Immobilisation of arsenic in contaminated soil by electrokinetics in an outdoor experiment.

Although landfilling is environmentally and economically unsustainable, it is the dominant soil remediation method in EU member states. This paper describes part of a study on mixed contaminants that investigated the stabilisation of arsenic (As) in contaminated soil in an outdoor box experiment with electrokinetic treatment (EK). The experiment was conducted in two 1 m3 boxes, each containing a 20 cm bottom layer of sand, overlaid with 20 cm of peat. In EK, a pulsating, low-voltage current was applied with the intention of corroding the zerovalent iron (Fe) electrodes, migrating ionic Fe species, and forming secondary iron minerals, thereby immobilizing As. Porewater samples were collected over two seasons to determine whether the treatment decreased the concentration of dissolved As. Sequential extraction was performed on the soil samples to determine whether the fraction of Fe-bound As increased. Reed canary grass was planted in one of the boxes during the second season and analysed for As uptake. The results showed that the treatment decreased the porewater As concentration in sand by 50-54 %, while the concentration of Fe increased. The sequential extraction of sand showed that the fraction of As bound to poorly crystalline Fe oxides increased during this time. This treatment effect was less visible in the peat. Moreover, the exchangeable As fraction increased in both peat and sand, most likely because of the decrease in redox potential at the end of the experiment. The plants grown in treated soil accumulated less As than those grown in untreated soil, indicating that the phytoavailable As fraction decreased. This study showed that EK remediation can be a suitable in situ remediation technique, mostly in sand. Future research should focus on redox control to further optimise EK remediation and ensure long-term As stability in treated soils.

Identification and Validation of Reference Genes for RT-qPCR Analysis in Reed Canary Grass during Abiotic Stress.

Reed canary grass (Phalaris arundinacea L.) is known for its tolerance to drought, heavy metals, and waterlogging, making it a popular choice for forage production and wetland restoration in the Qinghai-Tibet Plateau (QTP). To accurately assess gene expression in reed canary grass under different abiotic stresses, suitable reference genes need to be identified and validated. Thirteen candidate reference gene sequences were selected and screened using RT-qPCR to detect their expression levels in reed canary grass leaves under drought, salt, cadmium, and waterlogging stresses. Four algorithms were used to assess the stability of the expression levels of the candidate reference genes. The most stably expressed genes were UBC and H3 under drought Cd, ETF and CYT under salt stress, and ETF and TUB under waterlogging stress. GAPDH was found to be less stable under abiotic stresses. PIP-1, PAL, NAC 90, and WRKY 72A were selected as response genes for quantitative expression assessment under drought, salt, Cd, and waterlogging stresses to confirm the accuracy of the selected stable reference genes. These results provide a theoretical reference for assessing gene expression in reed canary grass under abiotic stresses.

Invasive Species Change Plant Community Composition of Preserved Prairie Pothole Wetlands.

Plant communities in North American prairie pothole wetlands vary depending on hydrology, salinity, and anthropogenic disturbance in and around the wetland. We assessed prairie pothole conditions on United States Fish and Wildlife Service fee-title lands in North Dakota and South Dakota to improve our understanding of current conditions and plant community composition. Species-level data were collected at 200 randomly chosen temporary and seasonal wetland sites located on native prairie remnants (n = 48) and previously cultivated lands that were reseeded into perennial grassland (n = 152). The majority of species surveyed appeared infrequently and were low in relative cover. The four most frequently observed species were introduced invasive species common to the Prairie Pothole Region of North America. Our results suggested relative cover of a few invasive species (i.e., Bromus inermis Leyss., Phalaris arundinacea L., and Typha ×glauca Godr. (pro sp.) [angustifolia or domingensis × latifolia]) affect patterns of plant community composition. Wetlands in native and reseeded grasslands possessed distinct plant community composition related to invasive species' relative cover. Invasive species continue to be prevalent throughout the region and pose a major threat to biological diversity, even in protected native prairie remnants. Despite efforts to convert past agricultural land into biologically diverse, productive ecosystems, invasive species continue to dominate these landscapes and are becoming prominent in prairie potholes located in native areas.

Physiological and molecular responses of Phalaris arundinacea under salt stress on the Tibet plateau.

Phalaris arundinacea, with its characteristics of rapid growth and high biological yield, is regarded as an excellent forage grass in the Qinghai-Tibetan Plateau region of China. To explore the physiological and molecular response mechanism of Phalaris arundinacea under salt stress, we monitored the biomass and physiological indexes of two locally grown strains under conditions of exposure to 150 and 300 mM NaCl solution. Z0611 exhibited better salt stress tolerance than YS. Transcriptome sequencing analysis showed that YS and Z0611 had 1713 and 4290 differentially expressed genes (DEGs), respectively, including on metabolic processes, single-organism process, catalytic activity, and plant hormone signal transduction in the GO and KEGG databases. We also identified a large number of genes involved in hormone signaling, antioxidant systems, ion homeostasis, and photosynthetic systems. Our study provides physiological and molecular insight for establishing a salt resistance database and mining salt tolerance genes in Phalaris arundinacea, and also provides theoretical guidance for the restoration of saline-alkali land on the Qinghai-Tibet Plateau.

Encapsulation of Cynara Cardunculus Guaiane-type Lactones in Fully Organic Nanotubes Enhances Their Phytotoxic Properties.

The encapsulation of bioactive natural products has emerged as a relevant tool for modifying the poor physicochemical properties often exhibited by agrochemicals. In this regard, natural guaiane-type sesquiterpene lactones isolated from Cynara cardunculus L. have been encapsulated in a core/shell nanotube@agrochemical system. Monitoring of the F and O signals in marked sesquiterpenes confirmed that the compound is present in the nanotube cavity. These structures were characterized using scanning transmission electron microscopy-X-ray energy-dispersive spectrometry techniques, which revealed the spatial layout relationship and confirmed encapsulation of the sesquiterpene lactone derivative. In addition, biological studies were performed with aguerin B (1), cynaropicrin (2), and grosheimin (3) on the inhibition of germination, roots, and shoots in weeds (Phalaris arundinacea L., Lolium perenne L., and Portulaca oleracea L.). Encapsulation of lactones in nanotubes gives better results than those for the nonencapsulated compounds, thereby reinforcing the application of fully organic nanotubes for the sustainable use of agrochemicals in the future.

Effect of phenyllactic acid on silage fermentation and bacterial community of reed canary grass on the Qinghai Tibetan Plateau.

BACKGROUND: This study aimed to investigate the effect of phenyllactic acid as an additive on silage fermentation and bacterial community of reed canary grass (RCG, Phalaris arundinacea L.) on the Qinghai Tibetan Plateau. At the heading stage, RCG was harvested, chopped and ensiled in small bag silos. The silage was treated without (control, 1.0 g/mL sterile water, on a fresh matter basis (FM)) or with phenyllactic acid (PLA, 3 mg/mL, FM), antimicrobial additive (PSB, a mixture of potassium sorbate and sodium benzoate, 2%, FM), lactic acid bacteria inoculant (LABi, L. plantarum + L. curvatus, 1 × 106 cfu/g, FM) and PLA + LABi, and then stored in a dark room at the ambient temperature (5 ~ 15 °C) for 60 days. RESULTS: Compared with control, PLA decreased lactic acid, acetic acid and ammonia-N contents, and subsequently increased CP content of RCG silage. PLA enhanced the growth of lactic acid bacteria and reduced the count of yeasts (P < 0.05) in RCG silage, with reduced bacterial richness index (Chao1), observed operational taxonomic units and diversity index (Simpson). In relative to control, moreover, PLA and PLA + LABi increased the relative abundance of Lactococcus in RCG silage by 27.73 and 16.93%, respectively. CONCLUSIONS: Therefore, phenyllactic acid at ensiling improved nutritional quality of RCG silage by advancing the disappearance of yeasts and the dominance of Lactococcus.

Aluminum Bioaccumulation in Reed Canary Grass (Phalaris arundinacea L.) from Rivers in Southwestern Poland.

This study aimed to determine aluminum levels in reed canary grass Phalaris arundinacea L.) in rivers in southwestern Poland­Bystrzyca, Strzegomka, and Nysa Szalona, together with their tributaries. The samples were collected in spring and autumn 2015−2018. The highest amounts of aluminum were recorded in the Nysa Szalona, and the lowest in the Bystrzyca. During the four-year cycle of studies, the highest values were recorded in the last year, and the lowest in the first year. The highest amounts of aluminum were found in all three rivers in the lowland tributaries. In the main rivers, higher amounts of aluminum were found at the mouth of the Nysa Szalona and Strzegomka reservoirs, while the opposite situation was found for the Bystrzyca. Higher aluminum contents were recorded in autumn than in spring, and the values of BCFW (aluminum bioaccumulation factor in relation to water) and BCFB (aluminum bioaccumulation factor in relation to bottom sediments) coefficients were also higher. The MPI (metal pollution index) was arranged in a series: Bystrzyca < Strzegomka < Nysa Szalona, while the degree of pollution was high for Bystrzyca and very high for the other two rivers. The variability in Al levels may be attributed to pollution level in the catchments, but also to successive modernization works carried out in the beds of the main rivers and their tributaries. All these works were carried out in a variable way and often covered only a fragment of the riverbed; therefore, the consequences of activity may have been visible in the catchment but not necessarily in the same vegetation cycles.

Chloride removal capacity and salinity tolerance in wetland plants.

Deicing with sodium chloride maintains safe roads in the winter, but results in stormwater runoff with high chloride (Cl-) content that causes various downstream problems. Chloride-rich water risks contaminating groundwater, shortening the lifespan of concrete and metal constructions, and being toxic to aquatic organisms. Current stormwater treatment methods are unable to remove Cl-, but wetland plants with high chloride uptake capacity have potential to decrease Cl- concentrations in water. The aim was to identify suitable plant species for removing Cl- from water for future studies on phytodesalination of water, by comparing 34 wetland plant species native to Sweden in a short-term screening. Additionally, Carex pseudocyperus, C. riparia, and Phalaris arundinacea was further compared as to their salinity tolerance and tissue Cl- concentration properties. Results show that Cl- removal capacity, tissue accumulation, and tolerance varied between the investigated species. Removal capacity correlated with biomass, dry:fresh biomass ratio, water uptake, and transpiration. The three tested species tolerated Cl- levels of up to 50-350 mg Cl- L-1 and accumulated up to 10 mg Cl- g-1 biomass. Carex riparia was the most Cl-tolerant species, able to maintain growth and transpiration at 500 mg Cl- L-1 during 4 weeks of exposure and with a medium removal capacity. Due to a large shoot:plant biomass ratio and high transpiration, C. riparia also had high shoot accumulation of Cl-, which may facilitate harvesting. Phalaris arundinacea had the highest removal capacity of the investigated species, but displayed decreased growth above 50 mg Cl- L-1. From this study we estimate that wetland plants can remove up to 7 kg Cl- m-2 from water if grown hydroponically, and conclude that C. riparia and P. arundinacea, which have high tolerance, large biomass, and high accumulation, are suitable candidates for further phytodesalination studies.

Retention and distribution of pesticides in planted filter microcosms designed for treatment of agricultural surface runoff.

Pesticides in agricultural surface water runoff cause a major threat to freshwater systems. Installation of filter systems or constructed wetlands in areas of preferential run-off is a possible measure for pesticides abatement. To develop such systems, combinations of filter materials suitable for retention of both hydrophilic and hydrophobic organic pesticides were tested for pesticide removal in planted microcosms. The retention of six pesticides frequently detected in surface waters (bentazone, MCPA, metalaxyl, propiconazole, pencycuron, and imidacloprid) was evaluated in unplanted and planted pot experiments with novel bed material mixtures consisting of pumice, vermiculite, water super-absorbent polymer (SAP) for retention of ionic and water soluble pesticides, and synthetic hydrophobic wool for adsorption of hydrophobic pesticides. The novel materials were compared to soil with high organic matter content. The highest retention of the pesticides was observed in the soil, with a considerable translocation of pesticides into the plants, and low leaching potential, in particular for the hydrophobic compounds. However, due to the high retention of pesticides in soil, environmental risks related to their long term mobilization cannot be excluded. Mixtures of pumice and vermiculite with SAP resulted in high retention of i) water and ii) both hydrophilic and hydrophobic pesticides but with much lower leaching potential compared to the mineral systems without SAP. Mixtures of such materials may provide near natural treatment options in riparian strips and also for treatment of rainwater runoff without the need for water containment systems.

Physiological and transcriptional responses of Phalaris arundinacea under waterlogging conditions.

As a high-yielding forage grass, Phalaris arundinacea widely distributed in the Qinghai-Tibet Plateau region of China. To explore physiological and molecular response mechanism of Phalaris arundinacea under waterlogging, we analyzed the biomass and physiological indexes of three locally grown strains under the submerged condition of 10 cm. The material Z0611 showed the strongest waterlogging resistance while the YS showed the weakest performance. Transcriptome sequencing analysis demonstrated that the YS and Z0611 had 17010 and 7566 differently expression genes (DEGs), respectively, which were mainly concentrated in the metabolic process, cell, ribosome, phenylpropanoid biosynthesis pathway in GO and KEGG databases. We also identified a large number of genes involved in carbohydrate metabolism, hormone signaling regulation, transcription factors, antioxidant system, and ethylene signaling. Our research may provide a scientific basis for the restoration of wetland environment on the Qinghai-Tibet Plateau, and lay a foundation for further exploration of the waterlogging resistance genes of Phalaris arundinacea and breeding of new strains resistant with waterlogging stress.

The role of rhizofiltration and allelopathy on the removal of cyanobacteria in a continuous flow system.

A continuous flow filtration system was designed to identify and quantify the removal mechanisms of Cyanobacteria (Microcystis aeruginosa) by hydroponic biofilters of Phalaris arundinacea compared to synthetic filters. The filtration units were continuously fed under plug-flow conditions with Microcystis grown in photobioreactors. Microcystis cells decreased at the two flow rates studied (1.2 ± 0.2 and 54 ± 3 cm3 min-1) and results suggested physical and chemical/biological removal mechanisms were involved. Physical interception and deposition was the main removal mechanism with packing density of the media driving the extent of cell removal at high flow, whilst physical and chemical/biological mechanisms were involved at low flow. At low flow, the biofilters decreased Microcystis cell numbers by 70% compared to the controls. The decrease in cell numbers in the biofilters was accompanied by a chlorotic process (loss of green colour), suggesting oxidative processes by the release of allelochemicals from the biofilters.

Macrophyte Potential to Treat Leachate Contaminated with Wood Preservatives: Plant Tolerance and Bioaccumulation Capacity.

Pentachlorophenol and chromated copper arsenate (CCA) have been used worldwide as wood preservatives, but these compounds can toxify ecosystems when they leach into the soil and water. This study aimed to evaluate the capacity of four treatment wetland macrophytes, Phalaris arundinacea, Typha angustifolia, and two subspecies of Phragmites australis, to tolerate and treat leachates containing wood preservatives. The experiment was conducted using 96 plant pots in 12 tanks filled with three leachate concentrations compared to uncontaminated water. Biomass production and bioaccumulation were measured after 35 and 70 days of exposure. There were no significant effects of leachate contamination concentration on plant biomass for any species. No contaminants were detected in aboveground parts of the macrophytes, precluding their use for phytoextraction within the tested contamination levels. However, all species accumulated As and chlorinated phenols in belowground parts, and this accumulation was more prevalent under a more concentrated leachate. Up to 0.5 mg pentachlorophenol/kg (from 81 µg/L in the leachate) and 50 mg As/kg (from 330 µg/L in the leachate) were accumulated in the belowground biomass. Given their high productivity and tolerance to the contaminants, the tested macrophytes showed phytostabilization potential and could enhance the degradation of phenols from leachates contaminated with wood preservatives in treatment wetlands.

Increasing ibuprofen degradation in constructed wetlands by bioaugmentation with gravel containing biofilms of an ibuprofen-degrading Sphingobium yanoikuyae.

The aim of this study was to investigate the removal of ibuprofen in laboratory scale constructed wetlands. Four (planted and unplanted) laboratory-scale horizontal subsurface flow constructed wetlands were supplemented with ibuprofen in order to elucidate (i) the role of plants on ibuprofen removal and (ii) to evaluate the removal performance of a bioaugmented lab scale wetland. The planted systems showed higher ibuprofen removal efficiency than an unplanted one. The system planted with Juncus effusus was found to have a higher removal rate than the system planted with Phalaris arundinacea. The highest removal rate of ibuprofen was found after inoculation of gravel previously loaded with a newly isolated ibuprofen-degrading bacterium identified as Sphingobium yanoikuyae. This experiment showed that more than 80 days of CW community adaptation for ibuprofen treatment could be superseded by bioaugmentation with this bacterial isolate.

A wetland plant, Phalaris arundinacea, accumulates nitrogen and phosphorus during senescence.

Secondary pollution resulting from shoot death is a difficult problem that complicated the application of wetland plants for water purification in northern wetlands. Phalaris arundinacea, a perennial herb with an obviously declining stage, or senescence, is a species that is often selected for water purification in Northern China; however, whether it reduces the secondary pollution risk via nitrogen (N) and phosphorus (P) accumulation during senescence or not remains unclear. To investigate this question, an experiment was conducted with containerized plants during the winter of 2016, after roughly half the leaves on the plants had withered. The experimental observations and analyses were conducted within 0, 2, 4, 6, and 8 weeks of the initiation of senescence. Results revealed that leaves continued to wither and shoot death occurred during weeks 4 to 6 and 8 to 10, respectively. However, no significant differences occurred in fresh biomass or in N and P accumulations of a single plant during senescence. The root biomass, root weight per volume, and total N content increased significantly, while total P content remained stable when leaves withered, respectively. H+-ATPase, a key enzyme for ion transportation, decreased after the leaves withered. However, root activity, evaluated by absorption surface per root volume, remained stable, and percentage of fine root length (diameter < 1 mm) increased significantly during senescence. In conclusion, the root activity and morphology enables P. arundinacea to accumulate N and P during senescence, which makes it a good choice for water purification in northern wetlands.

The Complete Chloroplast Genome Sequencing and Comparative Analysis of Reed Canary Grass (Phalaris arundinacea) and Hardinggrass (P. aquatica).

There are 22 species in the Phalaris genera that distribute almost all over the temperate regions of the world. Among them, reed canary grass (Phalaris arundinacea, tetraploid and hexaploid) and hardinggrass (P. aquatica, tetraploid) have been long cultivated as forage grass and have received attention as bio-energy materials in recent years. We aimed to facilitate inter-species/ploidies comparisons, and to illuminate the degree of sequence variation within existing gene pools, chloroplast (cp) genomes of three Phalaris cytotypes (P. aquatica/4x, P. arundinacea/4x and P. arundinacea/6x) were sequenced and assembled. The result indicated that certain sequence variations existed between the cp genomes of P. arundinacea and P. aquatica. Several hotspot regions (atpI~atpH, trnT-UGU~ndhJ, rbcL~psaI, and ndhF~rpl32) were found, and variable genes (infA, psaI, psbK, etc.) were detected. SNPs (single nucleotide polymorphisms) and/or indels (insertions and deletions) were confirmed by the high Ka/Ks and Pi value. Furthermore, distribution and presence of cp simple sequence repeats (cpSSRs) were identified in the three Phalaris cp genomes, although little difference was found between hexaploid and tetraploid P. arundinacea, and no rearrangement was detected among the three Phalaris cp genomes. The evolutionary relationship and divergent time among these species were discussed. The RNA-seq revealed several differentially expressed genes (DEGs), among which psaA, psaB, and psbB related to leaf color were further verified by leaf color differences.

Transcriptome characterization and differentially expressed genes under flooding and drought stress in the biomass grasses Phalaris arundinacea and Dactylis glomerata.

BACKGROUND AND AIMS: Perennial grasses are a global resource as forage, and for alternative uses in bioenergy and as raw materials for the processing industry. Marginal lands can be valuable for perennial biomass grass production, if perennial biomass grasses can cope with adverse abiotic environmental stresses such as drought and waterlogging. METHODS: In this study, two perennial grass species, reed canary grass (Phalaris arundinacea) and cocksfoot (Dactylis glomerata) were subjected to drought and waterlogging stress to study their responses for insights to improving environmental stress tolerance. Physiological responses were recorded, reference transcriptomes established and differential gene expression investigated between control and stress conditions. We applied a robust non-parametric method, RoDEO, based on rank ordering of transcripts to investigate differential gene expression. Furthermore, we extended and validated vRoDEO for comparing samples with varying sequencing depths. KEY RESULTS: This allowed us to identify expressed genes under drought and waterlogging whilst using only a limited number of RNA sequencing experiments. Validating the methodology, several differentially expressed candidate genes involved in the stage 3 step-wise scheme in detoxification and degradation of xenobiotics were recovered, while several novel stress-related genes classified as of unknown function were discovered. CONCLUSIONS: Reed canary grass is a species coping particularly well with flooding conditions, but this study adds novel information on how its transcriptome reacts under drought stress. We built extensive transcriptomes for the two investigated C3 species cocksfoot and reed canary grass under both extremes of water stress to provide a clear comparison amongst the two species to broaden our horizon for comparative studies, but further confirmation of the data would be ideal to obtain a more detailed picture.

Effects of citric acid and the siderophore desferrioxamine B (DFO-B) on the mobility of germanium and rare earth elements in soil and uptake in Phalaris arundinacea.

Effects of citric acid and desferrioxamine B (DFO-B) on the availability of Ge and selected rare earth elements (REEs) (La, Nd, Gd, Er) to Phalaris arundinacea were investigated. A soil dissolution experiment was conducted to elucidate the effect of citric acid and DFO-B at different concentrations (1 and 10 mmol L-1 citric acid) on the release of Ge and REEs from soil. In a greenhouse, plants of P. arundinacea were cultivated on soil and on sand cultures to investigate the effects of citric acid and DFO-B on the uptake of Ge and REEs by the plants. Addition of 10 mmol L-1 citric acid significantly enhanced desorption of Ge and REEs from soil and uptake into soil-grown plants. Applying DFO-B enhanced the dissolution and the uptake of REEs, while no effect on Ge was observed. In sand cultures, the presence of citric acid and DFO-B significantly decreased the uptake of Ge and REEs, indicating a discrimination of the formed complexes during uptake. This study clearly indicates that citric acid and the microbial siderophore DFO-B may enhance phytoextraction of Ge and REEs due to the formation of soluble complexes that increase the migration of elements in the rhizosphere.

Variation in sequences containing microsatellite motifs in the perennial biomass and forage grass, Phalaris arundinacea (Poaceae).

Forty three microsatellite markers were developed for further genetic characterisation of a forage and biomass grass crop, for which genomic resources are currently scarce. The microsatellite markers were developed from a normalized EST-SSR library. All of the 43 markers gave a clear banding pattern on 3% Metaphor agarose gels. Eight selected SSR markers were tested in detail for polymorphism across eleven DNA samples of large geographic distribution across Europe. The new set of 43 SSR markers will help future research to characterise the genetic structure and diversity of Phalaris arundinacea, with a potential to further understand its invasive character in North American wetlands, as well as aid in breeding work for desired biomass and forage traits. P. arundinacea is particularly valued in the northern latitude as a crop with high biomass potential, even more so on marginal lands.

Removal of diclofenac and sulfamethoxazole from synthetic municipal waste water in microcosm downflow constructed wetlands: Start-up results.

The objectives of this study were to investigate the start-up removal of pharmaceutical compounds diclofenac and sulfamethoxazole in microcosm downflow constructed wetlands and their effect on the performance of the studied constructed wetlands, and also to assess the effect of plants on the removal of these compounds. The experimental system that was used in this 86-day experiment consisted of 24 columns filled up to 70 cm with predominantly sandy material. Four types of columns were used (six replicates) depending on the presence of plants (Phalaris arundinacea L. var. picta L.) and the presence of pharmaceutical compounds in the influent. The influent was synthetic municipal waste water to which a mixture of 5 mg/L of diclofenac and 5 mg/L of sulfamethoxazole was added. The observed removal of diclofenac was moderate (approx. 50%) and the removal of sulfamethoxazole was relatively low (24-30%). It was found that the removal of diclofenac and sulfamethoxazole was not affected by the vegetation. The presence of diclofenac and sulfamethoxazole in the influent had significant effect on the effluent concentration of N-NO3 and the water loss in the columns, which in both cases were lower than in the control columns. The scope for further research was discussed.

Trace metal concentrations and their transfer from sediment to leaves of four common aquatic macrophytes.

In the present study, the concentrations of trace and alkali metals in leaves of four common helophytes, Sparganium erectum, Glyceria maxima, Phalaris arundinacea, and Phragmites australis, as well as in corresponding water and bottom sediments were investigated to ascertain plant bioaccumulation ability. Results showed that Mn and Fe were the most abundant trace metals in all plant species, while Co and Pb contents were the lowest. Leaves of species studied differed significantly in respect of element concentrations. The highest concentrations of Mg, Na, Fe, Mn, Cu, Pb, and Ni were noted in S. erectum while the highest contents of Co, Ca, Zn, and Cr in Phalaris arundinacea. Phragmites australis contained the lowest amounts of most elements. Concentrations of Co, Cr, Fe, and Mn in all species studied and Ni in all except for Phragmites australis were higher than natural for hydrophytes. The leaves/sediment ratio was more than unity for all alkali metals as well as for Cu and Mn in Phragmites australis; Cr, Co, and Zn in Phalaris arundinacea; Cr and Mn in S. erectum; and Cr in G. maxima. High enrichment factors and high levels of toxic metals in the species studied indicated a special ability of these plants to absorb and store certain non-essential metals and, consequently, their potential for phytoremediation of contaminated aquatic ecosystems.