The current study assesses the effect of fibrous clay minerals’ amendments and arbuscular mycorrhiza incubation on heavy metal uptake and translocation in Eucalyptus grandis and Ailanthus altissima plants. For doing so, Eucalyptus and ailanthus trees have been grown in a soil sample, contaminated with heavy metal iron ore mining and collected from southern Iran. The area under study is arid, with the majority of trees being ailanthus and eucalyptus. Amounts of Cd, Pb, Zn, Cu, and Mn have initially been at toxic levels which declined after cultivation. Fibrous clay minerals have been added to soils as a natural adsorbent to adsorb heavy metals like Pb, Cd, Zn, and Mn. Accumulation of the elements in the roots and shoots has been in the following order: Cu>Zn>Mn>Cd>Pb>Fe. The organ metal concentrations have not statistically translocated from roots to shoots of plants, except for Zn and Cu whose concentrations have been significantly higher in roots. Eucalyptus is well capable of extracting elements from contaminated soils, compared to ailanthus, particularly in case of Cu and Cd. The percentage of mycorrhizal colonization proves to be more in pots with ailanthus plants grown in contaminated soil, suggesting enhanced effect of high metal concentrations on plant infection by G. mosseae. AMF assists soil remediation by enhancing the growth and retention of toxic elements by ailanthus, while no substantial change has been observed between inoculated and non-inoculated eucalyptus plants by AFM, regarding translocation of elements to plants. The possibility of increasing metal accumulation in roots is interesting for phytoremediation purposes, since most high-producing biomass plants, such as eucalyptus, retain heavy metals in roots.

This research aims to study the effect of Mycorrizal fungus and Plant-Growth-Promoting Bacteria (PGPB) on Cadmium (Cd) uptake by one-year-old Eucalyptus Camaldulensis seedlings. The treatments have involved three levels of heavy metal (0, 30, and 60 mg/kg) for Cd, and three bacterial levels (no bacteria (B0), Bacillus (Ba105), and Pseudomonas (Ps36, Ps448)), inoculated with mycorrhizal fungus Glomus mosseae (M1) and non-inoculated with fungus (M0). Results show that absorption of these elements in plant increased as Cd concentration in soil became more. Inoculation by Ps448 bacteria had an incremental effect on Cd uptake by 90%, compared to the non-inoculated (control) samples. Moreover, inoculation of the plants with mycorrhizal fungus increased Cd uptake by 24%, compared to the control. Also, it has been observed that plant resistance to metal stress and plant growth under such conditions ascended in treatments wherein inoculation happened with mycorrhizal fungus and bacteria. The highest Cd heavy metal uptake has been observed in Eucalyptus (shoots and roots), treatment (C2B2M1) with 648.19 micrograms per one seedling in pot. According to the obtained results, Eucalyptus with biological factors (fungi and bacteria) has the ability to clean and purify the contaminated soil with Cd heavy metal.

Conserving water resources and protecting them from pollution are of high account in the natural cycle of our life. This study has tried to determine the refining potential and capacity of water hyacinth (Eichhornia crassipes) in order to remove the cadmium from water, studying the influence of factors such as initial concentration of cadmium, contact time, absorbent mass, and pH. Results have shown that the best efficiency of cadmium, more than 99%, was obtained in the optimum conditions (i.e. retention time of 30 hours, adsorbent dose of three plants (12 stems), and pH=6.6). By increasing the initial concentration of cadmium from 0.28 to 8.28 mg/L, the elimination efficiency did not change; moreover, by increasing the absorbent mass, the elimination efficiency increased from 98.4 to 99.8 and the lowest retention time was obtained for the balance. All experiments have been repeated three times, showing in the end that water hyacinth is able to absorb cadmium up to 8.28 mg/L. This process follows Freundlich isotherm (R2=0.98). Results of this study indicate that this plant can grow well at high levels of cadmium and the growth of water hyacinth is better in the presence of cadmium than control conditions (city water). Finally, it can be concluded that it is necessary to provide a reliable, cheap, and fast method to eliminate pollution. Eichhornia crassipes, a promising plant with great functionality, can be used as a refiner in order to eliminate the heavy metals in wastewater (sewage) effluents, particularly industrial sewage.