Two potential multi-metal hyperaccumulators found in four mining sites in Hunan Province, China

Multi-metal pollution in mines and their surrounding areas causes major environmental and health problems. An investigation on the soil quality in four mining sites revealed serious heavy metal (HM) contamination. The contents of As, Pb, Zn, Cd, Cu, and Sb showed high HM pollution. Compared with the national second soil environmental quality standard, the over-standard rates of As, Pb, Zn, Cd, Cu, and Sb were 97.8%, 80.0%, 82.2%, 68.9%, 88.9%, and 733%, respectively. Phytoextraction is an emerging remediation technology for HM-contaminated soil. However, hyperaccumulators that can simultaneously extract multi-metals have been rarely reported. A field survey was conducted in the four mining sites; results showed that Pteris vittata L. and Viola principis H. de Boiss were two potential multi-metal extractors. Two plant species could thrive on soils severely contaminated with multiple metals. P. vittata accumulated 4106 mg As kg(-1), 499.5 mg Pb kg(-1), and 321.5 mg Sb 1 in the aboveground parts; by comparison, V. principis accumulated 1032 mg As kg(-1), 2350 mg Pb kg(-1), and 1201 mg Cd kg(-1) in the aboveground parts. The bioaccumulation factor of P. vittata for As, Pb, Zn, and Sb was > 1. The bioaccumulation factor of V. principis for As, Pb, Zn, and Cd was also >1. Therefore, P. vittata is an As hyperaccumulator and a Pb and Sb accumulator. By contrast, V. principis is a Cd, Pb, and As hyperaccumulator. (C) 2016 Elsevier B.V. All rights reserved.