No full-text available
To read the full-text of this research,
you can request a copy directly from the author.
Invasive species based efficient green technology for phytoremediation of fly ash deposits
Abstract
The present investigation was focused to examine the phytoremediation potential of naturally grown Ipomoea carnea on fly ash (FA) deposits. I. carnea is an invasive species and mostly neglected by people but it has unusual characteristics which deals to phytoremediation. The metal accumulation of Cd, Pb, Cu, Cr, Mn and Ni ranged from 5.3 to 39.7, 7.4 to 30.6, 19.9 to 32.5, 9.5 to 20.6, 19.0 to 90.1, and 13.7 to 68.2 μg g− 1, respectively, in all the parts of I. carnea grown on barren FA deposits during two periods (pre- and post-monsoon). The bioconcentration factor (BCF) values of Cd, Pb, Mn, and Ni in root and stem were greater than 1 during both periods which indicates the metal accumulation potential of I. carnea. There is a dearth of study recommending the safe and effective green technology for the phytoremediation of FA dumps. In this regards, I. carnea was identified as an effective plant for phytoremediation in harsh environmental conditions of abandoned FA deposits.
... Aquatic macrophytes are known for their high potential of absorbing organic matter and nutrients into their tissues for growth, as well as cleaning polluted water sources [Rezania et al., 2015]. As an invasive species, water lettuce (WL; Pistia stratiotes L.) is a floating macrophyte, with high bio-accumulation and good tolerance for ecological-environmental factors [Pandey, 2012]. WL could be used for a phytoremediation process. ...
... Over the first period (days 0-7) of the experiment, we examined the WL's nutrient removal in wastewater at the still-water stage. Over the second period (days [10][11][12][13][14][15][16][17][18][19][20][21][22], wastewater with a concentration of about 15 mg/L of NH 4 + -N was slowly poured into ponds 1, 2 and 3, made of terraced Styrofoam containers, as shown in Figure 1. Small water pipes were connected to the ponds, and the wastewater flow rate was controlled to reach about 15 mL in the Styrofoam containers. ...
... As for NO 3 --N concentrations, on day 3, no significant differences between the treatments without WL and with WL were observed, as discussed above. On days 7 and 10, NO 3 --N concentrations in the treatment without WL were lower than those in the treatment with WL; inversely, on days 13,16,19 and 20,NO 3 --N concentrations in the treatment without WL were higher than those in the treatment with WL. The results indicated that WL contributed to nitrate reduction at the running-water stage on day 13. ...
... FA is a risk to the atmosphere by polluting water and land through the leaching of heavy metals in groundwater and air pollution due to its fine particle size in the surrounding atmosphere. The leaching of many heavy metals like Pb, Ni, Mn, Cr, Cd, Cu, Fe, etc. inflowing the environment and thus a big threat to habitats (Pandey 2012a(Pandey , b, 2020aYadav et al. 2022). It causes health-related issues such as cancer, genetic mutations, etc, and has also been noticed in nearby coal-based TPP residents (Kumar et al. 2022a). ...
... Phytoremediation, a green technology that removes heavy metals from the contaminated substrate, is gaining acceptance. In this study, naturally growing B. monnieri and A. oleracea are presented in Figure 2. The phytoremediation potential of plants can be resolute by the metal accumulating in different parts of plants (Pandey 2012a;Maiti and Pandey 2021;Yadav et al. 2021), whereas the plant growth is also a factor that represents the survival of plants in stressful conditions. BAF and TF of plants are represented in Table 3. ...
... Simultaneously, Pb and Co in the root against Fe, and Pb in the shoot, respectively. The phytoremediation capability of plants can be determined by the metal accumulation in different parts of plants (Pandey 2012a;Maiti and Pandey 2021;Yadav et al. 2021), whereas the plant growth is also a factor that represents the survival of plants in stressful condition. Bioconcentration and translocation factors of plants are represented in Figure 2. In B. monnieri TF for Cr and Mn is more than one, which means the mobility of metals in shoots is high and the plant is a phytoaccumulator. ...
... Metals present in soil become available to plants in a bioavailable form, which easily become absorbed by the roots and transfer into the shoot through suitable carriers. However, the transportation of metals in plants varies from plants to plant and species to species and further depends on many other factors such as the age of the plant, climatic regime, nature of soil, soil chemistry, ecotype, etc. [45,54,[140][141][142]. It seems that the transfer factors derived from different types and ranges of soil metal concentrations are not comparable. ...
... where C (shoot) indicates the metal concentration accumulated in the shoot part and C (root) indicates the metal concentration accumulated in the root part. The same factor was calculated by different researchers and denoted as the "shoot" part using different terms such as "aerial part" [39,51,62,98], stem [54,59,100,147], aboveground tissue part [50,56], and leaves [62,100,148]. Similarly, in the case of ferns, the term "frond" [65,97] and "cap" in case of mushroom [149] were also used to denote the shoot part. ...
... HNO 3 is often used for metal extraction from plant samples [48,180,204]. A binary acid mixture of HNO 3 and HClO 4 , which is the most widely used extractant (4:1 or 5:1 on in 3:1; v/v), has been mainly used by the researchers for many years for the estimation and determination of metal concentrations in plants [51,54,100,182,185,202,[205][206][207]. Sometimes, tertiary acid mixtures of HF, HNO 3 and HClO 4 [46,61,199,201,208] are also used for the same purpose. ...
This paper reviews research on phytoremediation (2002-2021), particularly for the estimation of plant efficiency and soil pollution indices, examining the extraction of metals from soil and plants growing under both artificial (spiked with specific metal) and natural conditions. From the analysis of >200 published experimental results, it was found that contamination factor and geo-accumulation index as well as translocation and bioconcentration factors are the most important soil pollution and plant efficiency metrices, respectively, which are gaining importance to assess the level of metal pollution and its transfer from soil to plant to find a better metal clean-up strategy for phytoremediation. To access the metal concentration, it was found that the most widely accepted extractants to dissolve and extract the metals from the soil and plant were HNO 3 and HClO 4 (mainly in 5:1; v/v or 4:1; v/v), which are used both in natural and artificial metal contamination studies. Moreover, plants such as Pteris vittata, Monochoria korsakowi, Lolium perenne, Festuca rubra, Poa pratensis, Ricinus communis, and Siegesbeckia orientalis can act as hyperaccumulators under both natural and artificial experiments and can be directly implemented into the fields without checking their further efficiency in phytoremediation.
... There have been many works devoted to experimental research on the development and chemistry of plant species on landfills under conditions of varied fertilization and variation in the species sown [13][14][15][16]. Fewer studies concern plants growing on combustion waste landfills under conditions of spontaneous succession [17,18]. Irrespective of the type of succession, developing vegetation plays an important role in limiting secondary emission of pollutants from these sites and thus mitigating their negative impact on the environment [18][19][20]. ...
... Fewer studies concern plants growing on combustion waste landfills under conditions of spontaneous succession [17,18]. Irrespective of the type of succession, developing vegetation plays an important role in limiting secondary emission of pollutants from these sites and thus mitigating their negative impact on the environment [18][19][20]. The most hazardous environmental toxins accumulated in combustion waste include heavy metals [21,22]. ...
... The BCF and TF are useful tools here. Both factors can be used to assess a plant's potential for phytostabilisation [18,31]. Szöcs and Schäfer [36], recommend the use of factors in statistical analysis, particularly in the case of non-parametric data distribution. ...
Coal bottom and fly ash waste continue to be generated as a result of energy production from coal in the amount of about 750 million tonnes a year globally. Coal is the main source of energy in Poland, and about 338 million tonnes of combustion waste has already been landfilled. The aim of the research was to identify factors determining the Cd, Pb, Zn and Cu phytostabilisation by vegetation growing on a coal combustion waste landfill. Soil and shoots of the following plants were analysed: wood small-reed, European goldenrod, common reed; silver birch, black locust, European aspen and common oak. The influence of the location where the plants grew and the influence of the interaction between the two factors (species and location) were significant. The tree species were more effective at accumulating heavy metals than the herbaceous plants. European aspen had the highest Bioaccumulation Factor (BCF) for cadmium and zinc. A high capacity to accumulate these elements was also demonstrated by silver birch, and in the case of cadmium, by common oak. Accumulation of both lead and copper was low in all plants. The Translocation Factors (TF) indicated that the heavy metals were accumulated mainly in the roots. European aspen, silver birch and European goldenrod were shown to be most suitable for stabilization of the metals analysed in the research.
... As the liquid/solid ratio and the time spent in contact with water increases, the risk that FA poses to the environment increases proportionally (Ibrahim 2015;Jankowski et al. 2006). However, numerous studies have shown that the total content of PTEs in FA decreases even after its deposition, although to a lesser extent ( Maiti and Jaiswal 2008;Mitrović et al. 2008;Pandey 2012;Kostić et al. 2018). This may be caused by an improvement in the physico-chemical properties of FA and an increase in the content of organic matter. ...
... These are initially devoid of any vegetation or have only sparse plant cover (Shaw 1996). However, the weathering of ash leads to the leaching of some phytotoxic elements from the root zone, creating conditions for colonisation by tolerant plants, most of the early colonisers being herbaceous in nature (Chu 2008; Maiti and Jaiswal 2008;Pandey et al. 2015;Pandey 2012;Kostić et al. 2018). Studies on the colonisation of plants in ash dumps have shown that this is a long process, with the formation of woody vegetation taking many years. ...
... Hence, in recent decades, emphasis has been placed on the importance of using plant species that have spontaneously infiltrated this kind of anthropogenically degraded habitat from the immediate surroundings (Shaw 1996;Djordjević-Miloradović 1998;Pavlović et al. 2004;Djurdjević et al. 2006;Chu 2008;Mitrović et al. 2008; Gupta and Sinha 2008;Kostić et al. 2012;Mitrović et al. 2012;Mustafa et al. 2012;Pandey 2012;Gajić et al. 2013;Morariu et al. 2013;Pandey et al. 2015;Żołnierz et al. 2016;Gajić et al. 2018;Panda et al. 2020a). The analysis of different species in different ash dumps has shown that most of those that spontaneously colonise these anthropogenically formed habitats and can be used for revegetation and, potentially, for phytoremediation due to their resistance to adverse conditions, come from the families Asteraceae, Amaranthaceae, Poaceae and Fabaceae (Table 22.5). ...
Fly ash (FA) as a product of coal combustion in thermal power plants is a hazardous material that is deposited in the immediate vicinity of power plants due to its low rate of utilisation. As a result, fertile agricultural land turns into fly-ash dumps, which disperse fine ash particles around the environment, and toxic materials and salts are leached into groundwater. Revegetating fly ash dumps has proven to be the best way to stabilise the ash both physically and chemically. However, the establishment of vegetation cover at such sites is severely hampered by the unfavourable physical and chemical properties of the unweathered ash, which contains high amounts of potentially toxic elements (PTEs). This chapter provides an overview and discusses the most important issues related to the establishment of vegetation cover at FA disposal sites and the role of plants in stabilising pollutants and mitigating their negative effects as well as their role in soil formation processes. Natural vegetation plays an essential role due to its tolerance to numerous stress conditions caused by pollution and its ability to accumulate PTEs. It has been established that the use of natural plants by means of auxiliary restoration of vegetation cover with the support of appropriate agronomic practices (integrated biotechnological approach) can effectively help control the spread of PTEs and support the phytoremediation of this type of environment. The overview has revealed that ash weathering and the development of vegetation have positive effects on the physical and chemical characteristics of wet FAs. Positive changes were manifested in the morphology and texture of ash, a decrease in alkalinity and salinity, the development of horizon A due to the accumulation of organic matter and an increase in organic carbon, nitrogen, phosphorus and adsorption capacity. These changes were most pronounced in the upper layer of the FA and are important indicators of the onset of soil formation processes. It is concluded that these processes and the time elapsed after the revegetation are the main driving factors. They are extremely important for the successful ecological reclamation of fly ash disposal sites and long-term environmental protection.
... Vegetative covering on FA dumps is an effective and sustainable way of rehabilitation (Pandey, 2012a). However, establishing natural vegetation cover on FA dumps is a long-term process but the addition of various promoters such as organic amendments (press mud, sewage sludge, farmyard manure, compost, biochar, etc.), a layer of soil, and bio-fertilisers (bacteria and fungi), can help speed rehabilitation. ...
... However, several naturally growing plants still show their potential to grow and survive on FA dumps after few years because of their innate capability ( Figure 2). In this aspect, worldwide, many naturally occurring plants have been noticed on FA dumps Pandey, 2012aPandey, , 2012bPandey, , 2013Pandey, , 2016. Several naturally growing plants have shown their potential for restoration of FA dumps through phytostabilisation and phytoextraction mechanisms (Barton et al. 2005;Pandey & Bhattacharya 2018). ...
... tora (Cr, Cu, and Fe), C. procera (Zn, and Co), C. Ziziphus nummularia (Gupta & Sinha, 2008;Kumari et al., 2013;Madhumita et al., 2018;Maiti & Pandey, 2021;Pandey, 2012aPandey, , 2012bPandey, 2015;Rau et al., 2009). Summarised data could pave way to frame restoration strategies at newly form FA dumps as per its respective spatial distribution of plants. ...
Fly ash is a prominent environmental by-product or residue that is produced during the combustion of coal for energy production in thermal power plant. The huge amount of fly ash generation is a global problem; still could not be found a safe and sustainable approach of fly ash disposal. The fly ash dumps not only creates air, water, and soil pollution but also poses noxious impact on human health by introducing toxins in food chain through biomagnification. The non-food vegetation cover can help to mitigate fly ash dump-related environmental health issues. However, alkaline pH, toxic metals, lack of microbes and pozzolanic properties of fly ash limit the plant growth. In this regard, ecological restoration of fly ash dumps through phytoremediation is a holistic approach. This review article focuses on the role of naturally occurring plants, tree plantation and microbial inoculation in ecological restoration of fly ash dumps and their role in the physicochemical changes of fly ash substrate. Application of organic material has been proved to establish vegetation cover on fly ash dumps as they provide essential nutrients to plant and microbial growth. Morphological, physiological and antioxidant response of plants grown on fly ash dumps are also discussed here in detail. Overall, this review summarises the different comprehensive approaches of fly ash dump restoration and compiles ways to convert barren fly ash dumps into useful dumpsites for deriving bioeconomy with phytoproducts. The outcomes of this learning are beneficial for classifying site-specific ecorestoration of fly ash dumps through integrated approach.
... The seedlings and saplings of P. juliflora were also present at the naturally vegetated site of Arkha dumpsite, indicating its adaptation to FA dump in the present tropical climate. Moreover, our previous studies at the Arkha dumpsite reported certain revegetated species' (i.e., S. munja and I. carnea) phytoremediation potential by translocating trace elements in plants' parts from FA technosol (Pandey, 2012;Pandey et al., 2012). ...
... The FA technosol offers an adverse and challenging environmental condition (e.g., absence or low availability of nutrients, very high or low pH, trace elements), which is often unsuitable for the growth and functioning of most plant communities (Maiti and Pandey, 2021). Indeed, our previous study in the present site (Arkha dump site, Raebareli, India) also reported a significant amount of trace elements in FA technosol, including Cd (19.0 μg g −1 ), Pb (15.2 μg g −1 ), Cu (66.7 μg g −1 ), Cr (22.0 μg g −1 ), Mn (45.1 μg g −1 ), and Ni (14.2 μg g −1 ) (Pandey, 2012). Hence, multipurpose plants with the proven ability to sustain adverse conditions have often been introduced (or naturally grown) in technosol environments for restoration purposes (Jambhulkar et al., 2018;Maiti and Pandey, 2021). ...
Technogenic soil (technosol) developed from coal fly ash (FA) landfilling has been considered a critical environmental problem worldwide. Drought-tolerant plants often naturally grow on FA technosol. However, the impact of these natural revegetations on the recovery of multiple ecosystem functions (multifunctionality) remains largely unexplored and poorly understood. Here we assessed the response of multifunctionality, including nutrient cycling (i.e., carbon, nitrogen, and phosphorus), carbon storage, glomalin-related soil protein (GRSP), plant productivity, microbial biomass carbon (MBC), microbial processes (soil enzyme activities), and soil chemical properties (pH and electrical conductivity; EC) to FA technosol ten years' natural revegetation with different multipurpose species in Indo-Gangetic plain, and identified the key factors regulating ecosystem multifunctionality during reclamation. We evaluated four dominant revegetated species: Prosopis juliflora, Saccharum spontaneum, Ipomoea carnea, and Cynodon dactylon. We found that natural revegetation initiated the recovery of ecosystem multifunctionality on technosol, with greater recovery under higher biomass-producing species (P. juliflora and S. spontaneum) than lower biomass-producing ones (I. carnea and C. dactylon). The individual functions (11 of the total 16 variables) at higher functionality (70 % threshold) also exhibited this pattern among revegetated stands. Multivariate analyses revealed that most of the variables (except EC) significantly correlated with multifunctionality, indicating the capability of multifunctionality to consider the tradeoff between individual functions. We further performed structural equation modeling (SEM) to detect the effect of vegetation, pH, nutrients, and microbial activity (MBC and microbial processes) on ecosystem multifunctionality. Our SEM model predicted 98 % of the variation in multifunctionality and confirmed that the indirect effect of vegetation mediated by microbial activity is more important for multifunctionality than their direct effect. Collectively, our results demonstrate that FA technosol revegetation with high biomass-producing multipurpose species promotes ecosystem multifunctionality and emphasizes the significance of microbial activity in the recovery and maintenance of ecosystem attributes.
... Invasive plant species invade the ecosystem and change their functions and processes by affecting nutrient cycling and reducing the biodiversity of native flora (Ehrenfeld, 2010;Simberloff et al., 2013). However, rather than getting eliminated from the ecosystem, these species are used for ecosystem restoration and the bioremediation of contaminated soil (Ewel and Putz, 2004;Pandey, 2012). In previous studies, invasive alien plant species such as Chromolaena odorata and Praxelis clematidea significantly enhanced soil nutrient levels (Koné et al., 2012;Wei et al., 2017). ...
... Comparatively, invasive plant species have higher adaptability to stressful environments (Ehrenfeld, 2010;Bai et al., 2020). According to previous studies, the high adaptability rate of invasive plants makes them a potentially better choice for removing soil pollutants (Tanhan et al., 2007;Sun et al., 2009;Pandey, 2012). Chlorophyll fluorescence parameters are the significant determinants of the performance and adaptability of plants in stressed environments. ...
Heavy metal (HM) contamination resulting from industrialization and urbanization during the Anthropocene along with plant invasion can severely threaten the growth and adaptation of local flora. Invasive alien plant species generally exhibit a growth pattern consistent with their functional traits in non-contaminated environments in the introduced range. However, it remains unclear whether invasive alien plants have an advantage over native plants in contaminated environments and whether this growth pattern is dependent on the adaptation of their leaf functional traits. Here, we selected two congeneric pairs of invasive alien and native grasses that naturally co-exist in China and are commonly found growing in contaminated soil. To evaluate the effect of cadmium (Cd) on the structural and physiological leaf traits, we grew all four species in soil contaminated without or with 80 mg/kg Cd. Invasive plants contained significantly higher concentrations of Cd in all three organs (leaf, stem, and root). They displayed a higher transfer factor and bioconcentration factor (BCF) of shoot and root than natives, indicating that invasive species are potential Cd hyperaccumulators. Invasive plants accumulated polyphenol oxidase (PPO) to higher levels than natives and showed similar patterns of leaf structural and physiological traits in response to changes in Cd bioconcentration. The quantifiable leaf structural traits of invasive plants were significantly greater (except for stomatal density and number of dead leaves) than native plants. Leaf physiological traits, chlorophyll content, and flavonoid content were also significantly higher in invasive plants than in natives under Cd stress conditions after 4 weeks, although nitrogen balance index (NBI) showed no significant difference between the two species. Chlorophyll fluorescence parameters decreased, except for Ilyas et al. Advantages of Leaf Functional Traits for Invasion the quantum yield of photosystem II (PSII) and the proportion of open photosystem II (qP), which increased under Cd stress conditions in both species. However, invasive plants exhibited higher fluorescence parameters than natives under Cd stress, and the decrement observed in invasive plants under Cd stress was greater than that in natives. High Cd adaptation of invasive grasses over natives suggests that invasive plants possess optimal leaf structural and physiological traits, which enable them to adapt to stressful conditions and capture resources more quickly than natives. This study further emphasizes the potential invasion of alien plants in contaminated soil environments within the introduced range. To a certain extent, some non-invasive alien plants might adapt to metalliferous environments and serve as hyperaccumulator candidates in phytoremediation projects in contaminated environments.
... Invasive plant species invade the ecosystem and change their functions and processes by affecting nutrient cycling and reducing the biodiversity of native flora (Ehrenfeld, 2010;Simberloff et al., 2013). However, rather than getting eliminated from the ecosystem, these species are used for ecosystem restoration and the bioremediation of contaminated soil (Ewel and Putz, 2004;Pandey, 2012). In previous studies, invasive alien plant species such as Chromolaena odorata and Praxelis clematidea significantly enhanced soil nutrient levels (Koné et al., 2012;Wei et al., 2017). ...
... Comparatively, invasive plant species have higher adaptability to stressful environments (Ehrenfeld, 2010;Bai et al., 2020). According to previous studies, the high adaptability rate of invasive plants makes them a potentially better choice for removing soil pollutants (Tanhan et al., 2007;Sun et al., 2009;Pandey, 2012). Chlorophyll fluorescence parameters are the significant determinants of the performance and adaptability of plants in stressed environments. ...
... Invasive plant species invade the ecosystem and change their functions and processes by affecting nutrient cycling and reducing the biodiversity of native flora (Ehrenfeld, 2010;Simberloff et al., 2013). However, rather than getting eliminated from the ecosystem, these species are used for ecosystem restoration and the bioremediation of contaminated soil (Ewel and Putz, 2004;Pandey, 2012). In previous studies, invasive alien plant species such as Chromolaena odorata and Praxelis clematidea significantly enhanced soil nutrient levels (Koné et al., 2012;Wei et al., 2017). ...
... Comparatively, invasive plant species have higher adaptability to stressful environments (Ehrenfeld, 2010;Bai et al., 2020). According to previous studies, the high adaptability rate of invasive plants makes them a potentially better choice for removing soil pollutants (Tanhan et al., 2007;Sun et al., 2009;Pandey, 2012). Chlorophyll fluorescence parameters are the significant determinants of the performance and adaptability of plants in stressed environments. ...
Heavy metal (HM) contamination resulting from industrialization and urbanization during the Anthropocene along with plant invasion can severely threaten the growth and adaptation of local flora. Invasive alien plant species generally exhibit a growth pattern consistent with their functional traits in non-contaminated environments in the introduced range. However, it remains unclear whether invasive alien plants have an advantage over native plants in contaminated environments and whether this growth pattern is dependent on the adaptation of their leaf functional traits. Here, we selected two congeneric pairs of invasive alien and native grasses that naturally co-exist in China and are commonly found growing in contaminated soil. To evaluate the effect of cadmium (Cd) on the structural and physiological leaf traits, we grew all four species in soil contaminated without or with 80 mg/kg Cd. Invasive plants contained significantly higher concentrations of Cd in all three organs (leaf, stem, and root). They displayed a higher transfer factor and bioconcentration factor (BCF) of shoot and root than natives, indicating that invasive species are potential Cd hyperaccumulators. Invasive plants accumulated polyphenol oxidase (PPO) to higher levels than natives and showed similar patterns of leaf structural and physiological traits in response to changes in Cd bioconcentration. The quantifiable leaf structural traits of invasive plants were significantly greater (except for stomatal density and number of dead leaves) than native plants. Leaf physiological traits, chlorophyll content, and flavonoid content were also significantly higher in invasive plants than in natives under Cd stress conditions after 4 weeks, although nitrogen balance index (NBI) showed no significant difference between the two species. Chlorophyll fluorescence parameters decreased, except for the quantum yield of photosystem II (ΦPSII) and the proportion of open photosystem II (qP), which increased under Cd stress conditions in both species. However, invasive plants exhibited higher fluorescence parameters than natives under Cd stress, and the decrement observed in invasive plants under Cd stress was greater than that in natives. High Cd adaptation of invasive grasses over natives suggests that invasive plants possess optimal leaf structural and physiological traits, which enable them to adapt to stressful conditions and capture resources more quickly than natives. This study further emphasizes the potential invasion of alien plants in contaminated soil environments within the introduced range. To a certain extent, some non-invasive alien plants might adapt to metalliferous environments and serve as hyperaccumulator candidates in phytoremediation projects in contaminated environments.
... The field studies with suitable plant species for plantation and restoration of FA dumps have been performed Gajić et al., 2016;Kumar et al., 2021). In addition, many investigators have assessed the heavy metal accumulation potential of plants grown on FA dumpsites (Maiti and Jaiswal, 2008;Pandey, 2012;Pandey, 2013;Kumari et al., 2013). Some studies are reported on natural colonization of vegetation on FA dumpsites worldwide such as Hong Kong (Chu, 2008), Poland (Jasionkowski et al., 2016), Serbia (Djurdjević et al., 2006), Kosovo (Mustafa et al., 2012), England (Shaw, 1992), United States (Mulhern et al., 1989), but very little is known about the plant diversity and ecological potential of naturally colonized plant species for ecorestoration of FA disposal areas. ...
... Some studies are reported on natural colonization of vegetation on FA dumpsites worldwide such as Hong Kong (Chu, 2008), Poland (Jasionkowski et al., 2016), Serbia (Djurdjević et al., 2006), Kosovo (Mustafa et al., 2012), England (Shaw, 1992), United States (Mulhern et al., 1989), but very little is known about the plant diversity and ecological potential of naturally colonized plant species for ecorestoration of FA disposal areas. The phytostabilization of FA dumpsites through naturally colonized plant species is more effective and affordable approach than man-made plantation (Pandey, 2012;Pandey, 2015;Mitrović et al., 2008). Colonizer plant species have the potential for ecorestoration of FA dumpsite because they respond better and can survive easily in comparison to introduced plant species (Pandey and Singh, 2011;Yadav et al., 2021). ...
Fly ash dump has been noticed as one of the hazardous dumpsites on the earth, which pollutes our environment. Therefore, an affordable and effective approach for the restoration of fly ash dumps is urgently required worldwide. In this direction, to find out potential plant species through the assessment of naturally colonized vegetation is a basic criterion of ecological restoration. With the above vision, the present study was performed to identify potential colonizer plants of fly ash dumps for ecological restoration. The intensive field studies were made during 2019–2020 to gather naturally occurring plants from fly ash disposal area of Koradi Thermal Power Plant, Nagpur, Maharashtra, India. Therefore, naturally colonizing plants were assessed on the basis of their dominance, ability of improving the rhizospheric FA, and ecological significance for their ecorestoration potential. Acacia nilotica L., Acmella oleracea L., Bacopa monnieri L., Cynodon dactylon (L.) Pers., Cyperus rotundus L., Dactyloctenium aegyptium L., Digitaria sanguinalis L., Trianthema portulacastrum L., Typha latifolia L. and Portulaca oleracea L. were recognized as potential plants for ecological restoration of FA dumps. Hence, the characteristics of above identified potential plant species can be used in ecological restoration of newly FA disposal areas.
... The most tolerant plant species are those that absorb and translocate the smallest amounts of toxic elements into the aboveground parts in relation to their concentration in the substrate (BAF < 1; TF < 1) [9,38]. Therefore, for the remediation of extremely large and highly contaminated areas with several pollutants present, as is the case with FA disposal sites, the use of phytostabilizer plants is of greater importance [23,39]. The use of accumulator plants in such habitats would allow the cycling of undesirable elements through the litter in the substrate/plant system, which would lead to their spread through the ecosystem. ...
... At L1, the concentration of As and Cr in the ash at this lagoon was in the critical range for plants ( Table 2 [77]), while the B, Cu, Ni, and Se concentration was higher than the average values, the Zn concentration fell within the range of average values, and Mn was lower than the average values for sandy to silty loam soils (Table 2 [45]). At L2, C PT of Ni and Se was similar to the concentration at L1, while the As, B, Cr, Cu, Mn, and Zn concentration was lower than in the ash at L1, as a result of weathering and the revegetation process [17,23,34]. Our previous research into the effects of weathering and vegetation on the development of substrate properties at L1 and L2 (3 and 11 years after revegetation) revealed a reduction in total concentrations of As, B, Cr, Cu, Mn, and Zn over time. ...
In this study, the potential of planted (Tamarix tetrandra Pall. ex M.Bieb. and Robinia pseudoacacia L.) and spontaneously colonized (Amorpha fruticosa L. and Populus alba L.) woody species for the phytoremediation of potentially toxic trace elements (TEs) such as As, B, Cr, Cu, Mn, Ni, Se, and Zn, from the chronosequence fly ash (FA) deposit lagoons (L1 and L2) at the ‘Nikola Tesla A’ Thermal Power Plant (TENT-A) in Serbia were analyzed. The differences in the pseodototal and bioavailable (DTPA-extractable) concentrations and mobility (AR index) of TEs in FA at the examined lagoons are a result of the time-conditioned influence of weathering (3 and 11 years respectively) and vegetation development on changing the basic physical and chemical properties of FA (texture, pH, EC, CEC, C, N, and bioavailable P and K) and its toxicity. This resulted in differences in the concentration of TEs in the roots and leaves of the examined plants at L1 and L2. All examined species accumulated Cr the most in the root (BAF > 1 and TF < 1), which suggests that they are good stabilizers of this element. Biological indices for As (BAF > 1 and TF < 1) identified T. tetrandra and A. fruticose as good stabilizers of As. P. alba stood out as accumulating the highest levels of B, Ni, and Zn, T. tetrandra the highest levels of Cu, Mn, and Se, and R. pseudoacacia the highest levels of As and B in leaves (BAF > 1; TF > 1), which makes them good extractors of these elements from the FA at TENT-A. However, due to toxic concentrations of As, B, Se, and Zn in their leaves, they are not recommended for the phytoremediation of the investigated lagoons through the process of phytostabilization. Under conditions of elevated total Cu and Ni concentration in FA, the content of these elements in the leaves of A. fruticosa at both lagoons were within the normal range. This, in addition to a good supply of essential Zn, the stabilization of As and Cr in the roots, an increase in BAF, and a decrease in TF for B with a decrease in its mobility in ash over time, singles this invasive species out as the best candidate for the phytostabilization of TEs in FA at the TENT-A ash deposit site.
... The accumulated Ba mass (Ba accum , Eq. (1)), the translocation factor (TF, Eq. (2)) (Pandey, 2012), and the mass translocation factor (mTF)which is based on the total mass of Ba accumulated in each part of the plant (Ribeiro et al., 2018) (Eq. (3))-were calculated to assess the potential of each treatment to move metals from the root to the aboveground plant tissues: ...
... The phytoextraction potential of the plant can be assessed using the TF (Pandey, 2012) and the mTF (Ribeiro et al., 2018). These two factors present different behaviors, because the TF considers only the concentration of contaminants in a certain part of the plant, and the mTF considers the content and produced biomass-the mass of the contaminant absorbed. ...
The management of initial planting density can be a strategy to increase barium phytoextraction from soil, reducing the time required for soil decontamination. To delimit the ideal planting density for barium (Ba) phytoremediation using Typha domingensis, we conducted a 300-day experiment in an area accidentally contaminated with barite. Four initial planting densities were tested: 4, 8, 12, and 16 plants m⁻² (D4, D8, D12, and D16 treatments, respectively). Plant development was evaluated periodically, and the phytoextraction efficiency was determined at the end of the trial. The initial planting density affected Ba phytoremediation by T. domingensis monoculture. Phytoextraction potential was better represented by the mass-based translocation factor (mTF) than the concentration-based translocation factor. D16 promoted the highest final number of plants and biomass production, but the mass of Ba in the aerial part did not differ among D8, D12, and D16. D4 resulted in more Ba accumulated belowground than aboveground (6.3 times higher), whereas D12 and D16 achieved the greatest mTFs. Higher absorption of Ba from soil can be achieved using less T. domingensis individuals at the beginning of the treatment (D4 and D8) but with high accumulation in belowground tissues. We conclude that the D8 density is considered the most appropriate if considering the phytoextraction potential and field management facilitated using fewer plants.
... Alien plants can be useful in ecosystem restoration, especially when native species are locally absent or extinct, or because the alien plants are more effective (Ewel and Putz 2004;Trueman and Erber 2013;Pandey et al. 2015a, b). Revegetation of degraded areas is crucial for maintaining ecological services and sustaining ecosystem functions (Pandey 2012). ...
... Invasive plants can also be used in phytoremediation of heavy metals in polluted and environmentally devastated areas (Dissanayake et al. 2002;Pandey 2012Pandey , 2016Fu et al. 2017). Erigeron annuus (L.) Desf. ...
The effect of shoot cutting was tested on cadmium, lead and zinc concentration in leaves and capitula of Erigeron annuus, an invasive species, which is considered as a potential phytoremediator. Plant material and soil were collected in the city center of Kraków, southern Poland, considered as one of the most contaminated cities in Europe. We proved that the concentration of zinc in leaves and capitula was higher after regrowth, concentration of cadmium was lower in capitula than in leaves, and the average value of bio-concentration factor for zinc and cadmium was less than 1, whereas for lead it was greater than 1 in both plant organs. Our results suggested that E. annuus can be potentially used for phytoremediation of lead and cutting the shoots can promote effectiveness of zinc removal from the contaminated soil.
... Pandey [65] reported that the potential of naturally occurring Ipomoea carnea plants to remove pollutants from fly ash (FA) deposits through a process is called phytoremediation. Despite being an invasive species that is often overlooked, I. carnea possesses unique characteristics that make it suitable for phytoremediation purposes. ...
The paper reviews the different strengthening techniques to control the displacement of piles of coal overburden wastes. In the present era, the urge for power and minerals is increasing due to rapid growth in industrialization. Thus, extracting minerals buried in the earth require the removal of topsoil or cover if the method involves open-cast mining. This method is only being applicable to minerals that are at shallow depths. Therefore, this method has been active in the industry for the past six decades, which lead to dumping overburden in nearby areas or in-pit. Hence, due to the scarcity of land, the concerned organization is forced to optimize the prior dumping site by increasing height and slope angle. Therefore, strengthening is very important, so it can withstand the additional imposed load generated by coal mine overburden wastes (CMOW). On the other hand, failure of CMOW is a major problem in mining sites, leading to soil erosion, air pollution, and acid mine drainage in those areas. Previously, researchers have proposed various methods of strengthening the CMOW dump using techniques like growing plants on the surface and anchoring the ground due to roots, geosynthetics, lime, cement, and fly ash mixture, etc. Further, the microbial-induced calcite precipitation technique has been established as a natural and beneficial technique in slope stability but has yet to be researched for its applicability in strengthening CMOW dumps in mining areas. Hence, the key motive of this review paper is to bring out various aspects of CMOW, such as status, scenarios, associated challenges, engineering properties, techniques to strengthen, and future action plans to adopt a novel method to overcome issues.
... Climate change exacerbates the problem by creating favorable conditions for invasive species to establish and spread and is likely to influence competitive interactions between native and invasive species (Finch et al. 2021;Walther et al. 2009). Ecologists, however, have long 4 proposed that instead of being eliminated, invasive plant species can be utilized for ecosystem restoration of degraded lands (Pandey 2012). Several policies and risk assessments are also currently in place to control the adverse effects of invasive species in forest ecosystems (Pötzelsberger et al. 2020). ...
Investigating invasive species’ morphoanatomical characteristics, such as leaf area and thickness of vascular tissues and storage cells, can reveal information about their adaptive ability and competitive advantage. Thus, we analyzed the variation in leaf, stem, and root morphoanatomical structure and stomatal conductance between shaded and sun-exposed seedlings of Broussonetia papyrifera to provide insights into management strategies to control its invasive ability. The variations in leaf area (LA), Leaf Mass per Area (LMA), stomatal density, thickness of palisade and spongy mesophyll tissues, thickness of xylem parenchyma cells, diameter of all xylem vessels in stem and roots and stomatal conductance were analyzed between shaded and sun-exposed seedlings. Results revealed that the LA and LMA of B. papyrifera were significantly larger in the sun-exposed than in the shaded condition. Seedlings exposed to sunlight also had thicker palisade mesophyll and xylem parenchyma cells. The diameter of xylem vessels in roots was also significantly higher in sun-exposed seedlings. Contrarily, a reverse pattern was observed in the diameter of stem xylem vessels (i.e., shaded > sun-exposed seedlings). Physiologically, a higher stomatal conductance was also observed in sun-exposed seedlings. In conclusion, we found significant variations in leaf, stem, and root morphoanatomy and stomatal conductance between shaded and sun-exposed seedlings of B. papyrifera. The findings of the present study may provide valuable implications for managing or controlling its invasibility in the introduced range. Keywords: freehand technique, invasive species, Moraceae, paper mulberry, stomatal conductance
... As a rule, post-combustion wastes are stored in ponds through the wet deposition (Haynes, 2009;Petrović and Fiket, 2022). Ecological restoration of ash dumps often reduces to bioremediation by woody plant species (Pandey, 2012(Pandey, , 2015Pietrzykowski et al., 2018), while in many cases these dumps are simply left for conservation, undergoing spontaneous revegetation (Kostić et al., 2022;Mukhopadhyay et al., 2017;Rakov and Chibrik, 2009). ...
Establishing the geochemical state of ash dumps of solid fuel thermal power plants in the absence of reclamation is extremely important in urban conditions. The current study was performed to assess the level, spatial distribution, soil pollution and risk of potentially toxic elements (PTEs) and polycyclic aromatic hydrocarbons (PAHs) in soils of abandoned ash dumps from the city of Tyumen, Russia. In general, the soils of as dumps had elevated levels of PTEs and PAHs compared to the crustal abundance and global soil background. A number of metals, namely Sr, Ni, Cu, Cr, Zn, and V, were concentrated in the soils of ash dumps (2–6 times), while As, Co, and Pb slightly exceeded the citywide average (up to 1.5 times). Naphthalene (NAP) was the only representative of the studied PAHs, the concentrations of which in the soils of ash dumps significantly exceeded the median content in urban soils of Tyumen. Elevated levels of NAP are likely a consequence of frequent fires occurring in grassy areas. Spatial patterns of pollutants are mainly controlled by the initial heterogeneity of technogenic substrates, rather than the post-depositional processes including vegetation and soil cover development. Low and moderate pollution and human health risks of PTEs and PAHs were revealed in topsoils of the studied sites. Although elevated levels of pollutants in coal ash dump soils are due to peat combustion, they pose less of an environmental risk than the more common coal ash dumps and are potentially suitable for a wider variety of management practices.
... Metallic and organic POCs and VOCs -Sesbania exalata -E. adenophorum -Ipomoea carnea -Hyperaccumulation, -Biomass harvest (Begonia et al., 2002;McGrath and Zhao, 2003;Pandey, 2012) (Huang et al., 2015;Lin et al., 2018b;Havryliuk et al., 2021;Naz et al., 2022) volatile organic compounds (VOCs), which have yet to be studied in an invasion context. Often, VOCs are also produced in the epidermal cells layer, facilitating easy volatilization through the cell membrane and cell wall at the plant-air interface (Dudareva et al., 2004;Heskes et al., 2012) during physical damage or active surface transportation (Adebesin et al., 2017). ...
... indica) have shown that between10-15% of soil Cd is accumulated in shoots and grains (Takahashi et al. 2021). The characteristics that make aromatic plants suitable for phytomanagement include, their perennial growth with multiple harvests, fast growth rate with high biomass production, easy and rapid propagation, extensive root system, easy to harvest, tolerant to local stress conditions (pH variability, trace elements toxicity, drought, and temperature), high trace element stabilization capacity, and unpalatable to livestock (Pandey, 2012). There are severalbenefits, ranging from ecological to socio-economic, when using aromatic plants for the phytomanagement of polluted sites (Pandey et al. 2015;Vangronsveld et al. 2009), including substrate and trace element stabilization, reduction of leaching and wind and water erosion and increased substrate fertility, carbon sequestration in the soil plant system, low risk of ingestion by livestock, and high value for essential oil production. ...
Trace elements pollution of soils became a global concern because of their persistence in the environment which can lead to accumulation in food chains up to toxic levels. At the same time, there is a shortage of arable land for growing food, fodder and industrial crops, which highlights the need for remediation/use of polluted land. Restoration of degraded lands has been included as a vital component of UN Sustainable Development Goals (SDGs). We summarize various sources of entry of important trace elements in the environment, available biological reclamation and management strategies and their limitations. Recent advances in phytomanagement approaches using aromatic crops to obtain economically valuable products such as essential oils and revalorize such polluted areas are reviewed. The worldwide application of this strategy in the last 10 years is illustrated through a choropleth map. Finally, the emerging concept of phytomanagement as a restorative and regenerative circular bio-economy is also discussed. STATEMENT OF NOVELTY Phytomanagement studies have remarkably increased during the last 4 years. However, there were limited studies on field application of this strategy. France is the leading country in phytomanaged polluted fields using aromatic plants. Applying aromatic plants based degraded land management models are a sustainable approach toward circular economy and to achieve the objectives of sustainable development goals (SDGs).
... The adsorption capacity of S. alterniflora showed an increased removal of Cu ions from the soil and freed the land from pollutants [151]. "Ipomoea carnea" is one of the Indian invasive species and has a great capability to accumulate more Cd, Cu, Cr, and Pb without any harmful effect on the plants [152]. ...
Heavy metals (HMs) normally occur in nature and are rapidly released into ecosystems by anthropogenic activities, leading to a series of threats to plant productivity as well as human health. Phytoremediation is a clean, eco-friendly, and cost-effective method for reducing soil toxicity , particularly in weedy plants (invasive plant species (IPS)). This method provides a favorable tool for HM hyperaccumulation using invasive plants. Improving the phytoremediation strategy requires a profound knowledge of HM uptake and translocation as well as the development of resistance or tolerance to HMs. This review describes a comprehensive mechanism of uptake and translocation of HMs and their subsequent detoxification with the IPS via phytoremediation. Additionally , the improvement of phytoremediation through advanced biotechnological strategies, including genetic engineering, nanoparticles, microorganisms, CRISPR-Cas9, and protein basis, is discussed. In summary, this appraisal will provide a new platform for the uptake, translocation, and detoxification of HMs via the phytoremediation process of the IPS.
... The adsorption capacity of S. alterniflora showed an increased removal of Cu ions from the soil and freed the land from pollutants [151]. "Ipomoea carnea" is one of the Indian invasive species and has a great capability to accumulate more Cd, Cu, Cr, and Pb without any harmful effect on the plants [152]. ...
... The adsorption capacity of S. alterniflora showed an increased removal of Cu ions from the soil and freed the land from pollutants [151]. "Ipomoea carnea" is one of the Indian invasive species and has a great capability to accumulate more Cd, Cu, Cr, and Pb without any harmful effect on the plants [152]. ...
Heavy metals (HMs) normally occur in nature and are rapidly released into ecosystems by anthropogenic activities, leading to a series of threats to plant productivity as well as human health. Phytoremediation is a clean, eco-friendly, and cost-effective method for reducing soil toxicity, particularly in weedy plants (invasive plant species (IPS)). This method provides a favorable tool for HM hyperaccumulation using invasive plants. Improving the phytoremediation strategy requires a profound knowledge of HM uptake and translocation as well as the development of resistance or tolerance to HMs. This review describes a comprehensive mechanism of uptake and translocation of HMs and their subsequent detoxification with the IPS via phytoremediation. Additionally, the improvement of phytoremediation through advanced biotechnological strategies, including genetic engineering, nanoparticles, microorganisms, CRISPR-Cas9, and protein basis, is discussed. In summary, this appraisal will provide a new platform for the uptake, translocation, and detoxification of HMs via the phytoremediation process of the IPS.
... The appropriate choice of plant species for remediation of soils, particularly these contaminated with heavy metals, determines faster restoration of land functionality [8]. Such plants feature a natural ability to tolerate high pollutant loads in the soil, rapid growth, high biomass yield, ability to form compact plant cover, dense bundle root system, low nutrient requirement, and adaptation to local climatic conditions [9][10][11][12]. The above reasons were drivers of elongated coach grass (Elymus elongates L.) and maize (Zea mays L.) choice of this research. ...
Plants, and microorganisms associated with them, offer an effective tool for removing pollutants, such as heavy metals, from the soil environment. The aim of this study was to determine changes caused by Ni²⁺, Co²⁺, and Cd²⁺ in the genetic diversity of soil-populating bacteria and the effect these heavy metals on the heating value of elongated coach grass (Elymus elongatus L.) and maize (Zea mays L.). Microorganisms support plants in removing heavy metals from soil. These plants can then be used for energetic purposes. The study aim was accomplished by determining counts of microorganisms and their resistance (RS) to Ni²⁺, Co²⁺, Cd²⁺, their colony development index (CD), ecophysiological diversity index (EP), and diversity established with the next generation sequencing (NGS) method. Further analyses aimed to establish test plants resistance to pollution with heavy metals and their heating value. Organotrophic bacteria turned out to be the most resistant to Co²⁺, whereas actinobacteria—to Cd²⁺ effects. At all taxonomic levels, the genetic diversity of bacteria was most adversely influenced by Cd²⁺ in the soil sown with Zea mays L. Bacteria belonging to Arthrobacter, Rhodoplanes, Kaistobacter, Devosia, Phycicoccus, and Thermomonas genera showed high tolerance to soil pollution with Ni²⁺, Co²⁺, and Cd²⁺, hence they should be perceived as potential sources of microorganisms useful for bioaugmentation of soils polluted with these heavy metals. Ni²⁺, Co²⁺, and Cd²⁺ had no effect on the heating value of Elymus elongatus L. and Zea mays L. The heating value of 1 kg of air-dry biomass of the tested plants was relatively high and ranged from 14.6 to 15.1 MJ. Elymus elongatus L. proved more useful in phytoremediation than Zea mays L.
... Hyperaccumulating plants are then harvested and often incinerated to eradicate the heavy metals from the substrate. In the case of immobilization, metals are no longer available to organisms (Dar et al., 2017;Pandey, 2012;Raj et al., 2020). ...
India is the second-largest producer of coal in the world and coal-fired power plants generate 72% of India's electricity. Untreated/partially treated coke-plant effluents contaminate the aquatic ecosystems by the release of organic and/or inorganic pollutants including heavy metals. Subsurface flow wetland is a sustainable technology based on a natural treatment process in which plants and microorganisms interact with each other to remediate heavy metals. Treatment methodologies incorporating natural wetlands or development of artificial wetlands is a holistic approach with multiple benefits to treat contaminated wastewater. Wetlands act as “metal-sinks” which play a vital role in the remediation of metal-contaminated environments. Plants commonly used in theses wetlands have been discussed in-depth in this chapter. The design specifications, feasibility, and utility of subsurface flow wetland to remediate metal-contaminated effluents have also been highlighted.
... For instance, some willow species (i.e., Salix alba and Salix fragilis) commonly used for phytoremediation in Europe are invasive in Brazil where they are threatening the survival of native species (Sühs et al., 2020). On the other hand, several researchers have highlighted the potential of some invasive species in brownfield reclamation due to their adaptability to very harsh environmental conditions (Wei et al., 2018;Pandey, 2012). ...
Adverse environmental effects related to unsustainable development are compelling people to welcome recent advances in technology that rely on principles of sustainability. The regeneration of contaminated brownfields has immense developmental potential that includes economic, social and environmental benefits, while reducing pressure on surrounding greenfield areas. Phytoremediation is a green technology that is highly suitable for most brownfield sites where pollution is moderate and environmental contaminants are dispersed over large surface areas. The current review centers on a description of phytoremediation, especially using woody plants, as an active component of the urban landscape. An overview of the additional environmental (i.e., beyond soil cleansing) and social benefits associated with this technology is provided, including the technical constraints and knowledge gaps that should be further addressed to make this technique efficient on a larger scale. The use of trees for the reclamation of brownfields shows several benefits in addition to depollution. Most tree species used for phytoremediation may actively reduce the volume of stormwater runoff and mitigate the risk of local flooding events. They can actively contribute to CO2 sequestration and function as highly aesthetic living barriers for noise and air pollution (PM) attenuation. Some uncertainties associated with the use of this reclamation technique in urban areas (i.e., BVOC emission, pollen production) still need to be addressed. Nevertheless, within the large family of green technologies, phytoremediation has huge potential to be used as an effective tool for the cleanup of contaminated urban brownfields, thus contributing to the development of more sustainable modern towns.
... The bioaccumulation of heavy metals in different plant species was calculated by dividing the average concentration of a particular heavy metal in shoots and roots by the total concentration in the rhizosphere fly ash (Formula 1). The translocation factor (TF) (Formula 2) for each metal for a particular plant was calculated as a ratio of concentration in shoots divided by the concentration in roots (Pandey 2012 ...
Discarding fly ash from a coal power plant into a dumpsite does not only contribute to deforestation and loss of productive land but also leads to contamination of air, soil, and groundwater. Therefore, fly ash should be managed properly to avoid the migration of contaminants. One management option is phytoremediation using adapted plants and as a prerequisite, there is a need to identify suitable plants that can be used for revegetation of fly ash dumpsites. To identify prospective plants, a survey was carried out by assessing the plants growing in Morupule B fly ash dumpsite based on their ability to accumulate heavy metals and their bioconcentration (BAF) and translocation factors (TF). Of the twenty-two-plant species growing in the fly ash dumpsite of Morupule B power plant station, N. glauca is a potential phytoextraction agent for Cu (TFCu = 1.02; BAFCu = 2.16) and Pb (TFPb = 1.38; BAFPb = 1.65); P. burchellii for Pb (TFPb = 1.61, BAFPb = 0.9) and Zn (TFZn = 1.35; BAFZn = 5.74); I. pes-tigridis for Pb (TFPb = 1.35; BAFPb = 1.56) and Zn (TFZn = 1.62; BAFZn = 7.43); A. pungens for Cr (TFCr = 1.22; BAFCr = 0.11), Cu (TFCu = 2.18; BAFCu = 1.14), and Zn (TFZn = 1.04; BAFZn = 1.44); E. hirta for Zn (TFZn = 1.54, BAFZn = 2.44); A. spinosus for Pb (TFPb = 1.29; BAFPb = 1.55); C. dactylon for Cu (TFCu = 1.86; BAFCu = 1.07) and Zn (TFZn = 1.00; BAFZn = 2.46); and D. aegyptium for Pb (TFPb = 1.19; BAFPb = 2.57). Other plants growing in the fly ash dumpsite are potential candidates for phytostabilization as they can tolerate a high concentration of metals and low essential nutrients. Also, different plant groups variably modified the pH, EC, OM, and exchangeable fractions of metals in the rhizosphere wherein grasses can increase the OM at higher rates, and it has a higher capacity to acidify and solubilize heavy metals in the rhizosphere leading to higher EC and available metals compared to other plant groups. Overall, the information presented is useful in identifying plants or their combinations for the phytoremediation of fly ash and other heavy metal-polluted environments.
... Phytoremediation is a green technology which removes metals from soil/ water through phytoextraction or phytostabilization strategies (Mahar et al. 2016;Pandey and Bajpai 2019). The literature shows that FA dump biostabilization was attempted through tree species (Babu and Reddy 2011), ferns (Kumari et al. 2013), native plants (Mustafa et al. 2012), invasive plants (Gupta and Sinha 2008;Pandey 2012;Pandey et al. 2020a, b) and grasses (Pandey and Bajpai 2019;Pandey et al. 2015Verma et al. 2014). Authors showed that native plants/initial colonizers are the most suitable candidates for restoration and phytoremediation purposes, because they are adapted to the substrate toxicity level, have more ecological importance than commercial plant species and can be established in a cost-effective manner. ...
The present study aimed to elucidate the remediation potential of visibly dominant, naturally growing plants obtained from an early colonized fly ash dump near a coal-based thermal power station. The vegetation comprised of grasses like Saccharum spontaneum L., Cynodon dactylon (L.) Pers., herbs such as Tephrosia purpurea (L.) Pers., Sida rhombifolia L., Dysphania ambrosioides (L.) Mosyakin & Clemants, Chromolaena odorata (L.) King & H.E. Robins along with tree saplings Butea monosperma (Lam.) Taub. The growth of the vegetation improved the N and P content of the ash. Average metal concentrations (mg kg−1) in the ash samples and plants were in order Mn (345.1) > Zn (63.7) > Ni (29.3) > Cu (16.8) > Cr (9.9) > Pb (1.7) > Cd (0.41) and Cr (58.58) > Zn (52.74) > Mn (39.09) > Cu (10.71) > Ni (7.45) > Pb (5.52) > Cd (0.14), respectively. The plants showed fly ash dump phytostabilization potential and accumulated Cr (80.19–178.11 mg kg−1) above maximum allowable concentrations for plant tissues. Positive correlations were also obtained for metal concentration in plant roots versus fly ash. Saccharum spontaneum showed highest biomass and is the most efficient plant which can be used for the restoration of ash dumps.
... Phytoremediation is a cost-effective technology widely used for decontamination of metal pollutant sites Singh and Tripathi, 2007;Wu et al., 2010;Yuan et al., 2016;Kumar et al., 2017). Researchers often use the stress tolerant invasive species which can grow under stress conditions (Pandey, 2012;Maiti et al., 2016). Metal accumulation potential of Bermuda grass naturally colonized on mine tailing of Guangdong Province, China was investigated and found higher tolerance to lead, zinc, and copper metal. ...
Bermuda grass [Cynodon dactylon (L.) Pers.] is a warm-season perennial grass widely distributed in tropical and subtropical countries. It is commonly planted for lawn cover, beautification, nutrition, fodder, golf courses, ground cover, and restoration of industrial waste lands. It is drought resistant, salt tolerant, highly versatile, adapted to hostile environmental conditions, and easily regenerates from seed and grass plugs. It is a fast-growing grass with aggressive root system that spreads by seeds and stolon. It is extremely tolerant to different stress conditions and valuable for soil conservation, and vegetation cover on industrial waste sites. Bermuda grass growing at different metal contaminated sites potentially accumulates various metals (As, Pb, Zn, Cd, Cu, Cr, Co, Mn, Ni, and Fe) and widely used for the phytoremediation of metal contaminated sites.
... Over time, native sown, and spontaneously colonized plant species on contaminated sites bind substrate with a fibrous root system, and they spread by seeds and rhizomes forming a dense vegetation cover. These plant species are stress-tolerant and they possess adaptive mechanisms to unfavorable environmental conditions, such as drought, high temperatures, toxicity, and/or deficiency of chemical elements (Pavlovic´ et al., 2004;Djurdjevic´ et al., 2006;Mitrovic´ et al., 2008;Kostic´ et al., 2012;Pandey, 2012Pandey, , 2015Gajic´ et al., 2013Gajic´ et al., , 2016Gajic´ et al., , 2019Pandey et al., , 2015aPandey et al., , 2015bPandey et al., , 2016Kumari et al., 2016;Randjelovic´ et al., 2016). ...
Festuca rubra L. as perennial, rhizomatous grass distributed worldwide tolerates different ecological conditions and grows in various habitats. This grass is used in ecorestoration of contaminated sites due to its extensive root system, good seedling vigor, fast growing, large biomass, and high tolerance to unfavorable environmental conditions. F. rubra has a high phytoremediation potential for As, B, Cu, Zn, Mn, Mo, and Se from fly ash. Despite the leaf chlorosis and necroses, deposited particles of fly ash on leaf surface, reduced photosynthetic efficiency, photopigments content, and high oxidative stress, this plants shows increased content of phenolics, ascorbate, and high total antioxidant activity. F. rubra growing on fly ash deposits shows a great adaptive potential indicating that this native grass has prominent role in ecosystem functioning, providing an excellent opportunity to implement this plant species in the police frameworks, sustainable management practices, and ecosystem services.
Natural environment are being contaminated by various anthropogenic activities and developing industrialization. This demands appropriate technologies to remediate polluted sites. Because of the site-specificity most of the traditional remediation methods are not economical. Traditional phytoremediation is among the safest and most effective tools for remediation. However, it is time consuming and could be efficient for one contaminant but inefficient for another. Limitation of phytoremediating plants such as incomplete degradation and metabolism of some xenobiotics led to the concepts of modifying plants and microbes to enhance the conventional phytoremediation process. This chapter highlights microbe-assisted phytoremediation and developments of new plant-microbe association for enhancing remediation of harmful compounds, and discusses the role of transgenic microbes associated with plants which play role in the process of phytoremediation and decontamination of polluted ecosystems.
Disposal of fly ash in dumps is posing serious environmental problem causing air pollution, groundwater contamination, and loss of valuable land making it unproductive dumpsites. Cultivation of plants using bioremediation technique is looked upon as one of the sustainable remedial solution to these fly ash dumpsites. In recent years, researches on the plantation of bio-energy crops over the fly ash dumpsites is creating renewed interest, as it serves remediation along with distinct energy outcomes creating a win-win situation. The issue of the slow growth of plants, due to lack of nutrients and microbial activities is being resolved through advances in bioremediation research done in conjunction with organic matter, microbial inoculants, and inclusion of wastewater. New researches are being done with different plants and microbes in the matrix combination and use wastewater to supplement nutrients requirement to find eco-friendly & sustainable solutions. The present paper critically reviews the research on bioremediation and amendments with specific to bio-energy plantation on fly ash dumps.
Fly Ash (FA) is usually considered unfavorable to plant growth and its disposal has become a serious environmental issue. However, some studies on revegetation on fly ash dumps showed some agricultural potential of the fly ash. The present study attempts to judiciously utilize the waste fly ash as a soil amendment and assess the feasibility of growth of energy plants viz. Jatropha on fly ash amended soil in varying percentages (0%, 5%, 10%, 20%). The study primarily focuses on growth and yield to judge the suitable content of fly ash favoring plant growth. Plastochron Index (PI) and plant morphological characteristics are used to assess the growth whereas, the yield is assesses based on biomass and other parameters estimated after completion of the experimental duration. The growth and yield assessment indicated better sustenance of Jatropha plant on soil amended with 10% fly ash
The ecological impacts of invasive alien plant species (IAPS) are well-documented, but
a dearth of studies exist concerning its economic, livelihood, biotechnological, and health risk assessment perspectives. IAPS management is currently expanding to ecological indicator and biotechnological aspects. Hence, this study aimed to investigate the phytoremediation potential, biomedical, and bio-safety applications of X. strumarium growing in different abandoned habitats in Khyber Pakhtunkhwa, Pakistan. In this study, 45 plants and soil samples were gathered from 15 abandoned sites and analyzed for Pb, Cd, Cu, and Zn concentrations; bioaccumulation (BA); and translocation factor (TF). The assayed Pb and Cd concentration was higher and above threshold in both soil–plant samples. BAF was found higher in roots than intact plants despite having a significant
accumulation of Cd, Pb, and Zn, which shows high metals tolerance of this IAPS. PCA-ordination explained a high cumulative variance (98.9%) and separated roads and densely populated sites with comparatively high metals concentration, indicating the pseudometallophyte nature of X. strumarium. Soil, sand, and plant biomass were shown to be the major determinants affecting the heavy metals concentration and its phytoremediation significantly, which may be due to the soil’s metalliferous nature in the study area. This IAPS exhibited strong translocation and hyperaccumulation capacity in different functional traits with comparatively high Pb, Cd, and Zn (≥1 TF) mobility and, hence, can effectively be used for Pb phytoextraction and phytostabilization of Cd, Cu, and Zn, respectively. Likewise, several other non-spontaneous IAPS growing on such abandoned habitats might be promising for developing a reasonable strategic framework for heavy metals mitigation and health risk implications in this region.
Keywords: invasive plants; X. strumarium; bioaccumulation and translocation; phytoremediation potential
Heavy metals, metaloids and persistent organic contaminants are released in the environment from industry, agriculture, urban zone, waste deposits and accidental spills presenting a serious threat for the ecosystems and health of human beings. Integrated phytobial remediation by bacteria and fungi has become a great challenge for successful removal of contaminants from polluted sites that is, combined plant/bacteria/fungi cross-talk offers effective tools to assist phytoremediation. Plant growth-promoting bacteria and mycorrhizal fungi obtain food for their metabolism whereas they promote plant growth, decrease metal(loid)s toxicity and degrade persistent organic compounds. This chapter focuses on joint action of plant/bacteria and fungi in removal of metal(loid)s, radionuclides, and chlorinated compounds, such as trichlorethylene, chlorinated pesticides, and polychlorinated biphenyls. Therefore, opportunities in exploitation of plant – bacteria-fungi interactions should be tailored in a framework platform and sustainable phytomanagement of polluted sites in the future around the globe.
Water underneath the Earth surface is considered to be in the purest form of available water, it normally looks clear as ground itself filters water and stores it within the aquifers. Nowadays groundwater contamination by heavy metals is one of the important matters of concern due to the limitations of available water resources and a shortage of a pure form of water. Fly ash that is a thermal waste is one of the major sources of heavy metal release and a reservoir of the same. So it is of the utmost importance to visualize the impact of tons generated and disposed of in nature. From this viewpoint, an attempt was made to understand the importance of groundwater, fly ash disposal practices followed, and its impact on the groundwater quality.
Water pollution is increasing due to urbanization and industrialization. Waste water pollution raised concern because of its influence on plants and humans. Water hyacinth ( Eichhornia crassipes ) is used for the removal of pollutants because of its phytoremediation efficiency. In this study, water hyacinth ( Eichhornia crassipes ) has been tested for simultaneous elimination of phenol and cyanide from mono and binary component aqueous solution in batch systems. The plant was grown at six concentrations of phenol and cyanide in the ratio of (10:1), i.e. 100:10, 200:20, 300:30, 500:50, 700:70 and 1000:100 mg/L in aqueous solution. The effect of process parameters such as initial concentration of phenol and cyanide and pH was evaluated. The plant was found capable of eliminating up to 96.42% of phenol (300 mg/L) and 92.66% of cyanide (30 mg/L) during the 13 days cultivation time at pH 8. The calculated K m of the root length elongation for phenol was 5.20 mm and the V max was 12.52 μg phenol/g root/h. However, the calculated K m of the root length elongation for cyanide was 0.39 mm and the V max was 14.99 μg cyanide/ g root/h. In the Eichhornia crassipes plant, the biochemical parameters such as chlorophyll, protein and sugar content have been indicated a decreasing trend due to uptake of phenol and cyanide throughout cultivation. Toxicity to 100–1000 mg/L of phenol and 10–100 mg/L of cyanide was measured by measuring the relative transpiration over 13 days. At 100 mg/L of phenol and 10 mg/L of cyanide, only a small reduction in transpiration but no morphological changes were noticed. Both pollutants are absorbed through the root of the Eichhornia crassipes plant by plasmalemma and become accumulated into the root cells and stem of a plant. Thus, this study will be beneficial for the decontamination of highly polluted waste water.
Phytoremediation is an environment friendly and sustainable way of restoration of contaminated land from trace metals, pesticides and other industrial dangerous pollutants. This technique distinguishes a different mechanism for reduction of environmental pollution from industrial waste. The variety of plants grown in contaminated areas has efficiency to develop a metabolism in various parts (leaf, stem, roots) for the phytoremediation of heavy metals and pesticides. The use of transgenic plants promotes the phytoremediation technology for the improvement of remediation in contaminated areas. The concept of using green plants for phytoremediation enhances the potential of soil for restoration and in achieving UN‐SDGs. The traditional methods have various side effects and loopholes. Thus, the chapter provides the techniques used in the application of phytoremediation and sustainable approach for the restoration of contaminated areas. In order to increase the phytoremediation potential, further research is needed in contaminated areas where industrial waste is dumped.
Essential oils (EOs) are complex liquid mixtures consisting of volatile organic compounds of vegetable origin, with a fragrant, insoluble in water, soluble in organic solvents or fats. EOs are extracted from flowers, leaves, fruits, bark and sometimes from the wood (camphor wood), using organic solvents or by distillation and steam entrainment. Chemically, the EOs is composed of mixtures of terpene hydrocarbons, aromatic hydrocarbons, terpenoids (alcohols, aldehydes, ketones), organic acids, pigments, ethers, esters, etc. One and the same essential oil can contain up to 50 different substances. Of these compounds, the most important are “terpene hydrocarbons” or terpenoid compounds and terpenoids appointed isoprenoids (mono‐, sesqui‐, di‐, ses‐, and triterpenes, monoterpenic alcohols, etc.) and their derivatives. In small quantities they contain classes of aliphatic compounds (alcohols, aldehydes, aliphatic esters, etc.), aromatics, macrocyclics and their derivatives (amines, organic sulfides, heterocyclic compounds, etc.). Among the compounds contained in a relatively large number of EOs can be highlighted: borneol, camphor, camphor, cedrol, eugenol, geraniol, limonene, linalool, menthol and myrcene, etc.
Reduction and degradation of several types of soil contaminants such as heavy metals, pesticides, emerging contaminants, etc. are one of the major serious global challenges in the present scenario. For removal of heavy metals from the environment, various physical and chemical methods are used with some limitations like high cost, intensive labor, alteration of soil properties, etc. which make it problematic at application level. In the present time, science offers a green technique, i.e., phytoremediation; plants are capable of uptake, translocate, transform, and immobilize hazardous metals and reduced their toxicity and concentration in the environment. So, there is an increasing interest in utilization of “invasive alien species” among plant’s kingdom in a productive way due to its easy availability, adaptability to changing climate, alternative mode of reproduction, phenotypic plasticity, and allelopathic in nature. These characteristics also make them more suitable for survival in high stress conditions. They can be used not only as a bioresource, but also as a method for the management of heavy metal polluted land. Invasive alien species are also source of medicines, fodders, and biofuel or bioenergy. The present chapter is focused on exploration of invasive alien plant species for various social aspects and phytoremediation of the heavy metal contaminated land.Graphical Abstract
KeywordsInvasive alien speciesPhytoremediationHeavy metalsContaminated soil
In this investigation, the ability and effectiveness of the aquatic macrophyte, Pistia stratiotes L. to improve the quality of eutrophic waters were studied at a lab scale by testing across four lake water samples. The removal of salts, solids and improving physiochemical properties including pH, DO, EC, TDS, Turbidity and NaCl concentration of water were monitored. In treatment with the Aquatic Plant (AP), a 100% survival rate of the species was observed without any visible symptoms of toxicity in the biomass. The extensive root system of the plant as well as the body biomass improved water quality after one week of treatment as determined by a marked decrease in Turbidity, TDS, EC and NaCl and with an increase in pH and DO levels. The DO increased many folds over 168 h or 7 days after treatments and served as a useful indicator of water quality. Considerable variation percentages (either reduction or increment) were observed in different parameters treated with the phytoremediator. The study findings indicate that the aquatic macrophyte has a significant potential for improving water quality parameters by removing pollutants from eutrophic lake water bodies.
The invasive weed Asystasia gangetica was investigated for its potential as a biomonitor and as a phytoremediator of potentially toxic metals (PTMs) (Cd, Cu, Ni, Pb, and Zn) in Peninsular Malaysia owing to its ecological resistance towards unfavourable environments. The biomonitoring potential of PTMs was determined based on the correlation analysis of the metals in the different parts of the plant (leaves, stems, and roots) and its habitat topsoils. In the roots, the concentrations (mg/kg dry weight) of Cd, Cu, Ni, Pb, and Zn ranged from 0.03 to 2.18, 9.22 to 139, 0.63 to 5.47, 2.43 to 10.5, and 50.7 to 300, respectively. In the leaves, the concentrations (mg/kg dry weight) of Cd, Cu, Ni, Pb, and Zn ranged from 0.03 to 1.16, 7.94 to 20.2, 0.03 to 6.13, 2.10 to 21.8, and 18.8 to 160, respectively. In the stems, the concentrations (mg/kg dry weight) of Cd, Cu, Ni, Pb, and Zn ranged from 0.03 to 1.25, 5.57 to 11.8, 0.23 to 3.69, 0.01 to 7.79, and 26.4 to 246, respectively. On the other hand, the phytoremediation potential of the five metals was estimated based on the bioconcentration factor (BCF) and the translocation factor (TF) values. Correlation analysis revealed that the roots and stems could be used as biomonitors of Cu, the stems as biomonitors of Ni, the roots and leaves as biomonitors of Pb, and all three parts of the plant as biomonitors of Zn. According to the BCF values, in the topsoil, the “easily, freely, leachable, or exchangeable” geochemical fractions of the five metals could be more easily transferred to the roots, leaves, and stems when compared with total concentrations. Based on the TF values of Cd, Ni, and Pb, the metal transfer to the stems (or leaves) from the roots was efficient (>1.0) at most sampling sites. The results of BCF and TF showed that A. gangetica was a good phytoextractor for Cd and Ni, and a good phytostabilizer for Cu, Pb, and Zn. Therefore, A. gangetica is a good candidate as a biomonitor and a phytoremediator of Ni, Pb, and Zn for sustainable contaminant remediation subject to suitable field management strategies.
Arsenic (As) is highly carcinogenic and toxic in nature. Increased levels of As contamination is a threat to health and environment, as it could accumulate into the agricultural soils and enters into the food chain. The conventional strategies of remediation, like capping, landfilling, excavation, and chemical methods for As, are found to be expensive and therefore cause imbalance in the ecosystem. Alternatively, phytoremediation techniques are eco-friendly and remove As from contaminated soil. As-resistant bacteria ameliorate the process of phytoextraction in As-hyperaccumulating plants, such as Pteris vittata. In this review, we have described the prospects of P. vittata, which is an As-hyperaccumulator, for the remediation of As-contaminated soil. The research information available on P. vitatta has been compiled, analysed and presented, with details of its response to As toxicity, mechanism of As uptake and transport, and detoxification/resistance mechanisms, to promote it as a model system for As-phytoremediation. Also, the role of soil microorganisms, which assist P. vittata in the process of As-remediation, has been discussed for improvement of phytoremediation efficiency.
Polluted sites, coal mine spoil, fly ash deposits, red mud dumpsites, and other dumpsites are a worldwide problem, contaminating nearby communities. These disposal sites are major source of environmental pollution. Phytoremediation has been popularized to remediate heavy metal-contaminated sites in the past few decades due to its cost-effectiveness and environmental sustainability. In this regard, the use of grasses is of utmost importance due to their rapid growth, large biomass, resistance to phytotoxicity, and genotoxicity by heavy metals as compared to herbs, shrubs, and trees. Phytostabilization by the compact root system of grasses retards the formation, mobility, and bioavailability of hazardous leachates by high uptake and accumulation of the complex mixtures of heavy metals within them. Such grasses prevent natural succession by weeds and other plants leading to safe grazing by animals. Among the members of Poaceae, aromatic grasses are economically important plants due to their essential oil production. They rank higher than edible grasses, which are susceptible to heavy metal contamination in their edible parts. This chapter describes the role of grasses in ecological and socio-economic sustainability of phytoremediation of polluted sites.
Continuous increase in polluted sites over the world has been recognized as a serious concern for ecological, social, and economic sustainability. This chapter explores lemongrass-based phytoremediation strategy for remediation and utilization of polluted sites with multiple benefits. Cymbopogon flexuosus is famous as an essential oil-bearing aromatic grass, and offers bioeconomy in term of essential oil yield. Moreover, lemongrass based cultivation on polluted sites has been suggested as a safe and feasible strategy. In conclusion, lemongrass is a valuable genetic resource for phytoremediation of polluted sites and waste dumpsites with multiple benefits, minimum inputs, and low risk.
Agricultural pollution is a global environmental concern. Agricultural pollution is mainly caused by the application of farming inputs (e.g., fertilizers and pesticides) and practices (e.g., excessive tillage of the land and runoff). Agricultural pollutants may include essential plant nutrients (e.g., excessive amounts of nitrate and phosphate), toxic inorganic (e.g., heavy metals), and organic compounds (e.g., pesticides). Due to their high toxicities, agricultural pollutants pose a grave threat to the biological system. Thus, the removal of such toxic substances is crucially important for the safety of the ecosystem and human health. Phytoremediation is believed to be a promising option for the removal of agricultural pollutants and holds a great promise as a mean to cleanup polluted water and soil environments. In this chapter, we compiled data regarding phytoremediation of organic and inorganic agricultural pollutants and discussed different strategies of plants for pollutant removal. Although plants alone have the ability to utilize different strategies to remove the toxic agricultural pollutants, integrated approaches such as microbes and plant associations (rhizoremediation) are seemed to be attractive options for improving removal of agricultural pollutants.
The study deals with the accumulation of Pb, Zn and Cd in an important mangrove species, Avicennia marina (Forssk.) Vierh., in the Vamleshwar mangrove ecosystem, near Narmada estuary, West coast of Gujarat, India with height differences of 0.5, 1.5, 2.5 meters and carried out under field conditions during October, 2009. The site was located on 21�30�11.55�� N latitude and 72�43�53.68�� E longitude. Mangrove receives heavy metal pollution from upstream areas of Narmada estuary and highly populated settlements. However, little is known about the capacity of mangrove plants to take up and store heavy metals in them. Water, sediment and plant parts such as roots, stems and leaves were analyzed for finding the trace metal accumulation of different height groups by Inductive Coupled Plasma Analyser (ICPA). Amount of the content of metals found in the water, sediment and plant parts were in the order of Pb>Zn>Cd. The average contents of heavy metals in the waters were 57.83 mg l-1 for Pb, 3.89 83 mg l-1 for Zn and 0.42 mg l-1 for Cd. It was observed that the average contents of Pb (73.6 mg l-1), Zn (8.1 mg l-1) and Cd (0.73 mg l-1) in the sediments were below the critical soil concentrations. The concentrations of heavy metals in different parts of Avicennia marina were in the order Roots>stem>leaf except for Cd, but Cd found higher in leaf. The ranges of the content of heavy metals in plants were 18.5-102.2 mg l-1 for Pb, 3.5-19.5 mg l-1 for Zn and 0.2-4.1 mg l-1 for Cd. The concentrations of all heavy metals in Avicennia marina except Pb were falling within the normal range and were much more in the plants have the highest height. The present study has shown the potential of Avicennia marina as a phytoremediation species for selected heavy metals in many mangrove ecosystems.
Metal mining gives access to very important resources but contributes to severe and diverse environmental problems. Until recently, little has been known about the remediation of mining sites in Latin America using metallophytes. The present study was designed to identify and characterize spontaneously growing heavy metal tolerant plant species in the area around the polymetallic Carolina mine in Hualgayoc (Cajamarca, Peru). The aim was to find species that are potentially useful for phytoremediation. Plants and soils were sampled and analysed for concentrations of As, Fe, Mn, Pb, Zn and Ti. The Translocation Factor (TF) and the Bioaccumulation Factor (BF) were determined and used to measure the amount of each element accumulated in shoots and roots of each plant species.
There has been much interest recently in the use of constructed wetlands for the removal of toxic trace elements from wastewaters. Wetland plants piny an important role in the trace elements removal process. It is not known, however, which wetland plant species absorb specific trace elements at the fastest rates. Such knowledge is essential to maximize the efficiency of trace element removal by wetlands. In this study, we investigated the potential of duckweed (Lemna minor L.) to accumulate Cd, Cr, Cu, Ni, Pb, and Se when supplied individually in a nutrient solution at a series of concentrations ranged from 0.1 to 10 mg L -1. The results show that under experimental conditions, duckweed proved to be a good accumulator of Cd, Se, and Cu, a moderate accumulator of Cr, and a poor accumulator of Ni and Pb. The highest concentrations of each trace element accumulated in duckweed tissues were 13.3 g Cd kg -1, 4.27 g Se kg -1, 3.36 g Cu kg -1, 2.87 g Cr kg -1, 1.79 g Ni kg -1, and 0.63 g Pb kg -1. Duckweed exhibited some symptoms of toxicity (e.g., reduced growth, chlorosis) at higher levels of element supply (except for Cr). The toxicity effect of each trace element on plant growth was, in descending order of damage, Cu > Se > Pb > Cd > Ni > Cr. We conclude that duckweed shows promise for the removal of Cd, Se, and Cu from contaminated wastewater since it accumulates high concentrations of these elements. Further, the growth rates and harvest potential make duckweed a good species for phytoremediation activities.
Ipomoea carnea was introduced to Egypt for ornamental purpose. It naturalized as a species along canals and drains, road sides, railways, waste lands and field edges in the Nile Delta. The rapid growth rate, spread and adaptability from aquatic to xerophytic habitats indicate that this invasive plant may potentially become another ecological disaster like water hyacinth. The present work monitored the demography of I. carnea populations at two locations in Nile Delta in terms of size structure (natality, mortality, survival & demographic flux) and assessed its standing crop and the correlation between its population characters and the prevailing environmental variables. Fifty permanent stands were established to represent the microvariations in seven habitats, where I. carnea occurs at both locations. The height from the ground and average diameter of the canopy for each permanent marked ramet (4355 ramets) were estimated monthly and its volume was calculated as a cylinder. The results revealed that sexual propagation of I. carnea from seeds is less common than vegetative propagation from decumbent branches. The variation in population natality varied in relation to habitat and time. I. carnea sprouts suffered relatively higher mortality rates than adult plants, indicating the sensitivity of the sprouts to temporal variation in some environmental factors. Months of July and January indicated negative values of demographic flux as a result of the increasing mortality and decreasing natality. In contrast, June had maximum value as no sprout and adult mortalities was moted in this month. The size distribution of I. carnea populations had negative skewed shape, where the big individuals (i.e., mature) exceeded the small ones (i.e., juveniles). The biomass of I. carnea was higher than the other species in the same habitats in the Nile Delta.
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.
The study deals with the accumulation of Pb, Zn and Cd in an important mangrove species, Avicennia marina (Forssk.) Vierh., in the Vamleshwar mangrove ecosystem, near Narmada estuary, West coast of Gujarat, India with height differences of 0.5, 1.5, 2.5 meters and carried out under field conditions during October, 2009. The site was located on 21°30´11.55´´ N latitude and 72°43´53.68´´ E longitude. Mangrove receives heavy metal pollution from upstream areas of Narmada estuary and highly populated settlements. However, little is known about the capacity of mangrove plants to take up and store heavy metals in them. Water, sediment and plant parts such as roots, stems and leaves were analyzed for finding the trace metal accumulation of different height groups by Inductive Coupled Plasma Analyser (ICPA). Amount of the content of metals found in the water, sediment and plant parts were in the order of Pb>Zn>Cd. The average contents of heavy metals in the waters were 57.83 mg l-1 for Pb, 3.89 83 mg l-1 for Zn and 0.42 mg l-1 for Cd. It was observed that the average contents of Pb (73.6 mg l-1), Zn (8.1 mg l-1) and Cd (0.73 mg l-1) in the sediments were below the critical soil concentrations. The concentrations of heavy metals in different parts of Avicennia marina were in the order Roots>stem>leaf except for Cd, but Cd found higher in leaf. The ranges of the content of heavy metals in plants were 18.5-102.2 mg l-1 for Pb, 3.5-19.5 mg l-1 for Zn and 0.2-4.1 mg l-1 for Cd. The concentrations of all heavy metals in Avicennia marina except Pb were falling within the normal range and were much more in the plants have the highest height. The present study has shown the potential of Avicennia marina as a phytoremediation species for selected heavy metals in many mangrove ecosystems.
A hardy, versatile, fast-growing plant helps to remove arsenic from contaminated soils.
Due to its wide industrial use, chromium is considered a serious environmental pollutant. Contamination of soil and water by chromium (Cr) is of recent concern. Toxicity of Cr to plants depends on its valence state: Cr(VI) is highly toxic and mobile whereas Cr(III) is less toxic. Since plants lack a specific transport system for Cr, it is taken up by carriers of essential ions such as sulfate or iron. Toxic effects of Cr on plant growth and development include alterations in the germination process as well as in the growth of roots, stems and leaves, which may affect total dry matter production and yield. Cr also causes deleterious effects on plant physiological processes such as photosynthesis, water relations and mineral nutrition. Metabolic alterations by Cr exposure have also been described in plants either by a direct effect on enzymes or other metabolites or by its ability to generate reactive oxygen species which may cause oxidative stress. The potential of plants with the capacity to accumulate or to stabilize Cr compounds for bioremediation of Cr contamination has gained interest in recent years.
The plants of Sesbania cannabina Ritz grown on different amendments of fly ash (FA), have shown a high accumulation of metals (Fe, Mn, Zn, Cu, Pb and Ni). The highest accumulation of Fe the and lowest level of Ni were recorded in these plants. The different amendments of fly ash with garden soil (GS) were extracted with DTPA and the levels of metals were found to be decreased with an increase in fly ash application ratio from 10% to 50% FA. The analysis of the results showed an increase in the level of malondialdehyde (MDA) content of the roots for all the exposure periods. The maximum increases of 136% (roots) and 120% (leaves) were observed in MDA content at 100% FA after 30 d of growth of the plant, compared to GS. The level of antioxidants was found to increase for all the exposure periods in the roots of the plants to combat metal stress. At 30 d, the maximum increase of 57% (ascorbic acid) and 78% (free proline) was observed in the roots of the plants grown on 100% and 10% FA, respectively, as compared to their respective GS. At 90 d, a maximum increase of 42% (cysteine) and 117% (NPSH) was recorded in the roots of the plants grown on 25% and 100% FA, respectively, as compared to their respective GS. In leaves, a significant increase in antioxidants i.e. cysteine, NPSH and free proline content was recorded after 30 d, whereas no such trend was observed for the rest of the exposure periods. The chlorophyll and carotenoid contents increased with an increase in the FA amendment ratio from 10% to 50% FA for all the exposure periods as compared to GS. In both roots and leaves, the level of protein content increased in all the amendments and 100% FA at 30 d as compared to GS. Thus, there is a balance in the level of MDA content and level of antioxidants in the plants at 90 d. In view of its tolerance, the plants may be used for phytoremediation of metals from fly ash contaminated sites and suitable species for plantation on fly ash land fills.
This paper reviews the ecological aspects of mined soil restoration, with special emphasis on maintaining a long-term sustainable vegetation on toxic metal mine sites. The metal mined soils are man-made habitats which are very unstable and will become sources of air and water pollution. Establishment of a vegetation cover is essential to stabilize the bare area and to minimize the pollution problem. In addition to remediate the adverse physical and chemical properties of the sites, the choice of appropriate vegetation will be important. Phytostabilization and phytoextraction are two common phytoremediation techniques in treating metal-contaminated soils, for stabilizing toxic mine spoils, and the removal of toxic metals from the spoils respectively. Soil amendments should be added to aid stabilizing mine spoils, and to enhance metal uptake accordingly.
A pilot scale study was conducted to find out the different forms of metals if fly ash (FA) and bioaccumulation of these metals in the naturally growing vegetation on FA dumps. The total, acid extractable, bioavailable and water soluble fraction of metals of Fe, Cu, Mn, Zn, Ni, Co and Pb, and their bioaccumulation coefficients (BAC) on naturally growing vegetation were determined. FA samples had a neutral pH, low electrical conductivity, low organic C and trace amounts of N and P. The relative abundance of total metals in FA were found in the order Fe >Mn >Zn >Ni >Co>Cu. The concentration of bioavailable (DTPA) metals depend on the type and nature of coal used in thermal power stations. In the water the extract solution, only Fe and Zn were found above detection limits. After one year only four species of naturally occurring herbaceous vegetation were found growing and Cynodon dactylon (grass) covered almost entire surface of the FA. Iron accumulated to the greatest extent in vegetation followed by Mn, Zn, Cu, Pb, Ni and Co. The sequence of BAC for different metals were Fe (202)>Mn(90)>Zn (63)>Pb(49)>Ni(41)>Cu(24). The experimental study revealed that Cynodon grass could be used for remediation of fly ash without any amendments, as this grass species act as metal excluder type.
Ladder brake ( Pteris vittata L.) is a newly discovered arsenic hyperaccumulator. No information is available about arsenic effects on ladder brake. This study determined the effects of different arsenic concentrations (50 to 1000 mg kg ⁻¹ ) or forms (organic vs. inorganic and arsenite vs. arsenate) applied to soils on growth and arsenic uptake by ladder brake. Young plants were grown in a greenhouse for 12 or 18 wk. Ladder brake was highly tolerant of arsenic and survived in soil containing up to 500 mg As kg ⁻¹ The fact that addition of arsenate up to 100 mg As kg ⁻¹ increased fern biomass by 64 to 107%, coupled with higher arsenic concentration in younger fronds at low soil arsenic concentrations and older fronds at high soil arsenic concentrations, implies that arsenic may be beneficial for fern growth. Addition of 50 mg As kg ⁻¹ was best for fern growth and arsenic accumulation, resulting in the highest fern biomass (3.9 g plant ⁻¹ ), bioconcentration factor (up to 63), and translocation factor (up to 25). With an exception of FeAsO 4 and AlAsO 4 , which had the lowest effects due to their low solubility, little difference was observed among other arsenic forms mainly because of arsenic conversion in soil. Aboveground biomass was mostly responsible for accumulation of arsenic by plant (75–99%). Up to 26% of the added arsenic was removed by ladder brake, showing the high efficiency of ladder brake in arsenic removal. The results suggest that ladder brake may be a good candidate to remediate arsenic‐contaminated soils.
Non wood plant are more common as raw material where wood is scarce. Ipomoea carnea Jacq has not enjoyed much favor for pulp and paper making as compared to wheat straw, rice straw etc. Structural determination studies has been carried out on the soda lignin of Ipomoea carnea Jacq prepared from soda spent liquor and soda anthraquinone spent liquor. Lignin of the non wood species investigated was found to have certain chemical groups such as carbonyl, methoxyl, total hydroxyl and phenolic hydroxyl groups. On comparing the results, the reactive groups were found to be same to that of Boswellia Serrata. Determination of groups is of importance in the study of the reactive lignin form paper making point of view. It was found that Ipomoea Carnea is having paper making properties.
Wastes may supply enough macronutrients to act as N, P, or K fertilizers and provide optimum macronutrients in forage plants. Alternatively, the waste may provide N at a C:N ratio that causes nitrogen deficiency and low protein levels. Macroelement fertility balance must be managed carefully to obtain both optimum plant growth and forage quality. Use of sewage sludge as N and P fertilizer has led to severe K deficiency unless K fertilizer is supplied. Woody wastes cause severe N deficiency unless adequate N is supplied or the wastes are composted with N fertilizer before application. Some microelements are so insoluble or strongly sorbed in soil that plant shoots do not have significantly increased concentrations of the elements even when soils are greatly enriched. These and other aspects of the subject are reviewed in the paper, which emphasizes management of land treatment sites. Refs.
High metal availability, arising from mining and industrial activities, disposal of sewage sludge or soil acidification, is an increasing problem in agriculture and forestry. Metal toxicity causes multiple direct and indirect effects in plants which concern practically all physiological functions. In this review we consider the effects of excess heavy metals and aluminium on those functions which will alter plant water relations. After a brief comment on the metal effects in cell walls and plasmalemma, and their consequences for cell expansion growth, the influences of high metal availability on the factors which regulate water entry and water exit in plants are considered. Emphasis is placed on the importance of distinguishing between low water availability in mine and serpentine soils and toxicity effects in plants which may impair the regulation of a plant's water household. Examples on water relations of both plants grown on metalliferous soil and hydroponics are discussed. The effects of metal toxicity on root growth, water transport and transpiration are considered. It is concluded that future research has to focus on the mechanisms of metal‐induced inhibition of both root elongation and morphogenetic processes within roots. In order to understand the relation between metal tolerance and drought resistance better, further studies into metal tolerance mechanisms at the cell wall, membrane and vacuolar level, as well as into the mechanisms of drought resistance of plants adapted to metalliferous soils are required.
Increasing areas of coal fly ash (FA) deposit pose a serious concern for its safe disposal to maintain the environment quality. Several thousand hectares of land have been occupied for the storage of FA all over the world. FA deposits cause serious environmental pollution through wind erosion and ground water contamination through leaching process. Naturally growing Saccharum munja on the derelict FA lagoons of NTPC Unchahar, India was identified as a native perennial grass in the rehabilitation process. We tested its ecological suitability for the effective restoration of FA lagoons in terms of their abundance and stabilization. The FA contains alkaline pH, and low organic C coupled with toxic metals i.e. Fe, Cd, Cr, Cu, Mn, Ni, Pb and Zn. The concentrations of these metals in different parts of the plant fall in the average range of plants and were found within toxic limits. Natural colonization of S. munja predominate in the areas of FA deposits with fast growth and high biomass which is used by local people for making ropes, baskets, mats, huts, etc. to support their livelihood. These results suggest that S. munja would be potentially useful to rehabilitate the FA dumps more efficiently if it is introduced properly on fresh lagoons to convert barren FA deposits into ecologically and socio-economically productive habitats without any inputs or maintenance.
The effect of particles on stomatal plugging was examined both in the field and in the laboratory. Evidence was obtained that the stomata of two experimental plants, Phaseoulus vulgaris and Zea mays, did not become plugged by fly ash from a power plant. Gaseous diffusion was increased in dusted leaves.
The present article briefly describes the concerns regarding the suitability of Vigna radiata L. for the revegetation of fly ash landfills.
Metal mining in Caveira and São Domingos (Portugal) generated large volumes of tailings with high total concentrations of trace elements, low pH and fertility. Autochthones plants growing spontaneously in mine areas are usually tolerant to unfavorable characteristics of tailings. The aim of this investigation was to analyze the behavior (trace elements uptake, accumulation and translocation from roots to shoots) of different populations of Cistus salviifolius plants growing spontaneously in contaminated and non-contaminated sites in order to evaluate the potential of this plant species for soils and mine wastes phytostabilization. Cistus salviifolius plants (roots and aerial parts) and soils were collected, in two mine areas (São Domingos and Caveira) and a reference area (Grândola), and were analyzed for arsenic, antimony, copper, lead, manganese and zinc concentrations. Cistus salviifolius showed tolerance for moderate acid soils (5.34
This study deals with the chemical nature of airborne particles and their accumulation in certain tropical plants growing around an industrial area. Particles of > 10.9, 1.6–5.4 and < 0.7 μm were significantly more abundant than those of 0.7–1.6 and 5.4–10.9 μm at all the polluted sites. The concentrations of chromium, copper, iron and lead were high in particles of < 10.9 and < 0.7 μm; while manganese and mercury were abundant in 5.4–10.9 and 0.7–1.6 μm-sized particles; and nickel was high in < 0.7 and 0.7–1.6 μm particles.The epidermal traits of five different plants (Cassia siamea, Calotropis procera, Ipmoea fistulosa, Zizyphus mauritiana and Mangifera indica) indicate unaltered stomatal indices, trichome length and trichome frequency in C. siamea, while stomatal index and trichom length decreased, and trichome frequency increased in all other plants. Changes in epidermal traits were found to be greatest in M. indica followed by I. fistulosa, C. procera, Z. mauritiana and C. siamea at all the polluted sites when compared to that of the reference site. A direct relationship was evident between the modified trichrome frequently and dust collecting efficiency of plants which was greatest in M. indica and lowest in C. siamea. Inspite of a low dust collecting efficiency, C. siamea accumulated heavy metals in greater amounts which indicates no relationship between the metal content of the deposited dust and accumulated metal content. This study, based on the differential accumulation of metals in different plants with relation to metal content of deposited-dust and modified epidermal traits, lists the species studied in the following order of tolerance (scavenging potential): C. siamea > Z. mauritiana > C. procera > I. fistulosa > M. indica.
Ipomoea carnea woody stems were pyrolyzed in a laboratory-scale reactor in the temperatures ranging from 350° to 600°C and at constant heating rate of 5°C/min. Yield, density, ash content, volatile matter, fixed carbon content and calorific value of the charcoal samples produced were evaluated. Charcoal yield ranged from 24.23% to 37.89 wt% and calorific value varied from 17.29 to 33.47 MJ/Kg. Conversion of charcoal fines to solid fuel improved combustion quality. Mass balance experiments of pyrolytic decomposition products of I. carnea yielded much higher percentages of non-condensable liquid (59.2–61.8 wt%) as compared to those of tar (4.2–4.8 wt%) and gas (7.3–8.2 wt%) fractions.
The combination of revegetation and application of stabilizing soil amendments on heavy metal-contaminated soils is generally considered to be a promising alternative to expensive classical remediation techniques. Here, we simultaneously investigated the effects of six cost-effective amendments (CaCO3, iron grit, fly ash, manure, bentonite and bone meal) on Cd, Zn and Pb leaching and phytoavailability (assessed using white lupin, Lupinus albus L.). The Cd and Zn leaching was reduced by all amendments mainly due to alkalinity increase. The Pb leaching was strongly affected by the dissolved organic carbon (DOC) release. Therefore, bone meal and manure treatments, which highly increased DOC concentrations in leachates, increased the flow-weighted mean Pb concentrations by 2.3 and 16 times, respectively. Surprisingly, while iron grit induced strong Cd and Pb leaching reductions, this amendment doubled Cd and Pb concentrations in shoots of white lupin. Conversely, the addition of bone meal reduced Pb concen
Several anthropogenic activities lead to the production of substantial amounts of aqueous effluents that contain various toxic trace and heavy metals and which pose potential threats to the wild habitat of wetlands. As a part of the remediation of heavy metals, it is necessary to identify some aquatic hyperaccumulator plants. To this end, a greenhouse study was conducted to investigate the phytotoxicity resulting from lead (Pb) and its accumulation in selected plant species. Lead was added from low to very high levels in a swell–shrink clayey soil (Typic Haplustert). Seven levels of Pb (0, 50, 100 200, 400, 600, and 800 mg kg–1 soil) were applied. Typha angustifolia L. of Typhaceae and Behaya plant (Ipomoea carnea L.) of the Convolvulaceae family were taken as test plants. Lead was added at high and low concentrations to determine whether an increase in concentration would Pb to an increased toxicity to the plants. Recorded weight of the Typha crop was reduced (6%) at 600 mg Pb kg–1 soil, and at greater doses of Pb, the dry-matter yield was inhibited considerably. In the case of Ipomoea, no growth retardation from Pb was observed. Most Pb accumulated in roots and then was transported to shoots. The Typha angustifolia L. and Ipomoea carnea L. plants show promise for the removal of Pb from contaminated wastewater because they can accumulate high concentrations of Pb in roots (1200 and 1500 mg Pb kg–1 respectively) and shoots (275 and 425 mg Pb kg–1 respectively). Lead uptake by both the plants increased with the increasing doses of Pb (50 to 800 mg kg–1 soil). Physiological parameters such as photosynthesis, respiration, chlorophyll content, and different enzyme activities including nitrate reductase (NR), peroxidase (POD), and succinate dehydrogenase (SD) were also studied for the evaluation of these plant species. In Typha plants, at greater doses of Pb, the rate of photosynthesis and chlorophyll content decreased whereas POD and SD activities increased to combat oxidative stress.
We developed a conceptual ecological model (CEM) for invasive species to help understand the role invasive exotics have in ecosystem ecology and their impacts on restoration activities. Our model, which can be applied to any invasive species, grew from the eco-regional conceptual models developed for Everglades restoration. These models identify ecological drivers, stressors, effects and attributes; we integrated the unique aspects of exotic species invasions and effects into this conceptual hierarchy. We used the model to help identify important aspects of invasion in the development of an invasive exotic plant ecological indicator, which is described a companion paper in this special issue journal. A key aspect of the CEM is that it is a general ecological model that can be tailored to specific cases and species, as the details of any invasion are unique to that invasive species. Our model encompasses the temporal and spatial changes that characterize invasion, identifying the general conditions that allow a species to become invasive in a de novo environment; it then enumerates the possible effects exotic species may have collectively and individually at varying scales and for different ecosystem properties, once a species becomes invasive. The model provides suites of characteristics and processes, as well as hypothesized causal relationships to consider when thinking about the effects or potential effects of an invasive exotic and how restoration efforts will affect these characteristics and processes. In order to illustrate how to use the model as a blueprint for applying a similar approach to other invasive species and ecosystems, we give two examples of using this conceptual model to evaluate the status of two south Florida invasive exotic plant species (melaleuca and Old World climbing fern) and consider potential impacts of these invasive species on restoration.
Abundance of naturally growing Azolla caroliniana (water fern) on the surface of metal enriched fly ash (FA) pond reflects its toxitolerant characteristics. Results indicate the efficiency of A. caroliniana for phytoremediation of FA pond because of its higher bioconcentration factor. The metal concentration ranged from 175 to 538 and 86 to 753mgkg(-1) in roots and fronds, respectively. Bioconcentration factor (BCF) values of all metals in root and frond ranged from 1.7 to18.6 and 1.8 to 11.0, respectively, which were greater than one and indicates the metal accumulation potential of A. caroliniana. Translocation factor (TF) ranged from 0.37 to 1.4 for various heavy metals. The field result proved that A. caroliniana is a potential accumulator for the examined heavy metals and can be used for phytoremediation of FA pond.
Fly ash (FA)—a coal combustion residue of thermal power plants has been regarded as a problematic solid waste all over the world. The conventional disposal methods for FA lead to degradation and contamination of the arable land. However, several studies proposed that FA can be used as a soil-additive that may improve physical, chemical and biological properties of the degraded soils and is a source of readily available plant micro- and macro-nutrients. Numerous studies revealed that the lower FA incorporation in soil modifies the physico-chemical, biological and nutritional quality of the soil. However, the higher dosage of FA incorporation results in heavy metal pollution and hinders the microbial activity. Practical value of FA in agriculture as an “eco-friendly and economic” fertilizer or soil amendments can be established after repeated field experiments for each type of soil to confirm its quality and safety. Integrated Organic/Biotechnological approaches should be applied for the reducing toxicity of FA contaminated site near thermal power plants. Overall, study reveals that FA could be effectively used in the barren or sterile soil for improving quality and enhancing fertility. The purpose of this paper is to explore the possibility of FA addition into degraded soils for improving nutritional and physico-chemical properties.
A pot soil experiment with 20 rice cultivars of different genotypes from different origins showed that the effects of lead (800 mg/kg Pb in soil) on rice growth and development varied greatly with different cultivars. The increases or decreases of the grain yields mainly resulted from the changes of the spikelets per panicle under soil lead treatment. Furthermore, the changes of spikelets per panicle correlated significantly and positively with the changes of dry straw weights. There existed significant differences among the cultivars in the lead uptake and translocation by rice plants, but the differences had no obvious relationship with rice genotypes. The lead concentrations decreased rapidly from roots to grains along rice plants, so the concentrations of lead in the grains were very low compared to other parts of the rice plants. The regression analysis showed that there were significant and negative correlations between connected organs of the rice plants, but positive correlations, mostly significant, between disconnected organs, for the lead concentrations in them. Lead concentrations in the leaves of heading stage showed a significant and positive correlation with that of the grains at ripening stage. Lead was not distributed uniformly in different parts of grain structure, and the lead accumulated in polished rice was only 32.88% of the total lead accumulated in grain.
We have developed a comprehensive ecological indicator for invasive exotic plants, a human-influenced component of the Everglades that could threaten the success of the restoration initiative. Following development of a conceptual ecological model for invasive exotic species, presented as a companion paper in this special issue, we developed criteria to evaluate existing invasive exotic monitoring programs for use in developing invasive exotic performance measures. We then used data from the selected monitoring programs to define specific performance measures, using species presence and abundance as the basis of the indicator for invasive exotic plants. We then developed a series of questions used to evaluate region and/or individual species status with respect to invasion. Finally, we used an expert panel who had answered the questions for invasive exotic plants in the Everglades Lake Okeechobee model to develop a stoplight restoration report card to communicate invasive exotic plant status. The report card system provides a way to effectively evaluate and present indicator data to managers, policy makers, and the public using a uniform format among indicators. Collectively, the model, monitoring assessment, performance measures, and report card enable us to evaluate how invasive plants are impacting the restoration program and how effectively that impact is being managed. Applied through time, our approach also allows us to follow the progress of management actions to control the spread and reduce the impacts of invasive species and can be easily applied and adapted to other large-scale ecosystem projects.
An investigation of the potential environmental and health impacts in the immediate aftermath of one of the largest coal ash spills in U.S. history at the Tennessee Valley Authority (TVA) Kingston coal-burning power plant has revealed three major findings. First the surface release of coal ash with high levels of toxic elements (As = 75 mg/kg; Hg = 150 microg/kg) and radioactivity (226Ra + 228Ra = 8 pCi/g) to the environment has the potential to generate resuspended ambient fine particles (< 10 microm) containing these toxics into the atmosphere that may pose a health risk to local communities. Second, leaching of contaminants from the coal ash caused contamination of surface waters in areas of restricted water exchange, but only trace levels were found in the downstream Emory and Clinch Rivers due to river dilution. Third, the accumulation of Hg- and As-rich coal ash in river sediments has the potential to have an impact on the ecological system in the downstream rivers by fish poisoning and methylmercury formation in anaerobic river sediments.
Coal-based power generation is a principal source of electricity in India and many other countries. About 15-30% of the total amount of residue generated during coal combustion is fly ash (FA). FA is generally alkaline in nature and contains many toxic metals like Cr, Pb, Hg, As and Cd along with many essential elements like S, B, Ca, Na, Fe, Zn, Mn and P. Dumped FA contaminates the biosphere by mobilization of its fine particles and hazardous metals. Despite the negative environmental impact of FA, coal continues to be a major source of power production in India and therefore FA disposal is a major environmental issue. To overcome this problem, FA dumping sites have been started as a potential resource for biomass production of tree species. Phytoremediation is a strategy that uses plants to degrade, stabilize, and remove contaminants from soils, water and waste FA. Phytomanagement of FA is based on the plants' root systems, high biomass, woody nature, native nature, and resistance to pH, salinity, and toxic metals. Recently Indian researchers mostly from the National Botanical Research Institute have been working on phytoremediation and revegetation of FA dykes, inoculation of bacterial strains for reducing FA stress and biomass production from FA dykes. Many international researchers have worked on reclamation, revegetation and utilization of FA. FA utilization saves resources, mainly land (topsoil), water, coal, limestone and chemical fertilizer. Safe utilization of FA is a major concern around the world and regulatory bodies are enforcing stringent rules for the proper management of FA. This article summarizes various viable avenues in India for FA utilization and environmental management.
Fly ash is a by-product of coal-fired electricity generation plants. The prevalent practice of disposal is as slurry of ash and water to storage or ash ponds located near power stations. This has lain to waste thousands of hectares of land all over the world. Since leaching is often the cause of off-site contamination and pathway of introduction into the human environment, a study on the genotoxic effects of fly ash leachate is essential. Leachate prepared from the fly ash sample was analyzed for metal content, and tested for mutagenicity and genotoxicity. Analyses of metals show predominance of the metals-sodium, silicon, potassium, calcium, magnesium, iron, manganese, zinc, and sulphate. The Ames Salmonella mutagenicity assay, a short-term bacterial reverse mutation assay, was conducted on two-tester strains of Salmonella typhimurium strains TA97a and TA102. For genotoxicity, the alkaline version of comet assay on fly ash leachate was carried in vitro on human blood cells and in vivo on Nicotiana plants. The leachate was directly mutagenic and induced significant (P<0.05) concentration-dependent increases in DNA damage in whole blood cells, lymphocytes, and in Nicotiana plants. The comet parameters show increases in tail DNA percentage (%), tail length (mum), and olive tail moment (arbitrary units). Our results indicate that leachate from fly ash dumpsites has the genotoxic potential and may lead to adverse effects on vegetation and on the health of exposed human populations.
Coal-fired power generation is a principal energy source throughout the world. Approximately, 70-75% of coal combustion residues are fly ash and its utilization worldwide is only slightly above 30%. The remainder is disposed of in landfills and fly ash basins. It is desirable to revegetate these sites for aesthetic purposes, to stabilize the surface ash against wind and water erosion and to reduce the quantity of water leaching through the deposit. Limitations to plant establishment and growth in fly ash can include a high pH (and consequent deficiencies of Fe, Mn, Cu, Zn and P), high soluble salts, toxic levels of elements such as B, pozzalanic properties of ash resulting in cemented/compacted layers and lack of microbial activity. An integrated organic/biotechnological approach to revegetation seems appropriate and should be investigated further. This would include incorporation of organic matter into the surface layer of ash, mycorrhizal inoculation of establishing vegetation and use of inoculated legumes to add N. Leaching losses from ash disposal sites are likely to be site-specific but a sparse number of studies have revealed enriched concentrations of elements such as Ca, Fe, Cd, Pb, and Sb in surrounding groundwater. This aspect deserves further study particularly in the longer-term. In addition, during weathering of the ash and deposition of organic matter during plant growth, a soil will form with properties vastly different to that of the parent ash. In turn, this will influence the effect that the disposal site has on the surrounding environment. Nevertheless, the effects of ash weathering and organic matter accumulation over time on the chemical, physical and biological properties of the developing ash-derived soil are not well understood and require further study.
Ladder brake (Pteris vittata L.) is a newly discovered arsenic hyperaccumulator. No information is available about arsenic effects on ladder brake. This study determined the effects of different arsenic concentrations (50 to 1000 mg kg(-1)) or forms (organic vs. inorganic and arsenite vs. arsenate) applied to soils on growth and arsenic uptake by ladder brake. Young plants were grown in a greenhouse for 12 or 18 wk. Ladder brake was highly tolerant of arsenic and survived in soil containing up to 500 mg As kg(-1). The fact that addition of arsenate up to 100 mg As kg(-1) increased fern biomass by 64 to 107%, coupled with higher arsenic concentration in younger fronds at low soil arsenic concentrations and older fronds at high soil arsenic concentrations, implies that arsenic may be beneficial for fern growth. Addition of 50 mg As kg(-1) was best for fern growth and arsenic accumulation, resulting in the highest fern biomass (3.9 g plant(-1)), bioconcentration factor (up to 63), and translocation factor (up to 25). With an exception of FeAsO4 and AlAsO4, which had the lowest effects due to their low solubility, little difference was observed among other arsenic forms mainly because of arsenic conversion in soil. Aboveground biomass was mostly responsible for accumulation of arsenic by plant (75-99%). Up to 26% of the added arsenic was removed by ladder brake, showing the high efficiency of ladder brake in arsenic removal. The results suggest that ladder brake may be a good candidate to remediate arsenic-contaminated soils.
A greenhouse study was conducted to evaluate the potential use of two legume species, Acacia auriculiformis and Leucaena leucocephala for growth on ameliorated lagoon ash with or without nitrogen (N(2))-fixing bacteria inoculation. Even though amendments of 30% (w/w) vermiculite or with sewage sludge compost were added to improve the chemical and physical limitations of lagoon ash, significant suppressions in biomass and plant nutrient content were found with ameliorated lagoon ash in comparison to an agricultural soil. The high proportion of clay-sized (<53 microm) ash particles limited root growth. In addition, heavy metal toxicity was a possible factor contributing to poor seedling growth. Higher plant productivity resulted from the sewage sludge compost-amended lagoon ash than with vermiculite due to a greater contribution of plant nutrients in the compost. Nodulation was inhibited in ameliorated lagoon ash but not in agricultural soil. High pH and electrical conductivity and elevated toxic metals may be important parameters that limit bacterial activity. Both species showed potential to establish on amended lagoon ash, with Acacia auriculiformis being the best adapted.
Contamination of heavy metals represents one of the most pressing threats to water and soil resources as well as human health. Phytoremediation can be potentially used to remediate metal-contaminated sites. This study evaluated the potential of 36plants (17species) growing on a contaminated site in North Florida. Plants and the associated soil samples were collected and analyzed for total metal concentrations. While total soil Pb, Cu, and Zn concentrations varied from 90 to 4100, 20 to 990, and 195 to 2200mg kg(-1), those in the plants ranged from 2.0 to 1183, 6.0 to 460, and 17 to 598mg kg(-1), respectively. None of the plants were suitable for phytoextraction because no hyperaccumulator was identified. However, plants with a high bioconcentration factor (BCF, metal concentration ratio of plant roots to soil) and low translocation factor (TF, metal concentration ratio of plant shoots to roots) have the potential for phytostabilization. Among the plants, Phyla nodiflora was the most efficient in accumulating Cu and Zn in its shoots (TF=12 and 6.3) while Gentiana pennelliana was most suitable for phytostabilization of sites contaminated with Pb, Cu and Zn (BCF=11, 22 and 2.6). Plant uptake of the three metals was highly correlated, whereas translocation of Pb was negatively correlated with Cu and Zn though translocation of Cu and Zn were correlated. Our study showed that native plant species growing on contaminated sites may have the potential for phytoremediation.
Agricultural and industrial activities cause heavy metal pollution in the soil, which adversely affect the plant growing therein. The plants of fenugreek (Trigonella foenum-graecum L.) were grown in soil amended with different percent of tannery sludge (TS) (10%, 25%, 35%, 50%, and 100% TS) in order to study the effect on antioxidant levels due to translocation of metals (Fe, Zn, Mn, Cu, Cr, Pb). The accumulation of the metals was found more in shoots than roots, except Fe and Cr. The level of metals in seeds of the plant increased with increase in sludge amendments ratio except Mn, which decreased in roots, shoots, and seeds of the plant. Chromium was found below detection limits in the seeds at 10% and 25% TS. Correlation coefficient (r) between total metal accumulation and extractable metals showed that Zn (P<0.01), Cr (P<0.01), and Cu (P<0.05) are significantly correlated, whereas, correlation with pH showed significant positive relation with all the studied metals except Mn. Significant positive correlation was recorded between metal accumulation (Fe, Zn, Cu) and electrical conductivity, cation exchange capacity, and organic matter, however, Zn, Cr, and Cu showed significant positive correlation with bulk density, nitrate, ammonia, and available phosphorus. The analysis of the results showed that total chlorophyll content showed significant (P< 0.5) increase in lower amendment of sludge (up to 35% TS at 30 d and 25% TS at 60 d) as over their controls. In roots, malondialdehyde, cysteine, non-protein thiol, proline, protein, ascorbic acid contents increased up to 35% TS at 30 d. Principal component analysis also showed that strong association exists among malondialdehyde, nonprotein thiol, protein, and cysteine contents in the plants grown on different amendments of TS. The level of antioxidants increased which enabled the plant to cope up the stress induced in the plants grown on lower amendments of TS, however, toxicity was observed at higher amendments.
A field study was conducted in the fly ash lagoons of Santandih Thermal Power Plant located in West Bengal (India) to find out total, EDTA and DTPA extractable metals in fly ash and their bioaccumulation in root and shoot portion of the naturally growing vegetation. Fly ash sample has alkaline pH and low conductivity. The concentration of total Cu, Zn, Pb and Ni were found higher than weathered fly ash and natural soil, where as Co, Cd and Cr were found traces. Five dominant vegetation namely, Typha latifolia, Fimbristylis dichotoma, Amaranthus defluxes, Saccharum spontaenum and Cynodon dactylon were collected in the winter months (November-December). Bioaccumulation of metals in root and shoot portions were found varied significantly among the species, but all concentration were found within toxic limits. Correlation between total, DTPA and EDTA extractable metals viz. root and shoot metals concentration were studied. Translocation factor (TF) for Cu, Zn and Ni were found less than unity, indicates that these metals are immobilized in the root part of the plants. Metals like Mn have TF greater than unity. The study infers that natural vegetation removed Mn by phytoextraction mechanisms (TF > 1), while other metals like Zn, Cu, Pb and Ni were removed by rhizofiltration mechanisms (TF < 1). The field study revealed that T. latifolia and S. spontaenum plants could be used for bioremediation of fly ash lagoon.
Present study is focused on the decontamination and/or revegetation of fly ash dykes through naturally growing plants, namely Calotropis procera, Cassia tora, Chenopodium album, Sida cardifolia, Blumea lacera. The results of sequential extraction study showed that maximum amount of metals (Na, K, Fe, Mn, Cr, Pb, Ni, Cd) were associated with residual and Fe-Mn fractions. Diethylenetriamine penta acetic acid (DTPA)-triethanolamine (TEA) extraction assessed the bioavailability of the metals. The total metal accumulation in tested plants was found in the order; C. album>S. cardifolia>C. tora>C. procera>B. lacera. The maximum bioconcentration factor (BCF) was recorded in S. cardifolia for the metals (Na, Fe, Zn, Cd), in C. procera for the metals (Mn, Cu, Ni, Cr) and in C. album for the metals (Co, Pb). However, the translocation factor (TF) of most of the metals was found more in S. cardifolia followed by C. album than other plants. Among all the plants, C. album have shown high BCF and low TF values for toxic metals (Pb, Cd) and suitable for phytostabilization of these metals. Principal component analysis was used to predict translocation behavior of the metals in different parts of the plants which was found similar for the metals (Cu, Zn, Mn, Cr). All examined plants are suitable for revegetation (naturally grows on fly ash dykes) and S. cardifolia and C. album may be used for decontamination purposes.
Vegetation impact by orienteering? A phytosociological long-term study
- S W Breckle
- H Breckle
- U Breckle
Breckle, S.W., Breckle, H., Breckle, U., 1989. Vegetation impact by orienteering? A phytosociological long-term study. Scientific Journal of Orienteering 5, 25-36.
Lignin from soda liquor and soda anthraquinone of Ipomoea carnea Jacq An as-sessment of the accumulation potential of Pb
- P Nandkumar
- I J Kumar
- P R Sajish
- R Kumar
- G Basil
- V Shailendra
Nandkumar, P., 2009. Lignin from soda liquor and soda anthraquinone of Ipomoea carnea Jacq. Australian Journal of Basic and Applied Sciences 3, 474476. Nirmal Kumar, I.J., Sajish, P.R., Nirmal Kumar, R., Basil, G., Shailendra, V., 2011. An as-sessment of the accumulation potential of Pb, Zn and Cd by Avicennia marina (Forssk.) Vierh. in Vamleshwar Mangroves, Gujarat, India. Notulae Scientia Bio-logicae 3, 36–40.
Phytoremediation of heavy metals from fly ash pond by Azolla caroliniana Ecotoxicology and Environmental Safety Impact of fly ash incorporation in soil systems
- V C Pandey
Pandey, V.C., 2012. Phytoremediation of heavy metals from fly ash pond by Azolla caroliniana. Ecotoxicology and Environmental Safety. http://dx.doi.org/10.1016/ j.ecoenv.2012.05.002. Pandey, V.C., Singh, N., 2010. Impact of fly ash incorporation in soil systems. Agricul-ture, Ecosystems and Environment 136, 16–27.
Chromium toxicity in plants Translocation of metals from fly ash amended soil in the plant of Sesbania cannabina L. Ritz: effect on antioxidant Uptake and translocation of metals in Fenugreek grown on soil amended with tannery sludge: involvement of antioxidants
- A K Shanker
- C Carlos
- H Loza-Tavera
- S Avudainayagam
- S Sinha
- A K Gupta
Shanker, A.K., Carlos, C., Loza-Tavera, H., Avudainayagam, S., 2005. Chromium toxicity in plants. Environment International 31, 739753. Sinha, S., Gupta, A.K., 2005. Translocation of metals from fly ash amended soil in the plant of Sesbania cannabina L. Ritz: effect on antioxidant. Chemosphere 61, 12041214. Sinha, S., Gupta, A.K., Bhatt, K., 2007. Uptake and translocation of metals in Fenugreek grown on soil amended with tannery sludge: involvement of antioxidants. Ecotox-icology and Environmental Safety 67, 267277.
Human and Ecological Risk Assessment of Coal Combustion Wastes (draft)
- Us Epa
US EPA, 2007. Human and Ecological Risk Assessment of Coal Combustion Wastes
(draft).
Production of solid fuel from Ipomoea carnea wood, energy sources, part A: recovery. Utilization, and Environmental Effects
- D Konwer
- R Kataki
- M Saikia
Konwer, D., Kataki, R., Saikia, M., 2007. Production of solid fuel from Ipomoea carnea
wood, energy sources, part A: recovery. Utilization, and Environmental Effects 29
(9), 817822.