Iron precipitate accumulations associated with waterways in drained coastal acid sulfate landscapes of eastern Australia

L. A. Sullivan, R. T. Bush

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66 Citations (Scopus)

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 (Fe 8 (OH) 5.5 (SO 4 ) 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 Fe 3+ 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.

Original languageEnglish
Pages (from-to)727-736
Number of pages10
JournalMarine and Freshwater Research
Volume55
Issue number7
DOIs
Publication statusPublished - 2004
Externally publishedYes

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schwertmannite
waterways
sulfates
iron
sulfate
acids
acid
minerals
acid sulfate soils
goethite
acid sulfate soil
mineralogy
mineral
physicochemical properties
acidity
chemical property
acid mine drainage
drainage water
remediation
micromorphology

Cite this

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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 (Fe 8 (OH) 5.5 (SO 4 ) 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 Fe 3+ 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.",
keywords = "Geochemistry, Goethite, Micromorphology, Mineralogy, Schwertmannite, Water quality",
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TY - JOUR

T1 - Iron precipitate accumulations associated with waterways in drained coastal acid sulfate landscapes of eastern Australia

AU - Sullivan, L. A.

AU - Bush, R. T.

PY - 2004

Y1 - 2004

N2 - 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 (Fe 8 (OH) 5.5 (SO 4 ) 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 Fe 3+ 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.

AB - 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 (Fe 8 (OH) 5.5 (SO 4 ) 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 Fe 3+ 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.

KW - Geochemistry

KW - Goethite

KW - Micromorphology

KW - Mineralogy

KW - Schwertmannite

KW - Water quality

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U2 - 10.1071/MF04072

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JO - Marine Freshwater Research

JF - Marine Freshwater Research

SN - 0067-1940

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