Cobalt in soil

Sanders J.R. The effect of pH on the total and free ionic concentrations of manganese, zinc and cobalt in soil solutions. J Soil Sci 1983 34 315-323. 

A method based on measurement of the ammonium pyrollidine dithiocarba-mate complex at 240.7 nm has been described for the determination of 0.5 m acetic acid [96] and nitric-perchloric acid-soluble cobalt in soils [95]. 

Under normal environmental conditions, cobalt is expected to bind strongly to soil and thus migration through soil would be very limited. Cobalt in soil can be taken up by plant roots and root vegetables but is not translocated to the aboveground parts of plants. 

Methods for the determination of cobalt in soils using thiazolylblue tetrazolium bromide [6] and nitrotetrazolium blue chloride [7] were described. The examined samples were subjected to preliminary separation of the analyte with dithizone. The interference from Fe(IIl) could be masked with ascorbic acid [7]. 

Cobalt in soil and a vitamin B12 injection was determined using the chromogenic reagent 4,4 -diazobenzenediazoaminoazobenzene in a micellar surfactant medium [10]. 

Taylor R, Xiu H, Mehadi A, Shuford J, Tadesse W (1995) Fractionation of residual cadmium, copper, nickel lead and zinc in previously sludge-amended soil. Comm Soil Sci Plant Ana 26 2193-2204 Taylor RM (1968) The association of manganese and cobalt in soils- further observations. J Soil Sci 19 77-80... 

E. Jean Mackenzie, Extractable Copper and Cobalt in Soils, Technical... 

Agriculture ndNutrition. Cobalt salts, soluble in water or stomach acid, are added to soils and animal feeds to correct cobalt deficiencies. In soil apphcation the cobalt is readily assimilated into the plants and subsequendy made available to the animals (56). Plants do not seem to be affected by the cobalt uptake from the soil. Cobalt salts are also added to salt blocks or pellets (see Feeds and feed additives). 

Cobalt is strongly adsorbed by Mn oxides. There are close relationships between Co and the easily reducible fraction of Mn (Mn oxides) in soils (Jarvis, 1984) and will be in detail discussed in next chapter. Cobalt is frequently accumulated in Mn nodules in soils (Mckenzie, 1975). It was suggested that the Co2+ ion was first sorbed, then slowly oxidized to Co3+ and became incorporated into the surface layers of the crystal lattice, releasing the Mn2+ ion into the solution (Bums, 1976 Mckenzie, 1975). X-ray photoelectron spectroscopy showed that Co3+ was present on the surface of bimessite after the sorption of the Co2+ ions took place (Murray and Dillard, 1979). Traina and Donor (1985) suggested that the Mn release during Co2+ sorption resulted not only from the oxidation of Co2+ to Co3+, but also... 

Co2+ to Co3+, but also from a direct exchange of Co2+ for Mn2+ produced during the redox reaction. The cobalt in arid soils, as indicated by Han et al. (2002b), mainly occurs in the residual and the Mn oxide (easily reducible oxide) fractions. Furthermore, after water saturation, the Co is transferred mainly from the Mn oxide fraction into the carbonate and exchangeable fraction. This will be discussed in detail in the next chapter. 

McKenzie R.M. The mineralogy and chemistry of soil cobalt. In Trace Element in Soil-Plant-Animal Systems, Nicholas, D.J.D., Egan, A.R., eds. New York Academic Press Inc., 1975. 

McLaren R.G., Lawson D.M., Swift R.S. The forms of cobalt in some Scottish soils as determined by extraction and isotopic exchange. J Soil Sci 1986a 37 223-243. 

We can see that the soluble and exchange forms of these metals are present in small amounts accounting merely for a few percent of the total metal content in soil. The content of organometal species is relatively high in the upper profile rich in humic species, whereas it drops sharply in the mineral horizons. Copper is extensively involved in the biogeochemical cycle in the Forest ecosystems and this is less profound for cobalt. It is noteworthy that a large part of metals (in particular, of copper) become bound to iron hydroxides. This is typical for various trace elements, including arsenic, zinc and other elements with variable valence. 

The most common simple cations in the soil solution are calcium (Ca2+), magnesium (Mg2+), potassium (K+), and sodium (Na+). Other alkali and alkaline-earth elements, when present, will be as simple cations also. Iron, aluminum, copper, zinc, cobalt, manganese, and nickel are also common in soil. Iron is present in both the ferrous (Fe2+) and ferric (Fe3+) states, while aluminum will be present as Al3+. Copper, zinc, cobalt, and nickel can all be present in one or both of their oxidations states simultaneously. Manganese presents a completely different situation in that it can exist in several oxidation states simultaneously. 

Examples of cations that are present in significantly lower concentrations than the simple cations are iron, manganese, zinc, copper, nickel, and cobalt. Except for cobalt, these have multiple oxidations states in soil as shown in Table 6.1. Because of their multiple oxidation states, they may be present as many more species than the simple cations. Typically, the higher oxidation states predominate under oxidizing conditions, while the lower oxidation states predominate under reducing conditions. However, it is common to find both or all oxidation states existing at the same time in either aerobic or anaerobic soil [7,8],... 

Sims JL. Molybdenum and cobalt. In Bartels JM (ed.), Methods of Soil Analysis Part 3 Chemical Methods. Madison, WI Soil Science Society of America and American Society of Agronomy 1996, pp. 723-737. 

Cobalt and nickel are Group VlllA and copper Group IB elements. They occur predominantly in the +2 oxidation state in soils as divalent cations, though Co + may be oxidized to Co forming very insoluble compounds with Mn oxides, and... 

Cohall is present in vitamin Bi to Ihe extent of about 4ci-. Lack of cobalt in tlie soil and feedstuffs prevents tuniinants from synthesizing all of the vilamin B j for their needs. Thus, cobalt can be added to feedstuffs as the chloride, sulfate, oxide, nr carbonate. Excessive cobalt intakes are toxic, causing a reduction in feed intake and body weight, accompanied by emaciation, anemia, debility, and elevated levels of cobull in the liver. It is of interest to note that clinical coball tnxiciiy closely resembles clinical cobalt deficiency. 

Adding cobalt to soils, either as cobalt sulfate, or as cobaltized superphosphate, can be used to increase the level of cobalt is plants and prevent cobalt deficiency in cattle and sheep. Cobalt fertilization may not be effective in prcvenling cobalt deficiency on alkaline soils because in these soils, the added cobalt quickly reverses to forms lhal arc not taken up by plants. Coball fertilization is more common in Australia than in the United Slates. In Ihe United Slates, eoball is usually added lo mixed feeds, mineral mixes, or salt licks... 

Wallace A, Alexander GV, Chaudhry FM. 1977. Phytotoxicity of cobalt, vanadium, titanium, silver, and chromium. Communication in Soil Science and Plant Analysis 8 751-756. 

Standing Committee of Analysts (DoE) (1979) The Analysis of Agricultural Materials -Cobalt, Nitric-Perchloric Acid Soluble in Soil Method 23, MAFF Technical Bulletin RB 427, HMSO, London, UK. 

Sillanpaa, M., andjansson, H. (1992). Status of cadmium, lead, cobalt and selenium in soils and plants of thirty countries. FAO Soils Bull. 65, Food and Agricultural Organization of the United Nations, Rome, Italy. 

A lack of cobalt in the soil can cause health problems, too. For example, sheep in Australia are subject to a disease known as Coast disease, due to a deficiency of cobalt in the soil. 

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