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Phytoremediation for phenanthrene and pyrene contaminated soils
GAO Yan-zheng,ZHU Li-zhong,
GAO Yan-zheng
,ZHU Li-zhong

环境科学学报(英文版) , 2005,
Abstract: Phytoremediation of soil contaminated with phenanthrene and pyrene was investigated using twelve plant species. Plant uptake and accumulation of these chemicals were evaluated. At the end of the experiment(45 d), the remaining respective concentrations of soil phenanthrene and pyrene in spiked vegetated soils, with initial phenanthrene of 133.3 mg/kg and pyrene of 171.5 mg/kg, were 8.71-16.4 and 44.9--65.0 mg/kg, generally 4.7%--49.4% and 7.1%--35.9% lower than their concentrations in the non-vegetated soils. The loss of phenanthrene and pyrene in vegetated spiked soils were 88.2%--93.0% and 62.3%--73.8% of the added amounts of these contaminants, respectively. Although plant uptake and accumulation of these compounds were evident, and root concentrations and RCFs (root concentration factors; defined as the ratio of PAH concentrations in roots and in the soils on a dry weight basis) of these compounds significantly positively correlated to root lipid contents, plant uptake and accumulation only accounted for less than 0.01% and 0.23% of the enhanced loss of these chemicals in vegetated versus non-vegetated soils. In contrast, plant-promoted microbial biodegradation was the dominant mechanism of the phytoremediation for soil phenanthrene and pyrene contamination. Results from this study suggested a feasibility of the establishment of phytoremediation for soil PAH contamination.
Phytoremediation and its models for organic contaminated soils.
Phytoremediation and its models for organic contaminated soils

Yan-Zheng Gao,Li-Zhong Zhu,
GAO Yan-zheng
,ZHU Li-zhong

环境科学学报(英文版) , 2003,
Abstract: Soil pollution has been attracting considerable public attentions over the last decades. Sorts of traditional physiochemical methods have been used to remove the organic pollutants from soils. However, the enormous costs and low efficiencies associated with these remediation technologies limit their availabilities. Phytoremediation is an emerging technology that uses plants to cleanup pollutants in soils. As overwhelmingly positive results have been shown, phytoremediation is a most economical and effective remediation technique for organic contaminated soils. In this paper phytoremediation and its models for organic contaminated soils are viewed. The mechanisms of phytoremediation mainly include the direct plant uptake of organic pollutants, degradation by plant-derived degradative enzymes, and stimulated biodegradation in plant rhizosphere. Phytoremediation efficiency is close related to physicochemical properties of organic pollutants, environmental characteristics, and plant types. It is no doubt that soil amendments such as surfactants improves the solubilities and availabilities of organic pollutants in soils. However, little information is available about effects of soil amendments on phytoremediation efficiencies. Phytoremediation models have been developed to simulate and predict the environmental behavior of organic pollutants, and progress of models is illustrated. In many ways phytoremediation is still in its initial stage, and recommendations for the future research on phytoremediation are presented.
Development of Profitable Phytoremediation of Contaminated Soils with Biofuel Crops  [PDF]
Kokyo Oh, Tao Li, Hongyan Cheng, Xuefeng Hu, Chiquan He, Lijun Yan, Yonemochi Shinichi
Journal of Environmental Protection (JEP) , 2013, DOI: 10.4236/jep.2013.44A008

Contamination of agricultural soil has been a worldwide concern, and phytoremediation is a promising alternative to conventional soil clean-up technology as a low cost and environment-friendly technology. However, the field application of phytoremediation is still limited, because of its low efficiency and long-period needed. In this paper, with discussion of the characteristics, mechanisms and development of phytoremediation, we suggested a profitable phytoremediation strategy using biofuel crops for both utilization and remediation of contaminated soil. In this strategy, the owners of contaminated sites possibly cost nothing, but obtain income through selling the biofuel crop for factories produced biofuel, thus the practical application of phytoremediation can be effectively promoted. In order to test the feasibility of the suggested strategy, a hydroponic cultural experiment and a pot experiment were carried out to assess the phytoremediation potential of some biofuel crops. The hydroponic cultural experiment showed that the two biofuel plants, sunflower and maize, had a better or similar accumulation level of Pb, Cu and Cd than the two accumulator plants. The pot cultural experiment showed that wheat and barley with white-rot-fungus inoculation greatly promoted crop biomass, soil microbial population, and dioxins removal efficiency. These results indicate that phytoremediation using biofuel plants possibly works effectively for remediation of contaminated soils as well as provide economic benefits to the owners of contaminated sites. Therefore, biofuel crops would be a reasonable choice for phytoremediation of contaminated soils.

Phytoremediation Mechanisms of Heavy Metal Contaminated Soils: A Review  [PDF]
Meriem Laghlimi, Bouamar Baghdad, Hassan El Hadi, Abdelhak Bouabdli
Open Journal of Ecology (OJE) , 2015, DOI: 10.4236/oje.2015.58031
Abstract: Phytoremediation is a green emerging technology used to remove pollutants from environment components. Mechanisms used to remediate soils contaminated by heavy metal are: phytoextraction, phytostabilisation, phytovolatilization and rhizofiltration. The two first mechanisms are the most reliable. Many factors influence the choice of the suitable phytoremediation strategy for soil decontamination. It depends on soil properties, heavy metal levels and characteristics, plant species and climatic conditions. The present review discusses factors affecting heavy metals uptake by plant species, the different phytoremediation strategies of heavy metal contaminated soils and the advantages and disadvantages of phytoremediation and each of its mechanisms.
Perennial Plants in the Phytoremediation of Lead-contaminated Soils  [PDF]
K. Cho-Ruk,J. Kurukote,P. Supprung,S. Vetayasuporn
Biotechnology , 2006,
Abstract: In this experiment, three local perennial plant species, Alternanthera philoxeroides, Sanvitalia procumbens and Portulaca grandiflora, were examined for their ability to uptake lead from lead contaminated soils (75 mg kg-1). Lead concentration in soil under all treatments decreased between 30-80% (62.61-23.18 mg kg -1) when compared to the control (75 mg kg -1). In all treatments, lead accumulation in the plants was higher on day 45 than what was found on days 55 and 65. Among these three species, A. philoxeroides showed a greater potential for lead accumulation than P. granaiflora and. S. procumbens. On day 45, A. philoxeroides showed significant differences in lead accumulation (29.99%) compared to that from P. granaiflora (13.03%) and S. procumbens (16.44%). Even though the amount of lead extracted by these three plants was small, the results showed that A. philoxeroides had the ability to extract an approximately 1.3-1.8 times greater amount than P. grandiflora and S. procumbens. Phytoremediation technology is environmentally friendly and cost-effective; A. philoxeroides may be a practicable alternative for protecting the soil in Thailand from leaching lead.
Phytoremediation of Soils Contaminated with Aluminium and Manganese by Two Arbuscular Mycorrhizal Fungi  [cached]
Elizabeth Alori,Oluyemisi Fawole
Journal of Agricultural Science , 2012, DOI: 10.5539/jas.v4n8p246
Abstract: Arbuscular Mycorrhizal Fungi (AMF) form symbiotic associations with the roots of many plants, and contribute to soil aggregation, structural stability and yield of plants in soils with low fertility. They have also been associated with cleaning of metal polluted soil. This study investigates the potential of AMF indigenous (Scutellospora reticulata and Glomus pansihalos) to Southern Guinea Savanna ecological zone of Nigeria to enhance phytoremediation of soils contaminated with Aluminium (Al) and Manganese (Mn). A 4x3x2 factorial pot experiment was used to assess the phytoremediation potential of indigenous AMF of alfisols contaminated with Al and Mn cropped with cowpea. The concentrations of the metals in soils and plants were determined by atomic absorption spectrophotometer. Data were analysed using Analysis of Variance (ANOVA). Both S. reticulata and G. pansihalos significantly reduced Al (F5, 21=791.4; p< 0.05) and Mn (F5, 21 =286; p< 0.05) contents of soils polluted with these metals. S. reticulata however showed a significantly higher remediating ability than G. pansihalos. It was observed that soil properties had a significant impact on bioremediation by AM fungi. It was concluded that S. reticulata and G. pansihalos indigenous to southern Guinea savannah have the potential for use in phytoremediation of soils polluted with Aluminium and Manganese.
Heavy Metals Contaminated Environments and the Road Map with Phytoremediation  [PDF]
Eucharia Oluchi Nwaichi, Om Parkash Dhankher
Journal of Environmental Protection (JEP) , 2016, DOI: 10.4236/jep.2016.71004
Abstract: This review presents the justification of research into heavy metals and clean-up technologies with particular emphasis on phytoremediation of heavy metals contaminated soils. The generating sectors and heavy metal contaminant contributors are reviewed alongside likely types. The new paradigm by researchers in response to negative impacts of various clean-up methodologies has been discussed. This work reports limitations and prospects of phytoremediation in view of the future direction and reviewed issues with bioavaliability, mobility, and response by plants to heavy metals in their environment. It reviews various plants used in phytoremediation of heavy metals and level of success recorded by teeming researchers. Diverse options available for optimization of this relatively novel technique to enhance performance have been elaborated. Suggestions for responsible abandonment of emitting sites and facilities, safety issues and appropriate disposal and management methods for plants used in this technology have been documented.
Interaction of Biosurfactant-Microorganism to Enhance Phytoremediation of Aged Polycyclic Aromatic Hydrocarbons (PAHs) Contaminated Soils with Alfalfa (Medicago sativa L.)

LIU Wei-wei,YIN Rui,LIN Xian-gui,ZHANG Jing,CHEN Xiao-min,LI Xuan-zhen,YANG Ting,

环境科学 , 2010,
Abstract: A pot experiment in greenhouse was carried out to investigate the interactive effect of rhamnolipids (RH) addition and PAHs-specific degrading bacteria (DB) inoculation on the phytoremediation efficiency for removal polycyclic aromatic hydrocarbons (PAHs) from agricultural soils. Results indicated that RH addition and DB inoculation promoted alfalfa (Medicago sativa L.) growth and PAHs degradation in the soil. After 90 days, residual PAHs concentration in soil reduced 30.0% and 49.6% for the treatment of RH and DB, respectively, but only 21.7% for control. For the treatment of RH+DB, residual PAHs concentration in soil reduced 53.9%, showing synergy effect of RH addition and DB inoculation. In addition, the average PAHs degradation gradually reduced with the increase of the PAHs rings, but DB inoculation promoted the degradation of four-ring PAHs and five-ring PAHs. The number of PAHs degrading bacteria and dehydrogenase activity increased with the removal ratio of PAHs. Therefore RH addition and PAHs-specific degrading bacteria inoculation were effective in enhancing the phytoremediation efficiency of the long-term PAHs contaminated soils.
Enhancement of heavy metal removal in phytoremediation of soils contaminated with heavy metals

LIAO Xiaoyong,CHEN Tongbin,YAN Xiulan,NIE Canjun,

环境科学学报 , 2007,
Abstract: Phytoremediation is a promising and environment-friendly method for cleanup of soils contaminated by heavy metals. Heavy metal removal in phytoremediation of soils contaminated with heavy metals can be enhanced by means of physics, chemistry and biotechnology. Phytoremediation efficiency has been proved to be elevated through applying some assistant measures, such as fertilization, irrigation, cultivation, additives, biotechnology and so on. Using these measures appropriately is helpful in increasing bioavailability of heavy metal in soils, enhancing growth of hyperaccumulator and improving the environment of plant growing. These measures using in phytoremediation of heavy metal polluted soils were summarized in this paper for identifying their function. Some promising hyperaceumulators should be paid more attention to further study. Undivided reagent for phytoremediation should be exploited for enhancing removal efficiency of heavy metal from soils. Engineering of phytoremediation will be further developed to dispose soil contamination with heavy metal.
Modeling Phytoremediation of Ni and Cd from Contaminated Soils Using Macroscopic Transpiration Reduction Functions  [cached]
M Davari,M Homaee,H Khodaverdiloo
Journal of Science and Technology of Agriculture and Natural Resources , 2010,
Abstract: Phytoremediation is a new, in-situ and emerging remediation technology for contaminated soils. This technology, compared to other methods, is a sustainable, natural, relatively cheap and applicable to large scale area. Modeling phytoremediation provides quantitative insight for the governing process as well as for managers to assess the remediated sites. The objective of this study was to introduce a macroscopic phytoremediation model for Ni and Cd- polluted soils. The proposed model assumes that relative transpiration reduction function can resemble total soilNi and Cd concentrations. Combining the related functions of soil and plant responses to soil Ni and Cd concentrations, the phytoremediation rate of Ni and Cd was predicted. In order to test the proposed model, large quantities of soil were thoroughly polluted with Ni and Cd. Upland Cress (Lepidum sativum) and Ornamental Kale (Brassica olerace var. Viridis) seeds were then germinated in the contaminated soils. The experimental pots were irrigated with fresh water to reach field capacity. Upland Cress and Ornamental Kale were harvested three and four times, respectively. At each harvest, relative transpiration, Ni and Cd contents of soil samples and plants were measured. Comparison of the maximum error, root mean square error, coefficient of determination, modeling efficiency and coefficient of residual mass indicated that the non-threshold non-linear model provide high efficiency to predict relative transpiration for Upland Cress and Ornamental Kale, respectively. The results also indicated that the proposed macroscopic model can well predict the phytoemediation rate of the Ni and Cd by Upland Cress (R2>0.83) and Ni by Ornamental Kale (R2=0.78).
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