Higher plants as bioindicators of metal contamination from Shangdong abandoned karst bauxite, southwestern China.

Abstract

Bauxite mining on karst generates numerous ecological and environmental problems, including metal pollution, water and soil erosion and destruction of vegetation. Among these, the most important environmental problem is soil metal pollution. Higher plants have a great ability to adsorb metals and can be used as biological indicators. However, the study of bioindicators for soil contamination in karst bauxite is not clear. Plants and their soil were collected from an abandoned karst bauxite area at Shangdong, Guizhou Province, southwestern China. Plants were collected and identified as Pteris vittata, Pinus massoniana, Miscanthus floridulus, Coriaria nepalensis, Artemisia argyi and Senecio scandens. The content of metals in plant roots were in the order: P.vittata>M.floridulus>C.nepalensis, other plants roots had no consistent pattern. Concentrations of metal in plants (P.vittata and M.floridulus) and soil were: soil > root > leaf > stem. Levels of metals in soil samples easily exceeded background values, indicating that soil had been contaminated. Al and Fe were highest in soil samples of P.vittata, with a good correlation. Results show that the metal content determined in plants is relatively high, particularly in P.vittata. Data also suggest that P.vittata colonies were able to tolerate and accumulate high levels of metal elements, which evidences their suitability for use as bioindicatord of soil metal contamination caused by mining activities.