|Year : 2015 | Volume
| Issue : 2 | Page : 58-60
Accumulation and Translocation of Heavy Metals by Amaranthus Retroflexus
Shahrzad Khoramnejadian1, Keivan Saeb2
1 Department of Environment, Damavand Branch, Islamic Azad University, Damavand, Iran
2 Department of Environment, Tonekabon Branch, Islamic Azad University, Tonekabon, Iran
|Date of Web Publication||27-Nov-2015|
Department of Environment, Damavand Branch, Islamic Azad University, Damavand
Source of Support: None, Conflict of Interest: None
Background: Phytoremediation is an ecofriendly method that recently used for contamination removal. Aim: n this article, phytoremediation of heavy metals (Cr, Cd, Cu, and Ni) by amaranth and Persian clover has been studied. Context: Soil samples with different amount of contamination were prepared. Contaminated soil samples keep in greenhouse and Amaranthus retroflexus cultivated in polypropylene pots. Before and after cultivation soil samples heavy metal amount has been analyzed. Result and Discussion: The amount of heavy metals in soils decreased after 120 days cultivation. Accumulations of heavy metals in plant tissues were measured. Translocation factor (TF) has been calculated. TF from root to upper part of plants in the order of Cr > Cu > Ni > Cd and TF from root to upper part of plants in the order of Ni > Cr > Cd > Cu. Amaranthus were resistance among high amount of heavy metal in soils. Result indicated that Amaranthus retroflexus has a good ability to remove heavy metal from contaminated soils. Conclusion: According to resultphytoremediation by Amaranthus retroflexus is a good and economical choice for remedy contaminated site.
Keywords: Amaranthus retroflexus , bioaccumulation, heavy metal, phytoremediation, translocation
|How to cite this article:|
Khoramnejadian S, Saeb K. Accumulation and Translocation of Heavy Metals by Amaranthus Retroflexus. J Earth Environ Health Sci 2015;1:58-60
|How to cite this URL:|
Khoramnejadian S, Saeb K. Accumulation and Translocation of Heavy Metals by Amaranthus Retroflexus. J Earth Environ Health Sci [serial online] 2015 [cited 2019 Nov 20];1:58-60. Available from: http://www.ijeehs.org/text.asp?2015/1/2/58/170581
| Introduction|| |
Heavy metal toxic effects on the human health have been known for a long time. Human communities used heavy metals from an ancient era. Ancient Egyptian used copper vessels to keep water fresh because copper has a negative effect on bacteria. Toxicity of lead and mercury has been known by romans. In ancient times, heavy metal contaminations occur locally and in a small scale. However, today's heavy metal comes from industrial or agricultural section to the environment. Soil contaminated by accumulation of heavy metals. Mining, waste disposal, industries, fertilizers, pesticides, animal manure and …, are the source of heavy metal in soils. Heavy metal finally adsorbs by soils and soils are the sink for them. The presence of heavy metals in soils affected the chemical and biological properties of soils. Toxic metals affected the biodegradation of organic contaminations. , Heavy metal source are natural and anthropogenic. Application of municipal sewage sludge, livestock manure, and composts to land increases the amount of As, Cd, Pb, Hg, Ni, Zn, and Sb to soils. Some of the heavy metals such as copper, zinc add to a diet of livestock, so the manure of these animals contains a high concentration of heavy metals. Irrigation by waste water in some countries increased the contamination of heavy metals in soils. Milling ores and, mining also are the source of heavy metal contamination in soils. Human health threatens by high concentration of trace metals. Arsenic is a trace element and toxic for plants, animals, and humans. Selenium is an essential elements, but toxic in high concentrations. Fertilizer specially phosphatics, are the source of cadmium and lead to soils. Chromium, mercury, copper and arsenic used in pesticides.
Huge investment needs for environment clean up industries. Annually, billion dollars have been used for site clean up all over the world. Three strategies used by plants for soil treatment:
Excavation, soil washing, thermal treatment, chemical reduction, and chemical oxidation are options for soil treatments, but those options needs high energy and cost. For soil remediation, some techniques are used, such as phytoremediation, immobilizations, and soil washing. 50 years ago a first research about bioremediation was done.
Phytoremediation term applied for the use of plants for remediation of organic and inorganic contaminant of soils. Some of the plants could accumulate a large amount of pollutants in their tissues.
Two major mechanisms in plants remove the contaminant: Phytoextraction and phytodegradations. Phytoextraction applied for removal inorganic contaminants such as salt, metals, metalloids, and radionuclide form soil through plant uptake. Phytodegradation used for organic contaminants such as petroleum hydrocarbons, pesticides, and so on. Phytoremediation is a cost effective option for cleanup metal contaminated area. Phytoremediation also is an eco- friendly technique for remediation contaminated site. Hyper accumulate plants have an ability to storage high amount of metal or metalloids that those amount are toxic for another plant. Hyperaccumulator plants could take up 2-5% metals by dry weights. By harvesting these plants, several amounts of pollutants remove from soils, and if these plants could be harvest several times a year, it's been more effective. Phytotoxicity is a limiting factor in phytoremediations, some soil properties can affected the growth of the vegetation. These parameters are salinity, pH, and nutrients. Soil pathogens could inhibit plant growth.
Amaranthus (amaranth) known as a cosmopolitan plant. Amaranth plant is native to Asia, Africa and America. Amaranth grows all year in the tropical region. This plant could grow everywhere and considered as a weed. Amaranth also cultivated as an ornamental plant. Researchers used Amaranthus retroflexus to uptake heavy metals.  In these research, phytoremediation of contaminated soil by A. retroflexus has been studied. Accumulation of heavy metals in roots and upper parts of A. retroflexus has been determined. Translocation factor (TF) also calculated.
| Materials and Methods|| |
The soil was collected from an agricultural field near Damavand city. Contaminated soil was collected from the mining area. Soils were passed through 4 mm stainless mesh and stored for 21 days in natural conditions, and every day aerated. Agricultural and polluted soils were mixed and aerated for 21 days. Plastic pots were considered for planting to avoid any leaking. Plastic pots prepared and contained agricultural soil and contaminated polluted soil for the sample. Samples with low contaminant: L (contain 1 part agricultural soil, ½ part contaminated soil), samples with intermediately concentration: I (contain same amount of part agricultural soil and contaminated soil), and samples with high concentration: H (contain 1 part agricultural soil, 2 part contaminated soil).
Amaranth (A. retroflexus) selected among native plant of Damavand region. Amaranths were planted in polypropylene pots. Plants were harvested after 120 days. Soil samples dried at 60°C in an oven. For wet digestion, HCl and HF add to samples. Plant materials divided into two part root and upper parts (include stem, leaf). Plant samples were washed by deionized water to removed surface soil. Plant parts dried at 75°C in an oven. Heavy metal analyzed by inductively coupled plasma optical emission spectrometry.
| Result|| |
According to [Table 1], after the cultivation of Amaranthus, the reduction of heavy metals has been seen in all samples. By phytoextractions, heavy metals decreased in soil samples. pH is an important factor in heavy metal absorption, in this study pH range between 7 and 7.5. Higher reduction rate has been observed in high contaminated samples. The result indicates that Amaranthus is a hyperaccumulator of heavy metals and during the growth period does not show any sign of phytotoxicity.
|Table 1: Result of soil analysis before and after Amaranthus cultivation|
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[Table 2] shows the accumulation of heavy metals in Amaranthus tissues. In all samples, heavy metals have trends to accumulate in roots than other part of plants. Amaranthus could take up heavy metals to high concentrations.
TF has been calculated to determine translocation of heavy metals from soil to root or from roots to upper parts of plants. TF indicate the ability of plants to accumulate heavy metals from soils. Metal mobilized in soils and adsorbs by roots. In the plant body, heavy metals were trapped by cells or transport through the cell membrane.  Water soluble form of heavy metal absorbs to root by osmosis then root pressure take up water. Transpiration in leaves provide a force for water movement to upper part. TFs have shown in [Table 3].
Chromium hexavalent is a harmful heavy metal to living organisms. The result shows the high accumulation of chromium in Amaranthus roots. However, TF of chromium from root to the upper part of plants does not show considerable transmit.
Cadmium is a poisoning for many plants and depends on a cadmium concentration. Amaranthus had an ability to accumulate cadmium and cadmium does not have a negative effect on germination, growth, and flowering.
Copper is an essential element for plants, but toxic in high concentrations.  The high absorption of copper was found in roots and translocation coppers from soil to roots were high. A higher ratio of translocation confirmed Amaranthus suitable for phytoremediation of the copper element.
Nickel also is an essential micronutrients and corporate with some enzymes. Like copper, a high concentration of nickel could cause plant poisoning. An increasing amount of nickel caused necrosis and deformation of plant parts. 
TF from soil to roots indicated the bioavailability of heavy metals in soils. High TF ratio of chromium and copper indicated that Amaranthus had the potential ability to phytoextraction of those heavy metals. Boulabah said that plants have a high accumulation of heavy metal in their roots and less in other parts is heavy metal excluder. 
| Conclusion|| |
In this manuscript, phytoremediation of contaminated soil by A. retroflexus has been studied. According the results, A. retroflexus is a hyper accumulator plants for Cr, Cd, Cu, and Ni. TF was calculated and indicated the higher accumulation of heavy metals in root than other part of plants. The amount of soil heavy metals decreased after Amaranthus cultivation and result indicated that heavy metals transmit from soils to roots of plants, but transmit form root to other parts were low.
Financial support and sponsorship
This research supported by the research fund of Damavand Branch, Islamic Azad University, Damavand, Iran.
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3]