A global perspective on soil science education at third educational level; knowledge, practice, skills and challenges

The pivotal role of soil as a resource is not fully appreciated by the general public. Improving education in soil science represents a challenge in a world where soil resources are under serious threat. Today’s high school students, the world’s future landowners, agriculturalists, and decision makers, have the potential to change society’s apathy towards soils issues. This research aimed to compare the level of soil education in high and/or secondary schools in forty-three countries worldwide, together comprising 62% of the world's population. Comparisons were made between soil science content discussed in educationally appropriate textbooks via a newly proposed soil information coefficient (SIC). Interviews with teachers were undertaken to better understand how soil science education is implemented in the classroom. Statistical analyses were investigated using clustering. Results showed that gaps in soil science education were most commonly observed in countries where soil science is a non-compulsory or optional subject. Soil science concepts are predominantly a part of geography or environmental science curricula. Consequently, considerable variability in soil science education systems among investigated countries exists. Soil information coefficient‘s outcomes demonstrated that a methodological approach combining textbooks and the use of modern digitally based strategies in the educational process significantly improved soil education performances. Overall, soil science education is under-represented in schools worldwide. Dynamic new approaches are needed to improve pivotal issues such as: i) promoting collaborations and agreements between high school and universities; ii) encouraging workshops and practical exercises such as field activities; and, iii) implementing technology tools. This, in turn, will prepare the next generation to contribute meaningfully towards solving present and future soil problems

Etude des interactions bactéries - phénanthrène - charbon actif en vue de l'élaboration d'une barrière perméable réactive

Permeable Reactive Barrier (PRB) is a new way for the remediation of contaminated groundwater, but up to now Polycyclic Aromatic Hydrocarbons (PAHs) were rarely considered. We investigated PAH - bacteria - materials interactions in order to validate the feasibility of PRB for PAH contamination. PHE Adsorption/desorption kinetics onto different materials, activated carbons (CA), pouzzolane (Pz) and pouzzolane coated with heavy fuel (PzF), were investigated. PHE biodegradation were performed on batch using PAH degrading bacteria and the PRB materials. CA was a good media for PRB process : Phenanthrene sorption capacity is 100 to 10000 fold higher than PzF and Pz. Phenanthrene mineralization with CA was higher than without material. Bacterial properties affected PHE biodegradation. Biofilm production improved PHE biodegradation by PAH degrading bacteria. Column studies showed that inoculation of the column improved its efficiency : adsorbed PHE degradation and increased retardation of PHE.Les Barrières Perméables Réactives constituent une voie nouvelle de traitement des aquifères contaminés. Les interactions bactéries - HAP - matériaux ont été étudiées en vue d'évaluer la faisabilité d'une BPR dans le cas d'une contamination par des HAP en testant trois matériaux, charbon actif (CA) et pouzzolane recouvertes (PzF) ou non (Pz) de fioul lourd. Des expériences d'adsorption/désorption du phénanthrène (PHE) en batch ont montré que CA présentait une capacité d'adsorption 100 à 10000 fois plus importante que PzF et Pz. La biodégradation de PHE en présence de CA est plus importante par rapport à des essais sans matériaux. Les propriétés physiologiques des bactéries affectent leur capacité à dégrader le PHE adsorbé. La formation de biofilm accentue la dégradation de PHE en présence de CA. Lors d'essais en colonne, l'inoculation par une souche dégradant les HAP améliore son efficacité : dégradation de PHE adsorbés sur CA et augmentation du retard sur le temps de sortie de PHE

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Etude des interactions bactéries - phénanthrène - charbon actif en vue de l'élaboration d'une barrière perméable réactive

Les Barrières Perméables Réactives constituent une voie nouvelle de traitement des aquifères contaminés. Les interactions bactéries - HAP - matériaux ont été étudiées en vue d'évaluer la faisabilité d'une BPR dans le cas d'une contamination par des HAP en testant trois matériaux, charbon actif (CA) et pouzzolane recouvertes (PzF) ou non (Pz) de fioul lourd. Des expériences d'adsorption/désorption du phénanthrène (PHE) en batch ont montré que CA présentait une capacité d'adsorption 100 à 10000 fois plus importante que PzF et Pz. La biodégradation de PHE en présence de CA est plus importante par rapport à des essais sans matériaux. Les propriétés physiologiques des bactéries affectent leur capacité à dégrader le PHE adsorbé. La formation de biofilm accentue la dégradation de PHE en présence de CA. Lors d'essais en colonne, l'inoculation par une souche dégradant les HAP améliore son efficacité : dégradation de PHE adsorbés sur CA et augmentation du retard sur le temps de sortie de PHE.Permeable Reactive Barrier (PRB) is a new way for the remediation of contaminated groundwater, but up to now Polycyclic Aromatic Hydrocarbons (PAHs) were rarely considered. We investigated PAH - bacteria - materials interactions in order to validate the feasibility of PRB for PAH contamination. PHE Adsorption/desorption kinetics onto different materials, activated carbons (CA), pouzzolane (Pz) and pouzzolane coated with heavy fuel (PzF), were investigated. PHE biodegradation were performed on batch using PAH degrading bacteria and the PRB materials. CA was a good media for PRB process : Phenanthrene sorption capacity is 100 to 10000 fold higher than PzF and Pz. Phenanthrene mineralization with CA was higher than without material. Bacterial properties affected PHE biodegradation. Biofilm production improved PHE biodegradation by PAH degrading bacteria. Column studies showed that inoculation of the column improved its efficiency : adsorbed PHE degradation and increased retardation of PHE.NANCY1-SCD Sciences & Techniques (545782101) / SudocSudocFranceF

Are endophytes essential partners for plants and what are the prospects for metal phytoremediation?

International audienceAims: Phytoremediation of soil contaminated by trace elements is a technology using plants and microorganisms to sequester, inactivate, or extract contaminants from the soil. The assemblage formed by the partnership between plants and microorganisms is referred to as the plant holobiont concept. Among holobiont microorganisms, endophytes are associated with the plant at its earliest growth stage and are localized inside plant tissues. While plant tissues shelter endophytic microbial communities, mutualistic endophytes have shown a potential for plant growth promotion that will deeply and durably benefit the plant holobiont. In this review, we describe the state-of-the-art knowledge of the endophytes’ role in plant growth promotion and the prospects for phytoremediation technologies.Results: Mutualistic symbionts have been demonstrated to improve plant growth, germination and yield. Indeed, they improve plant nutrition, increase plant resistance to bio-aggressors and stimulate plant metabolite productions. Research has shown that endophytes improve plant performance especially under extreme conditions such as drought, nitrogen deficiency, salinity and exposition to metal phytotoxicity. Endophyte inoculation has shown potential for plant growth promotion and has increased metal translocation in hyperaccumulator shoots by mitigating stresses from contaminated and naturally metal-rich soils.Conclusions: Endophytes have demonstrated their potential to enhance the plant’s physiological status under metallic stress, the growth of both roots and shoots, as well as increasing metal uptake in the shoot biomass of a wide diversity of hyperaccumulating plants. Endophyte-assisted phytoremediation is a promising technology for the remediation of polluted or naturally metal-rich soils

Impact of phenanthrene on primary metabolite profiling in root exudates and maize mucilage

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Répertoire de législation, jurisprudence et style des huissiers, par P. Leglize aîné,...

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Protective role of fine silts for PAH in a former industrial soil

International audienceAn original combined organic geochemistry and soil science approach was used to elucidate PAH availability controlling factors in a multi-contaminated industrial soil. Water granulodensimetric fractionation was applied to obtain five water-stable material fractions. These were characterized by elemental, molecular and mineral analysis, and microscopic observations. Among the different fractions, fine silts distinguished themselves by higher carbon and nitrogen contents, lower C/N ratio, an enrichment in total PAH and especially high molecular weight compounds, a coal tar signature and the lowest PAH availability. This fine silt fraction seemed to play a protective role for PAH that might be explained by its size and/or its specific reactivity. The mineral phases present in this fraction were proposed to explain the protection of organic matter. This led to a specific molecular signature of OM, having higher sorption properties both processes (sorption and mineral-bound protection) resulting in a lower PAH availability. (C) 2013 Elsevier Ltd. All rights reserved

Does fresh organic matter addition to an industrial soil have an impact on soil structure and on PAH concentration, repartition and availability?

A simulation of 10 years of maize culture was performed by incubation of industrial soilhighly contaminated by polycyclic aromatic hydrocarbons (PAH) and containing exclusivelyanthropogenic organic matter (OM) mixed with maize residue. The aim was to evaluate theimpact of the fresh OM incorporation on the soil structure and consequently on thecontaminants repartition, concentration and availability. Water granulodensimetricfractionation was carried out to isolate five water stable material fractions (coarse and finesands, coarse and fine silts and clays). The evolution of the added maize repartition in thesefractions was followed using δ13C. Total and available PAH content in the bulk soil as well asin the different fractions were determined by solvent and Tenax® resin extractionrespectively. The monitoring of soil structure showed an aggregation process in the amendedsoil after 3 months of incubation probably due to the promoting of microbial activity. Amongthe different fractions, fine silts distinguished themselves by enrichment in total organiccarbon and in δ13C due to the added carbon. However, the results showed no significantimpact on pollution, which remained stable in terms of concentration, distribution andavailability. This experiment suggests that a culture on this soil wouldn’t mobilize thepollution

Morphological and physiological responses of maize (Zea mays) exposed to sand contaminated by phenanthrene.

Phytoremediation is promising, but depends on clearly understanding contaminants' impact on plant functioning. We therefore focused on the impact of polycyclic aromatic hydrocarbons (PAH) on cultivated plants and understanding the impact of phenanthrene (PHE) on maize functioning (Zea mays). Cultivation was conducted under controlled conditions on artificially contaminated sand with PHE levels increasing from 50 to 750 mg PHE kg(-1). After four weeks, plants exposed to levels above 50 mg PHE kg(-1) presented decreased biomasses and reduced photosynthetic activity. These modifications were associated with higher biomass allocations to roots and lower ones to stems. The leaf biomass proportion was similar, with thinner blades than controls. PHE-exposed plant showed modified root architecture, with fewer roots of 0.2 and 0.4 mm in diameter. Leaves were potassium-deplete, but calcium, phosphorus, magnesium and zinc-enriched. Their content in nitrogen, iron, sulfur and manganese was unaffected. These responses resembled those of water-stress, although water contents in plant organs were not affected by PHE and water supply was not limited. They also indicated a possible perturbation of both nutritional functioning and photosynthesis