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.
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
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
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 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
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.
| 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.
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).