Document Type : Research Paper
Authors
1 College of Natural Resource and Environment, Science and Research Branch, Islamic Azad University
2 Departmant of Range Management, Science and Research Branch, Islamic Azad University, Tehran, Iran
3 Assistant Professor, Rangeland Research Division, Research Institute of Forests and Rangelands, Tehran, Iran
4 Professor, Faculty of Natural Resources, Campus of Agriculture and Natural Resources, University of Tehran, Karaj, Iran
5 Assistant Professor, Rangeland Research Division, Research Institute of Forests and Rangelands, Agricultural Research, Education and Extension Organization (AREEO), Tehran, Iran
Abstract
Abstract
Background and objectives
Halophyte plants grow and produce in very saline water and soil conditions; however, they do not compete with agricultural products for quality soil and water as the main sources of production. Halophytes can tolerate high salinity for various reasons such as morphological characteristics, vegetative form, physiology and mechanisms of salinity tolerance. Although there have been good studies on the growth and salinity tolerance of halophyte species, there is little information about the absorption of heavy elements and the phytoremediation ability of different halophyte species. Heavy metal pollution is a serious problem in the lands adjacent to mines, which can be remedied by methods such as phytoremediation, while more studies are needed in this field. The present study aimed to evaluate the potential of several species of saltwort in the phytoremediation of mineral-contaminated soils.
Methodology
For this purpose, the ability of five halophyte species, Haloxylon persicum, Tamarix ramossisima, and Halocnemum strobilaceum, in phytoremediation of heavy metals arsenic (As), copper (Cu), lead (Pb), and nickel (Ni) was investigated at the Miduk mining site. Miduk copper mine is located 42 km northeast of Babak city in Kerman Province.
The vegetation of this area includes short bushes and scattered forest trees such as Buxus hyrcana, Prunus antarctica, Pistacia atlantica, Calligonum comosum, Tamarix spp., and Astragalus spp. and bush plants such as Artemisia sieberi, Salsola richteri, Rheum ribes, Cirsium vulgare, Ferula communis and Ziziphora clinopodioides. Sampling was done from the five halophyte species at distances of 1000, 1500, 2000, and 5000 m from the Miduk copper mine, which included 4 repetitions and each repetition included 20 bases. The total number of plant and soil samples was 400 and 120, respectively. Sampling was done by harvesting the plant and then separating the shoot (aerial organs) and root (underground organ) at the flowering stage. As, Cu, Ni, and Pb elements were measured using the inductively coupled plasma ICP-OES device.
Results
The results showed significant differences between H. strobilaceum, H. persicum, and T. ramossisima species regarding the amounts of arsenic, copper, and lead in different components of plants and soil. Ha. persicum has the highest amounts of arsenic and copper in the shoot, roots, and soil. At a distance of 1000 m, the highest concentration of arsenic is observed in the shoot, roots, and soil, as well as copper values in the shoot and soil. At a distance of 5000 m, a lower concentration of copper in the soil and a higher concentration of arsenic can be seen in the soil. In the case of Ta. ramossisima species, the highest concentration of arsenic is observed in the root and the highest amount of lead is also observed in the shoot. The results confirmed the phytoremediation potential of all five halophyte species for the remediation of contaminated soils at a distance of 1000 m from the copper mine, while the species H. strobilaceum had a higher potential for phytoremediation of contaminated soils. Furthermore, environmental pollution was not observed in the area without pollution to moderate pollution; which probably indicated the lack of transfer of heavy metals to agricultural products in lands further away from the mine.
Conclusion
Significant differences in the distribution and concentration of elements have been observed between these species and at different distances, and these results can contribute to a better understanding of the environmental effects on the concentration and distribution of elements in plants. The results of this research showed the phytoremediation potential of plant species H. persicum, H. salicornica, S. rosmarinus, T. ramossisima, and H. strobilaceum, which indicated the acceptable ability of saline species to improve mineral-contaminated soils. The phytoremediation potential of H. strobilaceum species was higher than other species. Also, based on the indicators of the accumulation of elements and the low amount of contamination of the examined species in the points with a greater distance from the mine (more than 1500 m), it showed that agriculture in the area around the mine is observed with caution and periodic examination of the area in terms of concentration heavy metals are possible.
Keywords
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