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Glass manufacturing operations lead to an increasing number of abandoned slag heaps contaminated with metallic trace elements (MTE). However, the relative influence of edaphic factors on the biodiversity of glasswork wastelands is still poorly understood although closely related to sustainable land management practices. Therefore, the objectives of this research were to provide new insights into glasswork wastelands through the investigation of (i) Orthoptera, diurnal Lepidoptera, plant communities, and (ii) abiotic parameters in the topsoils. To that end, biodiversity indices were computed from ecological inventories performed on the herbaceous layer. In addition, soil samples were taken from the topsoil layer (0-10 cm) to assess agronomic properties, actually (CEC-exchangeable) and potentially bioavailable MTE fractions (DTPA-extractable) and pseudo-total MTE contents. On the one hand, the studied site was able to support a substantially higher than excepted biodiversity with orthopteran assemblages similar to grasslands and a diurnal Lepidoptera diversity comparable to urban parks. We also noted a positive influence of plant richness on the diurnal Lepidoptera community structure. On the other hand, topsoil analysis revealed a severe Pb contamination (1800-3100 mg kg -1 ) and a high potentially bioavailable Pb fraction (800-1300 mg kg -1 ). However, CEC-exchangeable MTE concentrations were all below the analytical quantification limits. Moreover, the site was characterized by a medium soil fertility. From these results, Pb contamination does not appear to be a primary limiting factor for the establishment of these communities. We assume that glasswork wasteland ecosytems are more affected by soil fertility or land management practices. To conclude, these sites are able to provide biodiversity ecosystem services, acting as wildlife sanctuaries for Orthoptera and diurnal Lepidoptera, and strategic metals by phytoextraction in a circular economy model. Thus, wasteland management practices should consider the local-scale drivers of biodiversity in order to reach at least the zero net loss of biodiversity., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Sustainable solutions aiming at limiting Reynoutria japonica invasion consist of frequent removal of its aerial biomass. The aims of this study were to measure the accumulation of metallic trace elements (MTE) in R. japonica, and to assess the eco-toxicological risk related to the valorization of the produced biomass. R. japonica fragmented rhizomes were regenerated in pots for 41 days on a control soil (CTL) or a moderately MTE-contaminated soil (POL, 3.6 mg Cd kg -1 DM). Growth traits were recorded, as well as MTE bioconcentration (BCF) and translocation factors (TF) from soil to plant organs. Whatever the MTE and plant organs, BCF remained below one (mean Cd-BCF for stem and leaf: 0.07 and 0.29 for CTL and POL, respectively), conversely to TF (until 2.2 for Cd and Ni in POL soil). When grown on the POL soil, R. japonica stem and leaf Cd content was close to the EU maximum regulatory limit for organic amendments or animal feed. Model simulations suggested that liver and kidney Cd concentrations would exceed the regulatory limit in food when adult cattle or sheep constantly ingest R. japonica grown on the POL soil over 200 to 800 days. The results of the present study will be useful to help managers in selecting efficient and safe solutions for the control of R. japonica invasion., (© 2022. The Author(s).)

Dark septate endophytes (DSEs) can improve plant stress tolerance by promoting growth and affecting element accumulation. Due to its ability to accumulate high Cd, Zn, and Ni concentrations in its shoots, Noccaea caerulescens is considered a promising candidate for phytoextraction in the field. However, the ability of DSEs to improve trace element (TE) phytoextraction with N. caerulescens has not yet been studied. The aim of this study was therefore to determine the ability of five DSE strains, previously isolated from poplar roots collected at different TE-contaminated sites, to improve plant development, mineral nutrient status, and metal accumulation by N. caerulescens during a pot experiment using two soils differing in their level of TE contamination. Microscopic observations revealed that the tested DSE strains effectively colonised the roots of N. caerulescens. In the highly contaminated (HC) soil, a threefold increase in root biomass was found in plants inoculated with the Leptodontidium sp. Pr30 strain compared to that in the non-inoculated condition; however, the plant nutrient status was not affected. In contrast, the two strains Phialophora mustea Pr27 and Leptodontidium sp. Me07 had positive effects on the mineral nutrient status of plants without significantly modifying their biomass. Compared to non-inoculated plants cultivated on HC soil, Pr27- and Pr30-inoculated plants extracted more Zn (+ 30%) and Cd (+ 90%), respectively. In conclusion, we demonstrated that the responses of N. caerulescens to DSE inoculation ranged from neutral to beneficial and we identified two strains (i.e. Leptodontidium sp. (Pr30) and Phialophora mustea (Pr27)) isolated from poplar that appeared promising as they increased the amounts of Zn and Cd extracted by improving plant growth and/or TE accumulation by N. caerulescens. These results generate interest in further characterising the DSEs that naturally colonise N. caerulescens and testing their ability to improve phytoextraction.

Human populations are threatened by chronic exposure to the Cd accumulated in foods after being taken up from soils by crops. To evaluate how phytoextraction with the hyperaccumulator Noccaea caerulescens as an annual crop or as a cover crop could modify the Cd mass balance in French agricultural soils, we simulated this process according to two scenarios. If current practices are maintained (first scenario), the average soil Cd content will increase by 2.9% after a century. If Cd content in P fertilizers is limited according to the European regulation project (second scenario), the decrease will be of about 4%. A phytoextraction crop with a 10 t dry matter (DM) ha -1 yield every 25 years would bring down the soil Cd content from 0.31 mg kg -1 to around 0.11 mg kg -1 . However, this scenario is relatively unrealistic, because high dry matter yield is unlikely and the cost of the process is elevated. Phytoextraction as a cover crop every four to five years would decrease the soil Cd content more quickly. This requires a 2.5 t DM ha -1 yield, which appears realistic. This cover crop phytoextraction would be cheaper. It would need annual sowing of 4 million ha and the production of around 10 million t of dry biomass. To meet such a requirement, any breeding of the hyperaccumulator should favour traits allowing a 3-4 month cultivation period in the autumn. Processes also have to be developed to recover energy, metal or beneficial compounds from the biomass produced by phytoextraction., (Copyright © 2018 Elsevier B.V. All rights reserved.)

To initiate the creation of phytoextraction cultivars, plants were selected from 60 populations of N. caerulescens for their high shoot biomass or Cd, Ni, and Zn concentrations. They were self-pollinated, and the selection and fixation were continued for three generations in greenhouse conditions. Selected plants showed a potential to produce 5-10 t dry matter ha -1 , which is required to decontaminate soils which have been moderately contaminated with Cd. However, the high biomass genotypes could not be fixed, probably both because of their complexity and to the sensitivity of this trait to environmental conditions, and plant density in particular. The selection led to an improvement to the Cd and Zn accumulation capacities of the plants, yet caused a decrease in their Ni accumulation. This is most likely due to a decline in Ni availability in soil, rather than to a deleterious effect of inbreeding. Metal accumulation appeared to be more heritable than biomass production and fixation for the former trait should be quicker than for the latter. The accumulation capacities of the selected plants permitted offtakes representing around 25% of the soil Cd in a single cropping. This potential has to be confirmed in field conditions.

Human populations are threatened by chronic exposure to the Cd accumulated in foods after being taken up from soils by crops. To decide whether and to what extent it is necessary to reduce the Cd content in cultivated soils, one needs to understand and predict its evolution. We therefore simulated the Cd mass balance in the soils under annual crops in France and in its 22 regions for the next century, following six scenarios of agricultural practices or regulatory conditions. If current cultivation practices are maintained, the average Cd content would increase by about 15% after a century, due to the input of Cd with P fertilizer applications. This represents around 85% of the soil Cd inputs and is nearly twice the Cd output caused by leaching and crop offtake. These results conflict with those recently obtained at the European level, due to three factors: the higher rate of P application in France than in Europe, a higher Cd content in the P fertilizers applied in France and a lower Cd leaching in French soils. Strict application of the good practices for P fertilization would stabilize the future soil Cd content at its present level. Assuming the current excessive P fertilization, the enforcement of a regulation limiting Cd content in the P fertilizers, as proposed by the European Union, would lead to a lesser increase in soil Cd, by 1.6% to 3.9% after a century. The combination of P fertilization good practices and Cd content limitation in P fertilizers would lead to a decrease in soil Cd content of between 3.0% to 5.2%. Organic agriculture would lead to an evolution of soil Cd content similar to that of conventional agriculture applying good practices. The accuracy of the mass balances could be ameliorated by a better assessment of Cd leaching., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Co-phytoremediation of both trace elements and polycyclic aromatic hydrocarbons (PAH) is an emerging technique to treat multi-contaminated soils. In this study, root morphological and structural features of the heavy metal hyperaccumulator Noccaea caerulescens, exposed to a model PAH phenanthrene (PHE) in combination with cadmium (Cd), were observed. In vitro cultivated seedlings were exposed to 2 mM of PHE and/or 5 μM of Cd for 1 week. Co-phytoremediation effectiveness appeared restricted because of a serious inhibition (about 40%) of root and shoot biomass production in presence of PHE, while Cd had no significant adverse effect on these parameters. The most striking effects of PHE on roots were a decreased average root diameter, the inhibition of cell and root hair elongation and the promotion of lateral root formation. Moreover, endodermal cells with suberin lamellae appeared closer to the root apex when exposed to PHE compared to control and Cd treatments, possibly due to modified lateral root formation. The stage with well-developed suberin lamellae was not influenced by PHE whereas peri-endodermal layer development was impaired in PHE-treated plants. Many of these symptoms were similar to a water-deficit response. These morphological and structural root modifications in response to PHE exposition might in turn limit Cd phytoextraction by N. caerulescens in co-contaminated soils.

One fundamental characteristic distinguishing urban soils from natural soils is the presence of technic materials or artefacts underlining the influence of human activity. These technic materials have different nature (organic or inorganic) and origins. They contribute to the enrichment of the soil solution by metallic trace elements. The present study aims to determine the effect of physical alteration of the technic coarse fraction on the bioavailability of metallic trace elements in urban Technosols. In general, results show that physical alteration increases the metallic trace elements water extractible concentrations of technic materials. The ability of lettuce to accumulate metallic trace elements, even at low concentrations, underlines the capacity of technic materials to contaminate the anthropised soil solution by bioavailable metals. The highest metal levels, accumulated by the various organs of the lettuce (leaves and roots), were measured in plants grown in presence of metallic particles mixtures. This indicates that the majority of metallic trace elements released by this technic constituent is bioavailable and explains the low plant biomass obtained. The abundant part of metallic trace elements released by the other technic constituents (building materials, bones, wood, plastic and fabric-paper) remains less bioavailable. Under anthropised soil conditions, technic materials have a significant effect on the metallic trace elements behavior. They impact the flow of these metallic elements in Technosols, which can increase their bioavailability and, therefore, the contamination of the food chain., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Phytoremediation, given the right choice of plant, may be theoretically applicable to multi-contamination. Laboratory and some field trials have proven successful, but this ideal technique is in all cases dependent on plant growth ability on (generally) low-fertility soil or media. While contaminant concentration has often been proposed as an explanation for plant growth limitation, other factors, commonly occurring in industrial soils, such as salinity, should be considered. The present work highlights the fact that besides contaminants (trace elements and PAH), soil salinity may strongly affect germination and growth of the hyperaccumulator Noccaea caerulescens. Elevated concentrations of nitrate proved highly toxic for seed germination. At the growth stage the salt effect (sulfate) seemed less significant and the limited biomass production observed could be attributed mostly to organic contamination., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

The increasing production of nanomaterials will in turn increase the release of nanosized byproducts to the environment. The aim of this study was to evaluate the behaviour, uptake and ecotoxicity of TiO(2) byproducts in the earthworm Eisenia fetida. Worms were exposed to suspensions containing 0.1, 1 and 10 mg/L of byproducts for 24 h. Size of TiO(2) byproducts showed aggregation of particles up to 700 μm with laser diffraction. Only worms exposed at 10 mg/L showed bioaccumulation of titanium (ICP-AES), increasing expression of metallothionein and superoxide dismutase mRNA (Real-time PCR) and induction of apoptotic activity (Apostain and TUNEL). TiO(2) byproducts did not induce cytotoxicity on cœlomocytes, but a significant decrease of phagocytosis was observed starting from 0.1 mg/L. In conclusion, bioaccumulation of byproducts and their production of reactive oxygen species could be responsible for the alteration of the antioxidant system in worms., (Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.)

Oxidation treatment helps to reduce the polycyclic aromatic hydrocarbon (PAH) load in contaminated soils but it may also have an effect on the soil quality. The impact of permanganate and Fenton oxidation on soil quality is investigated. Soil quality is restricted here to the potential for plant growth. Soil samples were collected from an agricultural field (S1) and a former coking plant (S4). Agricultural soil was spiked with phenanthrene (PHE) and pyrene (PYR) at two concentrations (S2: 700 mg PHE kg(-1), S3: 700 mg PHE kg(-1) and 2100 mg PYR kg(-1)). Soils were treated with both oxidation processes, and analyzed for PAHs and a set of agronomic parameters. A plant germination and growth test was run with rye-grass on treated soils. Results showed that both treatments produced the expected reduction of PAH concentration (from 64% to 97%). Besides, a significant loss of organic C and N, and strong changes in available nutrients were observed. Permanganate treatment increased the specific surface area and the cation exchange capacity in relation to manganese dioxide precipitation, and produced a rise in pH. Fenton oxidation decreased soil pH and increased the water retention capacity. Plant growth was negatively affected by permanganate, related to lower soil permeability and aeration. Both treatments had an effect on soil properties but Fenton oxidation appeared to be more compatible with revegetation.

Thlaspi caerulescens is known to hyperaccumulate high quantities of Cd with Cd concentrations up to 3000 mg kg(-1) in some populations from south of France. However, within these populations, the Cd concentrations can vary widely from plant to plant in a way that appears to be not entirely due to variations in soil Cd. The aim of this work was to investigate the variability in the Cd uptake ability of individual plants within a population and among seedlings grown from seeds from a single plant. Ten populations of T. caerulescens plants were selected from four locations (V: Viviez; SF: Saint Félix-de-Pallières; LB: Le Bleymard; CMA: Col du Mas de l'Air) depending of the extent and soil homogeneity of the site. One population from CMA consisted of the progeny of a single maternal plant. Hundred plants of each population were grown for three months in the same homogeneous and lightly Cd-polluted soil (about 20 mg total Cd kg(-1) dry soil). Cadmium uptake behavior of the plants was monitored by labeling the soil with 109Cd. To allow partial plant destruction, radioanalysis was performed on the largest leaf of each plant as an indicator of the total Cd concentration in plant shoots. Results showed significant differences in biomass production and Cd uptake by T. caerulescens between sites and between populations within sites. We observed a wide intra-population variation in biomass, Cd concentration and total Cd uptake. For these properties, 1 to 5 percents of the plants in each population varied by more than a factor of two from the mean values. The mean Cd uptake by the single-plant population from CMA was more than 40% higher than for the population at large. T. caerulescens would respond to traditional selection methods, which would significantly improve the phytoextraction of Cd.