Root growth of two grass species on iron ore tailings at elevated levels of manganese, iron, and copper

The iron ore tailings located on the coastal area of Tolo Harbour impose severe pollution problems to the environment. Two grass species, Paspalum distichum and Sporobolus virginicus, were found extensively on the excavated tailings, with the former found in waterlogged areas and the latter in dry areas. These plants may have a potential use in reclaiming the tailings.

The present experiment is aimed at studying the reclamation ability of the two local species. Samples of the grass species collected from the tailings were cultured in a series of concentrations of manganese, iron, and copper, separately. Heavy metal tolerance was found to be species specific. S. virginicus collected from the tailings had the higher index of tolerance (0.9) and ED₅₀ (0.85 ppm) to copper whereas P. distichum had the higher index of tolerance and ED₅₀ to manganese (0.98 and 9.2 ppm, respectively) and iron (0.66 and 41 ppm, respectively). Plants of the two species collected from uncontaminated sites showed low index of tolerance and ED₅₀ values for all three metals. Copyright © 1983 Published by Elsevier Inc.