Phytoremediation of Cd, Cr, Cu, Mn, Fe, Ni, Pb and Zn from aqueous solution using Phragmites cummunis, Typha angustifolia and Cyperus esculentus

A comparative bioaccumulation pattern and ultra structural changes were studied in Phragmites cummunis, Typha angustifolia and Cyperus esculentus in mixed metals solution of cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb) and zinc (Zn). P. cummunis was observed to be a shoot accumulator for Cr, Fe, Mn, Ni, Pb, and Zn. However, T. angustifolia was found to be a root accumulator for Cd, Cr, Cu, Fe, Ni and Pb. In addition, C. esculentus also accumulated most of the tested heavy metals in the roots, while Mn and Fe were translocated up to leaves. Further, the long term metal treatment showed maximum accumulation of all heavy metals in P. cummunis followed by T. angustifolia and C. esculentus. Among heavy metals, Fe was accumulated maximum, i.e., >1000 microg g(-1) by all three plants. Simultaneously, the adverse effects on biochemical parameters were noted earlier in C. esculentus than T. angustifolia and P. cummunis. Ultra structural observation showed the cellular changes in wetland plants after longer exposure. Results revealed that P. cummunis and T. angustifolia had more potential for tested metals than C. esculentus. This study established that these wetland plants could be used for heavy metals phytoremediation from metal containing industrial wastewater.     

The Effect of EDTA Addition on the Phytoremediation Efficiency of Pb and Cr by Echinochloa crus galii (L.) Beave and Associated Potential Leaching Risk

Metal-contaminated soils constitute a serious environmental problem with adverse consequences for human health. This study was conducted to determine phytoextraction efficiency of Echinochloa crus galii for Pb and Cr and the EDTA-assisted (0. 2.5, 5, 10 mmol kg^?1) phytoextraction and the potential for leaching of the metals during the phytoextraction process. The results revealed that the bioconcentration factors of roots of the plant were relatively higher than the bioconcentration factors of the shoot. Thus, the plant species of E. crus galii would be applicable for Pb and Cr phytostabilization. Addition of EDTA had virtually a significant effect on uptake of the metals by the plant and elevated Pb and Cr concentrations in plant organs as compared with the control. Optimum phytoextraction was observed when 5 mmol kg^?1 EDTA was added in a single dosage 60 days after the plant cultivation and consequently soil Pb and Cr concentration decreased with the passage of time.     

Effects of amendments on copper, cadmium, and lead phytoextraction by Lolium perenne from multiple-metal contaminated solution

Chemical amendments can increase metal uptake by plant roots and translocation to shoots, however their effectiveness can be influenced by the presence of other amendments and metal ions in a multiple-metal environment. A range of amendments and combinations were tested to explore their effect on phytoextraction of Cu, Cd, and Pb by perennial ryegrass (Lolium perenne) from solutions containing one or more of these metals. The amendments studied included EDDS (an aminopolycarboxylic acid), histidine (an amino acid), citric acid (an organic acid), rhamnolipid (a biosurfactant) and sulfate (an inorganic ligand). For all amendment treatments, the presence of multiple metals in solution reduced shoot concentrations of Cd and Cu, while Pb levels in shoots were generally enhanced by the presence of Cu. Although slightly toxic to the plants, EDDS (1 mM) was the most effective individual amendment for enhancing shoot metal uptake and translocation from solution without significantly reducing biomass yield. The combination Rhm+Cit+EDDS resulted in the highest shoot metal concentrations of all the treatments but also caused severe phytotoxicity. Amendment combinations Rhm+His and Sulf+Cit were less toxic for plant growth while moderately enhancing metal mass accumulation in shoots and thus could be considered as alternative treatments for enhanced phytoextraction.     

Chelator-assisted phytoextraction of arsenic,cadmium and lead by Pteris vittata L. and soil microbial community structure response

Abstract

Using biodegradable chelators to assist in phytoextraction may be an effective approach to enhance the heavy-metal remediation efficiencies of plants. A pot experiment was conducted to investigate the effects of ethylenediamine disuccinic acid (EDDS), citric acid (CA), and oxalic acid (OA) on the growth of the arsenic (As) hyperaccumulator Pteris vittata L., its arsenic (As), cadmium (Cd), and lead (Pb) uptake and accumulation, and soil microbial responses in multi-metal(loid)-contaminated soil. The addition of 2.5-mmol kg^?1 OA (OA-2.5) produced 26.7 and 14.9% more rhizoid and shoot biomass, respectively compared with the control, while EDDS and CA treatments significantly inhibited plant growth. The As accumulation in plants after the OA-2.5 treatment increased by 44.2% and the Cd and Pb accumulation in plants after a 1-mmol kg^?1 EDDS treatment increased by 24.5 and 19.6%, respectively. Soil urease enzyme activities in OA-2.5 treatment were significantly greater than those in the control and other chelator treatments (p?<?0.05). A PCR–denatured gradient gel electrophoresis analysis revealed that with the addition of EDDS, CA and OA enhanced soil microbial diversity. It was concluded that the addition of OA-2.5 was suitable for facilitating phytoremediation of soil As and did not have negative effects on the microbial community.     

Phytoextraction capacity of the Chenopodium album L. grown on soil amended with tannery sludge

The metal accumulation potential of Chenopodium album L. grown on various amendments of tannery sludge (TS) was studied after 60 days of sapling planted. The analysis of the results showed that the levels of pH, cation exchange capacity, organic carbon, organic matter and DTPA extractable metals (except Mn) of amendments increased by the addition of tannery sludge ratio. Shoot length of the plant increased by the addition of sludge, whereas, no marked change was observed in root length, fresh and dry weight of the plant. Accumulation of the metals in the plants was found in the order; Fe > Mn > Zn > Cr > Cu > Pb > Ni > Cd. Translocation of toxic metals (Cr, Pb, Cd) in different parts of the tested plant was found in the order; leaves > stems > roots. An increase in the photosynthetic pigments, carotenoid and leaf protein contents of the plants were found to increase with increase in sludge amendments. Correlation analysis between metal accumulation in the plants with DTPA extractable metals emphasized that Mn, Ni, Cr, Pb and Cd showed positive correlation (p < 0.05), whereas, Fe, Zn and Cu showed negative correlation. Transfer factor analysis emphasized that 10% TS amendments were suitable for phytoextraction of Cr. Overall analysis of the data exhibited that the plants may be used for phytoextraction of Cr from tannery waste contaminated soil as most of the metal was accumulated in harvestable part which is a matter of serious concern, whenever used for edible purposes.     

蕹菜典型品种中Cd、Pb、Cr、Ni 等重金属含量及其相关性

目的:蕹菜(Ipomoea aquatica Forsk.)Cd(镉)积累典型品种对Cd、Pb(铅)、C(r铬)、N(i镍)等多种重金属的吸收积累及相互关系。方法:采用盆栽试验,分析4个蕹菜Cd积累典型品种在6种土壤上的两茬茎叶及根Cd、Pb、Cr、Ni含量及相关性。结果:①品种和土壤对供试蕹菜典型品种Cd含量的效应均达显著水平(P<0.05),对Pb、Cr和Ni含量的效应因重金属、收获时期及部位而不同,二者对Cd、Pb含量具一定的交互效应。②两茬茎叶Cd含量平均值均为T308>GDB>QLB>QLQ,根Cd平均含量高于茎叶Cd平均含量;除Cr外,根Pb和Ni平均含量均高于茎叶。③Cd、Pb、Cr、Ni含量呈现复杂的相关关系。茎叶Cd含量与Pb含量正相关,且第一茬相关性极显著(P<0.01);Pb含量与Ni含量相关关系明显,第一茬茎叶、根Pb含量与Ni含量的正相关达到显著(P<0.05)或极显著水平(P<0.01),但第二茬茎叶Pb含量与Ni含量却显著负相关(P<0.05);Pb含量与Cr含量的相关性仅第一茬茎叶显著(P<0.05);Cr含量与Ni含量的相关性仅第二茬茎叶达极显著水平(P<0.01)。结论:蕹菜典型品种对Cd、Pb、Cr、Ni的吸收积累存在协同和拮抗两种作用。     

Phytoextraction of Pb and Cu contaminated soil with maize and microencapsulated EDTA

Chelate-assisted phytoextraction using agricultural crops has been widely investigated as a remediation technique for soils contaminated with low mobility potentially toxic elements. Here, we report the use of a controlled-release microencapsulated EDTA (Cap-EDTA) by emulsion solvent evaporation to phytoremediate soil contaminated with Pb and Cu. Incubation experiments were carried out to assess the effect of Cap- and non-microencapsulated EDTA (Ncap-EDTA) on the mobility of soil metals. Results showed EDTA effectively increased the mobility of Pb and Cu in the soil solution and Cap-EDTA application provided lower and more constant water-soluble concentrations of Pb and Cu in comparison with. Phytotoxicity may be alleviated and plant uptake of Pb and Cu may be increased after the incorporation of Cap-EDTA. In addition phytoextraction efficiencies of maize after Cap- and Ncap-EDTA application were tested in a pot experiment. Maize shoot concentrations of Pb and Cu were lower with Cap-EDTA application than with Ncap-EDTA. However, shoot dry weight was significantly higher with Cap-EDTA application. Consequently, the Pb and Cu phytoextraction potential of maize significantly increased with Cap-EDTA application compared with the control and Ncap-EDTA application.     

Exogenous salicylate application affects the lead and copper accumulation characteristics of Lemna gibba L

Previous studies have shown that salicylates can change the ion permeability of root cells. Therefore the possible effects of exogenous salicylate application on lead (Pb) and copper (Cu) accumulation and its protective role against DNA damage due to metal exposure in Lemna gibba were studied. L. gibba was exposed to 5, 10, and 25 microM Pb and Cu for six days in the presence and absence of sodium salicylate (SA) (0.1, 0.5, and 1 mM). At all concentrations tested, SA application decreased Pb accumulation. On the other hand, application of 0.5 mM SA increased Cu accumulation. SA did not reduce DNA damage resulting from Pb and Cu toxicity. In summary, SA may be useful for reducing Pb accumulation, and application of SA at 0.5 mM may be useful for the phytoextraction of Cu.     

Amendments and their combined application for enhanced copper, cadmium, lead uptake by Lolium perenne

Chemical amendments can enhance heavy metal phytoextraction by increasing metal bioavailability for plant root uptake and translocation to shoots, and by improving plant growth. This study assessed the effect of various amendments on plant growth and metal uptake over a 30-day period. An aminopolycarboxylic acid (EDDS), amino acid (histidine), organic acid (citric acid), biosurfactant (rhamnolipid), and inorganic ligand (sulfate) were applied as amendments individually or in combination to hydroponically grown ryegrass (Lolium perenne cv. SR4500) in the presence of a metal (Cu, Cd or Pb). EDDS (1 mM) was the most effective amendment (individually and in combinations) for enhancing Cu and Pb uptake to shoot tissue, while histidine was beneficial for increasing both Cu and Cd uptake. Individual treatments of citric acid, rhamnolipid and sulfate moderately enhanced shoot concentrations of Cu and Cd only. The combination of EDDS, rhamnolipid and citric acid resulted in the highest shoot metal levels, but also caused severe phytotoxicity. Translocation to shoot tissue was generally greater for amendments with higher affinity for the metal of interest, and metal mobility appeared to be influenced by speciation. Due to potential toxicity, amendment combinations may be more effective when applied shortly before harvesting.     

Accumulation, detoxification, and genotoxicity of heavy metals in Indian mustard (Brassica juncea L.)

Plants of Indian mustard (Brassica juncea L.) were exposed to different concentrations (15, 30, 60, 120 microM) of (Cd, Cr, Cu, Pb) for 28 and 56 d for accumulation and detoxification studies. Metal accumulation in roots and shoots were analyzed and it was observed that roots accumulated a significant amount of Cd (1980 microg g(-1) dry weight), Cr (1540 microg g(-1) dry weight), Cu (1995 microg g(-1) dry weight), and Pb (2040 microg g(-1) dry weight) after 56 d of exposure, though in shoot this was 1110, 618, 795, and 409 microg g(-1) dry weight of Cd, Cr, Cu, and Pb, respectively. In order to assess detoxification mechanisms, non-protein thiols (NP-SH), glutathione (GSH) and phytochelatins (PCs) were analyzed in plants. An increase in the quantity of NP-SH (9.55), GSH (8.30), and PCs (1.25) micromol g(-1) FW were found at 15 microM of Cd, however, a gradual decline in quantity was observed from 15 microM of Cd onwards, after 56 d of exposure. For genotoxicity in plants, cytogenetic end-points such as mitotic index (MI), micronucleus formation (MN), mitotic aberrations (MA) and chromosome aberrations (CA) were examined in root meristem cells of B. juncea. Exposure of Cd revealed a significant (P < 0.05) inhibition of MI, induction of MA, CA, and MN in the root tips for 24 h. However, cells examined at 24 h post-exposure showed concentration-wise recovery in all the endpoints. The data revealed that Indian mustard could be used as a potential accumulator of Cd, Cr, Cu, and Pb due to a good tolerance mechanisms provided by combined/concerted action of NP-SH, GSH, and PCs. Also, exposure of Cd can cause genotoxic effects in B. juncea L. through chromosomal mutations, MA, and MN formation.     

表面活性剂对长柔毛委陵菜(Potentilla griffithii var. velutina)修复重金属污染的促进作用

研究了十二烷基苯磺酸钠(SDBS)、十六烷基三甲基溴化铵(CTAB)、聚乙二醇辛基苯基醚(TritonX-100)等不同离子类型的表面活性剂对水稻土中重金属的解吸效果,并采用盆栽实验研究了上述3种表面活性剂对Zn超富集植物长柔毛委陵菜(Potentilla griffithii var. velutina)的生物量、吸收和富集重金属的影响.结果表明:CTAB对水稻土中Zn、Pb、Cd和Cu的解吸效果好于SDBS和TritonX-100,而且3种表面活性剂对各重金属的解吸率大小都为Cd>Zn>Cu>Pb.3种表面活性剂促进长柔毛委陵菜叶、柄和根的生物量增加了0.2～2.5倍,并且长柔毛委陵菜各部位的生物量大小为叶>柄>根.3种表面活性剂都增加了长柔毛委陵菜各部位对Zn、Cd吸收及其叶和柄对Pb、Cu的吸收,同时显著促进Zn、Pb、Cd和Cu从植物根部向地上部转运,从而增加了Zn、Pb、Cd和Cu在长柔毛委陵菜地上部的提取量和分布以及长柔毛委陵菜对Zn、Pb、Cd和Cu的富集能力;因此3种表面活性剂都提高了长柔毛委陵菜修复重金属污染土壤的效率.     

Eco-service enhancement in peri-urban area of coal mining city of Huaibei in East China

After 50 years of coal mining, Huaibei Mine, located at 50 km southeast of Xuzhou City in East China, has grown to a middle-size city of 600,000 people from a small village of 2000 farmers. The Zhahe Valley, with 400 km² of a built-up area and more than 100 km² of subsided peri-urban wetland at the city center, is surrounded by eight exhausted old mines and communities. In cooperation with the local city government, an ecological landuse change assessment and eco-city planning project has been carried out with a focus on the assessment, restoration and enhancement of the wetland as an eco-service to the community. The assessment includes relationships to Green House Gas emissions and heat island effects, as well as measures for a livable, workable, affordable and sustainable human settlement development through industrial transition, landscape design and capacity building. This paper will briefly introduce the main ecological approaches and results of the assessment, including measures such as changing the car-dominated transportation network to a rail-dominated network, transforming the coal-oriented high-carbon industry to a service-oriented low-carbon industry, the C-shape urban form to an O-shape with a green–blue core at the center, and the fragmentized collapsed land to integrative eco-service land.     

Heavy metal accumulation in iron plaque and growth of rice plants upon exposure to single and combined contamination by copper, cadmium and lead

A pot experiment was conducted to evaluate the bioaccumulation of heavy metals and growth response of rice plants after exposure to single and combined contamination by Cu, Cd and Pb. The results showed that the biomass production was not significantly affected by either single or combined treatment of Cu, Cd and Pb. Adding Cu (Cd, or Pb) separately all increased concentrations of the respective element in root and shoot (p < 0.001). In the combined contamination, Pb promoted both root and shoot absorption of Cu and Cd (p < 0.001), and Cu affected Cd and Pb absorption in the root, but Pb concentrations in both root and shoot were not affected by Cd application. The formation of iron plaques varied obviously with soil types. Heavy metal accumulation in iron plaques was induced by the three elements (p < 0.001). Furthermore, the three heavy metals exhibited an interactive relationship as measured by the Cu, Cd, Pb and Fe concentrations in root surface iron plaques. The iron plaques partially inhibited transfer of Pb to root and shoot, but no such effect was observed for Cu and Cd. This research indicates that the interaction among different heavy metal elements is very complex. It is very important to have a clear understanding on the associated mechanism and the consequential impact on plant growth.     

Heavy metal accumulation in iron plaque and growth of rice plants upon exposure to single and combined contamination by copper, cadmium and lead

A pot experiment was conducted to evaluate the bioaccumulation of heavy metals and growth response of rice plants after exposure to single and combined contamination by Cu, Cd and Pb. The results showed that the biomass production was not significantly affected by either single or combined treatment of Cu, Cd and Pb. Adding Cu (Cd, or Pb) separately all increased concentrations of the respective element in root and shoot (p < 0.001). In the combined contamination, Pb promoted both root and shoot absorption of Cu and Cd (p < 0.001), and Cu affected Cd and Pb absorption in the root, but Pb concentrations in both root and shoot were not affected by Cd application. The formation of iron plaques varied obviously with soil types. Heavy metal accumulation in iron plaques was induced by the three elements (p < 0.001). Furthermore, the three heavy metals exhibited an interactive relationship as measured by the Cu, Cd, Pb and Fe concentrations in root surface iron plaques. The iron plaques partially inhibited transfer of Pb to root and shoot, but no such effect was observed for Cu and Cd. This research indicates that the interaction among different heavy metal elements is very complex. It is very important to have a clear understanding on the associated mechanism and the consequential impact on plant growth.     

STABILITY OF ENHANCED YIELD AND METAL UPTAKE BY SUNFLOWER MUTANTS FOR IMPROVED PHYTOREMEDIATION

Plant biomass and metal shoot accumulation are key factors for efficient phytoextraction. In a previous study, chemical mutagenesis has been used to improve the phytoextraction potential of sunflowers. The main goal of the present study was to assess the stability of sunflower mutants with improved biomass and metal accumulation properties in the 3^rd and 4th generations. As compared to control plants, the best M₃ mutants showed the following improvement of metal extraction: Cd 3–5-fold, Zn 4–5-fold, and Pb 3–5-fold. The best M₄ sunflowers also showed enhanced metal extraction: Cd 3–4- fold, Zn 5–7-fold, Pb 6–8-fold and Cr 5–7-fold. The control sunflower inbred line IBL 04, grown directly on the field, accumulated metals in individual organs in the following decreasing order: Cd and Zn: leaves > stem > roots > flower > seeds; Cr: roots > flower > seeds > leaves > stem. The best sunflower mutants showed either higher metal accumulation in shoots or enhanced metal accumulation in roots, suggesting to improved phytoextraction or rhizofiltration efficiency, respectively.     

Phytoextraction of copper from contaminated soil by Elsholtzia splendens as affected by EDTA, citric acid, and compost

Phytoextraction of copper (Cu) from contaminated soils greatly depends on the metal bioavailability in the soils and metal uptake ability of the plant. In this study, the effects of chelators [ethylenediamine tetraacetic acid (EDTA), citric acid (CA)] and compost amendments on Cu phytoextraction potential by a tolerant and accumulating plant species (E. splendens) were examined in two types of contaminated soils, ie., the mined soil from Cu-mined area (MS) and a paddy soil polluted by Cu refining (PS). The results showed that EDTA application at 2.5-5.0 mmol kg(-1) increased phytoextraction of Cu by four- and eight-fold from both MS and PS, respectively, which is mainly attributed to increased H2O extractable Cu in the soil. The Cu amount extracted by the shoots of E. splendens reached 800-1000 microg Cu plant(-1) from the MS and 400-700 microg Cu plant(-1) from the PS at EDTA application rates of 2.5-5.0 mmol kg(-1). The application of CA at 5.0 mmol kg(-1) had minimal effects on Cu extractability in both soils and slightly decreased Cu extraction efficiency by E. splendens. Plant biomass production was enhanced by CA at 0.25 mmol L(-1) in nutrient solution, but inhibited by CA at 5.0 mmol kg(-1) in both MS and PS. Increasing the compost rate significantly decreased H2O extractable Cu in the MS, but raised H2O-extractable Cu in the PS, which resulted mainly front the reduced exchangeable Cu in the MS and the increased exchangeable and organic fractions of Cu in the PS by compost. At high compost rate (5%), the shoots of E. splendens extracted 3.6-fold higher Cu from the PS than from the MS. These results indicate that, among the soil amendments, efficiency of Cu phytoextraction is enhanced mostly by 2.5-5.0 mmol kg(-1) EDTA, followed by 5% (w:w) compost, whereas < 5.0 mmol kg(-1) CA has minimal effects on Cu phytoextraction by E. splendens in the PS. As for the MS, only 2.5-5.0 mmol kg(-1) EDTA can elevate the efficiency of Cu, while 5% compost amendment and < 5.0 mmol kg(-1) CA application have no marked effects on Cu phytoextraction by E. splendens.     

Comparison of organic and inorganic amendments for enhancing soil lead phytoextraction by wheat (Triticum aestivum L.)

Phytoextraction has received increasing attention as a promising, cost-effective alternative to conventional engineering-based remediation methods for metal contaminated soils. In order to enhance the phytoremediative ability of green plants chelating agents are commonly used. Our study aims to evaluate whether, citric acid (CA) or elemental sulfur (S) should be used as an alternative to the ethylene diamine tetraacetic acid (EDTA)for chemically enhanced phytoextraction. Results showed that EDTA was more efficient than CA and S in solubilizing lead (Pb) from the soil. The application of EDTA and S increased the shoot biomass of wheat. However, application of CA at higher rates (30 mmol kg(-1)) resulted in significantly lower wheat biomass. Photosynthesis and transpiration rates increased with EDTA and S application, whereas these parameters were decreased with the application of CA. Elemental sulfur was ineffective for enhancing the concentration of Pb in wheat shoots. Although CA did not increase the Pb solubility measured at the end of experiment, however, it was more effective than EDTA in enhancing the concentration of Pb in the shoots of Triticum aestivum L. It was assumed that increase in Mn concentration to toxic levels in soil with CA addition might have resulted in unusual Pb concentration in wheat plants. The results of the present study suggest that under the conditions used in this experiment, CA at the highest dose was the best amendment for enhanced phytoextraction of Pb using wheat compared to either EDTA or S.     

Effects of Municipal Sewage Sludge Doses on the Chlorophyll Contents and Heavy Metal Concentration of Sugar Beet (Beta vulgaris var. saccharifera)

The present study was conducted to assess the suitability of sewage sludge amendment (SSA) in soil for Beta vulgaris var. saccharifera (sugar beet) by evaluating the heavy metal accumulation and physiological responses of plants grown at a 10%, 25%, and 50% sewage sludge amendment rate. The sewage sludge amendment was modified by the physicochemical properties of soil, thus increasing the availability of heavy metals in the soil and consequently increasing accumulation in plant parts. Cd, Pb, Ni, and Cu concentrations in roots were significantly higher in plants grown at 25% as compared to 50% SSA; however, Cr and Zn concentration was higher at 50% than 25% SSA. The concentrations of heavy metal showed a trend of Zn > Ni > Cu > Cr > Pb > Cd in roots and Zn > Cu > Ni > Cr > Pb > Cd in leaves. The only instance in which the chlorophyll content did not increase after the sewage sludge treatments was 50%. There were approximately 1.12-fold differences between the control and 50% sewage sludge application for chlorophyll content. The sewage sludge amendment led to a significant increase in Pb, Cr, Cd, Cu, Zn, and Ni concentrations of the soil. The heavy metal accumulation in the soil after the treatments did not exceed the limits for the land application of sewage sludge recommended by the US Environmental Protection Agency (US EPA). The increased concentration of heavy metals in the soil due to the sewage sludge amendment led to increases in heavy metal uptake and the leaf and root concentrations of Ni, Zn, Cd, Cu, Cr, Pb, and Zn in plants as compared to those grown on unamended soil. More accumulation occurred in roots and leaves than in shoots for most of the heavy metals. The concentrations of Cd, Cr, and Pb were more than the permissible limits of national standards in the edible portion of sugar beet grown on different sewage sludge amendment ratios. The study concludes that the sewage sludge amendment in the soil for growing sugar beet may not be a good option due to risk of contamination of Cr, Pb, and Cd.     

Phytoremediation potential of Eichornia crassipes in metal-contaminated coastal water

The potential of Eichornia crassipes to serve as a phytoremediation plant in the cleaning up of metals from contaminated coastal areas was evaluated in this study. Ten metals, As, Cd, Cu, Cr, Fe, Mn, Ni, Pb, V and Zn were assessed in water and the plant roots and shoots from the coastal area of Ondo State, Nigeria and the values were used to evaluate the enrichment factor (EF) and translocation factor (TF) in the plant. The critical concentrations of the metals were lower than those specified for hyperaccumulators thus classifying the plant as an accumulator but the EF and TF revealed that the plant accumulated toxic metals such as Cr, Cd, Pb and As both at the root and at the shoot in high degree, which indicates that the plant that forms a large biomass on the water surface and is not fed upon by animals can serve as a plant for both phytoextraction and rhizofiltration in phytoremediation technology.