Article

Comparison of three ornamental plants for phytoextraction potential of chromium removal from tannery sludge

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Abstract

Based on pre-experimentation, three ornamental plants, Mirabilis jalapa, Impatiens Balsamin (I. Balsamin) and Tagetes erecta L., were selected as target plants to study the phytoextraction of chromium (Cr) in tannery sludge irrigated with four treatments according to Cr concentration gradient [Control (CK); 20.50 × 103 mg kg−1 (T1); 51.25 × 103 mg kg−1 (T2); 102.50 × 103 mg kg−1 (T3)]. Results of pot experiments showed that the biomass of Mirabilis jalapa and Tagetes erecta L. had no significant differences among the four treatments, while I. Balsamin showed a decline trend in the biomass with the increase of Cr concentration, probably due to some extent to the poisoning effect of Cr under treatment T2 or T3. Mirabilis jalapa accumulated Cr concentration, with 408.97, 124.97, 630.16 and 57.30 mg kg−1 in its roots, stems, leaves and inflorescence, respectively. The translocation factor and the bioaccumulation coefficient of Mirabilis jalapa are each greater than 1, indicating that Mirabilis jalapa has the strong ability to tolerate and enrich Cr by biological processes. Comparing accumulation properties of the three ornamental plants, in the amount and allocation, Mirabilis jalapa showed the highest phytoextraction efficiency and could grow well at the high Cr concentration. Our experiments suggest that Mirabilis jalapa is the expected flower species for Cr removal from tannery sludge.

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... However, to the best of our knowledge, there are no studies on combined application of ornamental plants and NPs in metal(loid) phytoremediation. The application of ZVI NP is reported to augment plant growth at low concentrations and maintain germination rate (Miao and Yan, 2013;Huang et al., 2018). Further due to surface binding of heavy metals to ZVI NP (Wang et al., 2020), the availability of metal(loid)s to plants increases at rhizospheric root zone. ...
... Karthik and Sharavanan (2016) showed the effectiveness of globose as a phytoremediator of Cr from soil along with mycorrhizal association. Considering balsamina, Miao and Yan (2013), reported the poor ability of this plant as an accumulator of Cr whereas Yasin et al. (2019) showed the effectiveness can be improved by amendment of EDTA for the uptake of soil Ni content. Supplementation of zero valent ZVI NP to balsamina can also take up soil e-waste as reported by Gao and Zhou (2013). ...
Article
The increasing industrialization and urbanization are also triggering environmental pollution, mostly unnoticed, in the case of soil pollution due to uncontrolled contamination by toxic elemental dispersion. The present study focused on this aspect and studied the clean-up of urban soil in a low-cost and eco-friendly way to restrict arsenic (As), lead (Pb) and mercury (Hg) contamination. Four potential ornamental plants, Catharanthus roseus (vinca), Cosmos bipinnatus (cosmos), Gomphrena globose (globosa) and Impatiens balsamina (balsamina) were used along with zero valent iron (ZVI) nanoparticles (Fe NPs) for remediation of the soil spiked with As (70 mg kg−1), Pb (600 mg kg−1) and Hg (15 mg kg−1) in a 60 d pot experiment. All plants were divided into four groups viz. control, spiked, spiked+20 mg kg−1 ZVI NP and spiked+50 mg kg−1 ZVI NP. FTIR and SEM were used for ZVI NP characterization. Soil and plant analyses and elemental assessments were done using ICP-MS, XRF and SEM. Among the four plants, cosmos showed the maximum accumulation of toxic elements (41.24 ± 0.022 mg kg−1 As, 139.15 ± 11.2 mg kg−1 Pb and 15.57 ± 0.27 mg kg−1 Hg) at 60 d. The application of ZVI NP at 20 mg kg−1 dosage was found to further augment plants’ potential for metal(loid)s accumulation without negatively hampering their growth. Cosmos were observed to reduce soil As from 81.35 ± 1.34 mg kg−1 to 28.16 ± 1.38 mg kg−1 (65.38%), Pb from 1132.47 ± 4.66 to 516.09 ± 3.15 mg kg−1 (54.42%) and Hg from 17.35 ± 0.88 to 6.65 ± 0.4 mg kg−1 (61.67%) at 60 d in spiked + 20 mg kg−1 ZVI NP treatment. Balsamina was the most sensitive plant and showed the least metal(loid)s accumulation. In conclusion, three of these plants are potent enough to use together for a better and enhanced removal of toxic elements from the contaminated soil with cosmos to be the best amongst these in urban areas.
... The identification and selection of plant species for phytoextraction is a continuous process, and many plants have been identified as remediation plants, but still very few reports about the use of ornamental plants for phytoremediation purposes exist, while presenting many benefits including abundance, exuberant vitality, and fast growth and also making the environment more beautiful as well. More importantly, most of ornamental plants are not related to our food chain (Cay et al. 2015;Miao and Yan 2013;Jelusic and Lestan 2015;Wang and Liu 2014;Zulfiqar et al. 2012). ...
... The EC is defined as the ratio of metal concentration in plant harvested tissue (roots, stem, or leaves) to that in the soil (Zayed et al. 1998). The TF represents the capability of a plant in carrying heavy metals from the roots to the shoots that are defined as the rate of metal concentration in plant shoots to that in plant roots (Miao and Yan 2013). ...
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In this study, tea saponin (TS) was extracted from tea camellia seed by microwave-assisted extraction. The potential of TS was compared with ethylenediaminetetracetic acid (EDTA), which is used as a common chemical agent to enhance uptake of cadmium (Cd) by Amaranthus caudatus, an ornamental plant in the natural vegetation of Turkey under pot conditions. The enrichment coefficient (EC) and translocation factor (TF) values were calculated to evaluate the removal efficiency of the TS and EDTA. The results showed that an increase in both TS and EDTA concentration significantly increased Cd uptake by A. caudatus, accumulating Cd in different parts of the plant. Higher EC and TF values obtained from stems, leaves, and inflorescences of A. caudatus showed that this plant might be cultivated and used as a hyperaccumulator in the uptake of Cd from the Cd contaminated soils. Thus, the present technique can efficiently reduce the metal load in the food chain; hence, it could be applied in catchment areas of urban cities where Cd contamination has become an unavoidable factor.
... It was determined that the lead removal efficiency of both plants (94.36% in fan flower and 94.92% in oleander) was higher than that of Cr (91.08% in fan flower and 95.96% in oleander) (Al-Anbari et al., 2018). In the study conducted to evaluate chromium removal from aquatic tanneries sludge with different Cr concentrations for ornamental plants (Mirabilis jalapa, Impatiens Balsamin and Tagetes erecta L.), especially Mirabilis jalapa has been determined to be the most effective in removing Cr from tannery sludge (51.25 × 10 3 mg kg -1 ) (Miao and Yan, 2013). In the study carried out to examine the ability of tolerating and accumulating chromium and zinc of marsh iris (I. ...
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High concentrations of chromium in the soil have a toxic effect on the living organisms in the soil ecosystem. If chromium, which is not an absolute essential element, accumulates in plants, it causes structural changes, causing a decrease in plant growth and also high toxicity due to its accumulation in biomass. Use of plants to remove chromium (Cr) from contaminated soils, it is an environmentally efficient, cost-effective, modern, applicable technique. The different species of plant and ornamental plants are used in this technique. In this study, the Kordes shrub rose used in landscaping in our province, Cr phytoremediation capacity was evaluated by growing at contaminated soil with Cr. In the study, the different doses of Cr (0, 50, 100, 500, 1000 mg kg-1) have been applied in Cr+3 and Cr+6 forms. In addition, two doses (0% and 3%) of leonardite were added to the pots to determine the effect on the developmental status of the plants and Cr uptake. In the study, plant height, number of branches, number of flowers, flower diameter, stem diameter, flower yield values and total wet and dry weight values at the end of the experiment were determined. At the end of the experiment, it was observed that generally developmental status of the plants was adversely affected at high Cr doses. Especially at 500 and 1000 mg kg-1 application doses was observed that the plants could not withstand Cr toxicity in a short time. It has been observed that plants treated with leonardite were healthier than those without. According to the data obtained at the end of the study, it was determined that the resistance of plant to high doses of Cr was low, but it showed better growth at 50 and 100 mg kg-1 doses.
... The use of ornamental plants as a test plant in a phytoremediation experiment is because of their high biomass which means they can accumulate more heavymetal concentration through their roots, into their tissues. Many studies have been conducted to evaluate the potentials of ornamental plants as in phytoremediation [5][6][7][8]. However, most of the selected ornamental plants used in all the studies were not indigenous and not commonly cultivated in Nigeria. ...
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A completely randomized design with three replicates was conducted at the Screen house of the Department of Crop Soil and Pest Management, Federal University of Technology Akure, Ondo State, to examine the phytoremediation potential of Codiaeum variegatum and Basella alba on contaminated soils from four locations. Soils were collected from the Mechanic workshop, Dumpsite, Forest Topsoils, and Effluent site, and filled into the buckets. Initial soil analysis was conducted on all the soils to determine heavy metal concentration (Cu, Cd, Ni, Pb, and Zn). At 12 weeks after planting, soil and plant (root and shoot) samples were analyzed to determine the heavy metals accumulated. WHO permissible limit value for heavy metal concentration in soil and plant were used as a standard to evaluate plant phytoremediation potential. Results from the study confirm the phytoreme-diation potential of C. variegatum and its high tolerance for the accumulation of heavy metals. B. alba plant also shows its potential in removing heavy metals from the soil, but it was not as tolerant as C. variegatum as B. alba planted in soils from mechanic workshop and effluent site had stunted growth.
... Overall, only calendula could be considered a possible candidate for phytoremediation of soils contaminated with low level of Cr (Ramana et al. 2013). In another experiment on three ornamental species cultured in pots containing substrate with four Cr concentrations, Impatiens balsamina showed a decline in the biomass as the dose of Cr increased, while in Mirabilis jalapa and Tagetes erecta the four treatments did not impact growth; TF and BF of M. jalapa were greater than 1, indicating this species is a good candidate for the remediation of Crpolluted soils (Miao & Yan 2013). In Vinca rosea grown in pots containing soil with levels of chromium from 10 to 60 mg kg -1 , plant height, fresh and dry weight decreased with high contamination levels of chromium. ...
... More significantly, most of the food is not about our chain. For this reason, phytochemistry seems to be a promising election by ornament plants ( Miao & Yan 2013;Kurt 2018). Use of ornamental plants such as Lonicera japonica Thunb, Salvia virgata Jacq., Althaea rosea Cavan, Dahlia hybrida (Cay et al., 2016), Salvia splendens, Tageteserecta, Abelmoschus manihot ( Wang & Zhou 2005), Impatiens balsamina, Althaea rosea, Calendula officinalis ( ), Chlorophytumcomosum ( Wang et al., 2012), Quamolitpennata, Antirrhinum majusL. ...
Article
The purpose of this study is to examine the bioaccumulation of ecotoxic metal cadmium (Cd) from soil and waste water by Tradescantia Fluminensis as an ornamental plant. The plants grown in soil and hydroponic systems contaminated with Cd for this purpose (0-100 mg kg ⁻¹ ). In this study, Cd accumulation and distribution in the Tradescantia Fluminensis were also investigated. Cd accumulation was the maximum in the root, followed by than the stem and leaves in pots and hydroponics. Translocation Factor (TF) and The Bioconcentration Factor (BCF) values were also calculated to appraise the efficacy of the plants being removed. The plant could well tolerate up to 100 mg kg ⁻¹ of Cd concentration level. Although the plant cannot be categorized as a hyperaccumulator, the plant has been very effective in Cd translocation from root to sprouting, as is evident from the data obtained from the BCF and TF values.
... The trend of Cr accumulation in Mirabilis jalapa L. was as follows: roots > stems > leaves > inflorescence. (Miao and Yan 2013) Helianthus annuus L. and Hydrangea paniculata Siebold. Nymphaea spontanea Landon. ...
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Accumulation of heavy metals (HMs) in soil, water and air is one of the major environmental concerns worldwide, which mainly occurs due to anthropogenic activities such as industrialization, urbanization, and mining. Conventional remediation strategies involving physical or chemical techniques are not cost-effective and/or eco-friendly, reinforcing the necessity for development of novel approaches. Phytoextraction has attracted considerable attention over the past decades and generally refers to use of plants for cleaning up environmental pollutants such as HMs. Compared to other plant types such as edible crops and medicinal plants, ornamental plants (OPs) seem to be a more viable option as they offer several advantages including cleaning up the HMs pollution, beautification of the environment, by-product generation and related economic benefits, and not generally being involved in the food/feed chain or other direct human applications. Phytoextraction ability of OPs involve diverse detoxification pathways such as enzymatic and non-enzymatic (secondary metabolites) antioxidative responses, distribution and deposition of HMs in the cell walls, vacuoles and metabolically inactive tissues, and chelation of HMs by a ligand such as phytochelatins followed by the sequestration of the metal–ligand complex into the vacuoles. The phytoextraction efficiency of OPs can be improved through chemical, microbial, soil amending, and genetic approaches, which primarily target bioavailability, uptake, and sequestration of HMs. In this review, we explore the phytoextraction potential of OPs for remediation of HMs-polluted environments, underpinning mechanisms, efficiency improvement strategies, and highlight the potential future research directions.
... Mirabilis jalapa, Impatiens balsamin and Tagetes erecta L., were selected as target plants to study the phytoextraction of chromium (Cr) in tannery sludge irrigated with four treatments according to Cr concentration gradient. Results displayed an escalated Cr accumulation, and surprisingly, the translocation factor and the bioaccumulation coefficient of Mirabilis jalapa came out to be greater than 1, indicating its strong ability to tolerate and enrich Cr by biological processes (Miao and Yan 2013). Iris (Iris savannarum), switch grass (Panicum virgatum), Tithonia rotundiflora, Coreopsis lanceolata, sunflower (Helianthus annuus), and marigold (Tagetes erecta) have also been identified as appealing candidates for phytoremediation and phytostabilization (Reed et al. 2013). ...
Chapter
Phytoremedial technologies such as phytoextraction, phytosequestration, phytodegradation, phytostabilization, rhizoremediation, evapotranspiration for improving the quality of polluted soil and water offer cheap, ecosystem friendly and simple alternative to other conservative approaches. Their novel use has gained practical application to clean up large hectares of spiked soils in many developed and developing countries. One of the main reasons for this remains the widespread diversity of hyperaccumulators which have been used for such remedial measures. Still a lot needs to be achieved through genetic and metabolic studies on these widely cultivated hyperaccumulator plants which can lead to better designed models customized for gaining popularity of the green technology backed by a steady economic turnover.
... In this study we have found the reduced biomass (fresh and dry weights) for all plant species at higher Cr levels ( Table 2). The decreased biomass mainly due to the inhibition of water and mineral uptake and might also be due to disturbed metabolic activities and low photosynthetic reactions under high Cr stress (Shanker et al. 2005;Miao and Yan 2013). ...
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Contamination of chromium signifies one of the major threats to soil system. Phytoremediation is a promising technique to reclaim metal-contaminated soil using plants which are capable to tolerate and accumulate heavy metals within in their tissues. The experiment reported in this article was carried out with six biofuel plant species, Cyamopsis tetragonoloba, Glycine max, Avena sativa, Abelmoschus esculentus, Sesamum indicum and Guizotia abyssinica, were subjected to eight Cr concentrations (0.5, 2.5, 5, 10, 25, 50, 75 and 100mg kg-1 soil) to investigate Cr toxicity, tolerance and accumulation. After 12 weeks of experiment, Cr phytotoxicity on morphological and biochemical parameters were evaluated. For six plant species, seed germination and most of growth parameters were significantly (p<0.05) reduced under high Cr stress. Chlorophyll contents were also decreased with increased Cr concentrations. Accumulation of Cr was higher in roots than shoot in all studied plants. Significant Cr accumulation was in the order of C. tetragonoloba > A. sativa > A. esculentus > S. indicum > G. max > G. abyssinica. Bioconcentration factor, bioaccumulation coefficient, translocation factor and phytoremdiation ratio suggested that C. tetragonoloba, A. sativa and A. esculentus being more tolerant; having higher Cr accumulation and could be a high efficient plants for reclamation of Cr-contaminated soils.
... As a consequence, the maximum permissible limit in drinking water is 0.01 mg/L for Cr(VI) and 0.10 mg/L for total Chromium (USEPA 2011), and in wastewater, its limit is 0.05 mg/L (USEPA 2013). Thus, Cr(VI) removal from drinking water is essential and carried out by various techniques namely, coagulation and sedimentation, electrocoagulation (Golder et al. 2007), precipitation (Guo et al. 2006), crystallization, Membrane filtration, Reverse osmosis (Hafez and El-Mariharawy 2004;Perez-González et al. 2012; Wang 2011), ion exchange (Galan et al. 2005), adsorption (Jabeen et al. 2011), bioremediation , phytoremediation (Narayani and Vidya 2012;Miao and Yan 2013) etc. However, these methods are limited by costly technology, high operational and maintenance cost, skilled labour requirement: particularly in membrane filtration, and sludge disposal (Sharma et al. 2009;Hu et al. 2011). ...
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Microcrystalline cellulose immobilized zerovalent iron nanoparticles (CI-1-3) with different loading of 6, 12 and 24% w/w Fe⁰ were synthesized by NaBH4 reduction under simultaneous co-precipitation of cellulose from ionic liquid ([BMIM]Cl)-water binary mixture. SEM, TEM, FTIR, VSM, XRD and XPS analysis were carried out to characterize the material. The electron microscopy studies revealed the immobilization of iron nanoparticle in the bulk and surface of microcrystalline cellulose with a size range of 20–100 nm. CI-1-3 showed strong interaction between cellulose hydroxyl moiety and nZVI, immobilized on the polymer and saturation magnetization of 3 emu/g for CI-2. The materials were studied for Cr(VI) adsorption which revealed the qmax value of 28.57, 58.82 and 38.48 mg Cr(VI)/g of CI-1-3, respectively. Graphical abstract Open image in new window
... Some of the Cr hyperaccumulator cosmopolitan ground vegetation listed in a review of Kumar and Maiti 2013 are Dicoma niccolifera, Sutera fodina, Leersia hexandra, Gynura pseudochina, Spartina argentinensis, Typha latifolia and Carex lurida. A common ornamental plant Mirabilis jalapa is also found to be an effective Cr hyperaccumulator as per the Cr contaminated sewage sludge experiment (Miao and Yan 2013). In a study by Ramana et al. 2015, it was found that Furcraea gigantea was able to phytoaccumulate Cr in their tissue. ...
Article
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Chromium from tannery waste dump site causes significant environmental pollution affecting surrounding flora and fauna. The primary aims of this study were to survey vegetation, investigate the degree of soil pollution occurring near tannery waste dump site and make a systematic evaluation of soil contamination based on the chromium levels found in plants and earthworms from the impacted areas. This paper presents the pollution load of toxic heavy metals, and especially chromium, in 10 soil samples and 12 species of plants. Soil samples were analysed for heavy metals by using ICP-MS/ICP-OES method. Results indicated that Cr in soils exceeded soil quality guideline limits (SQGL). The total chromium present in the above ground parts of plants ranged from 1.7 mg kg⁻¹ in Casuarina sp. to 1007 mg kg⁻¹ in Sonchus asper. The Cr bioaccumulation in Eisenia fetida from tannery waste soil ranged from 5 to 194 mg kg⁻¹. The high enrichment factor of Cr in S. asper and bioaccumulation factor in earthworms indicate that there is a steady increase of toxic chromium risk in this area, which could be correlated with the past dumping activity. Emphasis needs to be put on control measures of pollution and remediation techniques in such areas to achieve an ecologically sustainable industrialisation.
... patula) marigolds, and nugget 189 3 ORNAMENTAL PLANTS FOR HEAVY METALS PHYTOREMEDIATION marigold, a triploid hybrid between T. erecta and T. patula, could also provide economic benefits to the remediators with large-scale plantation on wastelands, providing flowers to sell. Many researchers reported that T. erecta can be applied to soil contaminated with Cd, Cr, Ni, Pb, As, and Cu (Rungruang et al., 2011;Bosiacki, 2008;Malarkodi et al., 2008;Miao and yan, 2013;Lal et al., 2008). T. patula has potential for remediation of areas contaminated with Cd, Fe, Cu, Pb (Wei et al., 2012;San et al., 2011;Chaturvedi et al., 2014), and for the degradation of organic pollutants; for example, Reactive Blue 160 (Patil and Jadhav, 2013) and benzo[a]pyrene (B[a]P) (Sun et al., 2011). ...
Chapter
Technogenic and anthropogenic activities are the major sources of heavy metals in the environment. Phytoremediation is the use of plants for environmental cleanup. Economically important plants with a short life cycle motivate local people provided they have phytoremediation application. In this context many ornamental plants have been evaluated for their potential in phytoremediation. As many ornamentals are not edible, the risk of contaminants entering the food chain is reduced. Ornamental plants have the added advantage of enhancing the environment’s esthetics besides cleaning up the environment and generating additional income, including additional employment opportunities. This chapter highlights the phytoremediation potential of terrestrial and aquatic ornamentals. Consequently, ornamental plants will add a new dimension to the field of phytoremediation and phytomanagement of contaminated aquatic and terrestrial environments.
... Clearly, tannery solution is a secondary source of chromium. However, due to lack of economic and effective techniques, chemical precipitation techniques using lime are still the dominant treatment processes in practical applications [2,3]. The resultant chromium precipitate, along with some organic compounds, is discharged as tannery sludge, which may impact the natural environment and human health negatively [4][5][6]. ...
Article
This paper presents a study regarding the preparation of MgCr2O4 from waste tannery solution, and chromium leaching behavior is also investigated with varying amounts of sulfate, chloride and calcium. The phase transformation, crystallinity index and crystallite diameter were characterized using XRD, FT-IR and thermal analysis. A well-crystallized MgCr2O4 was successfully prepared at 1400 °C. The sintering temperature had a major impact on the formation of MgCr2O4 compared with sintering time. The MgCr2O4 phase was observed initially at 400 °C and its crystallite diameter increased with increasing temperature. The concentration of total chromium leached and Cr(VI) decreased gradually with increasing temperature. The considerable amount of Cr(VI) was found in the leachate at 300–500 °C caused by Cr(VI) intermediary products. Sulfate and chlorine could impact the transformation efficiency of chromium adversely, and chlorine has a more significant effect than sulfate. The presence of calcium disturbed the formation of MgCr2O4 and new chromium species (CaCrO4) appeared, which resulted in a sharp increase in the concentration of leached Cr(VI). Incorporating Cr(III) into the MgCr2O4 spinel for reusable products reduced its mobility significantly. This was demonstrated to be a promising strategy for the disposal of chromium containing waste resource.
... More importantly, most of them are not related to our food chain. Thus, phytoremediation by ornamental plants seems to be a promising choice in the future (Miao and Yan 2013). Use of ornamental plants such as Tagetes erecta, Salvia splendens, Abelmoschus manihot (Wang and Zhou 2005), Impatiens balsamina, Calendula officinalis, Althaea rosea (Liu et al. 2008), Lonicera japonica (Liu et al. 2011), Chlorophytum comosum (Wang et al. 2012), Tagates patula (Sun et al. 2011 ), Quamolit pennata, Antirrhinum majus L. and Celosia critata pyramidalis (Cui et al. 2013) were reported in previous studies. ...
Article
In this study an ornamental plant of Althaea rosea Cavan was investigated for its potential use in the removal of Cd, Ni, Pb and Cu from an artificially contaminated soil. Effect of two different chelating agents on the removal has also been studied by using EDTA (ethylenediaminetetracetic acid) and TA (tannic acid). Both EDTA and TA have led to higher heavy metal concentration in shoots and leaves compared to control plants. However EDTA is generally known as an effective agent in metal solubilisation of soil, in this study, TA was found more effective to induce metal accumulation in Althaea rosea Cavan under the studied conditions. In addition to this, EDTA is toxic to some species and restraining the growth of the plants. The higher BCF (Bio Concentration Factor) and TF (Translocation Factor) values obtained from stems and leaves by the effects of the chemical enhancers (EDTA and TA) show that Althaea rosea Cavan is a hyper accumulator for the studied metals and may be cultivated to clean the contaminated soils.
... The inhibitory concentrations of chromium vary, depending on the factors such as its oxidation state and concentration. Cr(VI) in chromate (CrO 4 2-) is the major pollutant from leather industries, causing toxic and carcinogenic effects on humans [7]. The inhibitory chromium concentrations that caused 50 % decrease in the cumulative methane production were reported to range from 27 to 3000 mg/L [8]. ...
Article
Anaerobic batch experiments were conducted at mesophilic temperatures to investigate the possibility of biogas recovery from tannery sludge originating from a tannery wastewater treatment process. According to preliminary findings, the highest biogas yield was obtained as 0.172 L biogas/g VS added within an inoculum to substrate (I:S) ratio of 1:10 and at solids content of 10.6 %. The highest methane yield of 0.089 L CH 4 /g VS added was achieved within an I:S ratio of 1:2 during the experiments. Relatively lower biogas and methane yields could be attributed to the low organic content of raw sludge cake. Potential inhibitors of anaerobic digestion, such as heavy metals, particularly chromium, chloride and sulfate available in raw sludge cake did not seem to influence the process adversely. Despite lower methane yields, it seemed possible to employ anaerobic digestion process for stabilization and energy recovery from tannery sludge, since the biogas obtained could further be used in the wastewater treatment plant as a source of energy. Co-digestion of tannery sludge with another type of substrate available (e.g., tannery solid wastes) can be an alternative to achieve higher biogas and methane yields considerably.
... Many biosorbents have been used in past years for chromium ion (VI) removal; however, the search for an eco-friendly and low-cost biomaterials remains an active area of research. Biosorption potential of Araucaria leaves [10], Wheat (Triticum aestivum) shells [11], Litchi chinensis [12], Sunflower head waste-based biosorbent (FSH) [13], Corinadrum sativum [14], Wood apple shell [15], Mangifera indica bark dust [16], Tobacco leaf [17], Cow dung powder [18], Fruit peel of Trewia nudiflora plant [19], and Ornamental plants [20] have recently been tested for Cr(VI) biosorption. The present study focussed on assessing the ability of environmentally benign adsorbent Artemisia absinthium, which belongs to the family Asteraceae. ...
Article
Artimisia absinthium, a medicinal plant material, showed excellent adsorption in removing mutagenic Cr(VI) from aqueous solution along with Cu(II), Ni(II), and Zn(II). Various parameters like effect of pH, contact time, temperature, and initial concentration were investigated using batch process to optimize conditions for maximum adsorption. A. absinthium was characterized using scanning electron microscopy (SEM). Adsorption of Cr(VI) was favorable at pH 2 as 96% of Cr(VI) could be removed from aqueous solution. However, adsorption of Cr(VI) decreased to 73% in presence of electrolyte (0.1 N KNO3) at pH 2. The point of zero charge of A. absinthium was 3.9 in double distilled water. The adsorption data were analyzed using Langmuir, Freundlich, Temkin, Hasley, and Dubinin–Redushkeuich isotherm models at 30, 40, and 50°C. The maximum monolayer adsorption capacity towards Cr(VI) was found to be 46.99 mg g−1 at 30°C which was relatively large compared to some other similar adsorbents reported earlier. The kinetic data showed that pseudo-second-order rate equation was better obeyed than pseudo-first-order. The intra-particle diffusion model showed that Cr(VI) adsorption involved three different stages. The breakthrough and exhaustive capacities of the adsorbent were found to be 35 and 45 mg g−1, respectively, at pH 2. Desorption study showed that 93.05% Cr(VI) could be desorbed by column operation with 0.01 N NaOH solution.
... Phytoremediation is an eco-friendly, economical, safe, and efficient technology, and it has recently been receiving increasing attention. The abilities of various plants to enrich, degrade, and adsorb different kinds of pollutants have been investigated (Huang et al. 2010;Prado et al. 2012;Witters et al. 2012;Miao & Yan 2013). Phytoremediation has been used as an alternative strategy for treating phenol-polluted environments (Coniglio et al. 2008;Sosa Alderete et al. 2009). ...
Article
Removing phenol from wastewater has become a major challenge of international concern. Phytoremediation is a novel and eco-friendly method and is attracting an increasing amount of attention for treating phenol in wastewater. We studied the ability of Polygonum orientale, which is frequently present around water bodies and in wetlands in China, to phytoremediate phenol. We determined the inhibition concentration for phenol on P. orientale using emergency toxicology experiments and morphological observations. Isothermal and kinetic models were created to assess the adsorption process involved in phenol removal. Comparison tests in sterile conditions demonstrated that metabolic removal was the main way in which the phenol concentrations were decreased, and removal by adsorption played a smaller role. An orthogonal test was performed to determine the optimum conditions under which P. orientale will remove phenol, and these were found to be an initial phenol concentration of 5 mg L(-1), 100 % natural light, and a 13-day treatment time. These results provide a theoretical basis for increasing our understanding of the mechanisms involved in the removal of phenol by P. orientale and will help in developing its application in the greening of urban areas to provide both phytoremediation and esthetic landscaping.
Chapter
Metals are the constituents of the earth's crust which exist in the soil and other different ecosystems. The concentrations of heavy metal have increased drastically in recent times due to anthropogenic activities like industrialization, mine tailings, waste disposal, leaded gasoline and paints, pesticides, wastewater irrigation, coal combustion, and petrochemicals which affect the plant growth and metabolism of plants. Studies reveal that metal hyperaccumulation is exhibited in more than 500 plant species and about in 0.2% of flowering plants. These plants developed different type of mechanisms to hyperaccumulate the heavy metals from soil without causing deleterious effect on them. Various transporter molecules are associated in the uptake of metals through roots and translocate to shoots, leaves and sequester in plant vacuoles or cell walls. There are several biochemical, genetical, and molecular mechanisms associated with the hyperaccumulation of metals in plants. This study aims at hyperaccumulation of metals in plants by different mechanism.
Chapter
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Selecting a phytoextraction plant with moderate to high Cd-accumulating ability and high biomass based on the plant's compatibility with mechanized cultivation techniques may yield more immediately practical results. In the present study, six Chinese cabbage cultivars were grown in three soils, ranging from 0.15 to 2.25 mg Cd kg(-1) soil, to examine uptake and translocation of Cd in their tissues. The results indicated that the order of the shoot Cd concentration values in the cultivars was as follows: Beijingxiaoza 56 > Suancaiwang > Quansheng and Qiubo 60 > Xianfengkuaicai and Chunkang. Similar order was also found in the bioaccumulation factor (BAF), translocation factor (TF), and metal extraction ratio (MER). Several soil Cd fractions after Beijingxiaoza 56 harvesting decreased most. Beijingxiaoza 56 is thus promising for phytoextraction of Cd from soils with low to moderate (<2.25 mg kg(-1)) Cd contamination.
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Different dilution levels of tannery treated effluent and their corresponding concentration of chromium (Cr6+) were studied in a petridish culture experiment on seed germination and seedling growth in radish (Raphanus sativus L). The different concentrations of Cr6+ (2, 5 and 10 ppm) and treated tannery effluent (10, 25 and 50%) showed reduction in seedling growth and related enzymatic activities with increase in concentration of Cr6+ in treatments and effluent both. The low concentration of chromium (2 ppm) and effluent dilution (10%) showed significant growth reduction separately. At this concentration of chromium and effluent dilution chlorophyll content, amylase, catalase and protein contents remained unchanged while with increase in Cr6+ concentration (>2ppm) and effluent dilution (> 10%) in treatments showed growth inhibitory effects.
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Trivalent chromium (Cr3+) is essential for animal and human health, whereas hexavalent Cr (CrO42−) is a potent carcinogen and extremely toxic to animals and humans. Thus, the accumulated Cr in food plants may represent potential health hazards to animals and humans if the element is accumulated in the hexavalent form or in high concentrations. This study was conducted to determine the extent to which various vegetable crops absorb and accumulate Cr3+ and CrO42− into roots and shoots and to ascertain the different chemical forms of Cr in these tissues. Two greenhouse hydroponic experiments were performed using a recirculating-nutrient culture technique that allowed all plants to be equally supplied with Cr at all times. In the first experiment, 1 mg L−1 Cr was supplied to 11 vegetable plant species as Cr3+ or CrO42−, and the accumulation of Cr in roots and shoots was compared. The crops tested included cabbage (Brassica oleracea L. var. capitata L.), cauliflower (Brassica oleracea L. var. botrytis L.), celery (Apium graveolens L. var. dulce (Mill.) Pers.), chive (Allium schoenoprasum L.), collard (Brassica oleracea L. var. acephala DC.), garden pea (Pisum sativum L.), kale (Brassica oleracea L. var. acephala DC.), lettuce (Lactuca sativa L.), onion (Allium cepa L.), spinach (Spinacia oleracea L.), and strawberry (Fragaria × ananassaDuch.). In the second experiment, X-ray absorption spectroscopy (XAS) analysis on Cr in plant tissues was performed in roots and shoots of various vegetable plants treated with CrO42− at either 2 mg Cr L−1 for 7 d or 10 mg Cr L−1 for 2, 4 or 7 d. The crops used in this experiment included beet (Beta vulgaris L. var. crassa (Alef.) J. Helm), broccoli (Brassica oleracea L. var. Italica Plenck), cantaloupe (Cucumis melo L. gp. Cantalupensis), cucumber (Cucumis sativus L.), lettuce, radish (Raphanus sativus L.), spinach, tomato (Lycopersicon lycopersicum (L.) Karsten), and turnip (Brassica rapa L. var. rapifera Bailey). The XAS speciation analysis indicates that CrO42− is converted in the root to Cr3+ by all plants tested. Translocation of both Cr forms from roots to shoots was extremely limited and accumulation of Cr by roots was 100-fold higher than that by shoots, regardless of the Cr species supplied. Highest Cr concentrations were detected in members of the Brassicaceae family such as cauliflower, kale, and cabbage. Based on our observations and previous findings by other researchers, a hypothesis for the differential accumulation and identical translocation patterns of the two Cr ions is proposed.
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The aim of this study was to explore the potential of three aquatic weeds, water hyacinth, cabomba, and salvinia, as substrates for anaerobic digestion. A set of four pilot-scale, batch digestions were undertaken to assess the yield and quality (% methane) of biogas from each plant species, and the rate of degradation. A set of 56 small-scale (100 mL) biological methane potential (BMP) tests were designed to test the repeatability of the digestions, and the impact of drying and nutrient addition.The results of the pilot-scale digestions show that both water hyacinth and cabomba are readily degradable, yielding 267 L biogas kg−1 VS and 221 L biogas kg−1 VS, respectively, with methane content of approximately 50%. There is evidence that the cabomba fed reactor leaked midway through the digestion therefore the biogas yield is potentially higher than measured in this case. Salvinia proved to be less readily degradable with a yield of 155 L biogas kg−1 VS at a quality of 50% methane.The BMPs showed that the variability was low for water hyacinth and cabomba but high for salvinia. They also showed that the addition of nutrient solution and manure did not significantly increase the biogas yields and that drying was detrimental to the anaerobic degradability of all three substrates.Based on these results treatment of both water hyacinth and cabomba by anaerobic digestion can be recommended. Anaerobic digestion of Salvinia cannot be recommended due to the low biogas yields and high variability for this substrate.
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The future risk of a hypothesized Resource Conservation and Recovery Act (RCRA) site disposing of carcinogenic metals, arsenic, chromium, nickel, cadmium, and beryllium in the U.S. is assessed. Societal memory is assumed to be lost regarding the site. A human intrusion scenario on the site and a residential scenario one kilometer down-gradient of the groundwater flow direction from the site are assumed, starting at 1000 years after the site's closure. For the human intrusion scenario, the exposure pathways considered are fruit and vegetable intake, soil ingestion, and dermal contact with soil. The quantitative results obtained for the three pathways are as follows: lifetime excess cancer risk due to fruit and vegetable intake is 0.18; isk due to dermal contact with the soil is 0.12; and risk due to soil ingestion is 2.6 x 10ṫ. For the residential scenario, only qualitative discussion of exposure via groundwater is presented due to the large uncertainties. The U.S. EPA (Environmental Protection Agency) attention to and requirements concerning long-term risk from RCRA sites containing metal carcinogens, which never change due to radioactive decay, stand in sharp contrast to the stringent requirements over 10,000 years posed by EPA for geologic disposal of high level radioactive wastes, and the long-term requirements posed by the U.S. Nuclear Regulatory Commission for low level radioactive waste disposal sites.
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Phytoextraction has shown great potential as an alternative technique for the remediation of metal contaminated soils. The objective of this study was to investigate cadmium (Cd) phytoextraction ability of high biomass producing weeds in comparison to indicator plant species. The pot study conducted with 10 to 200 mg Cd kg−1 soil indicated that Ipomoea carnea was more effective in removing Cd from soil than Brassica juncea. Among the five species, B. juncea accumulated maximum Cd, but I. carnea followed by Dhatura innoxia and Phragmytes karka were the most suitable species for phytoextraction of cadmium from soil, if the whole plant or above ground biomass is harvested. In the relatively short time of this experiment, I. carnea produced more than 5 times more biomass in comparison to B. juncea. There were significant differences (p < 0.05) between the shoot length and shoot mass of control and treated plants.
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Arsenic (As) accumulation in food crops such as rice is of major concern. To investigate whether phytoremediation can reduce As uptake by rice, the As hyperaccumulator Pteris vittata was grown in five contaminated paddy soils in a pot experiment. Over a 9-month period P. vittata removed 3.5-11.4% of the total soil As, and decreased phosphate-extractable As and soil pore water As by 11-38% and 18-77%, respectively. Rice grown following P. vittata had significantly lower As concentrations in straw and grain, being 17-82% and 22-58% of those in the control, respectively. Phytoremediation also resulted in significant changes in As speciation in rice grain by greatly decreasing the concentration of dimethylarsinic acid (DMA). In two soils the concentration of inorganic As in rice grain was decreased by 50-58%. The results demonstrate an effective stripping of bioavailable As from contaminated paddy soils thus reducing As uptake by rice.
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Napropamide belongs to the amide herbicide family and widely used to control weeds in farmland. Intensive use of the herbicide has resulted in widespread contamination to ecosystems. The present study demonstrated an analysis on accumulation of the toxic pesticide napropamide in six genotypes of alfalfa (Medicago sativa), along with biological parameters and its residues in soils. Soil was treated with napropamide at 3 mg kg(-1) dry soil and alfalfa plants were cultured for 10 or 30 d, respectively. The maximum value for napropamide accumulation is 0.426 mg kg(-1) in shoots and 2.444 mg kg(-1) in roots. The napropamide-contaminated soil with alfalfa cultivation had much lower napropamide concentrations than the control (soil without alfalfa cultivation). Also, the content of napropamide residue in the rhizosphere was significantly lower than that in the non-rhizosphere soil. M. sativa exposed to 3 mg kg(-1) napropamide showed inhibited growth. Further analysis revealed that plants treated with napropamide accumulated more reactive oxygen species (O(2)(-) and H(2)O(2)) and less amounts of chlorophyll. However, not all cultivars showed oxidative injury, suggesting that the alfalfa cultivars display different tolerance to napropamide.
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The cordgrass Spartina argentinensis, which occurs in inland marshes of the Chaco-Pampean regions of Argentina, has been found to be a new chromium hyperaccumulator. A glasshouse experiment was designed to investigate the effect of Cr(6+) from 0 to 20 mmol l(-1) on growth and photosynthetic apparatus of S. argentinensis by measuring chlorophyll fluorescence parameters, gas exchange and photosynthetic pigment concentrations. Boron, calcium, chromium, copper, iron, manganese, magnesium, potassium and phosphorous concentrations were also determined. S. argentinensis showed phytotoxicity at tiller concentration of 4 mg g(-1) Cr, and symptoms of stress at tiller concentration of 1.5 mg g(-1) Cr, as well as reductions in leaf gas exchange, in chlorophyll a fluorescence parameters, in photosynthetic pigment contents and in the uptake of essential nutrients. Reductions in net photosynthetic rate could be accounted for by non-stomatal limitations. Moreover, the bioaccumulator factors exceeded greatly the critical value (1.0) for all Cr treatments, and the transport factors indicated that this species has a higher ability to transfer Cr from roots to tillers at higher Cr concentrations. These results confirmed that S. argentinensis is a chromium hyperaccumulator and that it may be useful for restoring Cr-contaminated sites.
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The potential of the extreme halophyte Arthrocnemum macrostachyum was examined to determine its tolerance and ability to accumulate cadmium for phytoremediation purposes. A glasshouse experiment was designed to investigate the effect of cadmium from 0 to 1.35 mmol l(-1) on the growth and the photosynthetic apparatus of A. macrostachyum by measuring chlorophyll fluorescence parameters, gas exchange and photosynthetic pigment concentrations. We also determined ash, cadmium, calcium, copper, iron, manganese, magnesium, phosphorous, sodium, and zinc concentrations, and C/N ratio. A. macrostachyum demonstrated hypertolerance to cadmium stress; it did not show phytotoxicity at shoot concentration as high as 70 mg kg(-1). The bioaccumulator factors exceeded the critical value (1.0) for all Cd treatments, and the transport factors indicated that this species has higher ability to transfer Cd from roots to shoots at lower Cd concentrations. At 1.35 mmol l(-1) Cd A. macrostachyum showed 25% biomass reduction after a month of treatment. Long-term effects of cadmium on the growth were mainly determined by variations in net photosynthetic rate (P(N)). Reductions in P(N) could be accounted by higher dark respiration and lower pigment concentrations. Finally, A. macrostachyum has the basic characteristics of a Cd-hyperaccumulator and may be useful for restoring Cd-contaminated sites.
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A field experiment was conducted with paddy (Oryza sativa L.) irrigated with different concentrations (Control, 2.5, 5, 10, 25, 50, 75, 100 and 200 mg/l) of chromium. The changes in growth, yield, nutrient content and chromium accumulation in the paddy are reported. The growth of shoot, root, total leaf area, fresh weight, dry weight and yield of the paddy gradually decreased with increasing Cr concentration. Similarly, the uptake of macronutrients (N, P, K) and micronutrients (Mn, Cu, Zn, Fe) were also gradually decreased. However, the chromium accumulation gradually increased with the increasing concentrations of chromium. Among the aquatic plants tested, Eicchornia crassipes showed better performance in accumulating higher amount of chromium. Similarly, certain grasses and weeds such as Cyperus rotundus, Cyperus kylinga, Marselia quadrifolia and Ludwigia parvifloria were used for the phytoremediation of chromium polluted soil. Among them, Cyperus rotundus accumulated higher amount of chromium than the other plants tested.
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Wastewater is often co-contaminated with chromium, chelating agents, and chloride. Influences of Cr(3+) speciation on Cr phytoremediation by Ipomonea aquatica were investigated. MINEQL+ was employed to estimate Cr speciation. Statistic regression was used to investigate the relationships between Cr speciation and accumulation. I. aquatica accumulated high Cr concentration (13,217 mg kg(-1)) in the root at Cr(3+) of 10 mg l(-1) and EDTA of 10(-4) M after 14 d growth. Pearson correlation analysis indicates that root Cr concentration significantly correlated with Cr-EDTA speciation (r = 0.67, p < 0.05) and Cr-Cl speciation (r = 0.91, p < 0.01). Shoot Cr concentration also significantly correlated with Cr-Cl speciation (r = 0.97, p < 0.01). An increase in Cl(-) concentration to 1.72 x 10(-4) M enhanced root Cr concentration; however, the accumulation of root Cr was inhibited at high Cl(-) concentration (5.76 x 10(-5) M). Microscopic image showed that a high portion of Cr(3+) accumulated on the root surface.
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Plants tolerate Cd by sequestering them through synthesizing phytochelatins with the general structure (t-Glu-cys)n-gly where n= 2-11 depending upon the species from which these peptides are isolated. Recent biochemical evidence suggests that these peptides are synthesized via posttranslationally activated, metal-dependent enzymatic pathways from the precursor glutathione. However, most of these studies are confined to terrestrial species and only a few studies have been made on higher aquatic plants. Recently H. verticillata and other aquatic higher plants have been reported to be hyperaccumulators of Cd and have demonstrated the ability to remove many toxic metals, including Cd, from wastewater. It is hypothesized that cadmium hyperaccumulating ability of the macrophyte is associated with induction of the metal chelating peptides, the phytochelatins (PCs), to copeup with high cellular Cd levels. In view of this, it was considered worthwhile to examine the induction of phytochelatins and changes in levels of glutathione and related metabolites in H. verticillata under Cd stress.
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Chromium (Cr), a transition metal, is one of the major sources of environmental pollution. It is discharged into the environment through the disposal of wastes from industries like leather tanning, metallurgical and metal finishing, textiles and ceramics, pigment and wood preservatives, photographic sensitizer manufacturing, etc. In the environment chromium occurs mainly in trivalent and hexavalent forms. The hexavalent chromium (Cr{sup 6+}) compounds are comparatively much more toxic than those of trivalent chromium (Cr{sup 3+}). The reason for such toxicity appears to be due to its rapid permeability through biological membranes and subsequent interaction with intracellular proteins and nucleic acids. The tanning industry, which commonly utilizes {open_quotes}chrome liquor{close_quotes} in the tanning process, discharges the effluents into the environment containing chrome salts in excess of the maximum permissible limits. Sludge deposition from such effluents, therefore, provides a natural environment for enrichment of chromium-resistant bacteria. Chromium-resistant microorganisms from such chromium-contaminated sediments have been isolated by several investigators. The present study was an attempt to evaluate the status of chromium-resistant bacteria in the tannery effluent sediments of Calcutta-based tanning industries. 14 refs., 2 figs., 6 tabs.
Article
To study the effects of praeruptorin C (Pra-C) on [Ca2+]i transients in cultured neonatal myocardiocytes. Using Ca(2+)-sensitive fluorescent indicator, Fura 2-AM, spontaneous cytosolic Ca2+ transients were measured in cultured myocardial cells of neonatal rats. Pra-C 10, 30 mumol.L-1 caused a decrease in the peak of Ca2+ transients. Pra-C 30 mumol.L-1 and 10-30 mumol.L-1 inhibited partly the stimulatory effects of CaCl2 4.8 mmol.L-1 and Bay k 8644 100 nmol.L-1 on peak Ca2+ transients, respectively. Pra-C did not cause any marked change in the basal [Ca2+]i level between beats. Pra-C inhibited the reduced [Ca2+]i transients after inhibition of sarcoplasmic reticulum Ca2+ release in ryanodine pretreated cells. Pra-C inferred with the Ca2+ influx responsible for excitation-contraction coupling in myocardiocytes.
Article
Plants of Nymphaea alba L. grown at various levels of chromium (VI) ranging from 1 to 200 microM accumulated chromium in concentration and duration-dependent manner. At all Cr levels, chromium accumulation by various plant tissues followed the order roots > leaves > rhizomes. Approximately 93% of total chromium present in the medium was accumulated by plants at lowest conentration (1 microM) used in the experiment. Chromium-induced toxicity appears at 1 microM chromium resulting in the build-up of delta-aminolevulinic acid (ALA) and reduced activities of delta-aminolevulinic acid dehydratase (ALAD) and nitrate reductase (NR), total chlorophyll (Chl) and protein contents. Ch1a was more sensitive than Ch1b to chromium toxicity. It could be inferred that chromium toxicity is not located at the level of ALA synthesis, but, probably at the ALAD activity which was more severely affected during chlorophyll biosynthesis. Finally, impaired chlorophyll biosynthesis resulted in reduced total chlorophyll content.
Article
Engineering plants with greater metal tolerance and accumulation properties is the key to developing phytoremediators. A recent study by Won-Yong Song et al. has shown that overexpressing the yeast vacuolar transporter YCF1 increases Pb and Cd tolerance and consequently increases the accumulation of these metals in shoots of transgenic Arabidopsis plants even though expression levels of YCF1 were relatively low. This technology can be used to engineer advanced phytoremediators, increasing their ability to pump heavy metals into a safe compartment while requiring only a small amount of transporters rather than a large amount of chelating peptide material.
Contaminated soils and waters pose a major environmental and human health problem, which may be partially solved by the emerging phytoremediation technology. This cost-effective plant-based approach to remediation takes advantage of the remarkable ability of plants to concentrate elements and compounds from the environment and to metabolize various molecules in their tissues. Toxic heavy metals and organic pollutants are the major targets for phytoremediation. In recent years, knowledge of the physiological and molecular mechanisms of phytoremediation began to emerge together with biological and engineering strategies designed to optimize and improve phytoremediation. In addition, several field trials confirmed the feasibility of using plants for environmental cleanup. This review concentrates on the most developed subsets of phytoremediation technology and on the biological mechanisms that make phytoremediation work.
Article
Short-term exposure of plants to heavy metals is often used for risk assessment of metal-enriched soils (OECD guideline 208) without considering the reliability of the assessment for long-term exposure, i.e. for the completion of a plant's life-cycle. In the present study with 15 orogenic soils three phases of the life-cycle of a Zn-Cd-resistant ecotype of Silene vulgaris were studied to improve risk assessment of metal-enriched soils. The first phase, i.e. emergence of seedlings was not related to the water-soluble or total metal concentration of the soils. Seedling mortality was low as long as the water-soluble metal concentration did not surpass 0.15 micromol Zn and 0.04 micromol Cu g(-1) dry soil. Curtailment of the life-cycle prior to flowering, i.e. the vegetative growth as second phase, occurred on those soils where roots and shoots were heavily enriched by Zn already in the seedling phase. In the third phase, i.e. the generative phase, time to flowering and yield differences between orogenic soils were substantial, but soil metal concentrations could not be directly related to timing of reproduction or biomass. Ranking of data showed a high inconsistency of the responses to metal exposure during the first phases of the life-cycle. It is concluded that total plant mass and seed mass are the only realistic endpoints of life-cycle bioassays in risk assessment as long as ranks are inconsistent between two successive early phases of the life-cycle.
Article
This article includes a survey of chromium (Cr) occurrence in different environmental compartments, its pathways in the environment and the cross-sectional presentation of Cr speciation methods against the background of Cr chemistry. The aim of the article is to demonstrate that knowledge of interconversion processes between different Cr forms is necessary to understand its behaviour and role in the environment, in addition to enabling reliable Cr speciation analysis to be performed. The current methods of Cr speciation are presented, characterized and their usefulness discussed. These must rely on superior separation and detection capabilities since Cr in environmental compartments is mostly at trace or ultra-trace level. The need for using unique techniques of sampling, storage, handling and separation for Cr speciation is documented.
Article
Five tree species (Acer pseudoplatanus L., Alnus glutinosa L. Gaertn., Fraxinus excelsior L., Populus alba L. and Robinia pseudoacacia L.) were planted on a mound constructed of dredged sediment. The sediment originated from a brackish river mouth and was slightly polluted with heavy metals. This preliminary study evaluated the use of trees for site reclamation by means of phytoextraction of metals or phytostabilisation. Although the brackish nature of the sediment caused slight salt damage, overall survival of the planted trees was satisfactory. Robinia and white poplar had the highest growth rates. Ash, maple and alder had the highest survival rates (>90%) but showed stunted growth. Ash, alder, maple and Robinia contained normal concentrations of Cd, Cu, Pb and Zn in their foliage. As a consequence these species reduce the risk of metal dispersal and are therefore suitable species for phytostabilisation under the given conditions. White poplar accumulated high concentrations of Cd (8.0 mg kg(-1)) and Zn (465 mg kg(-1)) in its leaves and might therefore cause a risk of Cd and Zn input into the ecosystem because of autumn litter fall. This species is thus unsuitable for phytostabilisation. Despite elevated metal concentrations in the leaves, phytoextraction of heavy metals from the soil by harvesting stem and/or leaf biomass of white poplar would not be a realistic option because it will require an excessive amount of time to be effective.
Article
Bacterial strains were isolated and enriched from the contaminated site of Tamil Nadu Chromates and Chemicals Limited (TCCL) premises, Ranipet, Tamil Nadu, India. The strain which was isolated from the highly contaminated location had shown high Cr(VI) reduction potential. Cr(VI) reduction was evaluated both in aerobic and anaerobic conditions. Though the aerobic system performed better than the anaerobic one, further study were carried out in the anaerobic condition due to its economic viability. At higher initial concentration, Cr(VI) reduction was not complete even after 108 h, however, specific Cr(VI) reduction, unit weight of Cr reduced/unit weight of biomass was greater at higher concentration. It was found that a bacterial concentration of 15+/-1.0 mg/g of soil (wet weight) 50 mg of molasses/g of soil as carbon source were required for the maximum Cr(VI) reduction. The bioreactor operated at these conditions could reduce entire Cr(VI) (5.6 mg Cr(VI)/g of soil) in 20 days. The Cr(III) thus formed was found to be strongly attached to the soil matrix and the mobility of Cr(III) was negligible as evident from the low concentration of Cr(III) in the leachate. This study showed that bioremediation is a viable, environmental friendly technology for cleaning-up the chromium contaminated site at TCCL, Ranipet, Tamil Nadu, India, and optimal operating conditions under laboratory conditions were evaluated.
Article
Short-term enhancement of lead (Pb) and zinc (Zn) uptake by corn (Zea mays L.) seedlings from a contaminated soil was compared using slow-release coated EDTA granules-a coated chelating agent (CCA), uncoated EDTA granules, and EDTA solution in a greenhouse experiment. Soil Pb and Zn fractions were determined using a sequential extraction scheme. Release of the metals in the soil was examined in a column leaching study. After only 7 days of seedling growth, shoot biomass was decreased by all EDTA treatments compared with the zero-EDTA control. The amount of shoot biomass produced was highest with uncoated EDTA, intermediate with CCA, and lowest with the EDTA solution. Shoot Pb contents were highest with solid EDTA, intermediate with CCA, and lowest with EDTA solution, and they were always higher with EDTA treatments than in controls. In contrast, shoot Zn contents following EDTA treatments were lower than in the control. Levels of soil dissolved organic carbon (DOC) in aqueous soil extracts were much lower after CCA application than following treatments with solid EDTA and EDTA solution. After 17 days of plant growth, when most of the chelating agent had been released from the CCA, soil organic carbon levels remained relatively constant and similar to those in the control, indicating that a relatively low chelating agent concentration can be maintained for the plants to take up the metals. The distribution of Pb in the sequential extraction procedure showed that the Pb level in the exchangeable+carbonate-bound fraction with CCA was significantly lower than that with solid EDTA or EDTA solution, further indicating that slow release of CCA improves the bioavailability of metals in the soil to match plant uptake of those metals. The results suggest that CCA can enhance shoot content of Pb but not of Zn from the contaminated soil in the short term, and may also reduce the risk of metal leaching from the soil.
Article
A substantial body of evidence has now accumulated that raises expectations that clean-up of Cd-contaminated land can be achieved through cultivation and harvest of selected clones of short-rotation coppice willow within a realistic crop lifecycle. Cd uptake rates into Salix are high compared to other trace elements and to other plant species. Effective phytoextraction would require (i) careful targeting of hotspots, (ii) repeated harvest prior to leaf fall and (iii) final removal of the root bole.
Article
In this study the effects of different levels of industrial wastes on growth traits and metal accumulation in aerial portions were determined for Populusxeuramericana clone I-214. The experiment started in April 2003. Scions of Populusxeuramericana clone I-214, were grown outdoor near Pisa (Italy), in lisimeters filled with soil naturally present in the land around the experimental site, were daily drip irrigated, hand weeded, monthly fertilized, pruned for a unique shoot and cultivated with four increasing treatments: soil non-amended, soil amended with 4.8 kgm(-2), with 9.6 kgm(-2) and with 19.2 kgm(-2) of fresh tannery waste. The climatic parameters were daily recorded throughout the whole experiment. Growth relieves were performed during the growing season. After six months since the plantation of the scions, aerial portions of every plant were harvested for biomass and metal content analyses. Data demonstrated that the waste exerted beneficial effects on poplars mainly through a general increase of growth traits and that the nutrients relocation is the mechanisms involved in modulating growth rate. The concentration and the amount of the mineral elements analysed (N, P, K, Na, Ca, Mg, S, B, Fe, Mn, Cu, Zn, Cr) changed determinately among treatments, organs and position. We concluded that phytoremediation strategies of tannery wastes might be possible and sustainable for polar plantations in soil amended with non-hazardous levels of industrial waste, which maintain total heavy metals concentration close to background values.
Article
The study was undertaken to assess the phytoremediation potential of four plants (Sida acuta, Ricinus communis, Calotropis procera, Cassia fistula) growing at a tannery sludge disposal site. Results showed that maximum amount of K, Fe and Ni was associated with residual fraction, whereas, Zn, Mn, Cr, Pb, Cd and Co was found in Fe-Mn oxide fraction. Cu and Na were mostly associated with organic matter and carbonate fraction, respectively. The results demonstrated that the levels of accumulation of metals was found high in all the studied plants and followed the order; C. procera>S. acuta>R. communis=C. fistula. The principal components analysis (PCA) revealed that translocation behavior of Cu, Zn and Mn, Cr were found similar in the plants. Correlation analysis between metal accumulation in the plants with DTPA extractable metals emphasized that S. acuta and C. fistula provide better value of correlation for most of the tested metals. The values of transfer factor were also found high for most of the tested metals in the plants of S. acuta. Overall, the plants of S. acuta and C. fistula were found suitable for the decontamination of most of the metals from tannery waste contaminated sites.
Article
The Siam weed, Chromolaena odorata (L.) King & Robinson, Family Asteraceae, was found to be a new Pb hyperaccumulator by means of field surveys on Pb soil and hydroponic studies. Plants from field collection accumulated 1377 and 4236mgkg(-1) Pb in their shoots and roots, respectively, and could tolerate soil Pb concentrations up to 100000 mgkg(-1) with a translocation factor of 7.62. Very low concentrations of Cd and Zn were found in plants collected from the field. Under nutrient solution culture condition, C. odorata from the contaminated site (CS) and from non-contaminated site (NCS) grew normally with all three metals (Pb, Cd, Zn) supplied. However, the relative growth rates of all treated plants decreased with increased metal concentrations. The percentage uptakes of Pb, Cd, and Zn by C. odorata increased with increasing metal concentrations. Pb concentration in shoots and roots reached its highest values (1772.3 and 60655.7mgkg(-1), respectively) at a Pb supply level of 10mgl(-1). While the maximum concentrations of Cd (0.5mgl(-1)) in shoots and roots of C. odorata were 102.3 and 1440.9mgkg(-1), and the highest concentrations of Zn (20mgl(-1)) were 1876.0 and 7011.8mgkg(-1), respectively. The bioaccumulation coefficients of Pb and Cd were greater than 1000. These results confirm that C. odorata is a hyperaccumulator which grows rapidly, has substantial biomass, wide distribution and has a potential for the phytoremediation of metal contaminated soils.
Article
Up to now, there was no document on ornamental plants that had been applied to phytoremediation, which can remedy contaminated environment and beautify it at the same time. Thus, the growth responses and possible phytoremediation ability of three ornamental plants selected from the previous preliminary experiments were further examined under single Cd or combined Cd-Pb stress. The results showed that these tested plants had higher tolerance to Cd and Pb contamination and could effectively accumulate the metals, especially for Calendula officinalis and Althaea rosea. For C. officinalis, it grew normally in soils containing 100 mg kg(-1) Cd without suffering phytotoxicity, and the Cd concentration in the roots was up to 1084 mg kg(-1) while the Cd concentration in the shoots was 284 mg kg(-1). For A. rosea, the Cd accumulation in the shoots was higher than that in the roots when the Cd concentration in soils was <100 mg kg(-1), and reached 100 mg kg(-1) as the criteria of a Cd hyperaccumulator when the Cd concentration in soils was 100 mg kg(-1). Their accumulation and tolerance to Cd and Pb were further demonstrated through the hydroponic-culture method. And A. rosea had a great potential as a possible Cd hyperaccumulator under favorable or induced conditions. Furthermore, the interactive effects of Cd and Pb in the three ornamentals were complicated, not only additive, antagonistic or synergistic, but also related to many factors including concentration combinations of heavy metals, plant species and various parts of plants. Thus, it can be forecasted that this work will provide a new way for phytoremediation of contaminated soils.
Article
The metal concentrations in a copper mine tailings and desert broom (Baccharis sarothroides Gray) plants were investigated. The metal concentrations in plants, soil cover, and tailings were determined using ICP-OES. The concentration of copper, lead, molybdenum, chromium, zinc, arsenic, nickel, and cobalt in tailings was 526.4, 207.4, 89.1, 84.5, 51.7, 49.6, 39.7, and 35.6mgkg(-1), respectively. The concentration of all elements in soil cover was 10-15% higher than that of the tailings, except for molybdenum. The concentration of copper, lead, molybdenum, chromium, zinc, arsenic, nickel, and cobalt in roots was 818.3, 151.9, 73.9, 57.1, 40.1, 44.6, 96.8, and 26.7mgkg(-1) and 1214.1, 107.3, 105.8, 105.5, 55.2, 36.9, 30.9, and 10.9mgkg(-1) for shoots, respectively. Considering the translocation factor, enrichment coefficient, and the accumulation factor, desert broom could be a potential hyperaccumulator of Cu, Pb, Cr, Zn, As, and Ni.
Proposed field study to evaluate phytoremediation and best management practices for removal of atrazine from agricultural run off. Abstracts of Papers of the 232nd
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Williams VL, Coats JR (2006) Proposed field study to evaluate phytoremediation and best management practices for removal of atrazine from agricultural run off. Abstracts of Papers of the 232nd American Chemical Society National Meeting, San Fran-cisco, CA. pp 518
Uptake and accumulation of cadmiumlead and zinc by Siamweed [Chromo-laena odorata (L.) King & Robinson]
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Tanhan MKP, Pokethitiyook R, Chaitarat R (2007) Uptake and accumulation of cadmiumlead and zinc by Siamweed [Chromo-laena odorata (L.) King & Robinson]. Chemosphere 68(2):323–329
Accumulation and tolerance characteristics of chro-mium in a cordgrass Chromium-hyperaccumulator, Spartina ar-gentinensis
  • Redondo-Gó S, Mateos-Naranjo E, Vecino-Bueno Feldman
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Redondo-Gó S, Mateos-Naranjo E, Vecino-Bueno Feldman SR (2010) Accumulation and tolerance characteristics of chro-mium in a cordgrass Chromium-hyperaccumulator, Spartina ar-gentinensis. J Hazar Mater 185(2–3):299–307
Soil physical and chemical analysis & description of soil profiles(in Chinese)
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Factors affecting chemical and biological reduction of Chromium (VI) in soil
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Proposed field study to evaluate phytoremediation and best management practices for removal of atrazine from agricultural run off. Abstracts of Papers of the 232nd
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Soil physical and chemical analysis & description of soil profiles
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