The effects of various components of water pollution on the behaviour of some aquatic macrophytes of the coastal rivers of Israel

Seven aquatic macrophytes, with an exclusive distribution in clean sections of two coastal rivers in Israel, were transplanted into polluted sites in the same rivers. Five species died shortly afterwards, whereas two survived uninjured. Three "clean water" species (Nymphaea caerulea, Ludwigia stolonifera and Scirpus litoralis) were treated with several water pollution factors. Detergents caused severe damage to all plants, whereas ammonium caused a temporary damage only in Nymphaea. Other factors, like anaerobiosis and increased levels of nitrate and phosphate had no effect on the plants. It is assumed that the present content of detergents in most polluted sections of the two rivers constitutes the main limiting factor for many hydrophytes and hygrophytes which occur in the non-polluted sections. The possible use of certain aquatic macrophytes as indicators for varying levels of pollution is discussed.