Zinc, Lead and Cadmium Tolerance, Uptake and Accumulation by the Common Reed,Phragmites australis(Cav.) Trin. ex Steudel

Abstract

Zinc (Zn), lead (Pb) and cadmium (Cd) tolerance in populations of seedlings of Phragmites australis raised from seeds collected from a mine site (Plombières, Belgium) contaminated with Zn, Pb and Cd and three ‘clean’ sites (Felixstowe, UK; Wisbech, UK; and Mai Po, Hong Kong) were studied under glasshouse conditions. Small differences were found between the metal-contaminated population and the three ‘clean’ populations when seedlings were grown in 1.0 μg ml −1 Zn and 10.0 μg ml −1 Pb treatment solutions. In general, however, different populations of seedlings showed similar growth responses, metal uptake and indices of Zn, Pb and Cd tolerance when cultured in the same metal-contaminated media for 89 d or in the same metal treatment solutions (ZnSO 4 :1.0 and 4.0 μg ml −1 Zn; Pb(NO 3 ) 2 : 10.0 and 25.0 μg ml −1 Pb; CdSO 4 : 0.5 and 1.0 μg ml −1 Cd) for 3 weeks. There was insufficient evidence to support the hypothesis that the metal-contaminated population has evolved to a Zn-, Pb- or Cd-tolerant ecotype but the results indicated some differentiation between the populations with that from Hong Kong being the least productive under the experimental conditions used. The implications of the findings on selection of provenances for use in constructed wetlands for wastewater treatment are discussed.