Vegetation Composition and Heavy Metal Uptake by Wild Plants at Three Contaminated Sites in Xiangxi Area, China

The plant species composition and their ability to accumulate heavy metals were investigated at three contaminated sites in Xiangxi area, Southern China. The concentrations of Cd, Pb, Zn, and Cu in more than 363 samples of 125 plant species were analyzed in the present study. The average concentrations of Cd, Pb, Zn, and Cu in the plants were 19, 81, 637, and 8 mg kg⁻¹, respectively. The highest concentration of Cd in above-ground plant tissues was found to be 287 mg kg⁻¹ in the leaves of Lobelia chinensis Lour, at the Datianwan site, followed by Solamim nigrum L. with 99 mg kg⁻¹ Cd in the leaves. They might be potential Cd hyperaccumulators. At the three contaminated sites, some dominant and relative dominant species with high accumulation potential of metals, such as Kalimeris indice (L.) Sch.-Bip. and Solanum nigrum L., might be suitable for use in the phytoextraction of contaminated soils. The dominant and relative dominant species with low accumulation of metals and dense fibrous root systems, such as Imperata cylindrical (L.) Beauv. var. major C. E. and Miscanthus floridulus (Labill.) Warb., might be suitable for stabilizing such metal contaminated sites.

Keywords::

• Cadmium
• Heavy metals
• Hyperaccumulator
• Mine spoils
• Phytoremediation
• Plant uptake
• Wild vegetation.

ACKNOWLEDGMENTS

This research project was supported by the Teaching and Research Award Program for Outstanding Young Teachers in Higher Education Institutions of MOE and the Research Grants Council of the Hong Kong SAR Government (PolyU 5046/02E).

Notes

*GB 15618–1995.

^a a.m., Arithmetic mean.

^b < below the detection limit (Pb: 0.50 mg kg⁻¹, Cd: 0.1 mg kg⁻¹).