Uptake of Metals by the Vegetation on Contaminated Sediment after Addition of Mycorrhizae

Plant species with the ability to accumulate high levels of metals without adverse effects to their growth are potential phytoremediators of metal-contaminated soils and sediments. The study determines the levels of heavy metals namely cadmium (Cd), copper (Cu), lead (Pb), zinc (Zn) and nickel (Ni) in vegetation. Contaminated sediments were collected from a site in Quebec city, Canada, on the St. Charles River. The experiment was laid out in a completely randomized block design with five replicates. The plot size was 7.5m x 4.5m with 1 m interplot and interblock size. There were four treatments namely: T1= 20% Festuca rubra, 20% Festuca eliator, 15% Agropyron repens, 15% Lolium perenne L., 21% Phleum pratense L., 5% Lotus corniculatus and 4% Trifolium repens, T2= Tanacetum vulgare), T3= T1 inoculated with Glomus intraradices and T4 = T3 inoculated with Glomus intraradices. Plots did not receive any chemical fertilizers. Only the grass and leguminous mix (T1 and T3) grew well in contaminated sediments. Concentrations of Cd, Cu, Pb, Zn and Ni in shoot tissues of mycorrhizal grass and leguminous mix were compared with non-mycorrhizal plants. The ratio of metals that can be taken up by plants to their total contents in the substrate is less than 1%. The results reveal that grass and leguminous mix had a strong physiological tolerance of metals.