Growth and metal accumulation in vetiver and two Sesbania species on lead/zinc mine tailings

Abstract

Abstract:The lead (Pb)/zinc (Zn) tailings contained high concentrations of heavy metals (total Pb, Zn, Cu and Cd concentrations 4164, 4377, 35 and 32 mg kg -1 , respectively), and low contents of major nutrient elements (N, P, and K) and organic matter. A field trial was conducted to compare growth performance, metal accumulation of Vetiver (Vetiveria zizanioides) and two legume species (Sesbania rostrata and Sesbania sesban) grown on the tailings amended with domestic refuse and/or fertilizer. It was revealed that domestic refuse alone and the combination of domestic refuse and artificial fertilizer significantly improved the survival rates and growth of V. zizanioides and two Sesbania species, especially the combination. However, artificial fertilizer alone did not improve both the survival rate and growth performance of the plants grown on tailings. Roots of these species accumulated similar levels of heavy metals, but the shoots of two Sesbania species accumulated higher (3-4 folds) concentrations of Pb, Zn, Cu and Cd than shoots of V. zizanioides. Most of the heavy metals in V. zizanioides were accumulated in roots, and the translocation of metals from roots to shoots was restricted. Intercropping of V. zizanioides and S. rostrata did not show any beneficial effect on individual plant species, in terms of height, biomass, survival rate, and metal accumulation, possibly due to the rather short experimental period of 5 months. Key words: growth performance, intercropping, Pb/Zn mine, Sesbania rostrata, Sesbania sesban, tailings amendment, Vetiveria zizanioides Email contact: Wensheng Shu <ls53@zsu.edu.cn> TRODUCTIONExploitation of mineral resource has resulted in the destruction of vast amounts of land. This has caused very serious environmental problems, which have received much attention from most countries in the world, including China. Revegetation of metalliferous mine tailings is necessary for long-term stability of the land surface. A good vegetation cover is beneficial in the restoration of contaminated land and results in enhanced amenity values as well as prevention of surface soil erosion (Baker et al., 1994). However, adverse factors such as acidity, nutrient deficiencies, toxic heavy metal ions, and poor physical structure, and their interactions of most mine tailings inhibit plant establishment and growth on the tailings (Pichtel and Salt, 1998). The toxicity of heavy metals and deficiency of major nutrients are often the limiting factors for plant establishment on mine tailings, therefore, the success of reclamation schemes should overcome the two major problems (Bradshaw, 1987).In general, amendments such as applications of organic materials (such as sewage sludge, domestic refuse) or inorganic fertilizer are necessary for establishment of plants on mine tailings. For long-terms remediation, metal tolerant species are commonly used for revegetation of mine tailings

Metal Accumulation in 5 Native Plants Growing on Abandoned Cu-Tailings Ponds

“…HNO 3 and conc. HClO 4, v/v) of accurately 0.5 g of plant tissue [28] followed by measurement of metal concentration using Atomic Absorption Spectrometry (AAS).…”

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