Lead, zinc and copper accumulation and tolerance in populations of Paspalum distichum and Cynodon dactylon

摘要

Both Fankou and Lechang lead/zinc (pb/Zn) mine tailings located at Guangdong Province contained high levels of total and DTPA-extractable Pb, Zn and Cu. Paspalum distichum and Cynodon dactylon were dominant species colonized naturally on the Tailings. Lead, zinc and copper accumulation and tolerance of different populations of the tow grasses growing on the tailings were Investigated. Tillers of these populations including those from an uncontaminated area were subjected to the following concentra- Tions: 5, 10, 20, 30 and 40 mg l~-1 Pb, 2.5, 5, 10, 20 and 30 mg l~-1 Zn, or 0.25, 0.50, 1 and 2 mg l~-1 Cu for 14 days, respectively, then Tolerance index (TI) and EC_50 (the concentrations of metals in solutions which reduce 50/100 of normal root growth) were calculated.