O'Sullivan, A.D.Conlon, R.Moran, B.Otte, M.2007-07-252007-07-252005O'Sullivan, A.D., Conlon, R., Moran, B., Otte, M. (2005) Characterisation of Constructed Wetland Substrates by Chemical Sequential Extraction and X-Ray Diffraction Analyses. Biology and Environment: Proceedings of the Royal Irish Academy, 105B(2), pp. 87-94.0791-7945http://hdl.handle.net/10092/278Substrates from four and a half year old constructed wetlands built to treat wastewater from an active metal mine were analysed for elevated metal and sulphur concentrations by chemical sequential extractions and x-ray diffraction analyses. Amounts of Fe, Pb, Zn and S were quantified in substrates from the first cells of multi-celled (in-series) treatment wetland systems at three different depths. The analyses showed that the majority of metals removed from the wastewater were retained in residual immobile forms in the upper 0-5 cm of the waterlogged anaerobic substrates. Although substantial concentrations of metals and sulphur were retained in the substrates, the amounts were generally not sufficient to allow accurate mineralogical identification by x-ray diffraction. Classification of the sediments using x-ray techniques was further confounded by the highly organic nature of the wetland substrates. These results suggest that chemical analyses of wetland substrates may still provide a clearer interpretation of metal accumulation over time, especially in wastewaters characterised by relatively low metal concentrations flowing through organically rich substrates. While x-ray diffraction can provide useful interpretation of sediment crystallography and mineralogy, there are limitations in using this technology to characterise young wetland substrates.enecological engineeringwetlandsmetalssulphursequential extractionx-ray diffractionJournal ArticleFields of Research::300000 Agricultural, Veterinary and Environmental Sciences::300800 Environmental Science::300803 Natural resources managementFields of Research::290000 Engineering and Technology::290800 Civil Engineering::290802 Water and sanitary engineeringFields of Research::250000 Chemical Sciences::259900 Other Chemical Sciences::259902 Environmental chemistry (incl. atmospheric chemistry)Fields of Research::250000 Chemical Sciences::250300 Organic Chemistry::250302 Biological and medical chemistry