F. and Kaupenjohann, M., Molybdenum at German Norway spruce sites: contents and mobility, Canadian Journal of Forest Research-Revue Canadienne De Recherche Forestiere, 2000, 30, 1034-1040.
A low level of available Mo in a soil may result from a low content of total Mo, a strong adsorption or fixation of molybdate ions by kaolinitic clay or hydrous oxides of iron or aluminum, leaching of available forms, or perhaps from a combination of these influences. Surface samples of 33 serpentine soils and 22 non-serpentine soils from the North Coast Range of California, southwestern Oregon and western Washington State, were analysed for available molybdenum. The serpentine soils show a generally low level of available Mo, with 26 of the 32 soils classified as deficient or very deficient. In contrast the non-serpentine soils were mostly only slightly deficient or not deficient. Recovery from visible Mo-deficiency symptoms in lettuce and tomato plants grown on two of the serpentine soils was obtained with Mo fertilization. Analyses for total Mo In a few of the soils did not show exceptionally low values, suggesting that the low available Mo status of the serpentine soils is probably due to adsorption or fixation of this element, and possibly also due to leaching of available forms of Mo. Mo levels were
Total Mo/mg (kg)-1 |
Available Mo/ mg (kg)-1 |
Non-serpentine soils |
|
2.38 |
0.034 |
8.73 |
0.217 |
Serpentine soils |
|
3.04 |
0.0075 |
4.14 |
0.013 |
6.11 |
0.036 |
8.63 |
0.034 |
9.5 |
0.17 |
Available Mo was determined using the fungus Aspergillus niger.
Walker, R.B., Low molybdenum status of serpentine soils of western North America, South African Journal of Science, 2001, 97, 565-568.
Molybdenum deficiency in soil in Nepal
Micronutrient problems in the food systems of the Himalaya are wide spread due to bedrock with low nutrient content, high erosion rates, poverty, subsistence agriculture, and increasing cropping intensity. Agriculturally based strategies for the reduction of micronutrient malnutrition will require knowledge of the scale and spatial patterns of soil deficiencies or excesses of some elements. The present article documents current knowledge about the micronutrient status of cultivated soil in Nepal. Most studies have recorded largely the same magnitude of deficiencies in this country. Some 80 to 90% of soil samples were deficient in boron (B), 20 to 50% in zinc (Zn), and 10 to 15% in molybdenum (Mo). These are important micronutrient deficiencies because they limit agricultural production and affect human nutrition directly or indirectly
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Andersen, P., A review of micronutrient problems in the cultivated soil of Nepal - An issue with implications for agriculture and human health, Mountain Research and Development, 2007, 27, 331-335.
Molybdenum adsorption capacities of soils
Mo maximum adsorption capacities (MoMAC) of 16 soils, primarily Oxisols, from Minas Gerais, Brazil were determined. The MoMAC varied from 0.15 to 2.02 mg g-1 and there were good correlations between MoMAC and soil clay content as well as between MoMAC and soil organic carbon content. The molybdate-catalysed reaction of potassium iodide and hydrogen peroxide was used to determine molybdenum (Mo) in Mehlich 1 (1:10) soil test extracts.
Fontes, R.L.F., Dallpai, D. L., Braga, J. M., and Alvarez, V. H., Determination of molybdenum in soil test extracts with potassium iodide plus hydrogen peroxide reaction, Communications in Soil Science and Plant Analysis, 2000, 31, 2671-2683.
Molybdenum adsorption to goethite
The interaction (adsorption) of molybdate and goethite displayed a fast relaxation time (reciprocal of rate constant, about 4 ms), that decreased with increasing temperature (283 to 303 K) and a slow time (about 60 ms) that did not depend on temperature. Activation energy of the fast process was 76 kJ mol-1. The fast relaxation, which was not affected by incubation time, represents Mo chemisorption to the goethite. The amount of Mo sorbed to the iron oxide increased with increasing incubation time. Slow relaxation is due to Mo transport within the suspension.
Lang, F., Pohlmeier, A., and Kaupenjohann, M., Mechanism of molybdenum sorption to iron oxides using pressure- jump relaxation, Journal of Plant Nutrition and Soil Science-Zeitschrift Fur Pflanzenernahrung Und Bodenkunde, 2000, 163, 571-575.
The mobility of Mo in soils and sediments depends on several factors including soil mineralogy and the presence of other oxyanions that compete with Mo for the adsorbent's retention sites. Tungstate and phosphate appear to be the strongest competitors of Mo for the adsorption sites of goethite, whereas little competitive effects were observed in the case of silicate and sulfate. The dominant complexes of adsorbed W and Mo on goethite 110 faces at low pH were diprotonated monodentate complexes, FeOW(OH)(5)(-0.5) and FcOMo(OH)(5)(-0.5) Mo and W are retained mainly by the formation of monodentate complexes on the goethite surface.
Xu, N., Christodoulatos, C., and Braida, W., Modeling the competitive effect of phosphate, sulfate, silicate, and tungstate anions on the adsorption of molybdate onto goethite, Chemosphere, 2006, 64, 1325-1333.
Molybdenum adsorption on soil minerals
Goldberg, S., Brown, G. E., Johnston, C. T., and Suarez, D. L., Mechanism of molybdenum adsorption on soil minerals evaluated using vibrational spectroscopy and surface complexation modeling, Abstracts of Papers of the American Chemical Society, 2006, 231
Influence of soil solution salinity on molybdenum adsorption by soils
Molybdenum adsorption on five arid-zone soils from California was investigated as a function of equilibrium solution molybdenum concentration (0 30 mg L-1), solution pH (4-8), and electrical conductivity. Molybdenum adsorption decreased with increasing pH. An adsorption maximum was found near pH 4. Molybdenum adsorption as a function of solution pH was independent of solution salinity from pH 4 to 8. Molybdenum adsorption for five soils as a function of solution molybdenum concentration obeyed the Langmuir adsorption isotherm equation. The constant capacitance model, a surface complexation model, was able to describe molybdenum adsorption as a function of solution molybdenum concentration and solution pH. Molybdenum adsorption was predicted using the soil chemical properties: cation exchange capacity, organic carbon content, inorganic carbon content, and iron oxide content. Under agricultural conditions (pit 4-8), molybdenum adsorption can be described without consideration of changes in soil solution salinity
The following surface complexation reactions were considered and the surface complexation constants were determined:
SOH + H+ = SOH2+
SOH = SO- + H+
SOH + H2MoO4 = SHMo4 + H2O
SOH + H2MoO4 = SMoO4- + H+ + H2O
where SOH, the surface functional group, represents both reactive surface hydroxyl groups on oxides and aluminol groups on clay mineral edges in soils.
Molybdenum adsorption isotherms were determined on five soils under conditions of low (EC = 0.32 dS m I) and high(EC = 7.9 dS m) electrolyte concentration. The Langmuir isotherm equation was fitted to the experimental adsorption data using nonlinear least-squares optimization (Kinniburgh. 1986).
Moads = (KMoeqM)/(1+KMoeq)
Here Moads is the molybdenum adsorption, Moeq is the equilibrium molybdenum solution concentration, M is the maximum molybdenum adsorption and K is a parameter fitted to the molybdenum adsorption data. With the exception of the Arlington subsoil, the molybdenum adsorption was not different at the 95% level of confidence for the two electrical conductivities. This result indicates that in the range of EC = 0.32 to 7.9 dS m, the magnitude of molybdenum adsorption is independent of soil solution salinity.
Goldberg, S., Influence of Soil Solution Salinity on Molybdenum Adsorption by Soils, Soil Science, 2009, 174, 9-13.
Mo in soil: availability enhanced by increased pH
The Mo availability in the soil was highest for soil application of lime (0.5 tonne/ha) followed by Mo @ 0.5 kg/ha
Hamza, S. and Sadanandan, A. K., Soil amendments and molybdenum on yield and quality of black pepper (Piper nigrum), Indian Journal of Agricultural Sciences, 2005, 75, 735-737.
Molybdenum Foliar Fertilization of Oilseed Rape - Influence of Soil Reaction
The effect of foliar fertilization with molybdenum on oilseed rape in thirty-three field trials on soils of different acidity (pH=4.1-7.1) is reported. Molybdenum at 30, 60 and 120 g Mo ha-1 was applied: in the spring, a few days after the growing season started; and during the early stem formation stage.
On very acidic and acidic soils, seed yields were 0.08 t ha-1 higher. A relative seed yield increase obtained through molybdenum fertilization depended on the concentration of manganese and percentage of the silt fraction in the soil.
Oilseed rape grown on slightly acidic and neutral soils responded to molybdenum fertilization with an average seed yield increase of 0.02t ha-1.
The amount of molybdenum added affected oilseed rape yields only for slightly acidic and neutral soils. Molybdenum at 30 g Mo. ha-1was less effective than molybdenum at 60 and 120 g Mo. ha-1.
Seed yields did not depend on the date of molybdenum application. There was no interaction between molybdenum application rates and application dates in either group of the trials.
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Stanislawska-Glubiak, E., The Influence of Soil Reaction on the Effects of Molybdenum Foliar Fertilization of Oilseed Rape, Journal of Elementology, 2008, 13, 647-654.
Acidic agricultural soils molybdenum addition and liming
Most soils in sub-Saharan Africa are acidic and have low calcium (Ca2+), magnesium (Mg2+) and molybdenum (Mo). Higher concentrations and contents of hydrogen ion (H+), aluminium (Al3+) and manganese (Mn2+) found in these acidic soils are the major causes of poor plant growth due to their toxicity to plants and micro organisms such as N-fixing bacteria. Molybdenum is a component of some bacterial nitrogenase and is important for plants that live in symbiosis with nitrogen-fixing bacteria such as Rhizobium. Calcium, magnesium and molybdenum deficient plants exhibit poor growth. The most common management practice to ameliorate these acidic soil problems is through the surface application of lime or molybdenum and/ or seed pelleting. The potential role(s) of lime and Mo in legumes with respect to growth, assimilation of metabolites, N-fixation and growth is given special attention in this review
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Bambara, S. and Ndakidemi, P. A., The potential roles of lime and molybdenum on the growth, nitrogen fixation and assimilation of metabolites in nodulated legume: A special reference to Phaseolus vulgaris L, African Journal of Biotechnology, 2010, 9, 2482-2489.
Phosphorus-Molybdenum Relationship in Soil and Red Clover
The phosphorus and molybdenum relationship in soil and red clover (Trifolium pratense L.) in a non-limed and limed acid Andisol of Southern Chile was studied.
The effect of different liming (0 and 2000 mg kg(-1)), P (0, 200 and 400 mg kg(-1)), and Mo (0, 0.58 and 0.96 mg kg(-1)) doses supply on soil available Mo was evaluated. The availability of P and calcium (Ca) in treated soils was determined.
Lime and more strongly P and Mo additions significantly (P <= 0.05) increased soil Mo availability.
Soil available P was not significantly (P <= 0.05) affected by liming and Mo treatments.
A significant high correlation (r = 0.579, at P <= 0.05) was observed among soil Mo availability and shoot Mo concentrations, and between soil available P and shoot concentration of P (r = 0.844, at P <= 0.01).
For all fertilization treatments, shoot Cu concentrations reached values considered normal for forage species. Simultaneous applications of high P and Mo rates could produce red clover shoot Cu/Mo ratios that should provoke Mo-induced Cu deficiency (molybdenosis) for cattle.
Red clover yield was not significantly different in limed and non limed soils. Red clover yield increased at increasing rates of P and Mo in both non-limed and limed soil.
The major practical implication of these results is that the application of Mo doses equal or superior to 200 g ha-1 to acid Andisols, is recommendable to obtain appropriate Mo shoot content on red clover.
P supply to these soils, rather than liming, is necessary to obtain sufficient values of shoot Mo concentrations in red clover
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Ribera, A. E., Mora, M. D., Ghiselini, V., Demanet, R., and Gallardo, F., Phosphorus-Molybdenum Relationship in Soil and Red Clover (Trifolium Pratense L.) on An Acid Andisol, Revista de la Ciencia del Suelo y Nutricion Vegetal, 2010, 10, 78-91.
Molybdenum in agriculture: application of molybdenum to leaves of winter beans
The objective was to evaluate the performance of irrigated winter beans, in a no-tillage system, with increasing levels of side dressing nitrogen application (zero, 30, 60, 90 and 120 kg ha-1) and its interaction with leaf application of molybdenum (zero and 80 g ha-1). The common bean can fix nitrogen in symbiosis with Rhizobium, but the fixed nitrogen is not enough to meet the nitrogen requirement of the plant. Molybdenum application aims to improve symbiosis in the Rhizobium-common bean plant, given its importance in the metabolism nitrogen, thus being able to reduce the application of nitrogen fertilizer. The research was carried out on soil previously cultivated with corn culture. The levels of nitrogen proved consistent regarding the effects on some production components, and on dry mass of plants, providing better development of irrigated beans cultivated under no-tillage. The application of molybdenum in leaves did not influence the majority of evaluated parameters
Barbosa, G. F., Arf, O., do Nascimento, M. S., Buzetti, S., and Freddi, O. D., Side dressing nitrogen and leaf molybdenum in the winter common bean plant, Acta Scientiarum-Agronomy, 2010, 32, 117-123.
Plants agriculture seed treatment
Molybdenum was applied as a concentrated suspension of Mo trioxide in waterto soybean seeds resulting in in higher soybean yields than in a control.
Lana, R. M. Q., de Faria, M. V., Bonotto, I., and Lana, A. M. Q., Cobalt and Molybdenum Concentrated Suspension for Soybean Seed Treatment, Revista Brasileira de Ciencia do Solo, 2009, 33, 1715-1720.
Plants rice beneficial effect of Mo and Ni interaction on plant growth
This is the first evidence for a beneficial effect of Mo and Ni interaction on plant growth. Upland rice plants, cultivar 'IAC 202,' were grown in nutrient solution until full tillering. Treatments consisted of ammonium nitrate or urea as nitrogen source plus molybdenum and/or nickel.
Moraes, M. F., Reis, A. R., Moraes, L. A. C., Lavres, J., Vivian, R., Cabral, C. P., and Malavolta, E., Effects of Molybdenum, Nickel, and Nitrogen Sources on the Mineral Nutrition and Growth of Rice Plants, Communications in Soil Science and Plant Analysis, 2009, 40, 3238-3251.
Plants alfalfa
Alfalfa crops were grown in the field at the University of Ankara over two seasons between 2001 and 2003 with sulfur supplied as gypsum at rates of 0 (control), 160 (S1), and 240 (S2) kg /ha.Sulfur fertilization increased sulfur concentrations and improved alfalfa hay yield for both years. Molybdenum concentration of the alfalfa was significantly reduced by S1 treatment in year 1. Applied S had no effect on copper.
Gunes, A., Inal, A., Pilbeam, D. J., and Kadioglu, Y. K., Effect of Sulfur on the Yield and Essential and Nonessential Element Composition of Alfalfa Determined by Polarized Energy Dispersive X-ray Fluorescence, Communications in Soil Science and Plant Analysis, 2009, 40, 2264-2284.
Plants lettuce accumulation of molybdenum in plants and soils following amendments of molybdenum compost
A limit for molybdenum loading of soil developed from compost additions is proposed as 55 mg Mo/ kg soil, a value which is presently greater than the Canadian Council for Ministers of the Environment (CCME) Guidelines for the use of type B compost in Canada
The growth of lettuce (Lactuca sativa L.) and barley (Hordeum vulgar) and accumulation of molybdenum in plants and soils were evaluated in a pot experiment following amendments of molybdenum compost (1.0 g/ kg) to a Truro sandy loam. Dry-matter yield: up to 25% molybdenum compost, no effect; at the 50% compost treatment dry-matter yield decreased.
pH: 50% compost treatments, soil pH increased an average of 0.5 units.
Extractable molybdenum:
50% compost treatments:
in the growth medium increased the nitric acid extractable molybdenum to 150 mg/ kg and diethylenetriaminepentaacetic acid extractable molybdenum to 100 mg/ kg;
tissue Mo concentration to 569 and 478 mg/ kg in the lettuce and barley.
25% compost treatment:
in the growth medium produced about 55 mg/ kg of total molybdenum;
tissue Mo concentration of 348 mg/ kg in lettuce and 274 mg/ kg in barley without any phytotoxicity.
Kashem, M. A. and Warman, P. R., Effect of High-Molybdenum Compost on Soils and the Growth of Lettuce and Barley, Communications in Soil Science and Plant Analysis, 2009, 40, 2225-2233.
Agriculture molybdenum application lettuce effect on nutrients
Ammonium heptamolybdate, (NH4)6Mo7O24 .4H2O, was applied under greenhouse conditions to head lettuce at doses Mo mg/kg 0, 0.25, 0.5. Nitrogen fertilizerNH4NO3 100 mg/kg phosphorus fertilizer KH2PO4 50 mg/ kg .
With increasing added molybdate
N, P and K contents of head lettuce increased;
Fe, Zn and Mn contents of plant decreased;
Cu content of plant was not affected.
Adiloglu, S., Adiloglu, A., Sumer, A., and Satana, A., Molybdenum Application on the Growth and Nutrient Element Contents of Head Lettuce (Lactuca sativa L.) in Acid Soils, Asian Journal of Chemistry, 2011, 23, 937-938.
Molybdenum and soil
Liming an acid soil increases molybdenum content in the root and leaf of Dutch tomato
Pseudogley is a typical acid soil predominating in Serbia and the wider region. Acid soils are not suitable for the cultivation of agricultural crops due to the hampered uptake of most nutrients owing to increased hydrogen ions.
In order to make pseudogley soil suitable for crop production, pH improvement measures should be employed. Soil acidity was neutralised by liming and the effect was evaluated of soil pH improvement on the Mo content in root and leaf of the Dutch tomato (Lycopericon esculentum Mill.) hybrid Belle planted under controlled conditions on pseudogley soil.
Three liming treatments were employed (1, 3 and 4 t/ha CaCO3). Liming of pseudogley caused an increase of molybdenum ion absorption into the root system of tomato. The root and leaf molybdenum content of tomato in each treatment were very low and insufficient for growth of tomato. To make pseudogley suitable for agricultural production soil pH must be increased and the available molybdenum in the soil.
Djuric, M.; Mladenovic, J.; Radovanovic, B.; Murtic, S.; Acamovic-Djokovic, G.; Pavlovic, R.; Boskovic-Rakocevic, Lj. Effect of liming on the molybdenum content in the root and leaf of tomato grown on pseudogley under controlled conditionsAfrican Journal of Biotechnology, 2011, 10, 83, 19402-19406.
Toxicity of molybdenum to soil organisms
To determine if long-term equilibration may alleviate molybdenum toxicity, earthworms, enchytraeids, collembolans and four plant species were exposed to three soils freshly spiked with sodium molybdate dihydrate, Na2MoO4.2H2O, and equilibrated for 6 or 11 months in the field with free drainage.
Total molybdenum concentrations in soil decreased by leaching, most (up to 98%) in sandy soil and less (54-62%) in silty and clayey soils.
Changes in residual molybdenum toxicity with time were inconclusive in sandy soil. In the other two soils, toxicity of residual total molybdenumwas significantly reduced after 11 months equilibration, with a median 5.5-fold increase in ED50s.
Molybdenumfixation in soil, i.e. the decrease of soil solution molybdenum concentrations at equivalent residual total soil molybdenum , was maximally a factor of 2.1 only.
This experiment shows natural attenuation of molybdate ecotoxicity under field conditions is related to leaching of excess molybdenumand other ions as well as to slow ageing reactions.
van Gestel, Cornelis A M; McGrath, Steve P; Smolders, Erik; Ortiz, Maria Diez; Borgman, Eef; Verweij, Rudo A; Buekers, Jurgen; Oorts, KoenEffect of long-term equilibration on the toxicity of molybdenum to soil organisms.Environmental pollution,2012, 162, 1-7.
Molybdenum in soil applications
Mo in fly ash
The concentrations of As, Cd, Hg, Mo, Ni, and Pb in fly ash are related to the S content of the coal. Generally, those feed coals with a high S content contain higher concentrations of these elements.
Goodarzi, F., Characteristics and composition of fly ash from Canadian coal-fired power plants, Fuel, 2006, 85, 1418-1427
Molybdenum and trace elements in bottom ash and fly ash
Two ash samples were taken from the 77 MW multi-fuel boiler (MFB) at the power plant of Stora Enso Oyj Heinola fluting board mill in Finland. The samples were analysed by X-ray diffraction (XRD) and inductively coupled plasma optic emission spectroscopy (ICP-OES).
Hematite (Fe2O3) and quartz (SiO2) were found in both the bottom ash and fly ash; anorthite (CaAl2Si2O8) and anhydrite (CaSO4) were detected only in the bottom ash.
Element concentrations in the fly ash were higher than in the bottom ash except sulfur which was more concentrated in the bottom ash (8030 mg/kg; d.w.) was than in the fly ash (5380 mg/kg; d.w.).
In the bottom ash, extractable molybdenum (8.2 mg/kg; d.w.) and sulfate (15.900 mg/kg; d.w.) concentrations exceeded the limit values for the acceptance of waste at inert waste landfills.
In the fly ash, the extractable concentration of chromium (1.8 mg/kg; d.w.) and sulfate (7200 mg/kg; d.w.) exceeded the limit values for the acceptance of waste at inert waste landfills. The extractable concentration of molybdenum (37.0 mg/kg; d.w.) exceeded the limit value for the acceptance of waste at non-hazardous waste landfills.
According to a three-stage sequential extraction procedure, in which elements in the bottom ash and fly ash were fractionated between acid-soluble (CH3COOH), reducible (NH2OH-HCl) and oxidisable (H2O2) + CH3COONH4) fractions, the concentrations of most elements were higher in all fractions of the fly ash than those in the bottom ash.
In the bottom ash, the extractable concentration of molybdenum (8.2 mg/kg; d.w.) in the acid-soluble fraction (CH3COOH), was higher than in the fly ash.
Approximately 52.7% of molybdenum in the fly ash was partitioned in the oxidisable fraction. Thus, molybdenum is not considered to be very mobile or bioavailable.
Poykio, R., Manskinen, K., Nurmesniemi, H., and Dahl, O., Comparison of trace elements in bottom ash and fly ash from a large-sized (77 MW) multi-fuel boiler at the power plant of a fluting board mill, Finland, Energy Exploration & Exploitation, 2011, 29, 217-233.
NOTE
From http://www.scotash.com/pdfs/FBA.pdf
Furnace Bottom Ash (FBA) is the coarse ash fraction produced in the furnaces of coal fired power stations when pulverised coal is fed into the boilers and burnt at high temperatures and pressures. [Incinerator bottom ash (IBA) is a form of ash produced in incineration facilities. This material is discharged from the moving grate of municipal solid waste incinerators.] Once combustion has taken place, the finer particles of ash of
Pulverised Fuel Ash (PFA) [Fly Ash: one of the residues generated in combustion, and comprises the fine particles that rise with the flue gases.] are carried out in the flue gases and captured in the precipitators. The coarser material (FBA) drops to the bottom of the boiler into a hopper. It is then removed by high-pressure water and pumped into storage lagoons where it can be dredged, stockpiled and allowed to drain. Chemically, FBA has similar properties to Pulverised Fuel Ash with the three predominant elements being silica, aluminum and iron, the oxides of which together account for approximately 85% of the material. There can be a small percentage of carbon particulate resulting from incomplete combustion, but percentage is low.
Mo from biosolids application to soil
Metal concentrations (As, Cd, Cu, Pb, Hg, Mo, Ni, Se, and Zn) in soil and bermudagrass [Cynodon dactylon (L.) Pers.] and forage from 10 fields were determined in the following categories of biosolids application: six or more years, less than six years and no applications Soil metal concentrations in all groups were similar to values reported for mineral soils in Georgia. The study indicated that toxic levels of metals had not accumulated in the soils due to long-term biosolids application.
Gaskin, J.W., Brobst, R. B., Miller, W. P., and Tollner, E. W., Long-term biosolids application effects on metal concentrations in soil and bermudagrass forage, Journal of Environmental Quality, 2003, 32, 146-152.
Alkaline-stabilized biosolids
Agricultural utilization of biosolids poses a potential risk to ruminant animals due to transfer of Mo from biosolids to forage to the animal in amounts large enough to suppress Cu uptake by the animal. Alkaline-stabilized biosolids (ASB) must be given particular consideration in assessment of Mo risk because the high pH of these biosolids could increase Mo and decrease Cu uptake by forage legumes. Application of ASB did not detectably increase extractable soil Mo (0- to 15-cm depth), but increased alfalfa Mo uptake in all cuttings. Although ASB increased extractable soil Cu, and alfalfa Cu content the Cu to Mo ratio was decreased by ASB to levels near 3. These results suggest that ASB may have a greater effect on Mo uptake and Cu to Mo ratio of forage legumes than do other biosolids.
Stehouwer, R.C. and Macneal, K. E., Effect of alkaline-stabilized biosolids on alfalfa molybdenum and copper content, Journal of Environmental Quality, 2004, 33, 133-140.
Molybdenum accumulation in plants onbiosolid- amended soils
Accumulation of heavy metals in soils amended with biosolids and the risk of their uptake into different parts of plants are topics of great concern.
This research reports the accumulation of several heavy metals and nutrients in soybeans grown on biosolid-applied soils and the use of remote sensing to monitor the metal uptake and plant stress. Field and greenhouse studies were conducted with soybeans grown on soils applied with biosolids at varying rates.
The plant growth was monitored using Landsat TM imagery in field studies and handheld spectroradiometer in greenhouse studies.
Soil and plant samples were collected and then analyzed for several elemental concentrations.
The chemical concentrations in soils and roots increased significantly with increase in applied biosolid concentrations.
Copper and molybdenum accumulated in the shoots of the metal-treated plants.
The spectral and Landsat TM image analysis revealed that the Normalized Difference Vegetative Index (NDVI) can be used to distinguish the metal stressed plants.
The NDVI showed significant negative correlation with increase in soil Cu concentrations followed by other elements.
The use of remote sensing to monitor soybean stress patterns and indirectly assesses soil chemical characteristics. (C) 2011 Elsevier B.V. All rights reserved
Sridhar, B. B. M., Vincent, R. K., Roberts, S. J., and Czajkowski, K., Remote sensing of soybean stress as an indicator of chemical concentration of biosolid amended surface soils, International Journal of Applied Earth Observation and Geoinformation, 2011, 13, 676-681.
Substance |
Mo/mg/kg mean, median |
triple superphosphate |
8-17, 13 |
monoammonium phosphate |
12-17, 15 |
diammonium phosphate |
10-21, 14 |
phosphate rock (Africa,USA,Peru) |
2-21, 6 |
commercial phosphate fertilisers, Iowa USA
Charter, R.A., Tabatabai, M.A., Schafer, J.W., Arsenic, Molybdenum, Selenium, And Tungsten Contents Of Fertilizers And Phosphate Rocks, Communications In Soil Science And Plant Analysis, 1995, 26, 3051-3062.
Sewage Sludge and municipal wastes
Mo in sewage sludge av 15 mg Mo/kg , range 1 – 40 mg Mo/kg
A.K. Furr, Lawrence, A.W., and Tong, S.S.C., Multielement and chlorinated hydrocarbons analysis of municipal sewege sludges of American cities, Environ. Sci. Technol., 1976, 10, 683 – 687.
Mo uptake from sewage sludge
The use of sewage sludge as a fertiliser continues to be controversial. Sewage sludge, a byproduct of wastewater treatment, consists mainly of human excreta plus inputs from industrial discharges. The sludge is contaminated with metals including Mo. The particular problem with Mo is the Mo-Cu antagonism leading to molybdenosis in cattle and other ruminants. A recent news item (Renner,R., Scientists debate fertilizing soils with sewage sludge, Environmental Science and Technology News, 2000, June 1, 243A) reports a Water Environment Research Foundation study which concludes that the danger to grazing animals associated with sludge derived Mo is small provided the sludge (20 - 30 mg Mo/kg dry weight) is applied at 'reasonable' rates to farms that follow good practice (cutting and drying animal forage before it is eaten, augmenting cattle diets with copper).
On the contrary a paper by McBride et al.(following paragraph) concludes that on pastures of alfalfa and clover Mo in forages can be elevated to 'unacceptable' levels by one or two sewage sludge applications. The McBride paper provides a useful review of Mo in soil and forage as well as results of their detailed study.
Sewage sludges, which are commonly applied to farmlands, can contain Mo in the range 5 - 50 mg Mo/kg.
Mo supplied from sludge is readily taken up by legumes in particular. Excessive uptake into red clover (Trifolium pratense L.) (>30 mg/kg) was seen in a soil that had been heavily amended with sewage sludge 20 y earlier, where the soil contained about 3 mg Mo/kg soil, three times the background soil concentration. Mo can have a long residual availability in sludge amended soils. The effect of sludge application was to decrease Cu to Mo ratios in legume forages, canola (Brassica napus var, napus) and soybeans [Glycine max (L.) Merr,] below the recommended limit of 2:1 for ruminant diets, a consequence of high bioavailability of Mo and low uptake of Cu added in sludge. Molybdenum uptake coefficients for alkaline-stabilized sludge were higher than for dewatered sludge, presumably due to the greater solubility of Mo measured in the more alkaline sludges and soils. Based on these molybdenum uptake coefficients, it is tentatively recommended that cumulative Mo loadings on forages grown on nonacid soils should not exceed
from alkaline-stabilized sludge 1.0 kg Mo/ha
from dewatered sludge 4.0 kg Mo/ha .
McBride, M.B., Richards, B. K., Steenhuis, T., and Spiers, G., Molybdenum uptake by forage crops grown on sewage sludge- amended soils in the field and greenhouse, Journal of Environmental Quality, 2000, 29, 848-854.
Heavy metals in municipal solid waste incineration bottom ash (MSWIBA) may leach into soil and groundwater and pose long-term risks to the environment. Toxicity characteristic leaching procedure (TCLP) was carried out on the MSWIBA from Macao. Heavy metals in leachates were determined by inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma atomic emission spectrometry (ICP-AES), and genotoxicity of leachates was also evaluated by micronucleus (MN) assay with Vicia faba root tip cells.
Concentrations of aluminium (Al), manganese (Mn), cobalt (Co), cadmium (Cd) and mercury (Hg) in the leachates were less than 0.01 mg l(-1), and those of iron (Fe), copper (Cu) and molybdenum (Mo) were less than 0.1 mg l(-1) The concentrations of chromium (Cr), zinc (Zn), selemium. (Se), strontium (Sr), barium (Ba) and caesium (Cs) were between 0.11 mg l(-1) and 2.19 mg l(-1). Lead (Pb) concentrations, in particular, reached as high as 19.6 mg l(-1), significantly exceeding the maximum concentration limit (5 mg l(-1) for lead by TCLP).
Compared with the negative group, a significant increase of MN frequencies was observed in the leachate-exposed groups (P < 0.05).
With the increase of heavy metals in the leachates, the toxic effects on the Vicia faba root tip cells increased, implying that heavy metals were the main factors causing the genotoxic effects.
Apart from chemical analysis, bioassays like the MN assay of Vicia faba root tip cells should also be included in a battery of tests to assess the eco-environmental risks of bottom ashes before decisions can be made on the utilization, treatment or disposal.
Feng, S. L., Wang, X. M., Wei, G. J., Peng, P. G., Yang, Y., and Cao, Z. H., Leachates of municipal solid waste incineration bottom ash from Macao: Heavy metal concentrations and genotoxicity, Chemosphere, 2007, 67, 1133-1137.
Molybdenum in sediments
This paper presents the results of measurements of the Mo isotopic composition in the bottom sediments (BS) of freshwater basins. Mo isotopic ratios were measured using a multicollector inductively coupled plasma mass spectrometer (MC ICP MS).
Malinovskii, D. N., Rodyushkin, I. V., and Ohlander, V., Determination of the isotopic composition of molybdenum in the bottom sediments of freshwater basins, Geochemistry International, 2007, 45, 381-389.
Molybdenum in sediments
In one perennially oxic and three seasonally anoxic lakes in Eastern Canada the authors measured
- in sediment porewater the vertical distributions of Mo, Fe; Mn, sulfide, sulfate, organic carbon, major ions, and pH
- in sediment cores from the same sites Mo, acid volatile sulfide, Fe, Mn, Al, organic C, Pb-210 and Cs-137.
The only input of anthropogenic Mo to these lakes comes from atmospheric deposition.
In the porewater of three seasonally anoxic basins the distribution of Mo was relatively monotonous: Mo is not redistributed in the sedimentary column during periods of anoxia.
In the porewater in a perennially oxic basin Mo profiles obtained at three sampling dates display sharp Mo peaks below the sediment-water interface, indicating redistribution subsequent to deposition. Diagenetic modeling of these latter porewater Mo profiles reveal that
- Mo is released at 1-2 cm depth as a consequence of the reductive dissolution of Fe oxyhydroxides
- scavenged both at the vicinity of the sediment-water interface, by re-adsorption onto authigenic Fe oxyhydroxides, and deeper in the sediments where dissolved sulfide concentrations are higher.
The estimated rate constant for the adsorption of Mo onto Fe oxyhydroxides is 36 ± 45 cm3mol-1s-1.
In sediments of the perennially oxic basin diagenetic modeling indicates that authigenic Mo represents about one-third of the total solid phase Mo in the first cm below the sediment-water interface and only one tenth below this horizon.
The sediment Mo concentrations are up to 3-16 times higher than the average lithogenic composition, depending on the lake. SedimentMo is mainly due to atmospheric deposition of anthropogenic Mo and not to the formation of authigenic Mo phases if it is assumed that no authigenicMo is accumulated in the seasonally anoxic lake sediments.
Reconstructed historical records of the atmospheric Mo deposition indicate maximum values in the 1970s and 1980s and significant decreases since then.
Emissions to the atmosphere associated with the smelting of non-ferrous ores and coal combustion appear to be the most important sources of anthropogenic Mo.
[Anthropogenic: derived from human activities.
Diagenesis: any chemical, physical, or biological change undergone by a sediment after its initial deposition and during and after its lithification.
Authigenic: of minerals, formed in place, rather than having been transported and deposited there.
Lithogenic:coming from rock.]
Chappaz, A., Gobeil, C., and Tessier, A., Geochemical and anthropogenic enrichments of Mo in sediments from perennially oxic and seasonally anoxic lakes in Eastern Canada, Geochimica et Cosmochimica Acta, 2008, 72, 170-184.
Molybdenum in sediments
Molybdenum is a trace metal used as a marker of paleoredox conditions of ancient depositional settings.
Pyrite is an important molybdenum host for enriched sedimentary rocks.
The relationship between Mo and pyrite in the Bancs Jumeaux Formation, a Jurassic succession in northern France consisting of limestone and pyrite-rich marls, has been studied. This formation is enriched in Mo compared to other redox-sensitive trace metals.
Their approach is grounded on bulk rock chemical analysis and delineation of two contrasting types of pyrite that can be extracted from the rocks: polyframboids and nonframboidal concretionary masses.
The morphological characteristics of both morphotypes were studied using scanning electronic microscopy. The polyframboids are richer in Mo than the concretions but are not markedly enriched in other trace metals. This discrepancy in geochemical composition could result from pyrite precipitation at different times during early diagenesis.
Their results indicate that the polyframboids would have formed very early in reducing "microniches", within dominantly dysoxic sediment. This early pyrite precipitation occurred at shallow depth below the sediment-water interface close to the abundant Mo source in overlying oxic seawater (molybdate ions), and would have fostered Mo-capture by the polyframboids in relatively large amounts. The concretions would have formed later during early diagenesis (within the sulfidic zone) under conditions of more limited Mo availability
Tribovillardi, N., Lyons, T. W., Riboulleau, A., and Bout-Roumazeilles, V., A possible capture of molybdenum during early diagenesis of dysoxic sediments, Bulletin de la Societe Geologique de France, 2008, 179, 3-12.
Molydenum isotopes in black shales - redox evolution of the Earth's oceans
The first complete suite of molybdenum isotope fractionation observations is reported for a sulfidic water column and sediment system, the meromictic Lake Cadagno, Switzerland, a small alpine lake with a pronounced oxygen-sulfide transition reaching up to H2S ca 200 microM in the bottom waters (or about 300 microM total sulfide: ΣS2- = H2S + HS- + S2-).
Molybdenum isotope studies in black shales can provide information about the redox evolution of the Earth's oceans, provided the isotopic consequences of molybdenum burial into its major sinks are well understood.
Previous applications of the molybdenum isotope paleo-ocean redox proxy assumed quantitative scavenging of molybdenum when buried into sulfidic sediments.
Molybdenum behaves conservatively in the oxic zone and non-conservatively in the sulfidic zone, where dissolved molybdenum concentrations decrease from 14 nM to 2-8 nM across this transition.
Dissolved molybdenumin the upper oxic waters has a δ98Mo (oxic) = 0.9 ± 0.1 parts per thousand, which matches that of the riverine input, δ98Mo (river) = 0.9 ± 0.1 parts per thousand.
In the deeper sulfidic waters, a subaquatic source delivers molybdenum at 1.55 ± 0.1 parts per thousand, but the dissolved Mo is even heavier at δ98Mo (sulfidic) = 1.8 parts per thousand. Sediment traps in the sulfidic zone of the lake collect particles increasingly enriched in molybdenum with depth, with de δ98Mo values significantly fractionated at -0.8 parts per thousand to -1.2 parts per thousand both near the chemocline and in the deepest trap.
Suspended particulates in the sulfidic waters carry lighter molybdenum than the ambient dissolved molybdenum pool by ca 0.3-1.5 parts per thousand.
Sedimentary molybdenumconcentrations correlate with total organic carbon and yield molybdenum levels which are two orders of magnitude higher than typical crustal values found in rocks from the catchment area.
Solid-phase molybdenum in the sediment shows a slightly positive δ98Motrend with depth, from δ98Mo= 1.2 parts per thousand to 1.4 parts per thousand
while the pore waters show dramatic enrichments of molybdenum (>2000 nM) with a relatively light isotope signature of δ98Mo= 0.9-1.0 parts per thousand.
These data are explained if molybdenum is converted to particle-reactive oxothiomolybdates in the sulfidic waters and is fractionated during removal from solution onto particles. Isotope fractionation is expressed in the water column, despite the high sulfide concentrations, because the rate of molybdenum removal is fast compared to the slow reaction kinetics of thiomolybdate formation. However, elemental and isotopic mass balances show that molybdenum is indeed quantitatively removed to the lake sediments and thus the isotopic composition of the sediments reflects sources to the sulfidic water. This efficient molybdenum drawdown is expected to occur in settings where H2S is very much in excess over molybdenum or in a restricted setting where the water renewal rate is slow compared to the molybdenum burial rate.
A model for the molybdenum isotope fractionation in sulfidic systems is presented.
Dahl, T. W., Anbar, A. D., Gordon, G. W., Rosing, M. T., Frei, R., and Canfield, D. E., The behavior of molybdenum and its isotopes across the chemocline and in the sediments of sulfidic Lake Cadagno, Switzerland, Geochimica et Cosmochimica Acta, 2010, 74, 144-163.
Molybdenum isotopes weathering
Pearce, C. R., Burton, K. W., von Strandmann, P. A. E. P., James, R. H., and Gislason, S. R., Molybdenum isotope behaviour accompanying weathering and riverine transport in a basaltic terrain, Earth and Planetary Science Letters, 2010, 295, 104-114.
E. Germany
The Malter Reservoir is about 30 km south of Dresden (eastern Germany) in a historical mining area of the eastern Erzgebirge. Within the whole core recovered from the deepest point of the lake, heavy metals are strongly enriched (parentheses refer to enrichment factors as compared with average shale): cadmium (290), silver (140), bismuth (90), antimony (25), lead (21), zinc (14), tin (13), uranium (9), tungsten (9), molybdenum (5), copper (4), thallium (3) and chromium (2). Enrichments are detectable for the whole registered time-period of 81 years. Peaks of up to 27 mg/kg silver, 37 mg/kg bismuth, 91 mg/kg cadmium, 410 mg/kg chromium, 240 mg/kg copper, 20 mg/kg molybdenum, 14000 mg/kg phosphorus, 740 mg/kg lead, 6,5 mg/kg antimony, 74 mg/kg tin, 52 mg/kg tungsten and 1900 mg/kg zinc reflect local events caused by human impact.
Muller, J., Ruppert, H., Muramatsu, Y., and Schneider, J., Reservoir sediments - a witness of mining and industrial development (Malter Reservoir, eastern Erzgebirge, Germany), Environmental Geology, 2000, 39, 1341-1351.
British Columbia
Sediment geochemical patterns in lakes in British Columbia are strongly influenced by proximity to Mo mineralization, with the highest Mo concentrations (max: 165 ppm) downslope of known prospects. Elevated centre-basin Mo concentrations of at least 12 ppm reflect the presence of adjacent porphyry Mo mineralization. Sediments at Tatin, Hanson and the Counts Lakes contain elevated median Mo concentrations of 8 ppm (max: 23 ppm), 7 ppm (max: 55 ppm) and 42 ppm (max: 165 ppm), respectively, relative to regional background of 1-2 pm. Mo Centre-basin results from Tatin Lake (12, 7-10, 23 ppm), Hanson Lake (11-12 ppm) and the Counts lakes (49, 160, 60, 33, 38, 56, 54, 83 ppm) exceed regional background by 3-80x.
Cook, S.J., Distribution and dispersion of molybdenum in lake sediments adjacent to porphyry molybdenum mineralization, central British Columbia, Journal of Geochemical Exploration, 2000, 71, 13-50.
The concentrations of dissolved trace elements (Li, B, Mn, Cu, As, Rb, Sr, Mo, Cd, Ba, Pb) in the Marne and Seine rivers in the Paris urban area were monitored over a 2-year period. Dissolved Mn, Cu and Cd increased rapidly in summer, whereas the concentration of Mo decreased. These variations were attributed to redox processes. During summer when the dissolved oxygen concentrations decrease, Mn, Cu, Cd and Pb are released into solution whereas Mo is immobilised.
Elbaz-Poulichet, F., Seidel, J. L., Casiot, C., and Tusseau-Vuillemin, M. H., Short-term variability of dissolved trace element concentrations in the Marne and Seine Rivers near Paris, Science of the Total Environment, 2006, 367, 278-287.
Fe, Mn, Cu, Zn, Mo and Cr were determined in May 2002 at 25 locations in the sediments of Laguna Caren. Mo showed homogeneous concentrations at all stations, with average level 160 mu g/g dry weight. High Cu/Fe and Mo/Fe ratios indicate the accumulation of these metals in sediments. Cu and Mo were found to be mainly associated to the organic matter-sulfides fraction
Pizarro, J., Rubio, M. A., Henriquez, J., and Gonzalez, M., Metals in sediments of an urban shallow lake in Santiago (Chile), Fresenius Environmental Bulletin, 2006, 15, 524-529.
Molybdenum isotopic composition in the bottom sediments (BS) of freshwater basins.
This paper presents the results of measurements of the Mo isotopic composition in the bottom sediments (BS) of freshwater basins. Mo isotopic ratios were measured using a multicollector inductively coupled plasma mass spectrometer (MC ICP MS).
Malinovskii, D. N., Rodyushkin, I. V., and Ohlander, V., Determination of the isotopic composition of molybdenum in the bottom sediments of freshwater basins, Geochemistry International, 2007, 45, 381-389.
Country |
Soil type |
Median Concentration/ppm |
[1] |
Soil |
0.2 - 5 |
[1] |
Igneous rocks |
1.5 |
[1] |
Shales |
2.6 |
[1] |
Sandstones |
0.2 |
[1] |
Limestones |
0.4 |
[2] |
Coal |
10 |
Canada[3] |
Calcareous |
6.0 |
Western US[1] |
Calcareous |
6.0 |
Eastern US[3] |
Acidic |
0.5 |
Irish Cattle Farms[4] |
dry mass |
0.03 - 6.5mg/kg |
British Columbia[5] |
dry mass |
24 microg/g |
World maximum[6] |
dry mass |
17 microg/g |
[1] Kubota, J., Molybdenum Status of United States Soils and Plants, in: Chappell, W. R. and Petersen, K. K. (ed.), Molybdenum in the Environment, 1977, 2, Ch. 6. Marcel Dekker, New York.
[2] Stone, L. R., Erdman, J. A., Fedder, G. L. and Holland, H. D., Molybdenum in an Area Underlain with Uranium Bearing Lignites in the Northern Great Plains, J. Range Manag. ,1983, 36, 280.
[3] Boila, R. J., Devlin, T. J., Drysdale, R. A. and Lillie, L. E., The Severity of Hypocupremia in Selected Herds of Beef Cattle in Northwestern Manitoba, Can. J. Anim. Sci., 1984a, 64, 899.
Boila, R. J., Devlin, T. J., Drysdale, R. A. and Lillie, L. E. (1984b), Geographic Variation in the Copper and Molybdenum Contents of Forages Grown in Northwest Mantiboa (Canada), Can. J. Anim. Sci. , 1984b, 64, 919.
[4] Mee, J.F., Rogers, P.A.M., Prevalence Of Iodine, Selenium, Copper And Cobalt Deficiencies On Irish Cattle Farms, Irish Veterinary Journal, 1996, 49, 160.
[5] Depieri, L.A., Buckley, W.T., Kowalenko, C.G., Micronutrient Concentrations Of Commercially Grown Vegetables And Of Soils In The Lower Fraser Valley Of British-Columbia, Canadian Journal Of Soil Science, 1996, 76, 173-182.
[6] Kabata-Pendias, A.and Pendias, H., Trace elements in soils and plants, CRC Press, Second edition, 1992.
Mo in soil
Av 1 –2 mg Mo/kg
Jarrell, W.M., Page, A.L, and Elseewi, A.A., Molybdenum in the environment, Residue Rev., 1980, 7, 41 – 43.
Mo-deficient < 0.2 mg Mo/kg
Mo-excessive > 0.7 mg Mo/ kg
Lener, J., Bibr, B., Effects of molybdenum on the organism, J. Hyg. Epidemiol. Microbiol. Immunol., 1984, 4, 405 – 419.
Molybdenum in barley on fly ash treated soil
A clay loam topsoil that tends to form surface crusts was mixed with unweathered fly ash from a western Canada coal burning power plant in mixtures ranging from 0 to 100% fly ash (v/v). Fly ash increased plant Mo concentrations to alter Cu/Mo such that it could be a concern for ruminant diets.
Sale, L.Y., Naeth, M.A., Chanasyk, D.S., Plant And Environment Interactions - Growth-Response Of Barley On Unweathered Fly Ash-Amended Soil, Journal Of Environmental Quality, 1996, 25, 684-691
Fly ash/% |
Mo/mg kg-1 |
Cu/mg kg-1 |
||||
Silage |
Grain |
Straw |
Silage |
Grain |
Straw |
|
0 |
0.02 |
0.02 |
0.02 |
4.33 |
3.73 |
2.67 |
6.25 |
3.67 |
0.02 |
5.33 |
7.47 |
4.77 |
5.67 |
12.5 |
7.33 |
3.33 |
15.67 |
8.33 |
8.83 |
7.13 |
25 |
12.33 |
4.00 |
21.33 |
7.90 |
6.23 |
9.77 |
Clay loam topsoil mixed with unweathered fly ash from a western Canada coal burning power plant in mixtures ranging from 0 to 100% fly ash (v/v).
Sale, L.Y., Naeth, M.A., Chanasyk, D.S., Plant And Environment Interactions - Growth-Response Of Barley On Unweathered Fly Ash-Amended Soil, Journal Of Environmental Quality, 1996, 25, 684-691.
Trace elements including molybdenum in industrially contaminated soils in India
The concentrations were determined of heavy metals (As, Ba, Co, Cr, Cu, Ni, Mo, Pb, Sr, V and Zn) in soils around Manali industrial area in Chennai, Southern India having petrochemicals, refineries, and fertilizers generating hazardous wastes. There were elevated concentrations of chromium (149.8-418.0 mg/kg), copper (22.4-372.0 mg/kg), nickel (11.8-78.8 mg/kg), zinc (63.5-213.6 mg/kg) and molybdenum (2.3-15.3 mg/kg).
Krishna, A.K. and Govil, P. K., Assessment of heavy metal contamination in soils around Manali industrial area, Chennai, Southern India, Environmental Geology, 2008, 54, 1465-1472.
Industrial Wastes - spent catalysts
Spent catalysts hazardous waste
Bioleaching of nickel, vanadium and molybdenum from hazardous spent refinery hydroprocessing catalysts by means of iron/sulfur oxidizing bacteria
Spent catalysts represent a large amount of refinery solid waste. These wastes have been classified as hazardous by the US Environmental Protection Agency. Hydroprocessing catalysts contain valuable base metals, nickel, vanadium and molybdenum. The exhaust catalyst was rich in nickel (45 mg/g), vanadium (44 mg/g) and molybdenum (94 mg/g). Before bioleaching, the solid was washed with Tween 80 and ethyl alcohol for hydrocarbon removal. Iron(II) was essential for metal extraction and for bacteria adaptation. In the presence of iron 83% nickel and 90% vanadium were bioleached but only 50% extraction with iron absent. For molybdenum, the highest extraction was about 50% after 26 days bioleaching in the presence of iron and 25 % extraction without iron.
