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Graphical abstract The ability of tobacco (Nicotiana tabacum L. cv. Badischer Geudertheimer) for phytomanaging and remediating soil ecological functions at a contaminated site was assessed with a potted soil series made by fading an uncontaminated sandy soil with a contaminated sandy soil from the Borifer brownfield site, Bordeaux, SW France, at the 0%, 25%, 50%, 75%, and 100% addition rates. Activities of sandblasting and painting with metal-based paints occurred for decades at this urban brownfield, polluting the soil with metal(loid)s and organic contaminants, e.g., polycyclic aromatic hydrocarbons, in addition to past backfilling. Total topsoil metal(loid)s (e.g., 54,700 mg Zn and 5060 mg Cu kg−1) exceeded by seven- to tenfold the background values for French sandy soils, but the soil pH was 7.9, and overall, the 1M NH4NO3 extractable soil fractions of metals were relatively low. Leaf area, water content of shoots, and total chlorophyll (Chl) progressively decreased with the soil contamination, but the Chl fluorescence remained constant near its optimum value. Foliar Cu and Zn concentrations varied from 17.8 ± 4.2 (0%) to 27 ± 5 mg Cu kg−1 (100%) and from 60 ± 15 (0%) to 454 ± 53 mg Zn kg−1 (100%), respectively. Foliar Cd concentration peaked up to 1.74 ± 0.09 mg Cd kg−1, and its bioconcentration factor had the highest value (0.2) among those of the metal(loid)s. Few nutrient concentrations in the aboveground plant parts decreased with the soil contamination, e.g., foliar P concentration from 5972 ± 1026 (0%) to 2861 ± 334 mg kg−1 (100%). Vulnerability to drought-induced embolism (P50) did not differ for the tobacco stems across the soil series, whereas their hydraulic efficiency (Ks) declined significantly with increasing soil contamination. Overall, this tobacco cultivar grew relatively well even in the Borifer soil (100%), keeping its photosynthetic system healthy under stress, and contaminant exposure did not increase the vulnerability of the vascular system to drought. This tobacco had a relevant potential to annually phytoextract a part of the bioavailable soil Zn and Cd, i.e., shoot removals representing here 8.8% for Zn and 43.3% for Cd of their 1M NH4NO3 extractable amount in the potted Borifer soil. Supplementary Information The online version contains supplementary material available at 10.1007/s11356-021-16411-y.

The extreme characteristics of mine tailings generally prohibit microbial processes and natural plant growth. Consequently, vast and numerous tailings sites remain barren for decades and highly susceptible to windblown dust and water erosion. Amendment-assisted phytostabilization is a cost-effective and ecologically productive approach to mitigate the potential transport of residual metals. Due to the contrasting and complementary characteristics of biosolids (BS) and biochar (BC), co-application might be more efficient than individually applied. Studies considering BS and BC co-application for multi-metal tailings revegetation are scarce. As tailings revegetation is a multidimensional issue, clearly notable demand exists for a study that provides a comprehensive understanding on the co-application impact on interrelated properties of physicochemical, biological, mineral nitrogen availability, metal immobilization, water-soil interactions, and impacts on plant cultivation and biomass production. This 8-month greenhouse study aimed at investigating the efficacy of co-application strategies targeting BS and carbon-rich amendments (BC or humic substances (HS)) to phytomanage a slightly alkaline Pb/Zn/Cu tailings with bioenergy crops (poplar, willow, and miscanthus). A complementary assessment linking revegetation effectiveness to ecosystem services (ES) provision was also included. Owing to their rich nutrient and organic matter contents, BS had the most pronounced influence on most of the measured properties including physicochemical, enzyme activities, NH

The INTENSE project, supported by the EU Era-Net Facce Surplus, aimed at increasing crop production on marginal land, including those with contaminated soils. A field trial was set up at a former wood preservation site to phytomanage a Cu/PAH-contaminated sandy soil. The novelty was to assess the influence of five organic amendments differing in their composition and production process, i.e. solid fractions before and after biodigestion of pig manure, compost and compost pellets (produced from spent mushroom substrate, biogas digestate and straw), and greenwaste compost, on Cu availability, soil properties, nutrient supply, and plant growth. Organic amendments were incorporated into the soil at 2.3% and 5% soil w/w. Total soil Cu varied from 179 to 1520 mg kg

Uptake of seven organic contaminants including bisphenol A, estriol, 2,4-dinitrotoluene, N,N-diethyl-meta-toluamide (DEET), carbamazepine, acetaminophen, and lincomycin by tomato (Solanum lycopersicum L.), corn (Zea mays L.), and wheat (Triticum aestivum L.) was measured. The plants were grown in a growth chamber under recommended conditions and dosed by these chemicals for 19 days. The plant samples (stem transpiration stream) and solution in the exposure media were taken to measure transpiration stream concentration factor (TSCF). The plant samples were analyzed by a freeze-thaw centrifugation technique followed by high performance liquid chromatography-tandem mass spectrometry detection. Measured average TSCF values were used to test a neural network (NN) model previously developed for predicting plant uptake based on physicochemical properties. The results indicated that moderately hydrophobic compounds including carbamazepine and lincomycin have average TSCF values of 0.43 and 0.79, respectively. The average uptake of DEET, estriol, acetaminophen, and bisphenol A was also measured as 0.34, 0.29, 0.22, and 0.1, respectively. The 2,4-dinitrotoluene was not detected in the stem transpiration stream and it was shown to degrade in the root zone. Based on these results together with plant physiology measurements, we concluded that physicochemical properties of the chemicals did predict uptake, however, the role of other factors should be considered in the prediction of TSCF. While NN model could predict TSCF based on physicochemical properties with acceptable accuracies (mean squared error less than 0.25), the results for 2,4-dinitrotoluene and other compounds confirm the needs for considering other parameters related to both chemicals (stability) and plant species (role of lipids, lignin, and cellulose).

Historical hard-rock mine activities have resulted in nearly half a million mining-impacted sites scattered around the US. Compared to conventional remediation, (aided) phytostabilization is generally cost-effective and ecologically productive approach, particularly for large-scale sites. Native species act to maintain higher local biodiversity, providing a foundation for natural ecological succession. Due to heterogeneity of mine waste, revegetation strategies are inconsistent in approach, and to avoid failure scenarios, greenhouse screening studies can identify candidate plants and amendment strategies before scaling up. This greenhouse study aimed to concurrently screen a variety of native species for their potential to revegetate Cu/Pb/Zn mine tailings and develop a high throughput and non-destructive approach utilizing computer vision and image-based phenotyping technologies to quantify plant responses. A total number of 34 species were screened in this study, which included: 5 trees, 8 grasses, and 21 forbs and legumes. Most of the species tested were Missouri native and prairie species. Plants were non-destructively imaged, and 15 shape and color phenotypic attributes were extracted utilizing computer vision techniques of PlantCV. Compared to reference soil, all species tested were negatively impacted by the tailings' characteristics, with lowest tolerance generally observed in tree species. However, significant improvement in plant growth and tolerance generally observed with biosolids addition with biomass surpassing reference soil for most legumes. Accumulation of Cu, Pb, and Zn was below Domestic Animal Toxicity Limits in most species. Statistically robust differences in species responses were observed using phenotypic data, such as area, height, width, color, and 9 other morphological attributes. Correlations with destructive data indicated that area displayed the greatest positive correlation with biomass and color the greatest negative correlation with shoot metals. Computer visualization greatly increased the phenotypic data and offers a breakthrough in rapid, high throughput data collection to project site-specific phytostabilization strategies to efficiently restore mine-impacted sites.

In situ stabilization of Cd, Pb, and Zn in an Austrian agricultural soil contaminated by atmospheric depositions from a smelter plant was assessed with a pine bark chip-derived biochar, alone and in combination with either compost or iron grit. Biochar amendment was also trialed in an uncontaminated soil to detect any detrimental effect. The pot experiment consisted in ten soil treatments (% w/w): untreated contaminated soil (Unt); Unt soil amended with biochar alone (1%: B1; 2.5%: B2.5) and in combination: B1 and B2.5 + 5% compost (B1C and B2.5C), B1 and B2.5 + 1% iron grit (B1Z and B2.5Z); uncontaminated soil (Ctrl); Ctrl soil amended with 1 or 2.5% biochar (CtrlB1, CtrlB2.5). After a 3-month reaction period, the soil pore water (SPW) was sampled in potted soils and dwarf beans were grown for a 2-week period. The SPW Cd, Pb, and Zn concentrations decreased in all amended-contaminated soils. The biochar effects increased with its addition rate and its combination with either compost or iron grit. Shoot Cd and Zn removals by beans were reduced and shoot Cd, Pb, and Zn concentrations decreased to common values in all amended soils except the B1 soil. Decreases in the SPW Cd/Pb/Zn concentrations did not improve the root and shoot yields of plants as compared to the Ctrl soil.

International audience; Brownfield surface is expanding in Europe, but as often abandoned or underused, these areas become refuge for microbial, faunal and floral biodiversity. However, brownfield sites are generally contaminated, likely posing severe environmental risks. At a former wood preservation site contaminated with Cu, we evaluated the efficiency of compost and dolomitic limestone incorporation into the soil, followed by revegetation with Cu-tolerant grassy species, as a phytomanagement option to increase vegetation cover and plant diversity while reducing pollutant linkages. 7 years of phytomanagement enhanced natural revegetation through the improvement of soil physicochemical properties, particularly with compost-based amendments. The compost incorporation increased soil Cu solubility; however, no increment in Cu availability and a reduction in Cu-induced phytotoxicity were observed with the compost. The improved soil nutrient availability and the soil phytotoxicity mitigation in compost-amended soils facilitated over the 7 years the growth of beneficial plant colonists, including leguminous species, which can potentially promote essential soil functions. Soil treatments did not affect Cu uptake and translocation by plants and shoot Cu levels indicated no risk for the food chain. Overall, a long-term phytomanagement combining an initial amendment of compost and dolomitic limestone with the cultivation of Cu-tolerant grassy populations can ameliorate such Cu-contaminated soils, by mitigating risks induced by Cu excess, ultimately allowing the development of a meadow that can provide ecological and economic benefits in terms of ecosystem services.Agrostis capillaris; Agrostis gigantea; Metal pollution; Organic amendments; Phytotoxicity; Phytoremediation

Mining activities have left a legacy of metals containing tailings impoundments. After mine closure, reclamation of mine wastes can be achieved by restoration of a vegetation cover. This study investigated the impact of biochar (BC), biosolids (BS), humic substances (HS), and mycorrhizal fungi (MF) for improving mine tailings fertility and hydraulic properties, supporting plant establishment, tailings revegetation, and enabling growth of energy crops. We conducted a pot trial by growing willow, poplar, and miscanthus in Pb/Zn/Cu mine tailings untreated or amended with two rates of amendments (low or high input). Biosolids resulted in the most significant changes in tailings properties, neutralizing pH and increasing organic carbon, nutrient concentrations, cation exchange capacity, water retention, and saturated hydraulic conductivity. The greatest increase in energy crops production was also observed in BS treatments enabling the financial viability of mine reclamation. Although BC resulted in significant improvements in tailings fertility and hydraulic properties, its impact on biomass was less pronounced, most likely due to lower N and P available concentrations. Increases in willow and miscanthus biomass were observed in HS and MF treatments in spite of their lower nutrient content. A pot experiment is underway to assess synergistic effects of combining BS with BC, HS, or MF.

International audience; Four macrophytes commonly used to clean up Cu contaminated effluents, i.e. Arundo donax L., Cyperus eragrostis Lam., Iris pseudacorus L. and Phalaris arundinacea L., were assessed to produce Cu-rich plant biomass intended for ecofriendly catalyst preparation. 7-month-old plants were exposed to a Cu gradient (0.08, 2, 10, 20 and 40 mu M Cu) in batch conditions during 2 months. Copper exposure affected the root DW yield of C. eragrostis from 2 mu M Cu, whereas I. pseudacorus and A. donax developed well. Maximum Cu concentration in the biomass of C. eragrostis and P. arundinacea (i.e. 255 and 838 mg Cu kg(-1) DW respectively) did not reach the 1000 mg Cu kg(-1) DW threshold value needed to produce Cu-ecocatalysts. Copper concentrations in the roots of I. pseudacorus and A. donax exceeded this threshold value at 40 mu M and over 10 mu M Cu, i.e. 1099 and 1809 mg Cu kg(-1) DW, respectively, making them relevant candidates for producing Cu-ecocatalysts.

The rapid increase of the world population constantly demands more food production fromagricultural soils. This causes conflicts, since at the same time strong interest arises on novel bio-based products from agriculture, and newperspectives for rural landscapes with their valuable ecosystemservices. 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. The authors are partners in the FACCE-SURPLUS project INTENSE and gratefully acknowledge financial support by the FACCE-JPI Programme SFS-05-2015: Strategies for crop productivity, stability and quality, grant number 652515.

Gentle remediation options (GRO), i.e. in situ stabilisation, (aided) phytoextraction and (aided) phytostabilisation, were implemented at ten European sites contaminated with trace elements (TE) from various anthropogenic sources: mining, atmospheric fallout, landfill leachates, wood preservatives, dredged-sediments, and dumped wastes. To assess the performance of the GRO options, topsoil was collected from each field trial, potted, and cultivated with lettuce (Lactuca sativa L.) for 48 days. Shoot dry weight (DW) yield, photosynthesis efficiency and major element and TE concentrations in the soil pore water and lettuce shoots were measured.GRO implementation had a limited effect on TE concentrations in the soil pore water, although use of multivariate Co-inertia Analysis revealed a clear amelioration effect in phytomanaged soils. Phytomanagement increased shoot DW yield at all industrial and mine sites, whereas in agricultural soils improvements were produced in one out of five sites. Photosynthesis efficiency was less sensitive than changes in shoot biomass and did not discriminate changes in soil conditions.Based on lettuce shoot DW yield, compost amendment followed by phytoextraction yielded better results than phytostabilisation; moreover shoot ionome data proved that, depending on initial soil conditions, recurrent compost application may be required to maintain crop production with common shoot nutrient concentrations.

International audience; A 2-year pot experiment was carried out to examine the aging effect of biochar (B), alone or combined with iron grit (Z), on Cu stabilization and plant growth in a contaminated soil (964 mg Cu kg− 1) from a wood preservation site. The experiment consisted in 3 soil treatments, either planted with Arundo donax L. (Ad) or Populus nigra L. (Pn): (1) untreated Cu-contaminated soil (Ad, Pn); (2) Unt + 1% (w/w) B (AdB, PnB), and (3) Unt + 1% B + 1% Z (AdBZ, PnBZ). After 22 months, the soil pore water (SPW) was sampled and roots and shoots were harvested. The SPW compositions at 3 and 22 months were compared, showing that the SPW Cu2 + concentration increased again in the PnB and PnBZ soils. Cultivation of A. donax enhanced the dissolved organic matter concentration in the SPW, which decreased its Cu2 + concentration but promoted its total Cu concentration in the Ad and AdB soils. Adding Z with B reduced both SPW Cu2 + and Cu concentrations in the pots cultivated by A. donax and P. nigra as compared to B alone. The B and BZ treatments did not enhance root and shoot yields of both plant species as compared to the Unt soil but their shoot Cu concentrations were in the range of common values.

Rinsing tanks of crop sprayers produce significant volumes of Cu-rich Bordeaux mixture effluents (BME) that can be treated by rhizofiltration in constructed wetlands (CWs). A pilot-scale CW (6 × 600 L) was developed to jointly rhizofiltrate such BME, produce Cu-rich root mat for ecocatalysis and provide usable shoot biomass with low Cu concentration. Three CW units were unplanted control (Ctrl) while three others were planted with Arundo donax L. ( Ad ) in floating racks. The rhizofiltration was carried out during 30 days in the early growing season. Total Cu concentration in the BME was 4.4 mg Cu L −1 . Copper removal peaked within the 48 first hours after Bordeaux mixture addition in the Ad and Ctrl units (i.e. 92 and 81% respectively). The BME Cu concentration met the requirement for indirect discharge of chemical industry effluents (i.e. 0.5 mg Cu L −1 ) at T 48h (0.4 ± 0.2) and T 21days (0.4 ± 0.1) for the Ad and Ctrl units, respectively. At day 30, in the Ad units, Cu concentration remaining in the water and distributed between A. donax roots, shoots was respectively 3.5, 33 and 0.5% of the initial Cu input. In the Ctrl units, Cu remaining in water was low (7%) and Cu removal (93%) could be partly explained by its immobilization in the Cu-rich biofilm (i.e. 207210 ± 18516 mg Cu kg −1 ) coating the vat wall. Foliar chlorophyll (i.e. a, b and total) and carotenoid contents decreased at day 30 but root and shoot dry weight (DW) yields increased by 23% and 47% per Ad unit, respectively. The shoot Cu concentration remained in the common range (i.e. 3–20 mg Cu kg −1 ) while the root Cu concentration reached 623 ± 140 mg kg −1 allowing 786 mg Cu removal by the root mat. Higher Cu concentration in BME or subsequent repetitions of treatment cycle must be tested to achieve at least 1000 mg Cu kg −1 DW in roots (threshold value for Cu-ecocatalyst) whereas the biofilm role must deserve more attention.

International audience; Two biochars, a green waste compost and iron grit were used, alone and in combination, as amendment to improvesoil properties and in situ stabilize Cu in a contaminated soil (964 mg Cu kg−1) from a wood preservationsite. The pot experiment consisted in 9 soil treatments (% w/w): untreated Cu-contaminated soil (Unt); Unt soilamended respectively with compost (5%, C), iron grit (1%, Z), pine bark-derived biochar (1%, PB), poultry-manure-derived biochar (1%, AB), PB or AB + C (5%, PBC and ABC), and PB or AB + Z (1%, PBZ and ABZ). After a3-month reaction period, the soil pore water (SPW) was sampled in potted soils and dwarf beans were grownfor a 2-week period. In the SPW, all amendments decreased the Cu2+ concentration, but total Cu concentrationincreased in all AB-amended soils due to high dissolved organic matter (DOM) concentration. No treatment improvedroot and shoot DWyields, which even decreased in the ABC and ABZ treatments. The PBZ treatment decreasedtotal Cu concentration in the SPWwhile reducing the gap with common values for root and shoot yieldsof dwarf bean plants. A field trial is underway before any recommendation for the PB-based treatments.

Background and aims Rapeseed ( Brassica napus L.) is a Cd/Zn-accumulator whereas soil conditioners such as biochars may immobilize trace elements. These potentially complementary soil remediation options were trialed, singly and in combination, in a pot experiment with a metal( loid )-contaminated technosol. Methods The technosol [total content in mg kg −1 Zn 6089, Cd 9.4, Cu 110, and Pb 956] was either amended (2% w/w) or not with a poultry manure-derived biochar. Rapeseed was cultivated for both soil treatments during 24 weeks up to harvest under controlled conditions. Results Biochar incorporation into the technosol promoted the As, Cd, Cu, Mo, Ni, Pb and Zn solubility. It decreased foliar B, Cu and Mo concentrations, and Mo concentration in stems, pericarps and seeds. But, it did not impact neither the biomass of aerial rapeseed parts (except a decrease for seeds), nor their C (except a decrease for stems), seed fatty acid, seed starch and soluble sugar contents, and antioxidant capacity in both leaves and seeds. Biochar amendment increased the phytoextraction by aerial plant parts for K, P, and S, reduced it for N, Ca, B, Mo, Ni and Se, whereas it remained steady for Mg, Zn, Fe, Mn, Cu, Cd and Co. Conclusions The biochar incorporation into this technosol did not promote Cd, Cu and Zn phytoextraction by rapeseed and its potential oilseed production, but increased the solubility of several metal( loid )s. Here Zn and Cd concentrations in the soil pore water were decreased by rapeseed, showing the feasibility to strip available soil Zn and Cd in combination with seed production.

International audience; Aided phytostabilization of a barren, alkaline metal(loid)-contaminated technosol developed on steel mill wastes, with high soluble Cr and Mo concentrations, was assessed in a pot experiment using (1) Ni/Cd-tolerant populations of Festuca pratensis Huds. , Holcus lanatus L. , and Plantago lanceolata L. sowed in mixed stand and (2) six soil treatments: untreated soil (UNT), ramial chipped wood (RCW, 500 m3ha−1), composted sewage sludge (CSS, 120 t DW ha−1), UNT soil amended with compost (5% w/w) and either vermiculite (5%, VOM) or iron grit (1%, OMZ), and an uncontaminated soil (CTRL). In the CSS soil, pH and soluble Cr decreased whereas soluble Cu, K, Fe, Mn, Mg, Ni and P increased. The RCW treatment enhanced soluble Fe, Mn, and Mg concentrations. After 15 weeks, shoot DW yield and shoot Cd, Cu, Fe, Mn, Mo, Zn, and Mg removals peaked for F. pratensis grown on the CSS soil, with lowest shoot Cr, Ni and Mo concentrations. Holcus lanatus only grew on the CTRL, UNT, and CSS soils and P. lanceolata on the CTRL soil. Best treatment, F. pratensis grown on the CSS soil, led to a dense grass cover but its shoot Mo concentration exceeded the maximum permitted concentration in forage.

International audience; Biomonitoring complements the physico-chemical analysis of environmental matrices, accounting for the subtle biological changes in organisms affected by exogenous chemicals. Here, the relationships between the concentrations of trace elements (TE) in the soil, soil-pore water and leaves of seven rooted macrophytes (Ranunculus acris L., Phragmites australis (Cav.) Trin. Ex Steud., Carex riparia Ehrh., Lythrum salicaria L., Iris pseudacorus L., Juncus effusus L., and Phalaris arundinacea L.) were investigated along an urban river – the Jalle d’Eysines River, France – with increasing TE contamination in riverbank soils, from its source to its confluence with the Garonne River. Copper, Zn, Cd, Cr, Pb, Ni, Mo and As were considered. Macrophytes were sampled in June 2011, at the peak of the growing season. For five species, a canonical correspondence analysis (CCA) was used to assess correlations between foliar TE concentrations and total TE concentrations in the soil. Along the Jalle d’Eysines River, P. australis and P. arundinacea are relevant biomonitors for soil Mo contamination. P. australis and C. riparia biomonitor soil Cd contamination, while R. acris is a relevant biomonitor of soil Ni contamination. Copper and Mo concentrations in the soil-pore water are monitored by, respectively P. arundinacea and P. australis.

During the past decades a number of field trials with gentle remediation options (GRO) have been established on trace elements (TE) contaminated sites throughout Europe. Each research group selects different methods to assess the remediation success making it difficult to compare efficacy between various sites and treatments. This study aimed at selecting a minimum risk assessment battery combining chemical and ecotoxicological assays for assessing and comparing the effectiveness of GRO implemented in seven European case studies. Two test batteries were pre-selected; a chemical one for quantifying TE exposure in untreated soils and GRO-managed soils and a biological one for characterizing soil functionality and ecotoxicity. Soil samples from field studies representing one of the main GROs (phytoextraction in Belgium, Sweden, Germany and Switzerland, aided phytoextraction in France, and aided phytostabilisation or in situ stabilization/phytoexclusion in Poland, France and Austria) were collected and assessed using the selected test batteries. Extractable TE concentrations generally decreased more significantly in soils managed by in situ stabilisation combined with phytoexclusion, phytostabilisation or phytoextraction than in soils only managed with phytoextraction. Pseudo-total TE concentrations did not change in the phytomanaged sites, except for one case, which was attributed to the dilution by the amendments. Among the single chemical extractions, the NH4NO3- and EDTA-extractions showed most frequently the differences in the extracted TE concentrations between the treated and untreated soils, while the most frequent correlations with the biological responses occurred for NH4NO3, followed by NaNO3-extractable TE. Pseudo-total (aqua regia extractable) concentrations showed weak correlation with the biological responses. Out of the bioindicators (plants, earthworms, and nematodes), dwarf beans, especially through root mass, followed by shoot length, and stress enzyme activities, were the most responsive indicators to the soil treatments. Even though the selective chemical extractions did not always show statistically significant changes in TE extractability, dwarf beans and stress enzymes developed a stronger response to the tested GRO options. Generally, the plant growth decreased with higher extractable TE concentrations in soil, while bean stress enzymes reacted in the opposite way, i.e. increased with increasing TE extractability. It is suggested that a minimum risk assessment battery to compare or monitor the sites phytomanaged by GROs might consist of the NH4NO3-extraction and the dwarf bean Plantox test including the stress enzyme activities. Validation of this assessment battery as a potential indicator of successful remediation should be further implemented for a broader range of soils and long-term treatments.

International audience; A bio-rack system was developed for treating Cu-contaminated freshwaters. Each pilot constructed wetland (CW, 110 dm3) contained 15 perforated vertical pipes filled with a mixture of gravel (diorite; 80%) and perlite (20%) and assembled as a rack. The whole experimental device consisted of 12 CW planted either with Phragmites australis, Phalaris arundinacea or Juncus articulatus, and unplanted as control (in triplicates). All plants were sampled at a Cu-contaminated site. The CWs were filled with a mix of freshwater (30%) from the Jalle d’Eysines River (Bordeaux, France) and tap water (70%). Water was spiked with Cu (2.5 μM, 158.5 μg L−1). Three CW batches were carried out, i.e. in early spring (March, S#1), beginning of the growing season (May, S#2), and peak growing season (June, S#3). The S#3 water was initially acidified to pH 6. For all batches, water was recirculated in the CW during 14 days. Physico-chemical parameters (pH, electrical conductivity, redox potential, BOD5 and Cu2+ concentrations) were measured every three days. Water pH of both S#1 and #2 ranged between 7.8 and 8.5 for all treatments during the experiment. Initial and final total Cu concentrations were analysed for all CWs and batches. Relative Treatment Efficiency Index (RTEI) indicated the plant effect compared to the unplanted CW. Free Cu2+ removal was

Intra-specific variability of root biomass production (RP) of six rooted macrophytes, i.e. Juncus effusus , Phragmites australis , Schoenoplectus lacustris , Typha latifolia , Phalaris arundinacea , and Iris pseudacorus grown from clones, in response to Cu exposure was investigated. Root biomass production varied widely for all these macrophytes in control conditions (0.08 μM) according to the sampling site. Root biomass production of T. latifolia and I. pseudacorus in the 2.5–25 μM Cu range depended on the sampling location but not on the Cu dose in the growth medium. For P. australis , J. effusus , S. lacustris , and P. arundinacea , an intra-specific variability of RP depending on both the sampling location and the Cu-dose was evidenced. This intra-specific variability of RP depending on the sampling location and of Cu-tolerance for these last four species suggests that Cu constitutive tolerance for all rooted macrophytes is not a species-wide trait but it exhibits variability for some species.