jesc.ac.cn Journal of Environmental Sciences 20(2008) 1469–1474 Accumulation of Pb, Cu, and Zn in native plants growing on contaminated sites and their potential accumulation capacity in Heqing, Yunnan LIU Xiaohai 1, ∗ , GAO Yuntao 2 , Sardar Khan 3,4 , DUAN Gang 1 , CHEN Aikui 5 , LING Li 6 , ZHAO Lei 1 , LIU Zhonghan 1 , WU Xuecan 1 1. Yunnan Institute of Environmental Science, Kunming 650034, China. E-mail: lxh@yies.org.cn 2. School of Chemistry and Bio-Science, Yunnan Nationalities University, Kunming 650031, China 3. Department of Soil Environmental Sciences, Research Center for Eco-Environmental Sciences, CAS, Beijing 100085, China 4. Department of Environmental Sciences, University of Peshawar, 25120 Peshawar, Pakistan 5. Department of Biology, Guangdong Institute of Educations, Guangzhou 510303, China 6. College of Baoshan Teacher, Baoshan 678000, China Received 18 October 2007, revised 20 February 2007; accepted 30 May 2008 Abstract Phytoremediation is one of the cost-effective and environmental friendly technologies used to remove contaminants from contaminated soils, which has been intensively studied during the last decade. Presently, few economical and effective remediation methods are available for the remediation of Pb contaminated sites. This study was conducted to assess the potential of 19 plants growing on contaminated sites in Pb mine area. Plants and associated soil samples were collected and analyzed for total metal concentrations. While total soil Pb, Cu and Zn concentrations varied from 1,239 to 4,311, 36 to 1,020 and 240 to 2,380 mg/kg, those in the plant shoots ranged from 6.3 to 2,029, 20 to 570, and 36 to 690 mg/kg, respectively. Among the plants, we found that one cultivated crop (Ricinus communis L.) and two native species (Tephrosia candida and Debregeasia orientalis) have a great potential for phytoremediation of Pb contaminated soils, the Pb hyperaccumulation capacity of the 3 plants was found as the order: R. communis > D. orientalis > T. candida in the investigated area. Key words: accumulation of Pb, Cu and Zn; cultivated crops; accumulator; lead mine; remediation Introduction The remediation of heavy metal contaminated sites is still a big challenge for researchers because of the non-degradability of these metals in the environment. Phytoremediation, a biological technology using plants to remove contaminants from soils has been intensively studied during the past decade due to its cost-effectiveness and environmental harmonies (Reeves and Baker, 2000; Kr¨ amer, 2005). This natural process accelerates sorption, precipitation and complexation reactions that occur natu- rally in soils to reduce the mobility (Bolan and Duraisamy, 2003). Chinese brake fern and Cretan brake fern were found to be hyperaccumulators for Arsenic (Wei and Chen, 2006) in China, but published reports regarding Pb accumulation by plants in China are few (Wei and Chen, 2001). Pb contamination is one of the major environmental problems in the world, particularly, in developing coun- tries. Currently, no efficient and cost-effective method is available for the remediation of Pb contaminated soils (Ye et al., 2001). Based on Baker and Brooks (1989), hyper accumulators are defined as plants that accumulate >1,000 * Corresponding author. E-mail: lxh@yies.org.cn. mg/kg of Pb, Cu, Co, Cr or Ni, or >10,000 mg/kg of Mn or Zn. Hyperaccumulators of Co (26 species), Cu (24), Mn (8), Ni (145), Pb (5), and Zn (4) have been reported (Baker and Brooks, 1989). The five hyper accumulators of Pb include Armeria martima, Thlaspi rotundifolium, Thlaspi alpestre, Alyssum wulfenianum, and Polycarpaea synandra. However, Shen and Liu (1998) defined a plant as a hyper accumulator in which the Pb concentrations in the above ground part is 10–500 times more than that in plants from non-contaminated sites, and enrichment coefficient >1. In the past, only a few species with the ability to bioconcentrate Pb, Cu and Zn have been reported, in both tropical and temperate climatic zones (Ernst, 1996; Baker and Brooks, 1989). Similarly, Sieghardt (1987) has also reported the Pb concentrations in plant roots and shoots of five species grown on Pb/Zn contaminated mining deposits in Bleiberg, South Austria, but he found no hyper accumulators among the studied plants, as defined by Baker and Brooks (1989). Most of the works focus on the phytoremediation of the metallic pollutants in soil, particularly on the metal hyper accumulation, which is the area of major scientific and technological interest in past years (Cunningham et al., 1995; Cunningham and Ow, 1996). Although some Pb,