Acidity sulfate soils

Dudas, M.J. 1984. Enriched levels of arsenic in post-active acid sulfate soils in Alberta. Soil Sci. Soc. Amer. Jour. 48 1451-1452. 

The HS formed further dissociates to (pK = 13.9). However in most submerged soils the concentration of Fe + in the soil solution is sufficient that virtually all is precipitated as amorphous ferrous sulfide and very small concentrations of H2S and HS remain in solution. The relations between the S04 -HS and Fe(OH)3-Fe " systems at neutral pH are shown in Figure 4.12. Amorphous ferrous sulfide may gradually crystallize as mackinawite (FeS). Under some circumstances pyrite is then formed, e.g. FeS(s) + S(s) FeS2(s), leading to potential acid sulfate soils (Section 7.3). 

Except in some coastal soils, histosols, acid sulfate soils, and soils artificially amended with sulfate, the total amount of sulfate present is usually small in... 

Acid sulfate soils are an especially difficult class of acid soil formed in former marine sediments that have been drained. The acidity is generated from the oxidation of pyrite in the soil resulting in acute aluminium toxicity, iron toxicity, and deficiencies of most nutrients, especially phosphate which becomes immobilized in ferric oxide. The development and management of acid sulfate soils are discussed in detail in Dost and van Breemen (1983) and Dent (1986). 

Nitrophenol degraded rapidly from flooded alluvial and pokkali (organic matter-rich acid sulfate) soils that were inoculated with parathion-enrichment culture containing 5-day-old cultures of Flavobacterium sp. ATCC 27551 and Pseudomonas sp. ATCC 29353 (Sudhaker-Barik and Sethunathan, 1978a). 4-Nitrophenol disappeared completely with the formation of nitrite, particularly in the inoculated soils rather than in the uninoculated soils. 

Ray et al. [77] used an indirect method based on AAS for the determination of sulfide in flooded acid sulfate soils. Hydrogen sulfide, evolved during the anaerobic metabolism of sulfate, is readily converted into insoluble metal sulfides, chiefly iron sulfide, in flooded acid sulfate soils. A method for determining sulfide is based on the precipitation of the sulfide as zinc sulfide and subsequent determination by methylene blue formation or iodine titrimetry. 

Ray et al. [77] have also described a method for determining sulfide in soil extracts involving the precipitation of zinc sulfide by the action of zinc on the hydrogen sulfide-flooded acid sulfate soil, and then indirect determination of sulfide by determining the zinc in the precipitate and also the zinc remaining in solution, after the precipitation by AAS. Over 85% of the sulfide was recovered in this procedure. 

Gosavi, K., J. Samrnut, S. Gifford, and J. Jankowski. 2004. Macroalgal biomonitors of trace metal contamination in acid sulfate soil aquaculture ponds. Sci. Total Environ. 324 25-39. 

Time All of these factors assert themselves over time, often over hundreds or thousands of years—but can even be hours (e.g., erosion oxidation of pyrite to form sulfuric acid in acid sulfate soils). 

Bronswijk, J. J, B. and J. E. Groenenberg 1993. SMASS A simulation model for acid sulfate soils. I. Basic principles. In D. Dent and M. E. F. van Mensvoort, Eds. Selected Paper, Saigon Symposium on Acid Sulfate Soils, Ho Chi Minh City, Vietnam, March 2-6 1992. ILRI Publication 52. Institute for Land Reclamation and Improvement, Wageningen, The Netherlands. 

Bronswijk, J. J. B., K. Nugroho, I. B. Aribawa, J. E. Groenenberg, and C. J. Ritsema. 1993. Modeling of oxygen transport and pyrite oxidation in acid sulfate soils. J. Environ. Qual. 22 544-554. 

Ritsema, C. J. and J, E. Groennenberg. 1993. Pyrite oxidation, carbonate weathering, and gypsum formation in a drained potential acid sulfate soil. Soil Sci. Am. J. 57 968-976. 

Satawathananont, S., W. H. Patrick, Jr., and P. A. Moore, Jr, 1991. Effect of controlled redox conditions on metal solubility in acid sulfate soils. Plant Soil 133 281-290. 

Fe3(OH)8), offering evidence that most iron (II) in reduced soils other than acid sulfate soils is present in this form. 

Sammut J., White I., and Melville M. D. (1996) Acidification of an estuarine tributary in eastern Australia due to drainage of acid sulfate soils. Mar. Freshwater Res. 47(5), 669-684. 

Bloomfield, C., 1972. The oxidation of iron sulphides in soils in relation to the formation of acid sulfate soils, and of ochre deposits in field drains. J. Soil Sci., 23 1—16. 

One exception is acid sulfate soils formed on coastal sediments due to the influence of sulfate in seawater (see Chapter 7). 

Stumm, W. Morgan, J.J. (1996) Aquatic Chemistry. 3rd Edn. Wiley-Interscience, New York, NY. Sullivan, L.A., Bush, R.T. McConchie, D.M. (2000) A modified chromium-reducible sulfur method for reducing inorganic sulfur optimum reaction time for acid sulfate soil. Aust. J. Soil Res., 38,... 

Harmsen, K., and Van Breemen, N. (1975a). Translocation of iron in acid sulfate soils II. Production and diffusion of dissolved ferrous iron. Soil Sci. Soc. Am. Proc. 39, 1148-1153. 

A second noteworthy flooded soil is acid sulfate soil. Sediments along tropical and subtropical coastlines and river deltas may contain significant quantities of Fe(II) sulfides. When dr ained, these sulfides oxidize to H2SO4 and the acidic Fe3+ ion. The soil acidity can increase to pH 2. Such conditions are highly phytotoxic and can be remedied under aerobic conditions only by extensive leaching and lime applications. If resubmerged, acid sulfate soils revert rapidly to near neutrality as the Fe(III) and sulfate are reduced back to Fe(II) sulfides. 

Figure 29 continued (c-e). Speciation of arsenic and selenium in an acid sulfate soil from the Western San Joaquin Valley (Panoche Hills, California, USA, Gewter series), c) pXRD applied to mixed Fe aggregates identifies jamsite, goethite, and feroxyhite (S-FeOOH). d-e) pSXRF elemental maps and scatterplots. As and Se are essentially associated with Fe in the oxide aggregates. and S are used as indicators for jarosite. Adapted from Strawn et al. (2002). 

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