• Korean Journal of Soil Science and Fertilizer
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• v.47 no.6
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• pp.491-495
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• 2014

Phytoremediation is a technology using plants and associated soil microbes to reduce the concentrations or toxic effects of contaminants in the environments. It is regarded as a cost-effective, efficient, eco-friendly, and solar-driven technology with good public acceptance. This study was conducted to find the plants accumulating heavy metals in soils contaminated with Cd and Pb. Experimental plots (plot size: $0.81m^2$) was artificially contaminated using a contaminated soil collected from a field in vicinity of Wondong mine (WD). Sunflower, corn and castor were tested for their potential to remove heavy metals from the contaminated soils. The results indicated that sunflower was most effective in accumulating heavy metals and thus remedying the soils among the three crops. Dry weight and heavy metal uptake of sunflower shoot differed with growth period. For example, the Cd content of shoots including leaf and stem were 0.31mg, 2.23 mg, and 0.96 mg per plot at 4, 8 and 12 weeks after planting in Cd4-WD treatment; in addition, the dry weight of the shoots in Cd8-WD treatment was reduced due to heavy metal toxicity. This experiment showed that sunflower absorbed Cd, Pb and Zn in their shoots up to 8 weeks of planting; thereafter heavy metals uptake was diminished. This implies that the efficiency of these plants in cleaning the contaminated soils may be high at the early stage of plant growth.

• Journal of Microbiology and Biotechnology
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• v.20 no.5
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• pp.862-870
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• 2010

Cyperus rotundus L. is a perennial herb that was found to be dominating an area in northeast Brazil previously contaminated with petroleum. In order to increase our knowledge of microorganism-plant interactions in phytoremediation, the bacterial community present in the rhizosphere and roots of C. rotundus was evaluated by culture-dependent and molecular approaches. PCR-DGGE analysis based on the 16S rRNA gene showed that the bacterial community in bulk soil, rhizosphere, and root samples had a high degree of similarity. A complex population of alkane-utilizing bacteria and a variable nitrogen-fixing population were observed via PCR-DGGE analysis of alkB and nifH genes, respectively. In addition, two clone libraries were generated from alkB fragments obtained by PCR of bulk and rhizosphere soil DNA samples. Statistical analyses of these libraries showed that the compositions of their respective populations were different in terms of alkB gene sequences. Using culturedependent techniques, 209 bacterial strains were isolated from the rhizosphere and rhizoplane/roots of C. rotundus. Dot-blot analysis showed that 17 strains contained both alkB and nifH gene sequences. Partial 16S rRNA gene sequencing revealed that these strains are affiliated with the genera Bosea, Cupriavidus, Enterobacter, Gordonia, Mycoplana, Pandoraea, Pseudomonas, Rhizobium, and Rhodococcus. These isolates can be considered to have great potential for the phytoremediation of soil with C. rotundus in this tropical soil area.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.04a
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• pp.38-41
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• 2001

It has been reported that some plants have the potential to metabolize the 2,4,6-trintroluene (TNT) in contaminated soils, sediments and natural water. In this study, the effects of TNT on germination and early seedling development of Abutilion avicennae was characterized in a germination test. Concentration up to 80 mg/L TNT did not affect germination but root and shoot growth, and fresh biomass decreased as TNT concentration increased. A series of axenic hydroponical batch culture of Abutilion avicennae at various initial TNT concentration was used to determine its transformation kinetics, to identify products formed, and to evaluate phytotoxic effects on the TNT transformation process. At higher initial TNT concentrations, TNT removal rate constant decreased, however, total amount of TNT removed was increased in the culture media. Reductive transformation products of TNT were not detected in the plant culture media but higher concentrations of reduced metabolites were detected in the root and stem extracts of plant material at the 7 days of batch incubation. From these results we concluded that Abutilion avicennae has an intrinsic capacity for taking up and transforming TNT.

• Microbiology and Biotechnology Letters
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• v.34 no.2
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• pp.83-93
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• 2006

In heavily industrialized areas, soil sites are contaminated with high concentrations of heavy metals. These pollutants are highly accumulated to the human body through the food web and cause serious diseases. To remove heavy metals from the soil, a potential strategy is the environmental friendly and cost effective phytoremediation. For the enhancement of remediation efficiency, the symbiotic interaction between the plant and plant growth-promoting rhizobacteria (PGPR) has been attended. In this review, the interaction of the plant and PGPR in the heavy metal-contaminated soil has been reviewed. The physicochemical and biological characteristics of the rhlzosphere can influence directly or indirectly on the biomass, activity and population structure of the rhizobacteria. The root exudates are offered to the soil microbes as useful carbon sources and growth factors, so the growth and metabolism of rhizobacteria can be promoted. PGPR have many roles to lower the level of growth-inhibiting stress ethylene within the plant, and also to provide iron and phosphorus from the soil to plant, and to produce phytohormone such as indole acetic acid. The plant with PGPR can grow better in the heavy metal contaminated soil. Therefore higher efficiency of the phytoremediation will be expected by the application of the PGPR.

• Journal of Ecology and Environment
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• v.42 no.4
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• pp.191-198
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• 2018

Improper management and unsanitary approaches are implemented in disposal of leachate, which has resulted in groundwater pollution at village Uruli Devachi, Pune, India. Various physico-chemical treatment methods are commercially available for leachate treatment. However, the application of biological methods viz. phytoremediation to the municipal solid waste landfill leachate has been limited. We report the remediation ability of Typha aungstifolia and Acrorus calamus that is capable of reducing hazardous constituents from the landfill leachate. After 96 h of hydraulic retention time (HRT), it was observed that T. aungstifolia-treated sample showed high reduction potential in reducing biochemical oxygen demand, chemical oxygen demand, hardness, total dissolved solids, Na, Mg, Ca and Ni whereas A. calamus showed greater reduction capacity for alkalinity, Cl, Cu, Zn and Cr. Furthermore, it was also observed that T. aungstifolia withstood longer HRT than A. calamus. In situ application of T. aungstifolia and A. calamus for remediation of landfill leachate carries a tremendous potential that needs to be further explored.

• Korean Journal of Environmental Agriculture
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• v.18 no.1
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• pp.28-34
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• 1999

This study was carried out to assess heavy metal pollution at 16 abandoned mining areas and to get basic data for phytoremediation. In most of surveyed area, there was no vegetation cover and soil reaction shows in low to moderate pH. Low CEC, low organic matter content were the general properties of these soils. Heavy metals content of these soils were exceed background level of unpolluted soil in Korea, especially Cu content was 2,634mg/kg at Jeil site, 3,415mg/kg Zn, 8.03mg/kg Cd at Yonhwa 2 site. This is far above tolerance limit In plant survey, very often observed plants were Pinus densiflora, and Rohinia psuedo-acacia in woody plant, Artemisia princeps, and Dianthus sinensis in herbs. Artemisia princeps had higher concentration of Zn, Cd and Dianthus sinensis had higher concentration than other plants. From the results, heavy metal concentration in plants and plant's ecotype properties, could be said that Artemisia princeps and Miscanthus sinensis have a potential of soil remediation plant. More studies are demanded to find the heavy metal tolerance species and to understand physiology property of tolerance plants, soil condition, climate etc., for successful soil remediation by plants.

• Korean Journal of Environmental Agriculture
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• v.21 no.2
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• pp.122-129
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• 2002

The removal rate of heavy metals from the wastewater, the accumulation and translocation of heavy metals in plants after transplanting, and the responses of water celery growth with different wastewater treatments were investigated to determine the potential ability of green-remediation with hydroponic culture of water celery. The removal rate and translocation of Cd, Cu, Ni and Pb from different wastewater to plants were compared with cultivation periods after transplanting. The removal rate of heavy metals from wastewater was different with each treatment but increased with growing periods of water celery plants. The removal rate of Cd, Cu, Ni and Pb in Artificial solution, Artificial solution+EDTA, Munmark industrical wastewater, Jungsun minewater is ranged from 22 to 73%, from 28 to 100%, from 13 to 92% and from 41 to 100% at 6 days after transplanting, respectively. The translocations of Cd, Cu, Ni and Pb from roots to shoots in Artificial solution, Artificial solution+EDTA, Munmark industrical wastewater, Jungsun minewater are ranged from 14 to 28%. 8 to 30%. from 28 to 45% and from 2 to 15% at 12 days after transplanting, respectively. In plant growth responses, it appears to be inhibited the plant growth over all treatments excepts for Munmark industrial wastewater in these glowing periods. Therefore the water celery might play a useful role in phytoremediation to clean up wastewater contaminated with Cd, Cu, Ni or Pb.

• Korean Journal of Plant Resources
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• v.21 no.3
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• pp.230-235
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• 2008

The aquatic fern Azolla spp. is of value as a bio-fertilizer for wetland paddy. It is popular and cultivated widely in other countries like China, Vietnam, and the Philippines, but has yet to be taken up in Korea, in a big way. It fixes nitrogen as high as 3-5kg N per day, because it contains nitrogen fixing blue-green algae, Anabaena azollae. Azolla's ability to create a light-proof mat that suppresses other weeds has been used for centuries in rice production. Azolla spp. has also the capacity to take up the heavy metals such as Mercury and Chromium (75${\sim}$100%) and may be used as a bioaccumulator in the phytoremediation. Azolla meal also can be used as an unconventional feed resource has a potential as a feedstuff for livestock.

• Journal of Soil and Groundwater Environment
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• v.19 no.3
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• pp.25-32
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• 2014

The amount of TPH contaminated soil treated at off-site remediation facilities is ever increasing. For the recycle of the treated-soil on farmlands, it is necessary to restore biological and physico-chemical soil characteristics and to remove residual TPH in the soil by an economic polishing treatment method such as phytoremediation. In this study, a series of experiments was performed to select suitable plant species and to devise a proper planting method for the phyto-restoration of TPH-treated soil. Rye (Secale cereale) was selected as test species through a germination test, among 5 other plants. Five 7-day-old rye seedlings were planted in a plastic pot, 20 cm in height and 15 cm in diameter. The pot was filled with TPH-treated soil (residual TPH of 1,118 mg/kg) up to 15 cm, and upper 5 cm was filled with horticulture soil to prevent TPH toxic effects and to act as root growth zone. The planted pot was cultivated in a greenhouse for 38 days along with the control that rye planted in a normal soil and the blank with no plants. After 38 days, the above-ground biomass of rye in the TPH-treated soil was 30.6% less than that in the control, however, the photosynthetic activity of the leaf remained equal on both treatments. Soil DHA (dehydrogenase activity) increased 186 times in the rye treatment compared to 10.8 times in the blank. The gross TPH removal (%) in the planted soil and the blank soil was 34.5% and 18.4%, respectively, resulting in 16.1% increase of net TPH removal. Promotion of microbial activity by root exudate, increase in soil permeability and air ventilation as well as direct uptake and degradation by planted rye may have contributed to the higher TPH removal rate. Therefore, planting rye on the TPH-treated soil with the root growth zone method showed both the potential of restoring biological soil properties and the possibility of residual TPH removal that may allow the recycle of the treated soil to farmlands.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.1
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• pp.55-64
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• 2008

A detailed understanding and appreciation of the important mechanisms operating at the soil:root interface, commonly identified as the rhizosphere, is critical for evaluating the potential for particular plant species to be successfully used as part of a phytoremediation technique. For specific plants, mechanisms may exist to overcome the inherit limitation of the phytoremediation technique when poorly mobile soil metals are of interest. In the present study, the influence of root exudates on the rhizosphere chemistry of soil and consequential metal uptake were investigated following culture of vetiver grass (Vetiveria zizanioides), recognized as a promising plant for land stabilization, in three different long-term contaminated soils and one non-contaminated control soil. The soil solution pH increased (0.3-1.1 units) following vetiver grass culture and dissolved organic carbon (DOC) also significantly increased in all soils with the highest increase in PP02 (23 to $173mg\;L^{-1}$). Chemical changes are contributed to root exudation by vetiver grass when exposed to high concentration of heavy metals. Chemical changes, consequently, influenced metal (Cd, Cu, Pb, and Zn) solubility and speciation in the rhizosphere. The highest solubility was observed for soil Ko01 (eg. 2091 and $318{\mu}g\;L^{-1}$ for Cd and Pb, respectively). Initial heavy metal solubility in soils varied with soil and either increased or decreased following vetiver grass culture depending on the soil type. An increase in pH following plant culture generally resulted in a decrease in metal solubility, while elevated DOC due to root exudation resulted in an increase in metal solubility via the formation of metal-DOC complexes. Donnan speciation demonstrated a significant decrease in free Cd and Zn in the rhizosphere and the concentration of Cd, Pb, and Zn in vetiver grass shoot was highly correlated with soluble concentration rather than total soil metal concentration.