The limitation of plant growth in the polluted mediums can be used as a factor to determine of plant tolerance and the toxic effect of these mediums. In this work, the effect of Pb
2+, Cd
2+, Ni
2+ and Zn
2+ (individually) on
Azolla filiculoides
growth in the aqueous solution and using this method to water post treatment were studied. During 15 days the biomass the fresh
Azolla with initial mass of 20 g was grown on the nutrient solution containing these metal ions, each in a concentration 4 mg/l. The presence of these ions, caused about 25%, 42%, 31% and 17% inhibition of biomass growth, respectively, in comparison to
Azolla control weight which had not heavy metals. The water salinity of 1, 2 and 4 g. NaCl/l decreased the removal of these heavy metals about 4-7%, 20-24% and 40-55%, respectively. The addition of total dissolved solids (TDS) from 50 to 300 ppm. (as CaCO
3) into the samples of containing heavy metals increased
Azolla growth, but decreased the control
Azolla growth.
