Aluminium in soil

Norrish, K. Taylor, R.M. (1961) The isomor-phous replacement of iron by aluminium in soil goethites. J. Soil Sci. 12 294-306... 

An early spectrophotometric method [ 1 ] for aluminium in soil involves the use of a Technicon sample changer, proportioning pump and automatic colorimeter. The method is based on the measurement of the rate of colour development in the reaction between aluminium and xylenol orange in ethanolic media. The calibration graph is rectilinear up to 2.7 mg/1 aluminium and the coefficient of variation is 4.5%. 

Flow injection analysis has been used to determine aluminium in soil. Reis et al. [2] studied the spectrophotometric determination of aluminium in soil using merging zones and sequential addition of pulsed reagents. 

In addition to the above method, based on the use of pyrocatechol violet, Tecator also describes a flow injection analysis for determining 0.5-0.5mg/l aluminium in soil extracts based on the measurement of the chromazurol-aluminium complex at 570 nm [4,5]. 

Mitrovic et al. [7] and Kozuh et al. [8] have carried out aluminium spe-ciation studies on soil extracts. Various workers [9-11] have discussed the determination of aluminium in soils. Using isotachoelectrophoresis, Schmidt and coworkers [12] were able to differentiate aluminium(III) and aluminium species in soil leachates. 

Tecator Ltd. (1985) Determination of Aluminium in Soil by Flow Injection Analysis, Application Note ASN 78-31/85, Tecator Ltd., Bristol, UK. 

Figure 3 Long-term declines in sulfate concentrations mitigate the mobilization of aluminium in soil solutions and stream water in the Hubbard Brook Experimental Forest, New Hampshire, USAf a-c, annual volume-weighted concentrations of a, inorganic monomeric aluminium (Ah) b, organic monomeric aluminium (Af) and c, sulfate (SO/ ) in mineral soil solutions at 750 m (%) and 730 m (O), and in stream water (triangles)...

Worked example 5.5 — effect of pH on concentration of aluminium in soil solution... 

Ritchie, G. S. P. (1995). Soluble aluminium in soils principles and practicalities. Plant and Soil, 171, 17-27. 

Aluminium in soils is closely connected to soil acidity and is also discussed in the chapters on acid soils and ion-water reactions. The acidity of acid soils is due to the reactions of water with exchangeable Al3+ on the surface of soil particles. The strong Al-water reaction repels H+ from the water molecules iuto the soil solution. This can create soil acidities as low as pH 4.5. Stronger acidity means other H+-yielding reactions—organic acids from soil organic matter decay, sulfur and sulfide oxidation, phosphate fertilizers, ammonia oxidation, acid rain, and Fe- and Mn-water reactions—are active. 

Kloppee H, Fliednee A, and Kordel W (1997) Behaviour and ecotoxicology of aluminium in soil and water - review of the scientific literature. Che-mosphere 35 353-363. 

The corrosion behaviour of aluminium in soil is not only a complex issue, but also an important one because of many relevant applications cables for electricity and telecommunications, water and gas distribution grids, embeddings of street signs, street lamps and various supporting structures, etc. 

In spite of corrosion tests in many different soils over almost a century, based on a great number of samples of different metals, it has not been possible to come up with a relationship between the typology of soils and the corrosion resistance of metals [5]. Consequently, the corrosion resistance of aluminium in soils is also very difficult to predict, because of the great diversity in the composition of soils [6, 7]. 

Dismuke, T. Coburn, S. K. Hirsch, C. M. Handbook of Corrosion Protection for Steel Pile Structures in Marine Environments, sl Ed., Washington, D.C., American Iron and Steel Institute, 1981. Kloppel, H. Fliedner, A. Kordel, W. Behaviour And ecotoxicol-ogy of Aluminium in Soil and Water, Chemosphere, 1997, 351, 353-363. 

Technical Committee Reports of the National Association of Corrosion Engineers, USA, on pipeline corrosion control, including Statement on Minimum Requirements for Protection of Buried Pipelines , Some Observations on Cathodic Protection Criteria , Criteria for Adequate Cathodic Protection of Coated Buried Submerged Steel Pipelines and Similar Steel , Methods of Measuring Leakage Conductance of Coatings on Buried or Submerged Pipelines , Recommended Practice for Cathodic Protection of Aluminium Pipe Buried in Soil or Immersed in Water ... 

Aluminium, boron, silicon Lead in soil slurries Toxic organic compounds... 

J. Gerke, W. Romer, and A. Jungk, The excretion of citric and malic acid by proteoid roots of Liipinus aihus L. effects on soil solution concentrations of phosphate, iron, and aluminium in the proteoid rhizosphere samples of an Oxisol and a Luvi.sol. Z. Pktnzenernaehr. Bodenk. I57 2S9 (1994). 

Humic acids and fulvic acids interact with a wide variety of cations. In addition to interacting with iron and aluminium, the species with which they are complexed in soils (57), they also form stable complexes with zirconium, thorium, the lanthanides and the uranyl ion. In the case of uranium it has been suggested that humic acids could be of considerable importance in the geological formation of secondary deposits of uranium (58). 

The omnipresence of aluminium in weathering environments results in most of the Fe oxides in soils, except lepidocrocite, being Al-substituted. The possible range of substitution as deduced from synthesis experiments (see Chap. 3) viz. up to Al/ (Fe Al) of ca. 0.33 in goethite and up to Al/(Fe Al) of ca. 0.16 in hematite is also found in soil goethites and hematites. Where the two oxides coexist on a small scale... 

Fluoride is a natural component of most types of soil, in which it is mainly bound in complexes and not readily leached. The major source of free fluoride ion in soil is the weathering and dissolution of fluoride rich rock that depends on the natural solubility of the fluoride compound in question, pH, and the presence of other minerals and compounds and of water. The major parameters that control fluoride fixation in soil through adsorption, anion exchange, precipitation, formation of mixed solids and complexes are aluminium, calcium, iron, pH, organic matter and clay [19,20]. 

The pH of the soil is an important parameter since it can affect the plant s ability to take up nutrients and the microbial activity in the soil that influences the processes required for plant nutrition. Changes in soil pH occur by the displacement of cations or by additions of sources of acidity such as hydrogen and aluminium ions (Tisdale ef al. 1993). 

And now another important question is Should these Venus sculptures be classed as ceramic materials Initial analyses proved that they were made of silicon-containing ash and mammoth bone and possibly also mammoth fat, but no aluminium oxide or potassium oxide - which are always present in clay - were found. A later analysis of the Venus of Vestonice led to the concusion that a mixture of mammoth fat and bone, mixed with bone ash and local loess had been used but still no traces of potassium nor of aluminium. In the eighties the Venus was examined using more sophisticated equipment and the result was no bone or other organic components and no stone fragments. In the period 1955-1965 some researchers concluded that the animal statues of Dolni Vestonice were made of clay, and they called this terra cotta which means burned soil . Present studies indicate that the loess of Dolni Vestonice was used as raw material for the animal figurines. 

Tecator [3] has described a flow injection method for the determination of 0.5 -100 mg/1 aluminium in 0.1M potassium chloride extracts of soils in which the acidified soil extract is injected into a carrier stream which has the same composition as the sample matrix, (i.e., 0.1 M KC1) and merged with a masking... 

Prokisch et al. [85] described a simple method for determining chromium speciation in soils. Separation of different chromium species was accomplished by the use of acidic activated aluminium oxide. Polarographic methods have been applied in speciation studies on chromium(VI) in soil extracts [86]. Mi-lacic et al. [88] have reviewed methods for the determination of chromium(VI) in soils. 

The determination of total iron in soils has been discussed by Jayman et al. [103]. This method is based on the formation of the 1,10-phenanthroline complex of iron. Unfortunately, aluminium also forms a similar complex which exhibits identical absorption characteristics. However, iron can be determined without interference following the removal of aluminium and phosphates. In this method, finely ground soil is ignited overnight at 450 °C and the residue... 

Thompson and Zao [170] have described a solvent extraction-inductively coupled plasma atomic emission spectrometric method for the determination of down to 0.02 - 0.03 xg/g of molybdenum in soils. The soil sample is pressure-leached with 6 M hydrochloric acid and at 120 °C for 15 minutes. The digest is then extracted with heptan-2-one to separate molybdenum from potentially interfering elements such as iron, aluminium, calcium and magnesium. This organic extract is then directly sprayed into an inductively coupled plasma atomic emission spectrometer operated at 1.65 to 1.7 kW power. 

Garcia Gutierrez [19] has described an azo coupling spectrophotometric method for the determination of nitrite and nitrate in soils. Nitrite is determined spectrophotometrically at 550 nm after treatment with sulfuric acid and N-1 -naphlhylclhylcnediamine to form an azo dye. In another portion of the sample, nitrate is reduced to nitrite by passing a pH 9.6 buffered solution through a cadmium reductor and proceeding as above. Soils were boiled with water and calcium carbonate, treated with freshly precipitated aluminium hydroxide and active carbon, and filtered prior to analysis by the above procedure. 

Thus, if a soil contained lOOOmg/kg of a metal then the concentration would be 8 mg/kg, with a range of 1.3 to 50.2 mg/kg in crops corresponding median values of the levels of metal in soil were 10 000 mg/kg and 100 000 mg/kg, respectively, at the 80 and 800 mg/kg levels. These levels would definitely be of environmental concern (see the maximum levels of manganese (2750 mg/kg), iron (77500mg/kg), arsenic (1375mg/kg), titanium (8600mg/kg) and aluminium (85 000 mg/kg) found in crops, as reported in Table 11.1. 

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