Application Of Ethylenediaminetetraacetic Acid Research Articles

Evaluation of the phytoremediation potential of Arundo donax L. for nickel-contaminated soil

ABSTRACTThis study investigates the accumulation and distribution of nickel in Arundo donax L. parts to assess the potential use of this plant in phytoremediation of Ni-contaminated soils. The effect of ethylene diamine tetra-acetic acid (EDTA) and nutrient solution containing NPK on the plant was proped. A 35-day pot experiment was performed in the laboratory and the pots were irrigated with Ni-contaminated solution combined or not with EDTA and NPK. The growth of plants was evaluated at the end of the experiment. The accumulation of Ni was analyzed by atomic absorption spectroscopy (AAS). The obtained results indicate that the plant was able to survive with high Ni content. The growth and the concentrations of Ni in the plant tissues were less affected. In the absence of the amendments, Ni was accumulated in the stems and leaves. However, the addition of NPK significantly reduced Ni concentration in the stems and leaves. The application of EDTA enhanced Ni uptake in roots. The translocation factor (TF) was greater than 1, which categorizes A. donax L. as a great candidate for Ni phytoextraction. A. donax L. is suitable for phytoremediation of Ni. This investigation contributes to the studies on the potential of phytoremediation technologies in Algeria.

EDTA-Enhanced Phytoextraction by Tagetes sp. and Effect on Bioconcentration and Translocation of Heavy Metals

Phytoextraction is one of the processes of phytoremediation, in which heavy metals are extracted by plant roots and shoots. For enhanced phytoextraction efficiency use of some chelating agent such as ethylenediaminetetraacetic acid (EDTA) is an effective approach to remove heavy metals from contaminated soils. In the present study, the effect of EDTA on the uptake of Zn, Cd, Pb, and Cu by Tagetes sp. was examined. The application of EDTA had inhibitory effects on the growth of the plants, but effectively increased the mobility of Zn, Cd, Pb, and Cu in soils, and significantly enhanced the accumulation of these heavy metals in aerial parts of the plants. The portions of Zn extraction from soil were increased by 1.71, 1.86 and 1.9 times, Cd extraction from soil was increased by 2.33, 2.44 and 2.46 times, Pb extraction from soil was increased by 1.65, 1.93 and 2.01 times and Cu extraction from soil was increased by 1.93, 1.95 and 2 times, under the treatments of 5 (E5), 10 (E10) and 15 mg EDTA/kg of soil (E15), respectively, compared to the control. The highest bioconcentration factor of shoot (BCFshoot) and the translocation factor (TF) were observed in E15 and highest remediation factor (RF) was observed in E10. But 5 mmol EDTA/kg of soil is the best treatment for selected heavy metals remediation because it has less toxic effects on plant as well as it is economical both cost wise and for the decorative flowers.

Enhanced Phytoremediation Capacity of Chenopodium album L. Grown on Pb-Contaminated Soils Using EDTA and Reduction of Leaching Risk

ABSTRACTLeaching of metals due to enhanced mobility during ethylenediaminetetraacetic acid (EDTA)-assisted phytoextraction has been demonstrated as one of the potential hazards associated with this technology. This study was conducted to determine phytoextraction efficiency of Chenopodium album L. for Pb and EDTA-assisted (1.5, 3, and 9 mmol kg−1) phytoextraction and potential for leaching of Pb. The results demonstrated that BCFshoot (bioconcentration factor) was relatively higher than the BCFroot. Translocation factor in the shoot was higher than the roots. Thus, plant species would be applicable for Pb phytoextraction. EDTA enhanced translocation of Pb from roots to shoots. Lead content in the plant parts was maximum in the shoot and root of 9EDTA and 3EDTA, respectively. However, there was no significant difference between 3EDTA and 9EDTA. Lead concentration in the plant parts increased significantly from vegetative stage into flowering stage. Lead content taken up by the plant was lowest when EDTA was applied in a single dose. Therefore, application of EDTA in several increments rather than a single split reduced the leaching risk. Totally, optimum phytoextraction was observed when 3 mmol kg−1 EDTA was added in triple dosage 60 days after the plant cultivation under triple application mode. The results indicated the plant has the potential for Pb phytoextraction, but it should not be used unless the biomass containing such accumulated metal is removed for disposal. Significant improvement over current ETDA-assisted phytoextraction of Pb may be possible but should be implemented cautiously because of environmental risk.

Influence of root dentin treatment on the push-out bond strength of fiber posts.

The aim of the present study was to assess whether different dentin conditioning protocols with different acids [phosphoric acid, ethylene diamine tetra acetic acid (EDTA), and polyacrylic acid (PAA)] influence the bond strength of fiber posts along the radicular depth when luted with self-adhesive resin cement. Twenty single-rooted teeth were randomly divided into four experimental groups (n=5) according to dentin treatment: Group 1: no treatment; Group 2: etching with 35% phosphoric acid for 10s; Group 3: 17% EDTA application for 60s; and Group 4: conditioning with 25% PAA for 30s. RelyX Fiber Posts were luted with the self-adhesive resin cement RelyX Unicem 2 Automix (3M ESPE). Roots were transversally sectioned into nine 1-mm thick specimens, three corresponding to each root third and a push-out test was performed. Data were analyzed by two-way ANOVA and Tukey test (p<0.05). Failure mode was determined and specimens with representative failures for each group were observed under scanning electron microscopy. According to the results, dentin treatment influenced the bond strength (p<0.001), whereas the root third did not (p>0.05). Fiber posts luted after treating dentin with phosphoric acid, and PAA exhibited the highest push-out bond strength values, while the lowest were obtained after EDTA application. Intermediate results were obtained when dentin was not conditioned. In conclusion, the bond strength of the self-adhesive resin cement RelyX Unicem 2 improves when root dentin is treated with 35% phosphoric acid or 25% PAA, before fiber posts luting irrespective of the root depth.

Effect of ethylene diamine tetra acetic acid chelator in the presence of chromium on growth and some physiological characteristics of sunflower.

Chromium is a heavy metal toxic for plants that due extensive industrial applications over the last decade, has become a serious environmental pollution. On the other hand, chelator dissolution and absorption of metal by the plant increase and their use in phytoremediation is important. The aim of this study was to evaluate the effect of different concentrations of chromium and ethylene diamine tetra acetic acid (EDTA) chelator on sunflower (Heliantus annuus L.) through the study of growth parameters, chlorophyll, and soluble sugar amounts and Cr accumulation in plants under hydroponic culture. In order to plant sunflower were treated with different concentrations of Cr (1, 2, 4 and 6 ppm) and EDTA (0, 1 and 3 mg/L) in the medium Hoagland. The results showed that the use of chromium reduced the length of shoots and roots, and chlorophyll, while it increased soluble sugars. Addition of EDTA to the metal increased the shoot and root length and chlorophyll content while it reduced soluble sugars. According to the results, the use of chromium heavy metal in medium increased the amount of it in shoot and root. EDTA application, particularly with higher levels of chromium led to its accumulation in shoot and root. This research suggested positive role of application of EDTA in the presence of chromium heavy metal in increasing the power of phytoremediation of sunflower.

Improving the efficiency of phytoremediation using electrically charged plant and chelating agents.

The low efficiency of phytoremediation is a considerable problem that limits the application of this environmentally friendly method on heavy metal-polluted soils. The combination of chelate-assisted phytoextraction and electrokinetic remediation could offer new opportunities to improve the effectiveness of phytoextraction. The current experiment aims to investigate the effects of electrical fields and chelating agents on phytoremediation efficiency. In a pot experiment using mine soil, poultry manure extract (PME), cow manure extract (CME), and ethylenediaminetetraacetic acid (EDTA) were applied to soil as chelating agents (2 g kg(-1)) at the beginning of the flowering stage. A week later, Helianthus annuus (sunflower) was negatively charged by inserting a stainless steel needle with 10 and 30 V DC electricity in the lowest part of the stems for 1 h each day for a 14-day period. At the end of the experiment, the shoot and root dry weight, lead (Pb) concentration in plant organs, translocation factor (TF), metal uptake index (UI), and soil available Pb (diethylene triamine pentaacetic acid (DTPA) extractable) were detected. Results indicated that the application of electrical fields had no significant impact on the shoot and root dry weights, while Pb concentration and UI increased in the 10-V EDTA treatment by 500 % compared to control. There was no significant difference between UI in 30- and 10-V EDTA treatments. Soil available Pb significantly increased in the 30-V treated soil. A positive correlation was observed between the available Pb in soil near the root and Pb concentration in shoot, its TF, and UI. In conclusion, a negatively charged plant along with the application of EDTA significantly increased the phytoremediation efficiency.

Phytoremediation of Cadmium from Soil Using Patience Dock (Rumex patientia L.)

ABSTRACTHerein is reported the remediation of cadmium in agricultural soil using patience dock (Rumex patientia L.). Potted experiments were performed on the campus of Namık Kemal University in greenhouse conditions. The soil was classified to have a neutral pH, low lime, and to be deficient in organic matter. The available phosphorus and the exchangeable potassium concentrations of the soil were both adequate. The soil was found to have a clay texture. Cadmium was added to the soil at 100 mg/kg. Ethylenediaminetetraacetic acid (EDTA) was added at one of four concentrations during the growing season of the patience dock. The plants were harvested after two months. The yield of the roots and shoots of patience dock decreased with increased application of EDTA. However, the mass of cadmium in the roots and shoots increased with EDTA application. These changes in the plant properties were statistically significant at the 1% significance level. These results show that patience dock (Rumex patientia L.) is suitable for the phytoremediation of cadmium.

Phytoextraction of potentially toxic elements by Indian mustard, rapeseed, and sunflower from a contaminated riparian soil.

The objective of this study was to quantify the phytoextraction of the potentially toxic elements Al, As, Cd, Co, Cr, Cu, Mo, Ni, Pb, Se, V, and Zn by Indian mustard, rapeseed, and sunflower from a contaminated riparian soil. To achieve this goal, a greenhouse pot experiment was established using a highly contaminated grassland soil collected at the Wupper River (Germany). The impact of ethylene-diamine-tetra-acetic acid (EDTA), humate (HK), and phosphate potassium (PK) on the mobility and uptake of the elements by rapeseed also was investigated. Indian mustard showed the highest efficiency for phytoextraction of Al, Cr, Mo, Se, and V; sunflower for Cd, Ni, Pb, and Zn, and rapeseed for Cu. The bioconcentration ratios were higher than 1 for the elements (except As and Cu), indicating the suitability of the studied plants for phytoextraction. Application of EDTA to the soil increased significantly the solubility of Cd, Co, Cr, Ni, and Pb and decreased the solubility of Al, As, Se, V, and Mo. Humate potassium decreased significantly the concentrations of Al and As in rapeseed but increased the concentrations of Cu, Se, and Zn. We may conclude that HK can be used for immobilization of Al and As, while it can be used for enhancing the phytoextraction of Cu, Se, and Zn by rapeseed. Phosphate potassium immobilized Al, Cd, Pb, and Zn, but enhanced phytoextraction of As, Cr, Mo, and Se by rapeseed.

Dry Matter Yield of Sunflower as Affected by EDTA and EDDS Application in Soil Remediation from Ibadan, Metropolis, Nigeria

Phytoremediation has been found to be cost effective in removing heavy metals (HM) from polluted soils. Enhanced phytoextraction with the use of chelating agents for solubility of metal in soils and their uptake in the aerial parts of plants had also been employed. Phytoextraction efficiency of plants will depend on the metal accumulated in the dry matter yield of plant. An attempt was made to study the influence of Ethylene diamine tetra acetic acid (EDTA) and ethylene diamine disuccinic acid (EDDS) on the growth and dry matter yield content of sunflower planted in heavy metal polluted soils in a greenhouse pot experiment. Total heavy metal contents of five metals (Cu, Cd, Cr, Pb and Zn) were determined by acid digestion with aqua regia solution. A greenhouse experiment was conducted to assess the phytoextraction potential of sunflower with EDDS and EDTA applied at seven weeks after planting. Treatments were laid out in a completely randomized design with four replicates. Data were collected on metal accumulation in root and shoot, Total metal uptake, shoot and root dry matter yield and analyzed using descriptive statistics and ANOVA at α0.05. Original Research Article Thomas and Omueti; IJPSS, 7(1): 67-79, 2015; Article no.IJPSS.2015.132 68 The result shows a significant increase in the overall accumulation of metals in the root and shoot of sunflower and dry matter yield with EDDS except for Zn. However, Zinc only recorded significant increase in shoot uptake at 3 mmol/kg EDDS. The application of EDDS at 3 and 9 mmol/kg did better in total uptake of Cu, Pb and Cd. Ethylene diamine disuccinic acid (EDDS) was more efficient than EDTA in mobilizing metal uptake in sunflower root and shoot and also in increasing total dry matter yield. Translocation factor of Cd, Pb and Cu were enhanced by the addition of EDDS than EDTA application.

The Effect of Application of EDTA on the Phytoextraction of Heavy Metals by Vetivera zizanioides, Cymbopogon citrates and Helianthus annuls

This study investigates the effect of the application of EDTA (ethylenediamine-tetraacetic acid) on the phytoextraction of Cd, Co, Cu, Ni, Pb, and Zn by Vetivera zizanioides, Cymbopogon citrates and Helianthus annuls harvested from experimental site (with EDTA) and a control area (without EDTA) in Zaria-Nigeria. The concentrations of Cd, Co, Cu, Ni, Pb, and Zn in different parts of each of the plant species collected from the experimental and control soils were determined using atomic absorption spectrophotometry. Application of 5 mmol/kg EDTA in soil did not affect plant growth but significantly increased Cd, Co, Cu, Ni, Pb, and Zn concentrations in shoots and roots of the plants. The concentrations of heavy metals measured in the tissues of plants collected from the experimental site were higher (P ≤ 0.05) than in the control. The percentage increase in the metal concentration for each plant specie were:- for Vetivera zizanioides, Cd – 75%, Co – 205%, Cu – 190%, Ni – 645%, Pb – 5% and Zn – 29%; for Cymbopogon citrates, Cd – 100%, Co – 109%, Cu – 551%, Ni – 907%, Pb – 39% and Zn – 50%; for Helianthus annuls, Cd – 21%, Co – 235%, Cu – 44%, Ni – 507%, Pb – 70% and Zn – 02%. The heavy metal concentrations were higher in leaves (P ≤ 0.05) than in roots of the plants. The translocation factor (TF) for all the metals studied were greater than 1.The results of this study demonstrated that EDTA is an efficient soil amendment in enhancing desorption of Cd, Co, Cu, Ni, Pb, and Zn from soil and in increasing their accumulation in plants. As for plant species tested, the effectiveness in the uptake of the metals studied was Helianthus annuls < Vetivera zizanioides < Cymbopogon citrates.

담수토양에서 메탄생성반응 보효소 니켈의 킬레이팅에 의한 메탄 생산량의 효과적 저감

Abstract BACKGROUND: Methane(CH 4 ) is considered as the secondmost potent greenhouse gas after carbon dioxide (CO 2 ). Methanogenesis is an enzyme-mediated multi-step process by methanogens. In the penultimate step, methylated Co-M is reduced by methyl Co-M reductase (MCR) to CH 4 involving a nickel-containing cofactor F430. The activity of MCR enzyme is dependent on the F430 and therefore, the bioavailability of Ni to methanogens is expected to influence MCR activity and CH 4 production in soil. In this study, different doses of EDTA(Ethylene Diamine Tetraacetic Acid) were applied in flooded soils to evaluate their suppression effect on methane production by chelating Ni of methanogenesis cofactor.METHODS AND RESULTS: EDTA was selected as chelating agents and added into wetland and rice paddy soil at the rates of 0, 25, 50, 75, and 100 mmol kg -1 before 4-weeks incubation test. During the incubation, cumulative CH 4 production patterns were characterized. At the end of the experiment, soil samples were removed from their jars to analyze total soil Ni and water-soluble Ni content and methanogen abundance. Methane production from 100 mmol application decreased by 55 and 78% in both soils compared to that from 0 mmol. With increasing application rate of EDTA in both soils, water-soluble Ni concentration significantly increased, but total soil Ni and methanogen activities showed negative relationship during incubation test.CONCLUSION: The decrease in methane production with EDTA application was caused by chelating Ni of coenzyme F430 and inhibiting methanogenesis by methyl coenzyme M reductase. Consequently, EDTA application decreased uptake of Ni into methanogen, subsequently inhibited Research Article Open Access

Phytoremediation of nickel (Ni) from agricultural soils using canola (Brassica napus L.)

The aim of this research is to propound an innovative method to remediate the nickel (Ni) pollution in agricultural soils by using canola (Brassica napus L.) plant. For this purpose, a field experiment was conducted on the campus of Namık Kemal University, namely its Faculty of Agriculture Research and Experimental Area, during 2011. Nickel (100 mg/kg) as NiSO4 forms was applied to each parcel. Then ethylene diamine tetra acetic acid (EDTA) chelate was applied to each parcel at four doses (0, 5, 10, and 15 mmol/kg) during the blossom period of the plants. The plants were harvested four months after planting. The soil in the samples was classified with neutral pH, low lime, and insufficient organic matter. The available phosphorus content and the exchangeable potassium content of research area were both found to be sufficient. The amount of available iron, manganese, and copper of the experimental soil was sufficient, but the available zinc amount of the soil was determined at a deficient level. The experimental area soil was classified to be in clay texture. According to the field experiment results, root and shoot yield of plants decreased with increasing EDTA doses. On the other hand, nickel amount of root and shoot of the plants increased with increasing EDTA application to the plants. These increases and decreases were found to be statistically significant at the level of 1%. According to the results of the experiment, heavy metal pollution of the soil of Tekirdağ province can be remediated by the phytoremediation method.

EDTA and citric acid-mediated phytoextraction of heavy metals from iron ore tailings using Andrographis paniculata: a comparative study

An experiment was conducted in the greenhouse to compare the effect of a synthetic chelator, ethylenediaminetetraacetic acid (EDTA), with that of a natural low molecular weight organic acid i.e. citric acid (CA) in enhancing the heavy metal extraction potential of Andrographis paniculata (Burm.f.) Wall. ex Nees from iron ore tailings (IOT). The chelator treatments were applied at doses of 0.05, 0.10 and 1.5 mmol kg−1dry tailings. IOT without any additives were used as control. The effect of IOT (both with and without additives) on growth, photosynthetic pigments (chlorophyll, pheophytins and carotenoids), antioxidant activity, as well as uptake and accumulation of various heavy metals (Fe, Cu, Zn, Ni, Cr, Cd and Pb) were analysed for four months. Results indicated that the total uptake (mass removal from tailings) of metals by A. paniculata was enhanced by the addition of chelators. The heavy metal concentrations in the parts of A. paniculata under all chelator treatments were significantly (p < 0.05) higher than those for the control, as the total concentration of Fe, Cu, Zn, Ni, Cr, Cd and Pb increased from 175.34, 118.72, 110.51, 2.5, 21.9, 1.026 and 10.2 μg g−1, respectively, to 184.17, 161.94, 157.69, 4.41, 26.17, 1.79 and 20.79 μg g−1 in the presence of CA, and 187.04, 176.12, 172.85, 5.44, 28.46, 2.254 and 22.14 μg g−1 with EDTA application even at the lowest dose of 0.05 mmol kg−1. By increasing the doses of EDTA and CA that were applied, we achieved further increased mobilisation of the targeted heavy metals from tailings to the plant roots. Though EDTA was more efficient in mobilising metals from tailings to the plant parts than CA, yet the reduction of plant biomass caused by it (EDTA) also exceeds that caused by the CA. Therefore, (low molecular weight organic acid such as) CA should be preferred during assisted phytoextraction over the synthetic chelator like EDTA which has unacceptable percolation risks associated with it.

EDTA enhanced plant growth, antioxidant defense system, and phytoextraction of copper by Brassica napus L.

Copper (Cu) is an essential micronutrient for normal plant growth and development, but in excess, it is also toxic to plants. The present study investigated the influence of ethylenediaminetetraacetic acid (EDTA) in enhancing Cu uptake and tolerance as well as the morphological and physiological responses of Brassica napus L. seedlings under Cu stress. Four-week-old seedlings were transferred to hydroponics containing Hoagland's nutrient solution. After 2 weeks of transplanting, three levels (0, 50, and 100 μM) of Cu were applied with or without application of 2.5 mM EDTA and plants were further grown for 8 weeks in culture media. Results showed that Cu alone significantly decreased plant growth, biomass, photosynthetic pigments, and gas exchange characteristics. Cu stress also reduced the activities of antioxidants, such as superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), and catalase (CAT) along with protein contents. Cu toxicity increased the concentration of reactive oxygen species (ROS) as indicated by the increased production of malondialdehyde (MDA) and hydrogen peroxide (H2O2) in both leaves and roots. The application of EDTA significantly alleviated Cu-induced toxic effects in B. napus, showing remarkable improvement in all these parameters. EDTA amendment increased the activity of antioxidant enzymes by decreasing the concentrations of MDA and H2O2 both in leaves and roots of B. napus. Although, EDTA amendment with Cu significantly increased Cu uptake in roots, stems, and leaves in decreasing order of concentration but increased the growth, photosynthetic parameters, and antioxidant enzymes. These results showed that the application of EDTA can be a useful strategy for phytoextraction of Cu by B. napus from contaminated soils.

The application of EDTA in drug delivery systems: doxorubicin liposomes loaded via NH4EDTA gradient

The applications of ethylenediaminetetraacetic acid (EDTA) have been expanded from the treatment of heavy metal poisoning to chelation therapies for atherosclerosis, heart disease, and cancers, in which EDTA reduces morbidity and mortality by chelating toxic metal ions. In this study, EDTA was used in a drug delivery system by adopting an NH4EDTA gradient method to load doxorubicin into liposomes with the goal of increasing therapeutic effects and decreasing drug-related cytotoxicity. The particle size of the optimum NH4EDTA gradient liposomes was 79.4±1.87 nm, and the entrapment efficiency was 95.54%±0.59%. In vitro studies revealed that liposomes prepared using an NH4EDTA gradient possessed long-term stability and delayed drug release. The in vivo studies also showed the superiority of the new doxorubicin formulation. Compared with an equivalent drug dose (5 mg/kg) prepared by (NH4)2SO4 gradient, NH4EDTA gradient liposomes showed no significant differences in tumor inhibition ratio, but cardiotoxicity and liposome-related immune organ damage were lower, and no drug-related deaths were observed. These results show that use of the NH4EDTA gradient method to load doxorubicin into liposomes could significantly reduce drug toxicity without influencing antitumor activity.

EDTA ameliorates phytoextraction of lead and plant growth by reducing morphological and biochemical injuries in Brassica napus L. under lead stress.

Brassica species are very effective in remediation of heavy metal contaminated sites. Lead (Pb) as a toxic pollutant causes number of morphological and biochemical variations in the plants. Synthetic chelator such as ethylenediaminetetraacetic acid (EDTA) improves the capability of plants to uptake heavy metals from polluted soil. In this regard, the role of EDTA in phytoextraction of lead, the seedlings of Brassica napus L. were grown hydroponically. Lead levels (50 and 100 μM) were supplied alone or together with 2.5 mM EDTA in the nutrient culture. After 7 weeks of stress, plants indicated that toxicity of Pb caused negative effects on plants and significantly reduced growth, biomass, chlorophyll content, gas exchange characteristics, and antioxidant enzymes activities such as superoxide dismutase (SOD), guaiacol peroxidase (POD), ascorbate peroxidase (APX), and catalase (CAT). Exposure to Pb induced the malondialdehyde (MDA), and hydrogen peroxide (H2O2) generation in both shoots and roots. The addition of EDTA alone or in combination with Pb significantly improved the plant growth, biomass, gas exchange characteristics, chlorophyll content, and antioxidant enzymes activities. EDTA also caused substantial improvement in Pb accumulation in Brassica plants. It can be deduced that application of EDTA significantly lessened the adverse effects of lead toxicity. Additionally, B. napus L. exhibited greater degree of tolerance against Pb toxicity and it also accumulated significant concentration of Pb from media.

The Impact of Three Different Canal Lubricants on Fracture, Deformity and Metal Slivering of ProTaper Rotary Instruments.

The aim of this in vitro study was to evaluate the effect(s) of three canal lubricants i.e. sodium hypochlorite, RC-Prep as the paste form of ethylenediaminetetraacetic acid (EDTA) and aqueous EDTA on the occurrence/incidence of fracture, deformity and metal slivering of ProTaper rotary instruments. A total of 120 mesial canals (i.e. mesiobuccal and mesiolingual) of first mandibular molars or buccal canals (i.e. mesiobuccal and distobuccal) of first maxillary molars, with curvatures of 10-20 degrees were selected and randomly divided into three groups of forty samples each. These selected canals all had approximate 19-21 mm working length and apical diameter equal to a #15 K-file. In each group, the root canals were prepared using ProTaper rotary instruments with an electric motor using one of the three aforementioned irrigants. Subsequently, samples were compared to each other at different magnifications (16×, 20×, 40× and 57×) for any fracture, deformity or metal slivering, by the Cox regression analysis. The fractures rate of samples in RC-Prep group was significantly higher compared to other groups (P=0.01). No evidence of instrument deformity was detected in any groups. A statistically significant reverse relation between metal slivering and instrument fracture was observed. Application of aqueous EDTA and/or sodium hypochlorite as intracanal lubricants caused less fracture of ProTaper instruments compared to canal lubrication with RC-Prep.

Comparative effects of chelants on plant growth, cadmium uptake and accumulation in nine cultivars of Ramie (Boehmeria nivea)

Chelate-induced phytoremediation has been considered as a promising measure for the remediation of heavy metal-contaminated soils. The plant growth and cadmium (Cd) accumulation in nine ramie cultivars pot-grown in Cd-contaminated soil were investigated following the application of ethylenediaminetetraacetic acid (EDTA) and ethylenediamine succinic acid (EDDS) at 5 mmol kg−1. Results showed that the application of chelants significantly affected the plant height and biomass with significant varietal difference. EDTA treatment resulted in reduced plant height and biomass in all cultivars tested, while EDDS application increased the plant height and aboveground biomass in most of the cultivars. Both chelants significantly increased the shoot Cd contents, being up to 60% and 54% more than those of control after EDTA and EDDS treatments, respectively. The chelants were found to reduce the root Cd content by 15% and 12% in EDTA- and EDDS-treated plants, respectively. They were found to significantly increase the value of translocation factor (TF), indicating that EDTA and EDDS can help Cd migrate from root to shoot. Cultivar Zhongzhu 1 showed a potential of extracting 0.104 t Cd ha−1. At the concentration of 5 mmol kg−1, EDTA treatment appeared to have greater impact on the plant growth and Cd accumulation than EDDS.

Effectiveness of Phytoremediation Technologies to Clean Up of Metalloids Using Three Plant Species in Iran

Phytoremediation is a potential, innovative, and cost-effective technology for non-destructive remediation of heavy-metal contaminated soils. A field trial was conducted to evaluate the phytoremediation efficiencies of three plants and the effects of ethylenediaminetetraacetic acid (EDTA) or ammonium addition [(NH4)2SO4 and NH4NO3] for assisting removal of heavy metals (Pb, Hg, and Cd) from contaminated soil. The tested plants include Amaranthus retroflexus, Sorghum bicolor, and Lolium perrene. Results showed that maximum concentration of Pb, Hg, and Cd were detected in shoots of A. retroflexus, S. bicolor, and L. perrene at high concentrations in pH=6.2. The application of EDTA as a chelating agent to soil was the most efficient to enhance the phytoavailability of Pb, Hg and Cd. The concentrations of Pb, Hg, and Cd in the shoots of A. retroflexus treated with EDTA were 57 mg/kg, 14.1 mg/kg, and 30 mg/kg, respectively. Results indicated that among the three plants, A. retroflexus had great potential in phytoremediation of contaminated soils.

Potential ofIgniscum sachalinensisL. andSalix viminalisL. for the Phytoremediation of Copper-Contaminated Soils

The potential ofSalix viminalisL. andIgniscum sachalinensisL. for phytoremediation of copper- (Cu-) contaminated soils was studied under greenhouse conditions. Approximately 5 kg of potted agricultural and sewage amended soils sampled from the top 0 to 20 cm depth in Neuruppin, Germany, was treated with CuSO4at concentrations 0 (control), 250, 750, and 1250 mg Cu kg−1soil and ethylenediaminetetraacetic acid (EDTA) at 1000 mg kg−1soil, respectively. Each plant species was grown on four replicates of each soil treatment. Copper accumulated in aboveground tissues tends to increase with increasing soil Cu concentration and was the lowest in stem and leaf of both plant species grown on control soils. At 750 and 1250 mg Cu kg−1soil, Cu accumulated in stem and leaf ofI. sachalinensisincreased by over 12- and 20-fold, respectively, whereas there was no vegetative growth inS. viminalisbeyond 250 mg Cu kg−1soil. Application of EDTA to sewage amended soils increased Cu accumulated in the stem and leaf, especially inI. sachalinensis. In general,I. sachalinensisseems to have the potential to tolerate high soil Cu content and simultaneously bioaccumulate Cu in tissues and thus may have better prospects for phytoremediation.