Removal of heavy metals from a metaliferous water solution by Typha latifolia plants and sewage sludge compost.
Typha latifolia plants, commonly known as cattails, were grown in a mixture of mature sewage sludge compost, commercial compost and perlite (2:1:1 by volume). Four Groups (A, B, C and D) were irrigated (once every two weeks) with a solution containing different concentrations of Cu, Ni, and Zn, where in the fifth (group M) tap water was used. At the end of the 10 weeks experimental period substrate and plants were dried, weighed and analysed for heavy metals. The amounts of all three metals removed from the irrigation solution, were substantial. In the roots and leaves/stems of T. latifolia the mean concentration of Zn reached values of 391.7 and 60.8 mg/kg of dry weight (d.w.), respectively. In the substrate of Group D all three metals recorded their highest mean concentrations of 1156.7 mg/kg d.w. for Cu, 296.7 mg/kg d.w. for Ni and 1231.7 mg/kg d.w. for Zn. Linear correlation analyses suggested that there was a linear relationship between the concentration of metals in the solutions and the concentration of metals in the substrates at the end of the experiment. The percentage removal of the metals in the substrate was large, reaching 100% for Cu and Zn in some groups and almost 96% for Ni in group D. The total amount of metals removed by the plants was considerably smaller than that of the substrate, due mainly to the small biomass development. A single factor ANOVA test (5% level) indicated that the build up in the concentration of metals in the roots and the leaves/stems was due to the use of metaliferous water solution and not from the metals pre-existing in the substrate. The contribution of the plants (both roots and leaves/stems) in the removing ability of the system was less than 1%.
Manios
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Technological and Educational Institute of Crete, Technical University of Crete, 71500 Crete, Heraklion, Greece. manios@steg.teiher.gr
Stentiford
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EI
Millner
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P
D000704:Analysis of Variance; D001673:Biodegradation, Environmental; D019216:Metals, Heavy / Q000737:chemistry*; D012722:Sewage / Q000032:analysis* / Q000737:chemistry; D032401:Typhaceae / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
D019216:Metals, Heavy; D012722:Sewage