Acid sulfate soil

Acid sulfate soils are naturally occurring soils, sediments or organic substrates (e.g. peat) that are formed under waterlogged conditions. These soils contain iron sulfide minerals (predominantly as the mineral pyrite) and/or their oxidation products. In an undisturbed state below the water table, acid sulfate soils are benign. However, if the soils are drained, excavated or otherwise exposed to air, the sulfides react with oxygen to form sulfuric acid.[1]

Release of this sulfuric acid from the soil can in turn release iron, aluminium, and other heavy metals and metalloids (particularly arsenic) within the soil. Once mobilized in this way, the acid and metals can create a variety of adverse impacts: killing vegetation, seeping into and acidifying groundwater[2][3] and surface water bodies,[4][5] killing fish and other aquatic organisms, and degrading concrete and steel structures to the point of failure.[1]

  1. ^ a b Identification & Investigation of Acid Sulfate Soils (2006), Department of Environment, Western Australia. Retrieved from portal Archived 2009-11-12 at the Wayback Machine
  2. ^ Mosley LM, Palmer D, Leyden E, Fitzpatrick R, and Shand P (2014). Changes in acidity and metal geochemistry in soils, groundwater, drain and river water in the Lower Murray River after a severe drought. Science of the Total Environment 485–486: 281–291.
  3. ^ Mosley, LM; Palmer, D; Leyden, E; Fitzpatrick, R; Shand, P (2014). "Acidification of floodplains due to river level decline during drought". Journal of Contaminant Hydrology. 161: 10–23. Bibcode:2014JCHyd.161...10M. doi:10.1016/j.jconhyd.2014.03.003. PMID 24732706.
  4. ^ Mosley, LM; Zammit, B; Jolley, A; Barnett, L (2014). "Acidification of lake water due to drought". Journal of Hydrology. 511: 484–493. Bibcode:2014JHyd..511..484M. doi:10.1016/j.jhydrol.2014.02.001.
  5. ^ Mosley, LM; Zammit, B; Jolley, A; Barnett, L; Fitzpatrick, R (2014). "Monitoring and assessment of surface water acidification following rewetting of oxidised acid sulfate soils". Environmental Monitoring and Assessment. 186 (1): 1–18. Bibcode:2014EMnAs.186....1M. doi:10.1007/s10661-013-3350-9. PMID 23900634. S2CID 46559400.