Greenhouse gas emissions from a Cu-contaminated soil remediated by in situ stabilization and phytomanaged by a mixed stand of poplar, willows, and false indigo-bush.

Phytomanagement of trace element-contaminated soils can reduce soil toxicity and restore soil ecological functions, including the soil gas exchange with the atmosphere. We studied the emission rate of the greenhouse gases (GHGs) CO2, CH4, and N2O; the potential CH4 oxidation; denitrification enzyme activity (DEA), and glucose mineralization of a Cu-contaminated soil amended with dolomitic limestone and compost, alone or in combination, after a 2-year phytomanagement with a mixed stand of Populus nigra, Salix viminalis, S. caprea, and Amorpha fruticosa. Soil microbial biomass and microbial community composition after analysis of the phospholipid fatty acids (PLFA) profile were determined. Phytomanagement significantly reduced Cu availability and soil toxicity, increased soil microbial biomass and glucose mineralization capacity, changed the composition of soil microbial communities, and increased the CO2 and N2O emission rates and DEA. Despite such increases, microbial communities were evolving toward less GHG emission per unit of microbial biomass than in untreated soils. Overall, the aided phytostabilization option would allow methanotrophic populations to establish in the remediated soils due to decreased soil toxicity and increased nutrient availability.

Aided phytostabilisation reduces metal toxicity, improves soil fertility and enhances microbial activity in Cu-rich mine tailings.

(Aided) phytostabilisation has been proposed as a suitable technique to decrease the environmental risks associated with metal(loid)-enriched mine tailings. Field scale evaluations are needed for demonstrating their effectiveness in the medium- to long-term. A field trial was implemented in spring 2011 in Cu-rich mine tailings in the NW of Spain. The tailings were amended with composted municipal solid wastes and planted with Salix spp., Populus nigra L. or Agrostis capillaris L. cv. Highland. Plant growth, nutritive status and metal accumulation, and soil physico- and bio-chemical properties, were monitored over three years (four years for plant growth). The total bacterial community, α- and ß-Proteobacteria, Actinobacteria and Streptomycetaceae were studied by DGGE of 16s rDNA fragments. Compost amendment improved soil properties such as pH, CEC and fertility, and decreased soil Cu availability, leading to the establishment of a healthy vegetation cover. Both compost-amendment and plant root activity stimulated soil enzyme activities and induced important shifts in the bacterial community structure over time. The woody plant, S. viminalis, and the grassy species, A. capillaris, showed the best results in terms of plant growth and biomass production. The beneficial effects of the phytostabilisation process were maintained at least three years after treatment.

Brownfields to green fields: Realising wider benefits from practical contaminant phytomanagement strategies.

Gentle remediation options (GROs) are risk management strategies or technologies involving plant (phyto-), fungi (myco-), and/or bacteria-based methods that result in a net gain (or at least no gross reduction) in soil function as well as effective risk management. GRO strategies can be customised along contaminant linkages, and can generate a range of wider economic, environmental and societal benefits in contaminated land management (and in brownfields management more widely). The application of GROs as practical on-site remedial solutions is still limited however, particularly in Europe and at trace element (typically metal and metalloid) contaminated sites. This paper discusses challenges to the practical adoption of GROs in contaminated land management, and outlines the decision support tools and best practice guidance developed in the European Commission FP7-funded GREENLAND project aimed at overcoming these challenges. The GREENLAND guidance promotes a refocus from phytoremediation to wider GROs- or phyto-management based approaches which place realisation of wider benefits at the core of site design, and where gentle remediation technologies can be applied as part of integrated, mixed, site risk management solutions or as part of "holding strategies" for vacant sites. The combination of GROs with renewables, both in terms of biomass generation but also with green technologies such as wind and solar power, can provide a range of economic and other benefits and can potentially support the return of low-level contaminated sites to productive usage, while combining GROs with urban design and landscape architecture, and integrating GRO strategies with sustainable urban drainage systems and community gardens/parkland (particularly for health and leisure benefits), has large potential for triggering GRO application and in realising wider benefits in urban and suburban systems. Quantifying these wider benefits and value (above standard economic returns) will be important in leveraging funding for GRO application and soft site end-use more widely at vacant or underutilized sites.

Dieldrin accumulation, distribution in plant parts and phytoextraction potential for several plant species and Cucurbita pepo varieties.

Dieldrin, an organochlorine pesticide (OCP) widely used for crop protection in the second half of the 20th century till the 70's, is worldwide still present in arable soils. It can be transferred to crops, notably cucurbits, depending on plant species and cultivars. Finding strategies to decrease OCP bioavailability in soil is therefore a main concern. Phytomanagement strategies could provide (i) ready-to-use short term solution for maintaining the production of edible plant parts with dieldrin concentrations below the Maximum Residue Limits (MRL) and (ii) long-term solution for dieldrin phytoextraction reducing progressively its bioavailability in the soil. This field study aimed at determining dieldrin accumulation capacities and allocation pattern in 17 non-Cucurbitaceae species and 10 Cucurbita pepo varieties, and assessing the dieldrin phytoextraction potential of these plant species when grown to maturity in a historically dieldrin-contaminated soil. Out of the non-Cucurbitaceae species, vetiver was the only one able to accumulate significant amounts of dieldrin, which mainly remained in its roots. All C. pepo varieties were able to uptake and translocate high dieldrin amounts into the shoots, leading to the highest phytoextraction potential. Despite the intraspecific variability in dieldrin concentration in zucchini plant parts, mainly in the reproductive organs, the phytoextraction capacity for shoots and fruits was high for all tested varieties (147 to 275 µg dieldrin plant-1, corresponding to 5.6 % of the n-heptane extractable soil dieldrin), even for the one with low fruit dieldrin concentration. Both food safety and phytoextraction could be achieved by selecting productive zucchini varieties displaying low dieldrin concentration in fruits and high one in shoots.

Developing principles of sustainability and stakeholder engagement for "gentle" remediation approaches: the European context.

Gentle Remediation Options (GRO) are risk management strategies or techniques for contaminated sites that result in no gross reduction in soil functionality (or a net gain) as well as risk management. Intelligently applied GROs can provide: (a) rapid risk management via pathway control, through containment and stabilisation, coupled with a longer term removal or immobilisation/isolation of the contaminant source term; and (b) a range of additional economic (e.g. biomass generation), social (e.g. leisure and recreation) and environmental (e.g. CO2 sequestration) benefits. In order for these benefits to be optimised or indeed realised, effective stakeholder engagement is required. This paper reviews current sector practice in stakeholder engagement and its importance when implementing GRO and other remediation options. From this, knowledge gaps are identified, and strategies to promote more effective stakeholder engagement during GRO application are outlined. Further work is required on integrating stakeholder engagement strategies into decision support systems and tools for GRO (to raise the profile of the benefits of effective stakeholder engagement and participation, particularly with sector professionals), and developing criteria for the identification of different stakeholder profiles/categories. Demonstrator sites can make a significant contribution to stakeholder engagement via providing evidence on the effectiveness of GRO under varying site contexts and conditions. Effective and sustained engagement strategies however will be required to ensure that site risk is effectively managed over the longer-term, and that full potential benefits of GRO (e.g. CO2 sequestration, economic returns from biomass generation and "leverage" of marginal land, amenity and educational value, ecosystem services) are realised and communicated to stakeholders.

Seed bank of Cu-contaminated topsoils at a wood preservation site: impacts of copper and compost on seed germination.

Is identification of seed bank (SB) species useful for sustainable management of vegetation restoration on Cu-contaminated soils? How does Cu contamination of the soil affect the SB and can incorporating compost into Cu-contaminated soils counter the effects of Cu? The topsoil SB was investigated at seven contaminated sub-sites of a wood preservation site. The germination parameters of the seeds were recorded using three substrates: a washed river sand (Sand), the same sand spiked with CuSO(4) to reach the same Cu concentrations as in the soil pore water (0.3 to 3.2 mg Cu/L) (Cu), and the same Cu-spiked sand amended with compost (CPM). The total number of germinated seeds (NGS) was 1,081. The whole seedling dataset enabled 12 plant species and eight families to be identified in the SB. Species richness and Shannon indexes were low. The addition of Cu in the germination substrate enhanced total NGS at one sub-site and the addition of CPM increased plant diversity at three sub-sites. SB composition varied with the sub-site but did not correlate with total soil Cu or with the Cu concentration in the soil pore water. Three species belonging to the Poaceae family dominated. In terms of total NGS, the dominant species were Portulaca oleracea and Agrostis capillaris. Similarities between SB and established vegetation were low but increased when the soil bulk density was reduced. The Cu-tolerant species P. oleracea and A. capillaris dominated in both the SB and the established vegetation. However, the pattern of SB and established vegetation differed and consequently SB was not a sufficient indicator to predict the future vegetation.

Inter and intraspecific variability of dieldrin accumulation in Cucurbita fruits: New perspectives for food safety and phytomanagement of contaminated soils.

Due to past agricultural practices, it is common to identify arable soils contaminated with persistent and potentially toxic organochlorine pesticides (OCPs). Occurrence of OCPs, including dieldrin, in vegetables can lead to chronic exposure of the consumers. Some market vegetables, particularly the Cucurbitaceae, are known to accumulate high OCP concentrations. Dieldrin concentration in Cucurbita fruits can exceed the Maximal Residue Limit (MRL) resulting in cultivation and sale restrictions for market gardeners. To assess the intra- and interspecific variability of Cucurbitaceae species for low dieldrin concentration in fruits could be a solution. Here, 24 varieties from seven Cucurbitaceae species were cultivated outdoors in large pots, until fruiting, in soils historically contaminated with dieldrin. More than 330 fruits were harvested and analyzed for determining the inter and intraspecific variability of dieldrin accumulation. Significant interspecific differences occurred with mean fruit concentration ranging between 4.2 ± 7.0 and 85.0 ± 19.4 µg dieldrin kg-1 fresh weigh (FW) in watermelons (C. lanatus L.) and cucumbers (C. sativus L.), respectively. Intraspecific differences only occurred for Cucurbita pepo L. with mean concentration ranging between 4.9 ± 1.1 and 70.3 ± 3.6 µg dieldrin kg-1 FW for the varieties Noire maraîchère and Orélia, respectively. For this plant species, the influence of soil concentration, plant exposure time and biomass on fruit dieldrin concentration depended mainly on varieties.

Copper distribution and hydrolase activities in a contaminated soil amended with dolomitic limestone and compost.

Chemical fractionation of copper in bulk soil and its distribution in the particle-size fractions were analyzed in a Cu-contaminated soil (674 ± 122 µg Cu g(-1), up to 1900 µg Cu g(-1) in the clay fraction) sampled from a wood preservation site left untreated and subsequently treated with dolomitic limestone (DL, 0.2% w/w) and compost (CM, 5% w/w), singly and in combination (DL+CM). Soil enzymatic activities of leucine aminopeptidase, cellulase, N-acetyl-ß-glucosaminidase, arylsulfatase, ß-glucosidase, acetate esterase, butyric esterase, and acid phosphatase were determined. Chemical speciation showed that Cu was mostly present in the acid-soluble and reducible fractions in both untreated and treated soils, whereas treatments with DL and CM reduced the soluble and exchangeable Cu fractions, due to Cu precipitation and complexation, and increased Cu bound to soil organic matter. Analysis of the particle-size fractions showed that more than 80% of Cu was in the silt and clay fractions and that treatment with CM increased the concentration of Cu in the sand size fractions. Soil treatment with DL and CM, singly or in combination, increased hydrolase activities, mainly in the clay fraction, with the largest positive effects on N-acetyl-ß-glucosaminidase, leucine aminopeptidase, and ß-glucosidase activities. Overall, results confirm that (1) Cu in contaminated soils is mainly bound to the silt-clay fraction, (2) CM additions change its allocation in the particle-size fractions, and (3) treatments with DL and CM singly and in combination reduce Cu solubility and its inhibitory effects on soil enzyme activities.

Intensify production, transform biomass to energy and novel goods and protect soils in Europe-A vision how to mobilize marginal lands.

The rapid increase of the world population constantly demands more food production from agricultural soils. This causes conflicts, since at the same time strong interest arises on novel bio-based products from agriculture, and new perspectives for rural landscapes with their valuable ecosystem services. Agriculture is in transition to fulfill these demands. In many countries, conventional farming, influenced by post-war food requirements, has largely been transformed into integrated and sustainable farming. However, since it is estimated that agricultural production systems will have to produce food for a global population that might amount to 9.1 billion by 2050 and over 10 billion by the end of the century, we will require an even smarter use of the available land, including fallow and derelict sites. One of the biggest challenges is to reverse non-sustainable management and land degradation. Innovative technologies and principles have to be applied to characterize marginal lands, explore options for remediation and re-establish productivity. With view to the heterogeneity of agricultural lands, it is more than logical to apply specific crop management and production practices according to soil conditions. Cross-fertilizing with conservation agriculture, such a novel approach will provide (1) increased resource use efficiency by producing more with less (ensuring food security), (2) improved product quality, (3) ameliorated nutritional status in food and feed products, (4) increased sustainability, (5) product traceability and (6) minimized negative environmental impacts notably on biodiversity and ecological functions. A sustainable strategy for future agriculture should concentrate on production of food and fodder, before utilizing bulk fractions for emerging bio-based products and convert residual stage products to compost, biochar and bioenergy. The present position paper discusses recent developments to indicate how to unlock the potentials of marginal land.

Microbial community structure and activity in trace element-contaminated soils phytomanaged by Gentle Remediation Options (GRO).

Gentle remediation options (GRO) are based on the combined use of plants, associated microorganisms and soil amendments, which can potentially restore soil functions and quality. We studied the effects of three GRO (aided-phytostabilisation, in situ stabilisation and phytoexclusion, and aided-phytoextraction) on the soil microbial biomass and respiration, the activities of hydrolase enzymes involved in the biogeochemical cycles of C, N, P, and S, and bacterial community structure of trace element contaminated soils (TECS) from six field trials across Europe. Community structure was studied using denaturing gradient gel electrophoresis (DGGE) fingerprinting of Bacteria, α- and ß-Proteobacteria, Actinobacteria and Streptomycetaceae, and sequencing of DGGE bands characteristic of specific treatments. The number of copies of genes involved in ammonia oxidation and denitrification were determined by qPCR. Phytomanagement increased soil microbial biomass at three sites and respiration at the Biogeco site (France). Enzyme activities were consistently higher in treated soils compared to untreated soils at the Biogeco site. At this site, microbial biomass increased from 696 to 2352 mg ATP kg-1 soil, respiration increased from 7.4 to 40.1 mg C-CO2 kg-1 soil d-1, and enzyme activities were 2-11-fold higher in treated soils compared to untreated soil. Phytomanagement induced shifts in the bacterial community structure at both, the total community and functional group levels, and generally increased the number of copies of genes involved in the N cycle (nirK, nirS, nosZ, and amoA). The influence of the main soil physico-chemical properties and trace element availability were assessed and eventual site-specific effects elucidated. Overall, our results demonstrate that phytomanagement of TECS influences soil biological activity in the long term.

Phytostabilization of a metal contaminated sandy soil. I: Influence of compost and/or inorganic metal immobilizing soil amendments on phytotoxicity and plant availability of metals.

In a lysimeter set-up, compost addition to an industrial contaminated soil slightly reduced phytotoxicity to bean seedlings. The "Phytotoxicity Index" (on a scale from 1 to 4) decreased from 3.5 to 2.8. The same treatment also reduced metal accumulation in grasses: mean Zn, Cd and Pb concentrations decreased respectively from 623 to 135, from 6.2 to 1.3 and from 10.7 to <6 mg kg-1 dry weight. When combined with inorganic metal immobilizing amendments, compost had a beneficial effect on plant responses additional to the inorganic amendments alone. Best results were obtained when using compost (C)+cyclonic ashes (CA)+steel shots (SS). The "Phytotoxicity Index" decreased to 1.7, highest diversity of spontaneously colonizing plants occurred, and metal accumulation in grasses reduced to values for uncontaminated soils. Based on the first year evaluation, C+CA+SS showed to be an efficient treatment for amendment assisted phytostabilization of the contaminated Overpelt soil.

Phytostabilization of a metal contaminated sandy soil. II: Influence of compost and/or inorganic metal immobilizing soil amendments on metal leaching.

A lysimeter approach (under natural climatologic conditions) was used to evaluate the effect of four metal immobilizing soil treatments [compost (C), compost+cyclonic ashes (C+CA), compost+cyclonic ashes+steel shots (C+CA+SS)) and cyclonic ashes+steel shots (CA+SS)] on metal leaching through an industrially contaminated soil. All treatments decreased Zn and Cd leaching. Strongest reductions occurred after CA+SS and C+CA+SS treatments (Zn: -99.0% and -99.2% respectively; Cd: -97.2% and -98.3% respectively). Copper and Pb leaching increased after C (17 and >30 times for Cu and Pb respectively) and C+CA treatment (4.4 and >3.7 times for Cu and Pb respectively). C+CA+SS or CA+SS addition did not increase Cu leaching; the effect on Pb leaching was not completely clear. Our results demonstrate that attention should be paid to Cu and Pb leaching when organic matter additions are considered for phytostabilization of metal contaminated soils.

Cadmium availability to wheat in five soil series from the Yonne district, Burgundy, France.

Preliminary results from the French ASPITET programme demonstrated that Cd background levels in agricultural soils can vary greatly (0.02-6.9 mg Cd kg(-1)) depending on parent material and pedogenic processes (Baize, 1997). However, the total Cd content in soil is often not significantly related to the Cd concentration in edible plant parts. A field case study was undertaken across the southern part of the Yonne district, Burgundy, France. This area has various soil series with either low or high geochemical Cd content in the topsoil. Cd availability in soils sampled at 16 sites belonging to five soil series was investigated using single extractions. In addition, shoots (at stem elongation) and grains (at harvest) of field-grown wheat were collected at the same sites and analysed for macronutrients and trace elements. Cd concentrations in grain varied from 0.015 to 0.146 mg Cd kg(-1) DM depending on soil characteristics, soil series, and plant mineral composition. Cd grain concentrations did not reflect total Cd content in the surface soil layer; however, they were correlated with Cd extracted by a 0.1 M calcium nitrate unbuffered solution, and to a lesser extent with either soil pH or CEC. These three parameters may be useful guides to predict Cd in wheat grain harvested in the Yonne district. An inverse relationship was found between Cd and Cu contents in grain. The highest Cd concentrations in wheat grain occurred in plants grown on Aubues soils which had marginal Cu and Zn deficiencies in shoots. In order of Cd accumulation in wheat grain, soil series may be ranked as follows: Domérien < Carixien, Terres Noires < Sols Marron < Aubues.

Evaluation of metal mobility, plant availability and immobilization by chemical agents in a limed-silty soil.

Metal-contaminated soils in the vicinity of industrial sites become of ever-increasing concern. Diagnostic criteria and ecological technologies for soil remediation should be calibrated for various soil conditions; actually, our knowledge of calcareous soil is poor. Silty soils near smelters at Evin (Pas de Calais, France) have been contaminated by non-ferrous metal fallout and regularly limed using foams. Therefore, the mobility, bioavailability, and potential phytotoxicity of Cd, Pb and Zn, were investigated using single soil extractions (i.e. water, 0.1 n Ca(NO(3))(2), and EDTA pH 7), and vegetation experiments, in parallel with a biological test based on (iso)-enzymes in leaves and roots, before and following soil treatment with chemical agents, i.e. Thomas basic slags (TBS), hydrous manganese oxide (HMO), steel shots (ST) and beringite. No visible toxicity symptoms developed on the above-ground parts of ryegrass, tobacco and bean plants grown in potted soil under controlled environmental conditions. Cd, Zn and Pb uptake resulted in high concentrations in the above-ground plant parts, but the enzyme capacities in leaves and roots, and the peroxidase pattern indicated that these metal concentrations were not phytotoxic for beans as test plants. The addition of chemical agents to the soil did not increase biomass production, but treatment with either HMO, ST or beringite markedly decreased the mobility of Cd, Zn and Pb. These agents were proven to be effective in mitigating the Cd uptake by plants. HMO and ST decreased either Pb or Zn uptake by ryegrass. TBS was effective in lowering Pb uptake by the same species. Beringite decreased Cd uptake by beans. If fallout could be restricted, the metal content of food crops in this area should be lowered by soil treatment. However, the differences in Cd uptake between plant species were not suppressed, regardless of the type of agents applied to the soil.

Thallium in French agrosystems--I. Thallium contents in arable soils.

The thallium (Tl) content of the upper horizons of 244 French soils was determined as the first step towards the creation of a reference data bank for total Tl content of arable soils. Forty soil samples were collected in the vicinity of potential anthropogenic sources of Tl, but the remainder came from rural areas. The distribution of Tl concentrations in soils was characterized by a median value of 0.29 mg Tl kg(-1) and a 90th percentile value of 1.54 mg Tl kg(-1). Very high pedogeochemical contents were found (up to 55 mg Tl kg(-1)) but none could be attributed to obvious anthropogenic pollution. Areas of very high Tl concentration belong to an epihercynian transgression zone with a contact between a sedimentary basin and a crystalline massif. This contact is associated with stratified mineralizations (Zn, Pb, F, Sb, Ba, Tl and pyrites). High Tl concentrations were common in limestone, marl or granite derived soils, and the Tl in limestones or marls is probably concentrated in the sulfides contained in these rocks because Tl has a high affinity to S. In granites, Tl may be in the micas and feldspars because Tl+ can replace K+ in these minerals. Silty or clay-silty soils showed the highest concentrations. These granulometric fractions contain the majority of the minerals, which are supposed to be the major hosts of Tl in soils, i.e. clay minerals, oxides and micas. Tl in the soils was positively correlated with Ba, V, Pb, Fe, Ni, Cd, Zn, Co, As and especially Mn. A significant proportion of Tl may be in the Mn oxides: in oxidizing conditions, Tl(III) could enter the Mn oxides by sorption, or Tl(I) could replace K(I) in the oxide.

Thallium in French agrosystems-II. Concentration of thallium in field-grown rape and some other plant species.

The aim of this study was to assess thallium (Tl) uptake into the aerial parts of selected crop species grown on French soils with high Tl content of pedogeochemical origin (0.3-40 mg Tl kg(-1) on a dry wt (DW) basis). Husked wheat and maize grains contained less than 4 microg Tl kg(-1) DW, but rape shoots accumulated Tl with a shoot-soil partition coefficient (PC) > 1, and rape seeds had PC > 3. Tl content of rape seed reached 33 mg Tl kg(-1) DW and higher concentrations in soil corresponded to increased concentrations in rape seeds. It is argued that parent material of the soil and pedogenesis have a considerable effect on Tl accumulation in rape seeds. These results show enhanced phytoavailability of Tl of pedogeochemical origin and prompt questions on the potential for food chain contamination by Tl in rape cattle cakes.

A microbial biosensor to predict bioavailable nickel in soil and its transfer to plants.

Ralstonia eutropha strain AE2515 was constructed and optimised to serve as a whole-cell biosensor for the detection of bioavailable concentrations of Ni2+ and Co2+ in soil samples. Strain AE2515 is a Ralstonia eutropha CH34 derivative containing pMOL1550, in which the cnrYXH regulatory genes are transcriptionally fused to the bioluminescent luxCDABE reporter system. Strain AE2515 was standardised for its specific responses to Co2+ and Ni2+. The detection limits for AE2515 were 0.1 microM Ni2+ and 9 microM Co2+, respectively. The signal to noise (S/N) bioluminescence response and the metal cation concentration could be linearly correlated: for Ni2+ this was applicable within the range 0.1-60 microM, and between 9 and 400 microM for Co2+. The AE2515 biosensor strain was found to be highly selective for nickel and cobalt: no induction was observed with Zn(II), Cd(II), Mn(II), Cu(III) and Cr(VI). In mixed metal solutions, the bioluminescent response always corresponded to the nickel concentrations. Only in the presence of high concentrations of Co2+ (2 mM), the sensitivity to nickel was reduced due to metal toxicity. AE2515 was used to quantify the metal bioavailability in various nickel-enriched soils, which had been treated with additives for in situ metal immobilisation. The data obtained with strain AE2515 confirmed that the bioavailability of nickel was greatly reduced following the treatment of the soils with the additives beringite and steel shots. Furthermore, the data were found to correlate linearly with those on the biological accumulation of Ni2+ in specific parts of important agricultural crops, such as maize and potato. Therefore, the test can be used to assess the potential transfer of nickel to organisms of higher trophic levels, in this case maize and potato plants grown on nickel-enriched soils, and the potential risk of transfer of these elements to the food chain.

Fatty acid composition of tomato leaves as biomarkers of metal-contaminated soils.

The aim of this study was to determine whether fatty acid composition of leaves, cotyledons or roots could be used as an indicator of the bioavailability and of the adverse effects of heavy metals on plants. Tomato seedlings were grown on soils obtained by mixing increasing amounts of a highly metal-contaminated soil with an uncontaminated sandy soil, and the fatty acid composition of plant tissues was analyzed. The fatty acid composition of roots and cotyledons of plants grown on contaminated soils was mostly the same as in the control plants. In contrast, significant changes in the fatty acid composition of primary leaves occurred. Our results clearly indicate a relationship between metal accumulation (Cd, Pb, Zn, and Cu) and the fatty acid composition of primary leaves, with the contribution of 18 C atom fatty acids (as 18:3 fatty acid and precursors) being more closely correlated with the availability of heavy metals in soils.

Arundo donax L., a candidate for phytomanaging water and soils contaminated by trace elements and producing plant-based feedstock. A review.

Plants and associated microorganisms are used to remediate anthropogenic metal(loid) contamination of water, soils and sediments. This review focuses on the potential of Arundo donax L. (Giant reed) for alleviating risks due to soils, water, and sediments contaminated by trace elements (TE), with emphasis on its advantages and limits over macrophytes and perennial grasses used for bioenergy and plant-based feedstock. Arundo donax is relevant to phytomanage TE-contaminated matrices, notably in its native area, as it possesses characteristics of large biomass production even under nutrient and abiotic stresses, fast growth rate, TE tolerance and accumulation mainly in below ground plant parts. Cultivating A. donax on contaminated lands and in constructed wetlands can contribute to increase land availability and limit the food vs. plant-based feedstock controversy. To gain more tools for decision-taking and sustainable management,further researches on A. donax should focus on: interactions between roots, TE exposure, and rhizosphere and endophytic microorganisms; biomass response to (a)biotic factors; sustainable agricultural practices on marginal and contaminated land; integration into local, efficient, energy and biomass conversion chains with concern to biomass quality and production; Life-Cycle Assessment including contaminant behavior, as well as environmental, agricultural and socio-economic benefits and drawbacks.

The effect of long-term Cd and Ni exposure on seed endophytes of Agrostis capillaris and their potential application in phytoremediation of metal-contaminated soils.

We examined whether long-term Cd exposure leads to beneficial changes in the cultivable endophytic bacteria present in the seeds of Agrostis capillaris. Therefore the cultivable seed endophytes of Agrostis capillaris growing on a long-term Cd/Ni-contaminated plot (Cd/Ni seeds) were compared with those originating from a non-contaminated plot (control seeds). We observed plant- and contaminant-dependent effects on the population composition between control and Cd/Ni seeds. Also differences in phenotypic characteristics were found: endophytes from Cd/Ni seeds exhibited more ACC deaminase activity and production of siderophores and IAA, while endophytes from control seeds, very surprisingly, showed more metal tolerance. Finally, the 3 most promising seed endophytes were selected based on their metal tolerance and plant growth promoting potential, and inoculated in Agrostis capillaris seedlings. In case of non-exposed plants, inoculation resulted in a significantly improved plant growth; after inoculation of Cd-exposed plants an increased Cd uptake was achieved without affecting plant growth. This indicates that inoculation of Agrostis with its seed endophytes might be beneficial for its establishment during phytoextraction and phytostabilisation of Cd-contaminated soils.