Iron precipitate accumulations associated with waterways in drained coastal acid sulfate landscapes of eastern Australia
L. A. Sullivan A B and R. T. Bush AA Centre for Acid Sulfate Soil Research, Southern Cross University, Lismore, NSW 2480, Australia.
B Corresponding author. Email: lsulliva@scu.edu.au
Marine and Freshwater Research 55(7) 727-736 https://doi.org/10.1071/MF04072
Submitted: 22 April 2004 Accepted: 16 August 2004 Published: 1 October 2004
Abstract
Iron precipitate accumulations from surface environments surrounding waterways (such as the side of drains and soil surface horizons) in acid sulfate soil landscapes were analysed for their mineralogy, micromorphology and chemical properties. Schwertmannite (Fe8(OH)5.5(SO4)1.25) was the dominant mineral in these accumulations. Goethite (α-FeOOH) was the other iron precipitate mineral identified in these accumulations and the data indicate that this iron mineral was formed from schwertmannite, often as pseudomorphs after schwertmannite. The schwertmannite in these accumulations had similar morphology and chemical properties to schwertmannite reported for environments affected by acid mine drainage. The activity of Fe3+ in the drainage waters in these landscapes appears to be controlled by schwertmannite during both low flow (dry season) and flood conditions. Iron precipitate accumulations contained appreciable amounts of stored acidity (i.e. titratable actual acidity of between 164 and 443 mol (H+) t–1, and 1900 to 2580 mol (H+) t–1 of schwertmannite upon complete conversion to goethite) that tends to buffer these waters to very acidic conditions (i.e. pHs ~3.0–3.5). The relationship between water quality (i.e. pH and sulfate concentration) and type of iron precipitate mineral formed should enable the mineralogy of the iron precipitates in these surface environments to be used to help identify the degree of severity of degradation in these acid sulfate soil landscapes and to monitor the effectiveness of remediation programmes.
Extra keywords: geochemistry, goethite, micromorphology, mineralogy, schwertmannite, water quality.
Acknowledgments
We would like to acknowledge the assistance of David Andrighetto in helping to collect and prepare some of the iron precipitate samples used in this study for analysis.
Ahern, C. R., McElnea, A. E., and Sullivan, L. A. (2004).
APHA (1998).
Bigham, J. M. , Schwertmann, U. , Carlson, L. , and Murad, E. (1990). A poorly crystallized oxyhydroxysulfate of iron formed by bacterial oxidation of Fe(II) in acid mine waters. Geochimica et Cosmochimica Acta 54, 2743–2758.
| Crossref | GoogleScholarGoogle Scholar |
Bigham, J. M. , Carlson, L. , and Murad, E. (1994). Schwertmannite a new iron oxyhydroxysulfate from Pyhasalmi, Finland, and other localities. Mineral Magazine 58, 641–648.
Ferguson, A. , and Eyre, B. (1999). Behaviour of aluminium and iron in acid runoff from acid sulphate soils in the lower Richmond River catchment. AGSO Journal of Australian Geology & Geophysics 17, 193–201.
Lin, C. , and Melville, M. D. (1993). Control of soil acidification by fluvial sedimentation in an estuarine floodplain, Eastern Australia. Sedimentary Geology 85, 271–284.
| Crossref | GoogleScholarGoogle Scholar |
![](../../media/share/OpenURL_Image.gif)
McElnea, A. E. and Ahern, C. R. (2004). Actual acidity method. In
Murad, E. (2002). Iron rich precipitates in mine drain environments: mineralogical characteristics and case studies. In ‘Proceedings of the 17th World Congress of Soil Science, Thailand. 14–21 August 2002’. p. 2078. (The Soil and Fertilizer Society of Thailand, Bangkok, Thailand.)
Murad, E. , and Rojik, P. (2003). Iron-rich precipitates in a mine drainage environment: Influence of pH on mineralogy. American Mineralogist 88, 1915–1918.
![](../../media/share/OpenURL_Image.gif)
Parkhurst, D. L. and Appelo, C. A. (1999). ‘User’s Guide to PhreeqC: a Computer Program for Speciation, Reaction Path, 1d-Transport and Inverse Geochemical Calculations.’ Water-resources Investigations Report 99–4259. (U.S. Geological Survey: Denver, CO, USA.)
Piene, A. , Tritschler, A. , Kusel, K. , and Peiffer, S. (2000). Electron flow in an iron-rich acidic sediment-evidence for an acidity-driven iron cycle. Limnology and Oceanography 45, 1077–1087.
![](../../media/share/OpenURL_Image.gif)
Regenspurg, S. , Brand, A. , and Peiffer, S. (2004). Formation and stability of schwertmannite in acidic mining lakes. Geochimica et Cosmochimica Acta 68, 1185–1197.
| Crossref | GoogleScholarGoogle Scholar |
![](../../media/share/OpenURL_Image.gif)
Sammut, J. , White, I. , and Melville, M. D. (1996). Acidification of an estuarine tributary in Eastern Australia due to drainage of acid sulfate soils. Marine and Freshwater Research 47, 669–684.
![](../../media/share/OpenURL_Image.gif)
Scheinost, A. C. , and Schwertmann, U. (1999). Color identification of iron oxides and hydroxysulfate: use and limitations. Soil Science Society of America Journal 63, 1463–1471.
![](../../media/share/OpenURL_Image.gif)
Tulau, M. J. (1999).
Tulau, M. J. (1999).
Tulau, M. J., and Naylor, S. D. (1999).
USEPA (1986).
van Breeman, N. (1972). Soil forming processes in acid sulphate soils. In ‘Proceedings of the International Symposium on Acid Sulphate Soils, Wageningen, The Netherlands. 13–20 August 1972’. (Ed. H. Dost.) ILRI Publication No. 18, pp. 66–128. (International Institute for Land Reclamation and Improvement: Wageningen, The Netherlands.)
van Breeman, N. (1976).
van Breeman, N. (1982). Genesis, morphology, and classification of acid sulfate soils in coastal plains. In
Willet, I. R., Melville, M. D. and White, I. (1993). Acid drainwaters from potential acid sulphate soils and their impacts on estuarine ecosystems. In
Williams, D. J. , Bigham, J. M. , Cravotta, C. A. , Trainaa, S. J. , Anderson, J. E. , and Lyon, J. G. (2002). Assessing mine drainage pH from the color and spectral reflectance of chemical precipitates. Applied Geochemistry 17, 1273–1286.
![](../../media/share/OpenURL_Image.gif)