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The present paper reports the heavy metal uptake by water lettuce (Pistia stratiotes L.) from paper mill effluent (PME) with its prediction modeling studies. Lab scale phytoremediation experiments were performed in glass aquariums to grow P. stratiotes in 0% (bore well water as a control), 25%, 50%, 75%, and 100% concentrations of PME. The influence of pH and heavy metal concentration in PME for the effective uptake and accumulation of heavy metal contents (∆Y: mg/kg) in plant tissues was modeled using two-factor multiple linear regression. The results showed that the selected input variables were supportive to develop prediction models with higher linear regression (R2 > 0.72), high model efficiency (ME: 0.92–0.99), low mean average normalizing error (MANE < 0.02), and statistically significant F > Prob values. Kruskal-Wallis one-way post hoc test indicated that the contents of Cd, Cu, Fe, Pb, and Zn in the roots, leaves, and whole plant were affected by PME concentration while the contents of Mn did not. The correlation studies showed that the bioaccumulation of heavy metals was found both element and PME concentration specific. This work represents an effective method to model heavy metal uptake by P. stratiotes from PME. Furthermore, this methodology can also be adopted for predicting effective metal uptake by plant species being used for the phytoremediation of heavy metals from industrial effluents. [ABSTRACT FROM AUTHOR]

The paper production is material intensive and generates enormous quantity of wastewater containing organic pollutants and heavy metals. Present study demonstrates the feasibility of constructed wetlands (CWs) to treat the heavy metals from pulp and paper industry effluent by using vertical flow constructed wetlands planted with commonly available macrophytes such as Typha angustifolia, Erianthus arundinaceus, and Phragmites australis. Results indicate that the removal efficiencies of the planted CWs for iron, copper, manganese, zinc, nickel, and cadmium were 74, 80, 60, 70, 71, and 70 %, respectively. On the other hand, the removal efficiency of the unplanted system was significantly lower ranging between 31 and 55 %. Among the macrophytes, T. angustifolia and E. arundinaceus exhibited comparatively higher bioconcentration factor (10 to 10) than P. australis. [ABSTRACT FROM AUTHOR]

In order to assess the potential of wetland plants to remediate metals from a paper mill effluent contaminated wetland site in Northeast India, 25 abundant plant species belonging to 15 different families, soil, and water samples from the sites were tested for Pb, Zn, Mg, and Fe by atomic absorption spectrophotometer. The results showed that metal accumulation by wetland plants differed among species and tissues. Plants thrived in high Pb, Zn, Mg, and Fe which indicated their tolerance. According to the criteria used for selecting plants for phytoremediation such as high metal tolerance, short life cycle, wide distribution, large shoot biomass and translocation factor (TF) >1; five species each were Mg and Fe accumulators, nine species were Pb accumulators and, eight species were Zn accumulators and the rest were excluders. Alternanthera sessilis was the only plant species that had TF > 1 for all the four metals. The study indicated great promise for phytoremediation, as these accumulators could be used in future for practical phytoremediation approaches and reduction of the risk from harmful metals to human health. [ABSTRACT FROM AUTHOR]

Aided phytostabilization is a technology that uses metal tolerant plants and organic and/or inorganic amendments to reduce soil metal bioavailability, while improving soil health. Our objective was to determine the effects of the application of amendments [sheep manure (SHEEP), poultry litter (POULTRY), cow slurry (COW), and paper mill sludge mixed with poultry litter (PAPER)], together with the growth of a metallicolous Festuca rubra L. population, on (i) chemical and microbial indicators of soil health and (ii) soil ecotoxicity, during the aided phytostabilization of a Zn/Pb contaminated mine soil. Amendment application led to an increase in soil pH, organic matter content, and inorganic salts, resulting in a decrease in Pb and Zn CaCl-extractable concentrations in soil, which, in turn, contributed to lower ecotoxicity and a stimulation of plant growth and soil microbial communities. The factor most affecting the metal extractability was probably soil pH. POULTRY was the best amendment in terms of increasing plant growth, chlorophylls content, and soil microbial biomass and activity, but resulted in higher levels of phytoavailable Pb and Zn. SHEEP and PAPER were more effective at reducing metal CaCl-extractability and, consequently, led to lower values of metal accumulation in plant tissues, thereby reducing the risk of metals entering into the food chain. When combined with the application of organic amendments, the metallicolous F. rubra population studied here appears an excellent candidate for aided phytostabilization. Our results indicate that the application of organic amendments is essential for the short-term recovery of highly contaminated metalliferous soils during aided phytostabilization. [ABSTRACT FROM AUTHOR]

Parboiling rice mills produce a large amount of wastewater. The effluent from the rice mill contains high concentration of organic and inorganic compounds. Continuous discharge of this wastewater from rice mills could be a major cause of eutrophication of the water bodies, leading to a robust and undesirable growth of vegetation and algal bloom. Eutrophication leads to deoxygenation of water bodies, resulting in the mortality of aquatic flora and fauna. It is therefore very important to treat wastewater and ensure safe disposal. There are various types of processes already in existence, but the most important thing is to select a cost-effective technique. Phytoremediation technique has shown promising results for low-income countries like India. It is useful for the small-scale industrial and domestic wastewater treatment. It is a slow process, requiring a large area of land. It is an eco-friendly approach and ideal for rural areas where there is ample land availability. This paper addresses the techniques used by various researchers for rice mill wastewater treatment and also focuses on reusing and recycling of waste from rice mills. The performance of every technique is discussed in detail with its specific advantages and disadvantages. This paper also focuses on the advanced techniques of water treatment with valuable by-products such as silica, activated adsorbent, electricity and methane gas. [ABSTRACT FROM AUTHOR]

As a cost-effective, environmentally friendly remediation technology, phytoremediation is defined as the use of green plants to remove pollutants from the environment or render them harmless and has been applied to a variety of contaminated sites throughout the world. There is a prominent phenomenon in which publications about phytoremediation increase each year and involve an increasing number of subject categories. This paper adopts the scientometric analysis method to assess the current state and explore the trends of phytoremediation research based on the bibliographic records retrieved from the Web of Science Core Collection (WoSCC). The results of this paper clearly answer the following questions. (1) What are the publishing characteristics of research on the topic of phytoremediation? What are the characteristics of academic collaboration in phytoremediation research? (2) What are the characteristics and development trends of phytoremediation research? (3) What are the hotspots and frontiers of phytoremediation research? Overall, the research method provides a new approach for the assessment of the performance of phytoremediation research. These results may help new researchers quickly integrate into the field of phytoremediation, as they can easily grasp the frontiers of phytoremediation research and obtain more valuable scientific information. This study also provides references for the follow-up research of relevant researchers. [ABSTRACT FROM AUTHOR]

Phytoremediation is a cost-effective and eco-friendly plant-based approach promising technique to repair heavy metal–contaminated soils. However, a significant quantity of plant residues needs to be properly treated and utilized. Pyrolysis is an effective technology for converting residues to biochar, which can solve the problem and avoid secondary contamination. This paper reviews the generation, and physicochemical properties of biochar from phytoremediation residues, and its application in soil improvement, environmental remediation, and carbon sequestration. In spite of this, it is important to be aware of the potential toxicity of heavy metals in biochar and the environmental risks of biochar before applying it to practical applications. Future challenges in the production and application of residue-derived biochar include the rational selection of pyrolysis parameters and proper handling of potentially hazardous components in the biochar. [ABSTRACT FROM AUTHOR]

Water pollution is exacerbated due to irrational human activities in China. Restoring and rebuilding river basin ecosystems are major ecological strategies at present. Controlling the non-point source pollution (NPSP) by reasonable management of land use in the basin and phytoremediation of contaminated waters is the optimum approach. Thus, it is significant to study on the relationship that between landscape change and the aquatic environment, as well as further to analyze on the combined effect of the landscape and water quality. This paper describes the application and development of the "source–sink" landscape theory in China, and the role of the theory in controlling NPSP. From this perspective, a landscape capable of generating NPSP would be a "source" landscape, such as farmland, while another capable of preventing NPSP would be a "sink" landscape, such as forests and wetland. Applying the source-sink landscape theory, it is possible to exert the ecological benefits of the landscape while playing the esthetic value of the landscape. Also, the purification mechanism of plants in contaminated water is discussed. Besides, it is vital that research on water body restoration should focus not only on single discipline but also on integration and coordination between various ones such as ecology, environmental science, and geography to jointly push up researches related to water body phytoremediation. Hopefully, this paper could help to control water pollution from a new perspective, also to improve water environment and benefit human lives. [ABSTRACT FROM AUTHOR]

Macleaya cordata (Willd.) R. Br. are proposed for the application in phytoremediation of heavy metal-contaminated soil. In this paper, the physiological response, subcellular distribution, chemical form, ultrastructure, and manganese (Mn) absorption characteristics of M. cordata under the stress of 0, 3, 6, 9, 12, and 15 mmol/L manganese concentration were studied by sand culture experiment. The results showed that M. cordata seedlings show high tolerance to Mn stress with a concentration of less than 6 mmol/L, while higher Mn concentration showed a significant toxic effect. A low concentration of Mn (≤ 6 mmol/L) can promote the synthesis of chlorophyll and soluble protein; furthermore, superoxide dismutase and peroxidase activities responded positively. The accumulation of Mn in the inactive metabolic part (cell wall and vacuole) of M. cordata leaves might be one of the main Mn detoxification mechanism. According to the ultrastructure of M. cordata, high-concentration Mn2+ (≥ 12 mmol/L) stress can cause M. cordata cells to be distorted and deformed, black precipitates appeared in the intercellular space, mitochondria decrease, chloroplasts shrink, hungry particles increased, and starch granules decrease. The uptake ability of different tissues for Mn is leaf > root > stem, and transport coefficient decreases with the increase of Mn concentration. Clearly, M. cordata has a certain tolerance to manganese, which has the ecological application potential in Mn-polluted areas. [ABSTRACT FROM AUTHOR]

Phytoremediation emerges as an innovative and eco-friendly technique to remediate textile dyes with the use of various categories of plants. In recent years, ornamental plants emerge as more attractive and effective substitute in comparison to edible plants for phytoremediation. Regardless of aesthetic value, some ornamental plants can be grown to remediate the sites contaminated with dyes, heavy metals, pesticides, or other organic compounds. In this review, we focus on pioneer research on synthetic dye removal using ornamental plants and evaluate the phytoremediation capability of ornamental plants for treatment of textile effluent. This paper also emphasized specific ornamental plants having high accumulation and tolerance ability for removal of dyes. The mechanisms explored for the phytoremediation of dyes by ornamental plants have also been explained. This review will also be helpful for researchers for exploring more new ornamental plants in phytoremediation technique. [ABSTRACT FROM AUTHOR]

Metals can accumulate in different parts of plant species in high concentrations, which gives the basis for the plant-based technology called phytoremediation. Among annual species, Amaranthus is a well-studied, potential metal accumulator genus; however, some conflicts are found among published results. Thus, we studied the metal (Cd, Cu, Fe, Ni, Pb, and Zn) accumulation potential of Amaranthus plant parts (root, stem, and leaf) by meta-analysis, furthermore, by calculation of bioaccumulation factor (BAF) values. After the extensive literature search and the calculation of relative interaction intensity (RII) values, we found significant accumulation for each metal by Amaranthus individuals growing on contaminated soils compared to plants collected from uncontaminated ones. Differences among plant parts were significant for Cu and Fe, minor for Ni, Pb, and Zn, and negligible for Cd. The BAF values indicated high accumulation in the leaf, moderate in root and stem for Cd, moderate in each plant part for Pb, and very low in each plant part for Fe, Ni, and Zn. We highlight that Amaranthus species are good prospects for metal phytoremediation projects, although, due to specific plant part-metal patterns, special attention should be paid to the harvesting practice. [ABSTRACT FROM AUTHOR]

Populus species are well documented for being potentially suitable for phytoremediation purposes regarding their accumulation characteristics. However, published results are contradictory. Based on the data gathered during an extensive literature search, we aimed to assess and revise the metal accumulation potential in the root, stem, and leaf of Populus species growing in contaminated soils, with meta-analysis. We evaluated the influences of pollution level, soil pH, and exposure time on the metal uptake patterns. We found accumulations of Cd, Cr, Cu, Pb, and Zn to be significant in each plant part, while that was only moderate for Ni, and limited for Mn. By calculating the soil pollution index (PI), we observed significantly intensive, PI-independent accumulation for Cd, Cr, Cu, Ni, Pb, and Zn. A decrease in soil pH significantly increased the uptake of Mn and significantly decreased the accumulation of Pb in the stem. Metal uptake was significantly influenced by exposure time as well; Cd concentration was significantly decreased in the stem, while concentrations of Cr in the stem and leaf, and Mn in the stem were significantly increased with time. These aforementioned findings support a well-founded metal-and-growth condition-specific application of poplars in phytoremediation processes, also triggering further in-depth assessments to enhance the efficiency of relevant poplar-based technologies. [ABSTRACT FROM AUTHOR]

Chlorinated volatile organic compounds (CVOCs) are persistent organic pollutants which are harmful to public health and the environment. Many CVOCs occur in substantial quantities in groundwater and soil, even though their use has been more carefully managed and restricted in recent years. This review summarizes recent data on several innovative treatment solutions for CVOC-affected media including bioremediation, phytoremediation, nanoscale zero-valent iron (nZVI)-based reductive dehalogenation, and photooxidation. There is no optimally developed single technology; therefore, the possibility of using combined technologies for CVOC remediation, for example bioremediation integrated with reduction by nZVI, is presented. Some methods are still in the development stage. Advantages and disadvantages of each treatment strategy are provided. It is hoped that this paper can provide a basic framework for selection of successful CVOC remediation strategies. [ABSTRACT FROM AUTHOR]

Heavy metals are one of the most hazardous inorganic contaminants of both water and soil environment composition. Normally, heavy metals are non-biodegradable in nature because of their long persistence in the environment. Trace amounts of heavy metal contamination may pose severe health problems in human beings after prolonged consumption. Many instrumental techniques such as atomic absorption spectrophotometry, inductively coupled plasma-mass spectrometry, X-ray fluorescence, neutron activation analysis, etc. have been developed to determine their concentration in water as well as in the soil up to ppm, ppb, or ppt levels. Recent advances in these techniques along with their respective advantages and limitations are being discussed in the present paper. Moreover, some possible remedial phytoremediation approaches (phytostimulation, phytoextraction, phyotovolatilization, rhizofiltration, phytostabilization) have been presented for the removal of the heavy metal contamination from the water and soil environments. [ABSTRACT FROM AUTHOR]

Soil pollution is rapidly increasing due to industrialization and urbanization. Heavy metal pollution raised concern because of its possible impact on plants and humans. Helianthus annuus L. is a good hyperaccumulator plant, used for the removal of heavy metals because of its phytoremediation efficiency. In the present study, we cultivated H. annuus plants in industrial contaminated soil collected from various industries like plastic, paper, dye, and textile of different areas of Jaipur (Rajasthan), Kashipur, Jaspur, and Bajpur (Uttrakhand), India. Plantlets accumulated a different range of Pb, Cd, Zn, Cu, Fe, and As (0.62–158.29, 0.8–59.6, 0.81–166.5, 0.09–101.89, 2.06–53.25, and 0.002–2.55 mg kg−1, respectively) from the industrial soil samples. Heavy metal analysis was done using flame and graphite furnace atomic absorption spectrophotometer. The effects of heavy metals were analyzed by studying the morphological, biochemical, and antioxidant enzymatic analysis. The results revealed that industrial contaminated soil had a significant impeding effect on the plantlets of H. annuus as noticed by the reduction in growth parameters compared to the standard. Furthermore, one-way ANOVA and principal component analysis (PCA) were applied for statistical analysis and to determine the correlation between plant growth parameters, removed heavy metals, and biochemical. Thus, this study will be helpful for the decontamination of highly affected industrial soil. [ABSTRACT FROM AUTHOR]

Mercury (Hg), the environmental toxicant, is present in the soil, water, and air as it is substantially distributed throughout the environment. Being extremely toxic even at low concentration, its remediation is utterly important. Therefore, it is necessary to detoxify the contaminant within the acceptable limits before threatening the environment. Although various conventional methods are being used, irrespective of high cost, it produces intermediate toxic by-product too. Biological methods are eco-friendly, clean, greener, and safer for the remediation of heavy metals corresponding to the conventional remediation due to their economic and high-tech constraints. Bioremediation is now being used for Hg (II) removal, which involves biosorption and bioaccumulation mechanisms or both, also mercuric ion reductase, exopolysaccharide play significant role in detoxification of mercury by acting a potential instrument for the remediation of heavy metals. In this review paper, we shed light on problems caused by mercury pollution, mercury cycle, and its global scenario and detoxification approaches by biological methods and result found in the literature. [ABSTRACT FROM AUTHOR]

The freely and abundantly available amphibious plant Indian pennywort Bacopa monnieri (L.) Pennell was able to phytoremediate sewage (greywater) quickly and substantially in SHEFROL® ("sheet flow root level") bioreactors, achieving reductions in the levels of several indicator parameters: suspended solids, chemical oxygen demand, biological oxygen demand, nitrogen, phosphorus, zinc, copper, nickel, and manganese to the extents of about 90%, 76–77%, 80%, 65%, 55%, 56%, 42%, and 41%, respectively at hydraulic retention times of just 6 h. As these indicators of primary, secondary, and tertiary treatments were achieved simultaneously in a single reactor compartment, the system presented in this paper promises to be simple, rapid, and economical, in achieving significant treatment of greywater. [ABSTRACT FROM AUTHOR]

Development of mineral resources and the increasing mining waste emissions have created a series of environmental and health-related issues. Nowadays, the ecological restoration of mining tailings has become one of the urgent tasks for mine workers and environmental engineers all over the world. Aim of the present paper is to highlight the previous restoration techniques and the challenges encountered during the restoration of mine tailings. As it is a common practice that, before restoring of tailings, the site should be evaluated carefully. Studies showed that the mine tailings’ adverse properties, including excessive heavy metal concentration, acidification, improper pH value, salinization and alkalization, poor physical structure and inadequate nutrition, etc., are the major challenges of their restoration. Generally, four restoration technologies, including physical, chemical, phytoremediation, and bioremediation, are used to restore the mining tailings. The working mechanism, advantages, and disadvantages of these techniques are described in detail. In addition, selection of the suitable restoration techniques can largely be carried out by considering both the economic factors and time required. Furthermore, the ecosystem restoration is perceived to be a more promising technology for mine tailings. Therefore, this extensive review can act as a valuable reference for the researchers involved in mine tailing restoration. [ABSTRACT FROM AUTHOR]

Mirabilis jalapa L. is an ornamental plant of the composite family, which was found hyperaccumulating Cd. Due to its larger biomass, developed root system, root exudation, and microbial interactions, certain organic pollutants in its rhizosphere can be effectively degraded. Thus, M. jalapacan be used to co-remediate heavy metal and organic pollutant co-contaminated soil. The aim of this paper is to explore the remediation capacity of M. jalapa for Cd-PAHs co-contaminated soil in the presence of five chelators or surfactants. The concentrations of Cd and PAHs in collected soil samples were 0.85 mg kg−1 Cd and 1.138 mg kg−1 PAHs (16 kinds of priority control polycyclic aromatic hydrocarbons by USEPA). The chelators or surfactants of EDTA, EGTA, CA, TW80, and SA were respectively spiked to the pots according to the experiment design at 1 month before the plant harvested. The results showed that the capacity of Cd in shoot of M. jalapa was 7.99 μg pot−1 without any addition (CK4, M. jalapa in original soil without amendment). However, Cd capacity in shoot of M. jalapa was increased (p < 0.05) by 31.7%, 181.7%, and 107.4% in treatment of REGTA, RCA and REGTA + SA, respectively. As for the degradation of PAHs in soil, there was no significant decrease (p < 0.05) in the treatment of CK2 (original soil spiked with 0.9 SA without M. jalapa), CK3 (original soil spiked with 0.3 TW80 without M. jalapa), and CK4 compared to the control CK1 (original soil without M. jalapa and amendment). When amendments were added to soils with M. jalapa,the PAHs concentrations in soils significantly decreased (p < 0.05) by 21.7%, 23.8%, 27.0%, 19.8%, 21.8%, 31.2%, and 25.5% for the treatment of REDTA + SA, REDTA + T80, REGTA + SA, REGTA + T80, RCA + T80, RSA + T80 + EDTA, and RSA + T80 + CA, respectively. Basically, Cd capacity in shoot of M. jalapa was improved by chelators. PAHs degradation was caused by the existence of surfactants in rhizosphere of M. jalapa. But the roles of different chelators or surfactants were quite distinct. In short, the Cd capacity in the shoot and PAHs degradation in the rhizosphere of M. jalapa in the treatment of REGTA + SA were all significantly increased (p < 0.05), which was more practical for M. jalapa phytoremediating Cd-PAHs co-contaminated soil. [ABSTRACT FROM AUTHOR]

The objective of this paper is to demonstrate an interdisciplinary strategy combining both engineering- and biology-based approaches for stormwater and wastewater treatment. The work involves a novel and environmentally friendly surface material that can withstand urban load over its design service life, allows preliminary treatment through filtration, and diverts water to the subsurface to conduct secondary treatment below the surface through phytoremediation via the extensive rooting systems of trees. The present study highlights an interdisciplinary low-impact development (LID) approach developed for a polluted industrial wastewater site, for a cleaner and greener environment. The LID system involves (i) rhizofiltration and phytoremediation methods for removing heavy metals and organic pollutants using a hybrid poplar and aspen species; (ii) porous infrastructure produced using industrial waste, referred to as geopolymer pavers; and (iii) use of Silva cells as a tree-friendly and load support system. The design of the pavers over the Silva cells is innovative as it can deal with rainwater runoff and urban transportation loads simultaneously. The proposed system has the ability to extract heavy metals that are common in urban runoff or domestic and industrial effluents thus preserving the ecosystem naturally. The test site is only 15 m2, but designed for a water-retention capacity of 2 m3 (roughly 1:100 year design volume draining a 10 × 10 m parking lot), and remediation levels for Cu and Zn are expected to reach 180 mg/kg dry weight and 1200 mg/kg dry weight, respectively. [ABSTRACT FROM AUTHOR]

Combustion wastes are characterised by extremely low N contents. Therefore, introduction of nitrogen-fixing species at the first stage of their biological reclamation is required. This paper presents an assessment of the growth parameters of alders (Alnus sp.) 10 years after their introduction to a disposal site of lignite combustion waste in Central Poland. Black (Alnus glutinosa) and grey alders (Alnus incana) were planted directly in the combustion waste. The soil amendment included three variants: control with pure combustion waste, admixture of lignite culm and addition of acid sand. Both alder species displayed good growth parameters comparable to those of alders in natural habitats. However, black alder had better growth parameters, such as stand density index (SDI), diameter at breast height (DBH) and height (H) than grey alder. The lignite amendment exerted a positive effect on tree growth, reflected in a higher SDI and H, whereas the acid sand amendment did not affect any of the growth parameters of the studied alder species. Despite the good growth parameters, the measured N:P and N:K ratios in the alder leaves largely differed from the optimal values indicating insufficient P and K supply at the combustion waste disposal site. This may pose a threat to further development of the introduced tree plantings. The introduction of alders along with the lignite addition into the planting holes seems to be a successful method of combustion waste revegetation. [ABSTRACT FROM AUTHOR]

The paper discussed the effects of growth agents and mercury on the growth of four herb species subjected to a pot experiment: Aloe vera, Setcreasea purpurea, Chlorophytum comosum, and Oxalis corniculata. We determined the height and biomass production of selected plants treated with different growth agents and different concentrations of mercury solutions. We evaluated the relative growth rate (RGR) of the experimental plants. The aim of the study was to explore potential novel solutions to the shortcoming of the low speed of phytoremediation. The results showed that the upper parts of Aloe vera and Chlorophytum comosum had the fastest growth in the treatment with water only. In contrast, the upper parts of Setcreasea purpurea grew most intensely after the treatment with Lvyebao Fertilizer, whereas the aboveground parts of Oxalis corniculata had the fastest growth after the application of water and the occasional use of Green Cake Fertilizer. In addition, the tolerance to mercury of Oxalis corniculata was the strongest, whereas that of Chlorophytum comosum was the lowest among the species investigated. [ABSTRACT FROM AUTHOR]

This paper aimed to evaluate the ecological risk posed by the accumulation of heavy metals in the salt-affected soils of the habitat covered by the EU Natura 2000 program in relation to the activity of soil redox enzymes. The research was carried out in the halophyte reserve in Ciechocinek (north-central Poland) which is a very specific habitat as it undergoes a long-term human impact related to both the operation of the medical spa town and the agricultural use of soils in the adjacent areas. The obtained results showed that the content of Zn, Cu, Pb, and Cd in the studied soils exceeded the Polish standards. Based on the obtained data and statistical analysis, it was found that metals may come from two different sources: emission from household boiler rooms (Pb, Cd) and corroded brine sewage pipeline (Zn, Cu).They are characterized by limited mobility due to alkaline environment and strong sorption properties of the clay fraction and organic matter. The correlation analysis indicates that the dehydrogenase activities were negatively correlated with soil electrical conductivity (EC) ( r = − 0.665, P < 0.05). Taking into account the protective status of the area, it is difficult to indicate definitely the solution concerning the land management. However, according to the authors, one should pay special attention to a possibility of using halophytes which occur within the reserve for phytoremediation. [ABSTRACT FROM AUTHOR]

The present paper aims to assess the phytoremediation performance based on pollution removal efficiency of the highly polluted region of Alur Ilmu urban river for its applicability of on-site treatment. Thirteen stations along Alur Ilmu were selected to produce thematic maps through spatial distribution analysis based on six water quality parameters of Malaysia's Water Quality Index (WQI) for dry and raining seasons. The maps generated were used to identify the highly polluted region for phytoremediation applicability assessment. Four free-floating plants were tested in treating water samples from the highly polluted region under three different conditions, namely controlled, aerated and normal treatments. The selected free-floating plants were water hyacinth ( Eichhornia crassipes), water lettuce ( Pistia stratiotes), rose water lettuce ( Pistia sp.) and pennywort ( Centella asiatica). The results showed that Alur Ilmu was more polluted during dry season compared to raining season based on the water quality analysis. During dry season, four parameters were marked as polluted along Alur Ilmu, namely dissolve oxygen (DO), 4.72 mg/L (class III); ammoniacal nitrogen (NH-N), 0.85 mg/L (class IV); total suspended solid (TSS), 402 mg/L (class V) and biological oxygen demand (BOD), 3.89 mg/L (class III), whereas, two parameters were classed as polluted during raining season, namely total suspended solid (TSS), 571 mg/L (class V) and biological oxygen demand (BOD), 4.01 mg/L (class III). The thematic maps generated from spatial distribution analysis using Kriging gridding method showed that the highly polluted region was recorded at station AL 5. Hence, water samples were taken from this station for pollution removal analysis. All the free-floating plants were able to reduce TSS and COD in less than 14 days. However, water hyacinth showed the least detrimental effect from the phytoremediation process compared to other free-floating plants, thus made it a suitable free-floating plants to be used for on-site treatment. [ABSTRACT FROM AUTHOR]

Ricinus communis L . (castor bean or castor oil plant) was found growing on metal-contaminated sites (4) of peri-urban Greater Hyderabad comprises of erstwhile industrial areas viz Bollaram, Patancheru, Bharatnagar, and Kattedan industrial areas. During 2013-2017, about 60 research papers have appeared focusing the role of castor bean in phytoremediation of co-contaminated soils, co-generation of biomaterials, and environmental cleanup, as bioenergy crop and sustainable development. The present study is focused on its use as a multipurpose phytoremediation crop for phytostabilization and revegetation of waste disposed peri-urban contaminated soils. To determine the plant tolerance level, metal accumulation, chlorophyll, protein, proline, lipid peroxidation, oil content, and soil properties were characterized. It was noticed that the castor plant and soils have high concentration of metals such as cadmium (Cd), lead (Pb), iron (Fe), manganese (Mn), and zinc (Zn). The soils have high phosphorous (P), adequate nitrogen (N), and low concentration of potassium (K). Iron (Fe) concentrations ranged from1672±50.91 to 2166±155.78 mg kg in the soil. The trend of metal accumulation Fe>Zn>Mn>Pb>Cd was found in different plant parts at polluted sites. The translocation of Cd and Pb showed values more than one in industrial areas viz Bollaram, Kattedan, and Bharatnagar indicating the plants resistance to metal toxicity. Chlorophyll and protein content reduced while proline and malondialdehyde increased due to its tolerance level under metal exposure. The content of ricinoleic acid was higher, and the fatty acids composition of polluted areas was almost similar to that of the control area. Thus, R. communis L. can be employed for reclamation of heavy metal contaminated soils. [ABSTRACT FROM AUTHOR]

Water is a basic necessity of life, but due to overextraction and heavy input of nutrients from domestic and industrial sources, the contamination level of water bodies increase. In the last few decades, a potential interest has been aroused to treat wastewater by biological methodologies before discharge into the natural water bodies. Phytoremediation using water hyacinth is found to be an effective biological wastewater treatment method. Water hyacinth ( Eichhornia crassipes), a notorious weed, being the most promising plant for removal of contaminants from wastewater is studied extensively in this regard. It has been successfully used to accumulate heavy metals, dyes, radionuclides, and other organic and inorganic contaminants from water at laboratory, pilot, and large scale. The plant materials are also being used as sorbent to separate the contaminant from water. Other than phytoremediation, the plant has been explored for various other purposes like ethanol production and generation of biogases and green manures. Such applications of this have been good support for the technocrats in controlling the growth of the plant. The present paper reviews the phytoremedial application of water hyacinth and its capability to remove contaminants in produced water and wastewater from domestic and isndustrial sources either used as a whole live plant grown in water or use of plant body parts as sorbent has been discussed. [ABSTRACT FROM AUTHOR]

This paper analyses the capacity of the rape ( Brassica napus) to extract Cd and Zn from the soil and the effect of these metals on the morphometric parameters of the plant (length, weight, surface area, fractal dimension of leaves). Rape plants were mostly affected by the combined toxicity of the Cd and Zn mixture that caused a significant reduction in the rate of seed germination, the plant biomass quantity and the fractal dimension. In the case of Cd soil pollution, the bioaccumulation factor (BAF), bioaccumulation coefficient (BAC) as well as the heavy metal root-to-stalk translocation factor (TF) were determined. The results showed that B. napus had a great potential as a cadmium hyperaccumulator but not as an accumulator of Zn or Cd + Zn mixture. The efficiency of phytoextraction rape was 0.8-1.22 % for a soil heavily polluted with cadmium. [ABSTRACT FROM AUTHOR]

The actual amount of fresh water readily accessible for use is <1 % of the total amount of water on earth, and is expected to shrink further due to the projected growth of the population by a third in 2050. Worse yet are the major issues of water pollution, including mining and industrial waste which account for the bulk of contamination sources. The use of aquatic macrophytes as a cost-effective and eco-friendly tool for phytoremediation is well documented. However, little is known about the fate of those plants after phytoremediation. This paper reviews the options for safe disposal of waste plant biomass after phytoremediation. Among the few mentioned in the literature are briquetting, incineration and biogasification. The economic viability of such processes and the safety of their economic products for domestic use are however, not yet established. Over half of the nations in the world are involved in mining of precious metals, and tailings dams are the widespread legacy of such activities. Thus, the disposal of polluted plant biomass onto mine storage facilities such as tailing dams could be an interim solution. There, the material can act as mulch for the establishment of stabilizing vegetation and suppress dust. Plant decomposition might liberate its contaminants, but in a site where containment is a priority. [ABSTRACT FROM AUTHOR]

Urban environmental quality in brownfield redevelopment sites is of vital importance after most of former industrial areas were replanned or changed into residential and recreational areas. Hence, it is necessary to rethink if those brownfield redevelopment sites have been cleaned up so that there will be no negative health impacts to local residents. Under such a circumstance, this paper aims to evaluate the contamination level of heavy metals within a brownfield redevelopment site in China, namely, the Tiexi old industrial zone in Shenyang. Surface soil and dust samples were collected from local industrial sites, residential/commercial sites, traffic sites, and recreational sites, respectively. Our analysis results revealed that although the soils in the brownfield redevelopment sites had been treated and remediated, heavy metal pollution still exists in certain sites, especially in the current industrial sites that will be planned into residential/commercial or recreational zones, and the current residential sites where the former industrial sites located, showing that past industrial activities did and will continue to influence the soil quality. Further health risk assessment indicates that As and Pb generated from industrial sites and traffic sites has a potential to pose serious health risks to local residents, especially children. The hotspots with more serious health risks to children are mainly concentrated in the areas close to the former Shenyang Smelting Plant. After one decade of redevelopment, the Tiexi old industrial zone has become a new urban area which is not suitable for large-scaled soil remediation efforts. Thus, the phytoremediation by trees or herbs in heavy-metal-contaminated land is more appropriate and should be embedded into urban green land planning. This study provides innovative policy insights on urban brownfield redevelopment to both governmental officials and related stakeholders so that they can make appropriate remediation actions. [ABSTRACT FROM AUTHOR]

Lead (Pb) is one of the most toxic elements on earth. The harmful effects of Pb at higher concentrations were seen on plant vegetation because plants are directly exposed towards it. Indian mustard, a well-known hyperaccumulator plant is the most promising crop for the environment, engaged in a variety of scenarios for ecological cleanup. In the present study, we used ethylene diamine tetraacetic acid (EDTA), a chelating agent that is of remarkable efficiency. The pot experiments were conducted in soil pretreated with 1000 mgkg-1 Pb with different concentrations of EDTA (2-10 mmol). All the growth parameters were reduced significantly in the plants treated with Pb and EDTA, however, a non-significant effect was observed in 5 mmol EDTA compared to Pb alone treatment. Photosynthetic pigments yield, nitrate reductase activity and NPK content were affected negatively; in contrast, superoxide dismutase and catalase activity was increased in Pb and Pb+EDTA treated in both the varieties. The Pb accumulation was elevated significantly by the augmentation of 5 mmol EDTA in both varieties. Accumulation of Pb in the shoot was higher in PM 25 than in P. Vijay, whereas root Pb accumulation showed the opposite, i.e., more Pb in roots of P. Vijay than PM 25. Moreover, The Pb accumulation per plant was observed more in P. Vijay as compared to PM 25. Hence, the present study implies that the augmentation of Pb-polluted soil with EDTA works well while dealing with B. juncea assisted phytoremediation and P. Vijay to be a stronger variety than PM 25. Further, 5 mmol of EDTA was optimum for phytoremediation of the soil polluted with up to 1000 mg Pb kg-1 soil. [ABSTRACT FROM AUTHOR]

The choice of plant for phytoremediation success requires knowledge of how plants respond to contaminant exposure, especially their roots which are instrumental in supporting rhizosphere activity. In this study, we investigated the responses of plants with different architectures represented by beetroot ( Beta vulgaris), a eudicot with a central taproot and many narrower lateral roots, and tall fescue ( Festuca arundinacea), a monocot possessing a mass of threadlike fibrous roots to grow in crude oil-treated sand. In this paper, scanning electron microscopy was used to investigate modifications to plant root structure caused by growth in crude oil-contaminated sand. Root structural disorders were evident and included enhanced thickening in the endodermis, increased width of the root cortical zone and smaller diameter of xylem vessels. Inhibition in the rate of root elongation correlated with the increase in cell wall thickening and was dramatically pronounced in beetroot compared to the roots of treated fescue. The latter possessed significantly fewer ( p < 0.001) and significantly shorter ( p < 0.001) root hairs compared to control plants. Possibly, root hairs that absorb the hydrophobic contaminants may prevent contaminant absorption into the main root and concomitant axile root thickening by being sloughed off from roots. Tall fescue exhibited greater root morphological adaptability to growth in crude oil-treated sand than beetroot and, thus, a potential for long-term phytoremediation. [ABSTRACT FROM AUTHOR]

The paper describes the fieldwork at the Italian test site of the abandoned mine of sphalerite and galena in Ingurtosu (Sardinia), with the aim to assess the applicability of a 'toolbox' to establish the optimized techniques for remediation of soils contaminated by mining activities. A preliminary characterization-including (hydro)geochemistry, heavy metal concentration and their mobility in soil, bioprospecting for microbiology and botany-provided a data set for the development of a toolbox to deliver a microbially assisted phytoremediation process. Euphorbia pithyusa was selected as an endemic pioneer plant to be associated with a bacterial consortium, established with ten selected native strains, including metal-tolerant bacteria and producers of plant growth factors. The toolbox was firstly assessed in a greenhouse pot experiment. A positive effect of bacterial inoculum on E. pithyusa germination and total plant survival was observed. E. pithyusa showed to be a well-performing metallophyte species, and only inoculated soil retained a microbial activity with a high functional diversity, expanding metabolic affinity also towards root exudates. These results supported the decision to proceed with a field trial, investigating different treatments used singly or in combination: bioaugmentation with bacterial consortia, mycorrhizal fungi and a commercial mineral amendment. Microbial activity in soil, plant physiological parameters and heavy metal content in plants and in soil were monitored. Five months after the beginning, an early assessment of the toolbox under field conditions was carried out. Despite the cold season (October-March), results suggested the following: (1) the field setup as well as the experimental design proved to be effective; (2) plant survival was satisfactory; (3) soil quality was increased and bioaugmentation improved microbial activity, expanding the metabolic competences towards plant interaction (root exudates); and (4) multivariate analysis supported the data provided that the proposed toolbox can be established and the field trial can be carried forward. [ABSTRACT FROM AUTHOR]

The Three Gorges Dam on the Yangtze River in China has created a major reservoir in which the water level fluctuates annually by about 30 m, generating a drawdown zone of up to 350 km in summer. Since construction of the dam, there has been scientific and public interest in how to use the drawdown zone resources in environmentally sustainable ways. To this end, and with government support, an international conference was held in Chongqing Municipality (China) in October 2011 on the subject of conservation and ecofriendly utilization of wetlands in the Three Gorges Reservoir. The conference proceedings were subsequently published in the Journal of Chongqing Normal University. The proceedings reports are reviewed here in the context of other relevant literature. The proceedings included papers on ecology, ecodesign and ecological engineering, erosion control, plant production and carbon sequestration, phytoremediation of pollution, hydrosystem management, and others. Several of the reports derive from experimental work conducted at a research field station on the Three Gorges Reservoir situated in Kaixian County, Chongqing Municipality. Plant communities in the drawdown zone are declining in diversity and evolving. Experimental plantings of flood-tolerant edible hydrophytes in a dike-pond system reveal their potential to provide economic returns for farmers, and flooding-tolerant trees, such as cypresses, also show promising results for stabilizing soils in the drawdown zone. Flood-tolerant natural plant communities vary strongly with depth and their composition provides useful indicators for revegetation strategies. In the region surrounding the reservoir, remnant natural broad-leaved evergreen forests are most effective in sequestering carbon, and within the drawdown zone, carbon is mostly stored below ground. There is strong interest in the potential of aquatic plants for removal of pollutants, notably N and P, from the reservoir water by means of floating beds. Other examples of applying ecodesign and ecological engineering strategies for restoration and management of rivers and lakes are also given. Scientific studies have provided valuable advice for ecofriendly utilization of the reservoir drawdown zone and further studies of the evolving condition of the reservoir can be expected to pay additional practical dividends. [ABSTRACT FROM AUTHOR]

One of the burning problems of our industrial society is the high consumption of water and the high demand for clean drinking water. Numerous approaches have been taken to reduce water consumption, but in the long run it seems only possible to recycle waste water into high quality water. It seems timely to discuss alternative water remediation technologies that are fit for industrial as well as less developed countries to ensure a high quality of drinking water throughout Europe. The present paper discusses a range of phytoremediation technologies to be applied in a modular approach to integrate and improve the performance of existing wastewater treatment, especially towards the emerging micro pollutants, i.e. organic chemicals and pharmaceuticals. This topic is of global relevance for the EU. Existing technologies for waste water treatment do not sufficiently address increasing pollution situation, especially with the growing use of organic pollutants in the private household and health sector. Although some crude chemical approaches exist, such as advanced oxidation steps, most waste water treatment plants will not be able to adopt them. The same is true for membrane technologies. Incredible progress has been made during recent years, thus providing us with membranes of longevity and stability and, at the same time, high filtration capacity. However, these systems are expensive and delicate in operation, so that the majority of communities will not be able to afford them. Combinations of different phytoremediation technologies seem to be most promising to solve this burning problem. To quantify the occurrence and the distribution of micropollutants, to evaluate their effects, and to prevent them from passing through wastewater collection and treatment systems into rivers, lakes and ground water bodies represents an urgent task for applied environmental sciences in the coming years. Public acceptance of green technologies is generally higher than that of industrial processes. The EU should stimulate research to upgrade existing waste water treatment by implementing phytoremediation modules and demonstrating their reliability to the public. [ABSTRACT FROM AUTHOR]

In the present study, the fertilization potential of biosolids (sewage sludge; SS) for the cultivation of Aloe vera plants was investigated using block design. Pot experiments were conducted in this study using 50, 100, 150, and 200 g/kg of SS. Results showed that SS-fertilized soils significantly (p < 0.05) affected the proximate, biochemical, and heavy metal parameters of A. vera plants. In particular, the T4 treatment gave the best results with maximum plant height 62.21 ± 0.10 cm, number of leaves per plant 18.00 ± 4.00, shoot-to-root ratio 6:1, fresh weight 1972.10 ± 0.07 g per plant, dry weight 175.49 ± 0.15 g per plant, total chlorophyll content (TCC) 0.41 ± 0.02 mg/g fwt., carotenoids 0.25 ± 0.04 mg/g, total flavonoids 7.55 ± 0.05 mg/g, total tannins 3.87 ± 0.06 µg/g, ascorbic acid 532.14 ± 0.10 µg/g, superoxide dismutase (SOD) 46.28 ± 0.19 µg/g, catalase (CAT) 119.23 ± 0.17 µg/g, salicylic acid 3.05 ± 0.12 mg/ml and anthraquinones 0.45 ± 0.04 mg/ml, respectively. The proximate plant characteristics were 96.25 ± 2.71% moisture content, crude protein 0.93 ± 0.05%, crude fiber 5.78 ± 0.44%, crude lipid 3.25 ± 0.02%, lignin 10.74 ± 0.30%, cellulose 13.56 ± 1.06%, hemicellulose 7.24 ± 0.14%, ash 8.75 ± 0.03%, and carbohydrate contents 52.18 ± 1.10% in comparison with control treatment. The bioaccumulation factor showed that heavy metal accumulation was in the order of Cd < Ni < Cu < Pb < Cr < Zn < Fe. The prediction models developed on the basis of soil properties showed good fitness results for the prediction of heavy metal uptake by A. vera plants. The study presented a sustainable approach for managing SS in an eco-friendly way while producing good-quality A. vera plants. [ABSTRACT FROM AUTHOR]

Nickel (Ni) is an essential element for plants; however, excessive uptake of Ni causes phytotoxicity in plants. The phytotoxic effects of Ni on the growth of quinoa and the underlaying mechanisms for Ni tolerance and phytoremediation are unknown. Hence, the present study investigated Ni tolerance and accumulation potential of two quinoa genotypes (Puno and Vikinga). Both genotypes were exposed to Ni (0, 100, 200, 300, and 400 μM) in half-strength Hoagland nutrient solution for three weeks. Results revealed that shoot and root lengths, biomass, stomatal conductance, and chlorophyll contents were decreased with the increase of Ni concentration. Excessive uptake of Ni resulted in the limited uptake of K by root and its translocation to shoot. Ni caused oxidative stress in plants by overproduction of H2O2 leading to lipid peroxidation of cell membranes. Genotype Puno showed greater tolerance to Ni than Vikinga based on tolerance index, lower bioconcentration factor, and translocation factor. Greater tolerance of Puno was mainly attributed to improved physiological responses and amelioration of oxidative stress by induction of antioxidant enzymes such as peroxidase (POD), catalase (CAT), superoxide dismutase (SOD), and ascorbate peroxidase (APX). It was revealed through multivariate analysis that Ni had strong negative correlations with growth and physiological attributes and positive associations with oxidative stress attributes. The study demonstrated genotypic variation in response to varying Ni concentrations and Puno performed better than Vikinga for phytostabilization of Ni-contaminated soils. [ABSTRACT FROM AUTHOR]

Enrofloxacin (Enro) has been widely encountered in natural water sources, and that water is often used for irrigation in crop production systems. Due to its phytotoxicity and accumulation in plant tissues, the presence of Enro in water used for crop irrigation may represent economical and toxicological concerns. Here, we irrigated two ornamental plant species (Zantedeschia rehmannii Engl. and Spathiphyllum wallisii Regel.) with water artificially contaminated with the antimicrobial enrofloxacin (Enro; 0, 5, 10, 100, and 1000 μg L−1) to evaluate its effects on ornamental plant production, as well as its accumulation and distribution among different plant organs (roots, leaves, bulbs, and flower stems), and examined the economic and environmental safety of commercializing plants produced under conditions of pharmaceutical contamination. The presence of Enro in irrigation water was not found to disrupt plant growth (biomass) or flower production. Both species accumulated Enro, with its internal concentrations distributed as the following: roots > leaves > bulbs > flower stems. In addition to plant tolerance, the content of Enro in plant organs indicated that both Z. rehmannii and S. wallisii could be safety produced under Enro-contaminated conditions and would not significantly contribute to contaminant transfer. The high capacity of those plants to accumulate Enro in their tissues, associated with their tolerance to it, indicates them for use in Enro-phytoremediation programs. [ABSTRACT FROM AUTHOR]

Phytoremediation technology, as an eco-friendly and cost-effective approach, is widely used to restore soil contaminated by heavy metal(loid)s. However, the adaptability and absorption capacity of plants to multiple elements are the crucial factors affecting the application of phytoremediation in mining areas. In this study, dominant native plant species and their paired soils were collected near a lead-zinc mine in Inner Mongolia, to assess the ecological risk of heavy metal(loid)s and phytoremediation potential. The results showed that Cd and As were the dominant soil pollutants, with levels of 90.91% and 100%, respectively, exceeding the risk intervention values for soil contamination of agricultural land. The rates of Pb, Cu, and Zn exceeding the risk screening values were 69.70%, 60.61%, and 96.97%, respectively. Extremely high ecological risk of heavy metal(loid)s was observed in this area. The ability of native plants accumulating heavy metals varied among species. The bioconcentration factor (BCF) varied from 0.14 to 2.59 for Cd, 0.02 to 0.45 for As, 0.06 to 0.76 for Pb, 0.05 to 2.69 for Cr, 0.15 to 1.00 for Cu, and 0.22 to 4.10 for Zn. Chinese Cinquefoil Herb (Potentilla chinensis Ser.) showed the potential to accumulate multiple toxic elements based on the biomass, shoot content, translocation factor (TF), BCF, and metal extraction rate (MER), while, other species showed the potential to accumulate single toxic element: goosefoot (Chenopodium album L.), Lespedeza daurica (Laxm.) Schindl. and peashrubs (Caragana korshinskii Kom.), Herba Artemisiae Scopariae (Artemisia capillaris Thunb.), alfalfa (Medicago sativa L.), and Moldavian Dragonhead (Dracocephalum moldavica L.) for Cd, As, Cr, Cu, and Zn, respectively. Furthermore, wild leek (Allium ramosum L.), cogongrass (Imperata cylindrica (L.) Beauv.), fringed sagebrush (Artemisia frigida Willd.), and field bindweed (Convolvulus arvensis L.) were selected for phytostabilization of specific elements, considering the heavy metal contents in the roots and low TF values. This study provides a reference for selecting appropriate species for the remediation of heavy metal-contaminated soils in certain mining areas. [ABSTRACT FROM AUTHOR]

Rare earth elements (REEs) are a group of elements whose concentration in numerous environmental matrices continues to increase; therefore, the use of biological methods for their removal from soil would seem to be a safe and reasonable approach. The aim of this study was to estimate the phytoextraction efficiency and distribution of light and heavy (LREEs and HREEs) rare earth elements by three herbaceous plant species: Artemisia vulgaris L., Taraxacum officinale F.H. Wigg. and Trifolium repens L., growing at a distance of 1, 10, and 25 m from the edge of a frequented road in Poland. The concentration of REEs in soil and plants was highly correlated (r > 0.9300), which indicates the high potential of the studied plant species to phytoextraction of these elements. The largest proportion of REEs was from the group of LREEs, whereas HREEs comprised only an inconsiderable portion of the REEs group. The dominant elements in the group of LREEs were Nd and Ce, while Er was dominant in the HREEs group. Differences in the amounts of these elements influenced the total concentration of LREEs, HREEs, and finally REEs and their quantities which decreased with distance from the road. According to the Friedman rank sum test, significant differences in REEs concentration, mainly between A. vulgaris L., and T. repens L. were observed for plants growing at all three distances from the road. The same relation between A. vulgaris L. and T. officinale was observed. The efficiency of LREEs and REEs phytoextraction in the whole biomass of plants growing at all distances from the road was A. vulgaris L. > T. officinale L. > T. repens L. For HREEs, the same relationship was recorded only for plants growing at the distance 1 m from the road. Bioconcentration factor (BCF) values for LREEs and HREEs were respectively higher and lower than 1 for all studied plant species regardless of the distance from the road. The studied herbaceous plant species were able to effectively phytoextract LREEs only (BCF > 1); therefore, these plants, which are commonly present near roads, could be a useful tool for removing this group of REEs from contaminated soil. [ABSTRACT FROM AUTHOR]

Korean government has made and will continue to make a considerable investment in contaminated soil remediation to rectify the problems that arise from soil pollution. Quantitative information on the benefits of contaminated soil remediation is widely demanded by the public as well as the government. This article aims to assess the external benefits of contaminated soil remediation. A survey of 1000 randomly selected households was undertaken in Korea. The results show that the marginal willingness to pay values for a 1% decrease in human health hazard, a 1% improvement in biodiversity restoration, and 1000 new job creation by contaminated soil remediation are estimated to be KRW 204 (USD 0.17), 593 (0.50), and 238 (0.20) per household per year. The findings can provide policy-makers with useful information for both evaluating and planning the contaminated soil remediation. [ABSTRACT FROM AUTHOR]

The article describes new strategies for the remediation of soils contaminated with organic and inorganic pollutants. The aim of this study is to investigate the synergistic effects of combining plant-microorganism-functional materials for a more effective reduction of soil contamination with toxic chemicals. The innovative triad involves functional materials as a habitat for microorganisms, which helps to control the release of pollutants into the soil solution from the adsorbed form. This, in turn, reduces the toxic effect on microorganisms and plants. Microorganisms play a complex role, consisting of partial biodegradation of pollutants, stimulation of plant growth, and support for nutrient supply. Plants synthesize root exudates that facilitate microorganisms in biodegrading organic pollutants and stimulate their growth. The plant takes up pollutants through the root system, which can be further supported by endophytic microorganisms. The cooperation of the three players produces a synergistic effect that enhances the effectiveness of rhizodegradation supported by functional materials, which is more effective than using microorganisms, phytoremediation, or functional materials alone. The combination of physicochemical methods (functional materials) and microbiological methods (bacteria and fungi, rhizosphere, symbiotic and non-symbiotic) supported by plants (hyperaccumulators) is a promising approach for reducing chemicals from soil. Key examples of the synergistic effects of combining plant-microorganism-functional materials have been provided in this article. [ABSTRACT FROM AUTHOR]

Modeling plants for biomass production and metal uptake from surrounding environment is strongly dependent on the moisture content of soil. Therefore, experiments were conducted to find out how soil moisture affects the phenotypic traits, photosynthetic efficiency, metabolic profile, and metal accumulation in the hyperaccumulating ecotype of Sedum alfredii (S. alfredii). A total of six water potential gradients were set: 0 ~ −15 kPa (T1), −15 ~ −30 kPa (T2), −30 ~ −45 kPa (T3), −45 ~ −60 kPa (T4), −60 ~ −75 kPa (T5), and −75 ~ −90 kPa (T6). Different water potential treatments had a significant effect on plant growth and metal uptake efficiency. Compared to T3, T2 was more effective in promoting plant growth and development, with an increase in biomass of 23% and 17% in both fresh weight (FW) and dry weight (DW), respectively. T2 and T3 had the highest cadmium (Cd) content in the shoot (280.2 mg/kg) and (283.3 mg/kg), respectively, whereas T1 had the lowest values (204.7 mg/kg). Cd availability for plants in the soil was affected by moving soil moisture cycles. Changes in soil moisture that were either too high or too low compared to the ideal soil water content for S. alfredii growth resulted in a significant reduction in Cd accumulation in shoots. Tryptophan, phenylalanine, and other amino acids were accumulated in T5, whereas only tryptophan and phenylalanine slightly increased in T1. Sugars and alcohols such as sucrose, trehalose, mannitol, galactinol, and mannobiose increased in T5, while they decreased significantly in T1. Interestingly, in contrast to T1, the two impaired metabolic pathways in T5 (galactose and starch metabolism) were identified to be glucose metabolic pathways. These findings provide scientific information (based on experiments) to improve biomass production and metal uptake efficiency in hyperaccumulating ecotype of S. alfredii for phytoremediation-contaminated agricultural fields. [ABSTRACT FROM AUTHOR]

Intercropping improves the phytoremediation of soil trace metal contamination. Dripping irrigation could further promote the phytoremediation of trace metals by influencing their speciation and total amount in soil. However, there is currently insufficient information elucidating this synergistic effect. In this study, the combined effect of drip irrigation and intercropping on the phytoremediation of Cu-contaminated soil was testified by investigating the changes of Cu spatial distribution and speciation in soil irrigated by dripping or sprinkling methods, as well as Cu bioconcentration factor and translocation factor by plants. Results showed that after a 30-day drip irrigation, the Cu level in soils near the drip outlet decreased by 4.7% and that in Triticum aestivum L. (T. aestivum) roots intercropped with Helianthus annuus L. (H. annuus) and Zea mays L. (Z. mays) dropped by 53.2% and 25.1%, respectively, relative to sprinkler irrigation. Meanwhile, the total Cu and exchangeable Cu levels in soils 6 cm away from the drip outlet increased by 10.8% and 20.4% after 30 days of drip irrigation, leading to 41.1% and 40.0% increases of Cu content in remediation plants H. annuus and Z. mays seedlings as compared to the values by sprinkler irrigation. Therefore, the drip irrigation enhanced the effect of intercropping on Cu phytoremediation. [ABSTRACT FROM AUTHOR]

Potentially toxic elements (PTE) in soil like copper (Cu) have been common in agricultural and mining areas worldwide. The sustainable remediation of these areas has been shown to have high socio-environmental relevance and phytoremediation is one of the green technologies to be considered. The challenge is to identify species that are tolerant to PTE, and to assess their phytoremediation potential. The objective of this study was to evaluate the physiological response of Leucaena leucocephala (Lam.) de Wit and to determine the species tolerance and phytoremediation potential to concentrations of Cu in the soil (100, 200, 300, 400 and 500 mg/dm3). The photosynthetic rate was not affected, while the content of chlorophylls decreased as Cu concentrations increased. There was an increased in stomatal conductance and water use efficiency from the treatment of 300. The root biomass and the length were bigger than the shoots, in the treatments above 300. Cu accumulation was greater in the roots than in the shoot of the plants, thus, the Cu translocation index to the shoot was lower. The ability to absorb and accumulate, mainly, Cu in the roots, allowed the development and growth of plants, since the parameters of photosynthesis and biomass accumulation were not affected by the Cu excess. This accumulation in the roots is characterized as a strategy for the phytostabilization of Cu. Therefore, L. leucocephala is tolerant to the Cu concentrations evaluated and has a potential phytoremediation of Cu in the soil. [ABSTRACT FROM AUTHOR]

Organic fertilization and mycorrhization can increase the phytoremediation of copper-contaminated soils. The time of vermicomposting alters the properties of vermicompost, which can affect copper's availability and uptake. Therefore, this study sought to evaluate the effect of different organic fertilizers and mycorrhization on copper-contaminated soil phytoremediation. The soil was contaminated with 100 mg Cu kg−1 dry soil and received mineral fertilizer (MIN), bovine manure (CM), and vermicompost produced in 45 days (V45) or 120 days (V120), all in doses equivalent to 40 mg kg−1 dry soil of phosphorus. Half of the jack bean (Canavalia ensiformis) plants were inoculated with the arbuscular mycorrhizal fungus Rhizophagus clarus. At plant flowering, the dry mass and concentrations of Cu, Zn, Mn, Ca, Mg, P, and K in the soil, solution, and plant tissue were determined, in addition to mycorrhizal colonization, nodulation, photosynthetic pigments, and oxidative stress enzyme activity. Organic fertilization increased plant growth and copper accumulation in aerial tissues. These effects were more evident with the V120, making it suitable for use in copper phytoextraction. Mycorrhization increased root and nodule dry mass, making it recommended for phytostabilization. C. ensiformis nodulation in Cu-contaminated soils depends on vermicompost fertilization and mycorrhization. Hence, the copper phytoremediation by C. ensiformis is increased by using organic fertilization and mycorrhization. [ABSTRACT FROM AUTHOR]

Phytoremediation is a cost-effective nature-based solution for brownfield reclamation. The choice of phytoextraction or phytostabilization strategies is highly relevant when planning full-scale treatments. A suitable approach to identify such species involves the evaluation of plants that grow spontaneously on the contaminated sites. Here, we sought to determine the phytoremediation potential of three spontaneous plant species, namely the trees Acer pseudoplatanus L (A. pseudoplatanus) and Betula celtiberica Rothm. & Vasc (B. celtiberica), and the shrub Buddleja davidii Franch (B. davidii), for the recovery of an urban brownfield. To determine the response of the species to the degree of contamination, we conducted soil and vegetation sampling inside and outside the site. The concentrations of As, Cu, and Zn in soil and plant samples were measured, and then various indexes related to phytoremediation were calculated. The translocation factor and transfer coefficient indicated that vegetation outside the brownfield had phytoextraction capacity while the same plants inside the brownfield revealed phytostabilization properties. Given our results, we propose that the selected species are suitable for phytostabilization strategies in areas with high concentrations of contaminants, whereas they could be used for phytoextraction only in soils with low or moderate levels of pollution. [ABSTRACT FROM AUTHOR]

Phytoremediation technology is an effective method to remove formaldehyde indoors, but the purification capacity and physiological response of plants to formaldehyde under the simultaneous influence of light and CO2 have not been examined in previous studies. In this study, formaldehyde fumigation experiments were conducted on the C3 plants Epipremnum aureum A. and Chlorophytum comosum L., and the crassulacean acid metabolism (CAM) plant Dieffenbachia maculate A. The phytoremediation performance and physiological response of plants were studied. The initial concentration of formaldehyde was established at 11.950 ± 1.442 m g ∙ m - 3 ; the light intensities were 448 ± 7 Lx , 1628 ± 22 Lx , and 3259 ± 22 Lx , respectively; and the concentrations of CO2 were 455 ± 29 ppm , 978 ± 50 ppm , 2020 ± 66 ppm , and 3006 ± 95 ppm , respectively. The results indicated that the highest purification rates of formaldehyde by E. aureum, D. maculata, and C. comosum were 55.8%, 43.7%, and 53.2%, respectively. The light intensity had a positive effect on the formaldehyde purification rates of all three plants and positively stimulated peroxidase (POD) activity, while the CO2 concentration had no significant impact on the formaldehyde purification capacity and plants' physiological characteristics. Exposure to formaldehyde inhibited formaldehyde dehydrogenase (FADH) activity and positively stimulated catalase (CAT) activity. The superoxide dismutase (SOD) activity positively correlated with the formaldehyde purification capacity of plants. [ABSTRACT FROM AUTHOR]

With the development of industries and excessive use of petroleum compounds, petroleum pollution has become a serious threat to the environment. The aim of this study was to the effect of petroleum levels on the biological activities of soil affected by phytoremediation and bioaugmentation. A surface soil sample was collected from the polluted areas around Bandar Abbas Oil Refinery Company, and the petroleum-degrading bacteria were isolated. M. yunnanensis (native) was selected among the isolated colonies for further experiment. The used soil in this study was a surface soil collected from Baghu region of Bandar Abbas, Sothern Iran, and treatments were added to soil samples. To evaluate removal of petroleum levels (0, 4, and 8%) from the soil by phytoremediation (control, sorghum, barley, and bermudagrass) and bioaugmentation (control, A. brasilense (non-native) and M. yunnanensis) and bioaugmented phytoremediation, a factorial pot experiment with completely randomized design and three replications was performed. The results demonstrated that sorghum and bermudagrass were more resistant than barley to the toxic effects of petroleum. Positive effect of bacteria on dry weight in polluted soil was greater than in the non-polluted soil. The degradation of petroleum reaches 77% in sorghum + M. yunanesis + 4% petroleum. Plants had stronger ability to degrade total petroleum hydrocarbon (TPH), while bacteria could better degrade polyaromatic hydrocarbons (PAHs). Application of bacteria and plants stimulated soil biological characteristics (dehydrogenase, arylsulfatase, lipase, bacterial population, and respiration) in polluted soil. Among measured enzymes, dehydrogenase exhibited a stronger response to petroleum levels. Four-percent level had greater irritating effect on soil biological properties. Plants and bacteria rely on differences in biological properties to attain synergy in petroleum degradation. Results indicated that M. yunnanensis has a high ability to remove petroleum from soil, and plants enhance the efficiency of this bacterium. [ABSTRACT FROM AUTHOR]

One of the consequences of mining is the release of heavy metals into the environment, especially water bodies. Phytoremediation of areas contaminated by heavy metals using Vetiver grass and Indian mustard is cost-effective and environmentally friendly. This study aimed at enhancing remediation of heavy metal contaminated water through the simultaneous hybrid application of clay minerals (attapulgite and bentonite) and Vetiver grass or Indian mustard. A 21-day greenhouse experiment was carried out to investigate the effectiveness of the clay minerals to improve heavy metal phytoremediation. The highest accumulation of aluminium (Al) by Vetiver grass was 371.8 mg/kg in the BT2.5VT treatment, while for Mn, the highest accumulation of 34.71 mg/kg was observed in the AT1VT treatment. However, Indian mustard showed no significant uptake of heavy metals, but suffered heavy metal toxicity despite the addition of clay minerals. From this study, it was evident that bentonite added at 2.5% (w/v) could improve the phytoremediation capacity of Vetiver grass for Al and Mn polluted water. The current laboratory-scale findings provided a basis for field trials earmarked for remediation in a post-mining coal environment in South Africa. This remediation approach can also be adopted in other places. [ABSTRACT FROM AUTHOR]

Heavy metals in soil pose a serious threat through their toxic effect on the human food chain. Phytoremediation is a clean and green potentially cost-effective technology in remediating the heavy metal-contaminated soil. However, the efficiency of phytoextraction is very often limited by low phytoavailability of heavy metals in soil, slow growth, and small biomass production of hyper-accumulator plants. To solve these issues, accumulator plant(s) with high biomass production and amendment(s) which can solubilize metals in soil is required for better phytoextraction. A pot experiment was conducted to assess the efficiency of phytoextraction of sunflower, marigold, and spinach as affected by the incorporation of Sesbania (solubilizer) and addition of gypsum (solubilizer) in nickel (Ni)-, lead (Pb)-, and chromium (Cr)-contaminated soil. A fractionation study was conducted to study the bioavailability of the heavy metals in contaminated soil after growing the accumulator plants and as affected by using soil amendments (Sesbania and gypsum). Results showed that marigold was the most efficient among the three accumulator plants in phytoextraction of the heavy metals in the contaminated soil. Both sunflower and marigold were able to reduce the bioavailability of the heavy metals in the post-harvest soil, which was reflected in their (heavy metals) lower concentration in subsequently grown paddy crop (straw). The fractionation study revealed that carbonate and organically bound fractions of the heavy metals control the bioavailability of the heavy metals in the experimental soil. Both Sesbania and gypsum were not effective in solubilizing the heavy metals in the experimental soil. Therefore, the possibility of using Sesbania and gypsum for solubilizing heavy metals in contaminated soil is ruled out. [ABSTRACT FROM AUTHOR]