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International audience; Chlordecone (CLD), was widely applied in banana fields in the French West Indies from 1972 to 1993. The WISORCH model was constructed to assess soil contamination by CLD and estimated that it lasts from 100 to 600 years, depending on leaching intensity and assuming no degradation. However, recent studies demonstrated that CLD is degraded in the environment, hence questioning the reliability of previous estimations. This paper shows how to improve the model and provides insights into the long-term dissipation of CLD. In-situ observations were made in nearly 2545 plots between 2001 and 2020, and 17 plots were sampled at two dates. Results of soil analyses showed an unexpected 4-fold decrease in CLD concentrations in the soil, in contrast to simulations made using the first version of WISORCH at the time. Neither erosion, nor CLD leaching explained these discrepancies. In a top-down modeling approach, these new observations of CLD concentrations led us to implement a new dissipation process in the WISORCH model that corresponds to a DT50 dissipation half-life of 5 years. The new version of the improved model allowed us to update the prediction of the persistence of soil pollution, with soil decontamination estimated for the 2070s. This development calls for re-evaluation of soil pollution status. Further validation of the new version of WISORCH is needed so it can contribute to crop management on contaminated soil.

International audience; The widespread use of pesticides in agriculture during the last several decades has contaminated soils and different Critical Zone (CZ) compartments, defined as the area extended from the top of the vegetation canopy to the groundwater table, and it integrates interactions of the atmosphere, lithosphere, biosphere, and hydrosphere. However, the long-term fate, storage, and transfer dynamics of persistent pesticides in CZ in a changing world remain poorly understood. In the French West Indies, chlordecone (CLD), a toxic organochlorine insecticide, was extensively applied to banana fields to control banana weevil from 1972 to 1993 after which it was banned. Here, to understand CZ trajectories we apply a retrospective observation based on marine sediment core analyses to monitor long-term CLD transfer, fate, and consequences in Guadeloupe and Martinique islands. Both CLD profiles show synchronous chronologies. We hypothesized that the use of glyphosate, a postemergence herbicide, from the late 1990s onward induced CZ modification with an increase in soil erosion and led to the release of the stable CLD stored in the soils of polluted fields. CLD fluxes drastically increased when glyphosate use began, leading to widespread ecosystem contamination. As glyphosate is used globally, ecotoxicological risk management strategies should consider how its application affects persistent pesticide storage in soils, transfer dynamics, and widespread contamination.

International audience; In Guadeloupe, the use between 1972 and 1993 of chlordecone, an organochlorine insecticide, has permanently contaminated the island’s soil, thus contaminating the food chain at its very beginning. There is today a strong societal requirement for an improved mapping of the contaminated zones. Given the extent of the areas to be covered, carrying out soil tests on each plot of the territory would be a long and expensive process. In this article, we explore a method of demarcating polluted areas. The approach adopted consists in carrying out, using surface water analyses, a hydrological delimitation that makes it possible to distinguish contaminated watersheds from uncontaminated ones. The selection of sampling points was based on the spatial analysis of the actual and potential contamination data existing at the beginning of the study. The approach was validated by soil analyses, after having compared the contamination data of the watersheds with the soil contamination data of the plots within them. The study thus made it possible to highlight new contaminated areas and also those at risk of contamination and to identify the plots to be targeted as a priority during future analysis campaigns by State services.

Partie B; International audience; Incidental zinc sulfide nanoparticles (nano-ZnS) are spread on soils through organic waste (OW) recycling. Here we performed soil incubations with synthetic nano-ZnS (3 nm crystallite size), representative of the form found in OW. We used an original set of techniques to reveal the fate of nano-ZnS in two soils with different properties. 68 Zn tracing and nano-DGT were combined during soil incubation to discriminate the available natural Zn from the soil, and the available Zn from the dissolved nano-68 ZnS. This combination was crucial to highlight the dissolution of nano-68 ZnS as of the third day of incubation. Based on the extended X-ray absorption fine structure, we revealed faster dissolution of nano-ZnS in clayey soil (82% within 1 month) than in sandy soil (2% within 1 month). However, the nano-DGT results showed limited availability of Zn released by nano-ZnS dissolution after 1 month in the clayey soil compared with the sandy soil. These results highlighted: (i) the key role of soil properties for nano-ZnS fate, and (ii) fast dissolution of nano-ZnS in clayey soil. Finally, the higher availability of Zn in the sandy soil despite the lower nano-ZnS dissolution rate is counterintuitive. This study demonstrated that, in addition to nanoparticle dissolution, it is also essential to take the availability of released ions into account when studying the fate of nanoparticles in soil.

Gold-mining activities have been demonstrated to result in significant environmental pollution by Hg, Pb, and Mn, causing serious concerns regarding the potential threat to the public health of neighboring populations around the world. The present study focused on heavy-metal contamination in the eggs, blood, feed, soil, and drinking water on chicken farms, duck farms, and free-grazing duck farms located in areas < 25 km and > 25 km away from a gold mine in northern Thailand. In an area < 25 km away, Hg, Pb, and Mn concentrations in the eggs of free-grazing ducks were significantly higher than > 25 km away (p < 0.05). In blood, Hg concentration in free-grazing ducks was also significantly higher than those in an area > 25 km away (p < 0.05). Furthermore, the Pb concentration in the blood of farm ducks was significantly higher than in an area > 25 km away (p < 0.05). The concentration of Cd in drinking water on chicken farms was significantly higher for farms located within 25 km of the gold mine (p < 0.05). Furthermore, a high correlation was shown between the Pb (r2 = 0.84) and Cd (r2 = 0.42) found between drinking water and blood in free-grazing ducks in the area < 25 km away. Therefore, health risk from heavy-metal contamination was inevitably avoided in free-grazing activity near the gold mine. The incremental lifetime cancer risk (ILCR) in the population of both Pb and Cd exceeded the cancer limit (10−4) for all age groups in both areas, which was particularly high in the area < 25 km for chicken-egg consumption, especially among people aged 13–18 and 18–35 years old. Based on these findings, long-term surveillance regarding human and animal health risk must be strictly operated through food chains and an appropriate control plan for poultry businesses roaming around the gold mine.

In Senegal, the environmental impact of artisanal small-scale gold mining (ASGM) using mercury (Hg) is poorly documented despite its intensification over the past two decades. We report here a complete dataset including the distribution and speciation of Hg in soil, sediment, and water in pristine and ASGM impacted sites of the Gambia River ecosystem (Kedougou region - eastern Senegal). Selective extraction showed that soils surrounding ASGM activities were contaminated with elemental Hg [Hg(0)] at concentrations up to 3.9 mg kg−1. In the Gambia River, high total Hg (THg: 1.16 ± 0.80 mg kg−1) and methylmercury (MeHg: 3.2 ± 2.3 ng g−1) were also measured in sediment samples collected at ASGM sites. Along the stream, THg concentrations in sediment decrease with distance from the ASGM sites, while those of methylmercury increase downstream. The study of THg and MeHg partitioning between filtered surface water and suspended particles demonstrate that particulate transport is responsible for the downstream dissemination of the Hg contamination from ASGM sites. Sedimentation of fine particles enriched in Hg downstream ASGM sites likely favors MeHg production and accumulation in sediment. Although elemental Hg is weakly labile, surface soil erosion may also provide important and long-term Hg inputs to downstream aquatic ecosystems, where it can be oxidized and methylated. Finally, the dissemination of THg and MeHg downstream from the ASGM sites in the Gambia River may constitute a long-term source of contamination and can have a large scale impact on the aquatic ecosystem through biomagnification.

National audience; L’objectif principal du projet ImOTEP est d’améliorer les connaissances sur la contamination des sols par les composés aromatiques polycycliques, qui se limitent exclusivement aujourd’hui aux seuls HAP. Il s’agit de déterminer l’impact des traitements par oxydation chimique appliqués sur des sols contaminés par des composés aromatiques polycycliques sur 1/ la chimie de leurs fractions moléculaires 2/ le potentiel écotoxique de ces mêmes fractions dans les sols et l’eau (ex. liquide résiduel et lixiviats) 3/ le mode d’action de ces contaminants.

Growing vegetables in the city is a growing concern for city dwellers while soils are still unknown and little studied. Urban soils are now known to keep traces of past or recent pollution. Before 2012, not any soil analysis was carried out before the establishment of allotment gardens in Nantes. The city relies on research carried out by local scientists for the management of its collective gardens: action thresholds have been defined from the four levels of anomalies suggested by Le Guern et al. (2013) in order to prevent health risks. The allotment gardens of the Contrie have contents of lead (Pb) and copper (Cu), to a lesser extent, above the respective thresholds of 100 mg/kg and 60 mg/kg. A management plan has been established with the advices of Cécile Le Guern (BRGM). The scenarios both tend towards a partial remediation of the soil and a reconversion of part of the contaminated gardens into an edible public garden. Compatibility between feeder functions and lead contaminated soils was verified. The fruits accumulate little Pb with a variable accumulation according to the category of fruit (nuts < pome and stone fruits < berries). Chicken eggs accumulate very little lead: the “worst case scenarios” (417 and 458 µg Pb/kg) have minimal provisional tolerable weekly intake (PTWI) for eggs (2.25 and 1.4%). Honey is the matrix that accumulated the least Pb compared to pollen and bees.; Le jardinage en ville connaît un engouement croissant alors que les sols sont encore peu connus et étudiés. Les sols urbains sont aujourd'hui connus pour garder les traces de pollutions passées ou récentes. Avant 2012, aucune analyse de sols n'était réalisée avant l 'implantation de jardins familiaux nantais. La ville s'appuie sur des recherches menées par des scientifiques locaux pour la gestion de ses jardins collectifs : des seuils d'intervention ont été définis à partir des niveaux d’anomalies proposés par Le Guern et al. (2013) afin de prévenir les risques sanitaires. Les jardins familiaux de la Contrie présentent des teneurs en Pb et Cu, dans une moindre mesure, supérieures aux seuils respectifs de 100 mg/kg et 60 mg/kg. Un plan de gestion a été établit avec les recommandations de C. Le Guern (BRGM). Les scénarios tendent tous deux vers une mise aux normes des sols partielle et une reconversion d'une partie des potagers contaminés en jardin public nourricier. La compatibilité entre fonctions nourricières et sols contaminés au plomb a été vérifiée. Les fruits sont considérés comme de faibles accumulateurs de Pb avec une accumulation variable selon la catégorie de fruit (fruits à coque < fruits à pépins et noyaux < baies). Les œufs de poule accumulent très peu le plomb : les « pires scénarios » (417 et 458 µg Pb/kg) présentent des doses hebdomadaire tolérables provisoires (PTWI) minimes pour les œufs (2,25 et 1,4 %). Le miel est la matrice qui accumule le moins de Pb en comparaison avec le pollen et les abeilles.

International audience

L'utilisation abusive des pesticides sur les légumes constitue des sources potentielles de contamination pour les consommateurs et l'environnement. La présente étude a été initiée pour caractériser les pratiques de traitements phytosanitaires des cultures maraîchères et les risques sanitaires et environnementaux liés à l'usage des pesticides. Une enquête a été réalisée auprès de 47 producteurs maraîchers dans les bas-fonds de Bamadougou et de Doumanaba dans la région de Sikasso pour caractériser leurs pratiques. Des échantillons d'eau d'irrigation, de sol, de produits végétaux et de pesticides ont été prélevés et analysés pour déterminer les teneurs en résidus de pesticides et de matières actives. Les résultats ont montré que les chenilles étaient les bio-agresseurs les plus importants et que la lutte chimique était la plus utilisée contre ces nuisibles. Il ressort de nos résultats de l'utilisation de ATTAKAN C 344 SE (insecticide du cotonnier) sur les cultures maraîchères, de l'emploi de formulation EC pour le traitement des semences et de la réutilisation des emballages vides. Les teneurs en matières actives détectées étaient nettement inférieures à celles déclarées sur l'étiquette pour ATTAKAN C 344 SE utilisé sur la tomate dans le bas-fond de Doumanaba. Outre les matières actives des deux formulations commerciales (ATTAKAN C 344 SE et LAMBDA SUPER 2,5 EC) utilisées l'année de l'étude par deux exploitants maraîchers, les résidus d'autres substances ont été détectés. Il s'agit de l'Heptachlore dans l'eau d'arrosage à Ziguéna, du Lindane dans le sol à Ziguéna et à Bamadougou, de la Perméthrine dans le sol à Bamadougou et du Chlorothalonil dans le sol à Ziguéna. Les mauvaises utilisations révélées par les enquêtes et les résultats d'analyse au laboratoire sont des indicateurs qui témoignent des risques pour les consommateurs et l'environnement.

International audience; Sourcing and understanding the fate of anthropogenic metals in a historical contamination context is challenging. Here we combined elemental and isotopic (Pb, Zn, Cu) analyses with X-ray Absorption Spectroscopy (XAS) measurements (Zn) to trace the fate, in undisturbed soil profiles, of historical metal contamination emitted by a 167-year-old Pb-Ag smelter decommissioned 100 years ago located in the Calanques National Park (Marseilles, France). Lead isotopic measurements show that entire soil profiles were affected by 74 years of Pb emissions up to similar to 7 km from the smelter under the main NNW wind, and indicate particulate transfer down to 0.8 m at depth. This vertical mobility of anthropogenic Pb contrasts with previous studies where Pb was immobilized in surface horizons. The contribution of anthropogenic Pb to the total Pb concentration in soil was estimated at 95% in surface horizons, and 78% in the deepest horizons. Zinc isotopic signatures of past emissions that are enriched in light isotopes compared to the natural geological background (-0.70 +/- 0.04% and -0.15 +/- 0.02%, respectively), were detected only in the surface horizons of the studied soils. Using XAS analyses, we showed that anthropogenic Zn was transformed and immobilized in surface horizons as Zn-Layered Double Hydroxide, thus favoring the enrichment in heavy isotopes in these surface horizons. No clear evidence of copper contamination by the smelter was found and Cu isotopes point to a bedrock origin and a natural distribution of Cu concentrations.

Environmental pollution through heavy metals is an upcoming universal problem that relentlessly endangers human health, biodiversity and ecosystems. Hence remediating these heavy metal pollutants from the environment by engineering soil microbiome through metatranscriptomics is befitting reply. In the present investigation, we have constructed size fractionated cDNA libraries from eukaryotic mRNA of cadmium (Cd) contaminated soil and screened for Cd tolerant genes by yeast complementation system by using Cd sensitive ycf1Δ mutant. We are reporting one of the transformants PLCe10 (from library C, 1–4 kb) with potential tolerance towards Cd toxicity (40 μM–80 μM). Sequence analysis of PLCe10 transcript showed homology to von Willebrand factor type D domain (VWD) of vitellogenin-6 of Ascaris suum encoding 338 amino acids peptide. qPCR analysis revealed that PLCe10 induced in presence of Cd (32 fold) and also accumulated maximum amount of Cd at 60 μM Cd. This cDNA was further tested for its tolerance against other heavy metals like copper (Cu), zinc (Zn) and cobalt (Co). Heterologous complementation assays of cDNA PLCe10 showed a range of tolerance to Cu (150 μM–500 μM), Zn (10 mM–12 mM) and Co (2–4 mM). Results of the present study suggest that cDNA PLCe10 is one of the functional eukaryotic heavy metal tolerant genes present among the soil microbial community and could be exploited to rehabilitate metal contaminated sites.

International audience; Purpose Salinisation is a threat not only to arable land but also to freshwater resources. Nevertheless, salinisation impacts have been rarely and only partially included in life cycle assessment (LCA) so far. The objectives of this review paper were to give a comprehensive overview of salinisation mechanisms due to human interventions, analyse the completeness, relevance and scientific robustness of existing published methods addressing salinisation in LCA and provide recommendations towards a comprehensive integration of salinisation within the impact modelling frameworks in LCA.Methods First, with the support of salinisation experts and related literature, we highlighted multiple causes of soil and water salinisation and presented induced effects on human health, ecosystems and resources. Second, existing life cycle impact assessment (LCIA) methods addressing salinisation were analysed against the International Reference Life Cycle Data System analysis grid of the European Commission. Third, adopting a holistic approach, the modelling options for salinisation impacts were analysed in agreement with up-to-date LCIA frameworks and models.Results and discussion We proposed a categorisation of salinisation processes in four main types based on salinisation determinism: land use change, irrigation, brine disposal and overuse of a water body. For each salinisation type, key human management and biophysical factors involved were identified. Although the existing methods addressing salinisation in LCA are important and relevant contributions, they are often incomplete with regards to both the salinisation pathways they address and their geographical validity. Thus, there is a lack of a consistent framework for salinisation impact assessment in LCA. In analysing existing LCIA models, we discussed the inventory and impact assessment boundary options. The land use/land use change framework represents a good basis for the integration of salinisation impacts due to a land use change but should be completed to account for off-site impacts. Conversely, the land use/land use change framework is not appropriate to model salinisation due to irrigation, overuse of a water body and brine disposal. For all salinisation pathways, a bottom-up approach describing the environmental mechanisms (fate, exposure and effect) is recommended rather than an empirical or top-down approach because (i) salts and water are mobile and theirs effects are interconnected; (ii) water and soil characteristics vary greatly spatially; (iii) this approach allows the evaluation of both on-and off-site impacts and (iv) it is the best way to discriminate systems and support a reliable eco-design.Conclusions This paper highlights the importance of including salinisation impacts in LCA. Much research effort is still required to include salinisation impacts in a global, consistent and operational manner in LCA, and this paper provides the basis for future methodological developments.

La problématique de la contamination des sols urbains et agricoles par les éléments traces métalliques (ETM) est un enjeu majeur en termes de santé publique et de protection de l’environnement. Dans le contexte de l’expansion de l’agriculture urbaine et des jardins communautaires souvent localisés sur des sites contaminés, il existe un intérêt fort pour le développement de méthodes de décontamination moins coûteuses que les méthodes de remédiation conventionnelles et qui préservent l’intégrité et la fertilité du sol. La phytoextraction est une technique écologique de remédiation des sols contaminés en ETM qui repose sur l’utilisation de plantes accumulatrices de métaux pour diminuer les concentrations en ETM dans le sol. La crucifère européenne Noccaea caerulescens (tabouret calaminaire), hyperaccumulatrice de zinc (Zn), cadmium (Cd) et nickel (Ni), s’est imposée comme plante phytoextractrice modèle vu ses étonnantes capacités d’accumulation in natura. Cependant, les conditions de culture optimales de N. caerulescens sont largement méconnues.L’optimisation de la phytoextraction du Cd et du Zn avec N. caerulescens a donc constitué l’objectif principal de ce travail. Nous avons mené des essais de terrain à Bruxelles sur des sites dont les sols sont modérément contaminés en ETM. Le premier objectif était de comparer l’efficacité d’extraction des populations calaminaires du Sud de la France (CAL-SF) et des populations non-métallicoles luxembourgeoises (NMET) de N. caerulescens. En parallèle, un deuxième objectif était de tester l’effet de plusieurs pratiques de culture sur la croissance et l’accumulation afin de développer un itinéraire technique performant. Un dernier objectif était d’étudier l’influence des paramètres édaphiques sur l’efficacité de la phytoextraction. Nous avons mis en évidence pour la première fois sur le terrain que les populations NMET sont nettement plus efficaces pour l’extraction du Zn que les populations CAL-SF et qu’elles combinent à la fois une meilleure production de biomasse et une plus grande résistance aux herbivores et aux pathogènes. Ce travail de thèse souligne que le cycle de vie – annuel ou bisannuel – est un déterminant important de la vitesse de croissance, du rendement d’extraction et du cycle de culture à privilégier. Nos résultats montrent que l’itinéraire technique le plus performant est celui d’un repiquage à l’automne de plantules à cycle bisannuel à densité élevée (100-120 plantes m-²), suivi d’une longue saison de culture (12 mois), tandis que pour des plantes annuelles il faut favoriser une installation au printemps. Enfin, la croissance de N. caerulescens est essentiellement stimulée par des hautes teneurs en matière organique, une faible densité apparente, une texture limoneuse et un bon apport en azote. Ce dernier élément entraîne cependant une baisse des concentrations en ETM dans les plantes quand sa teneur augmente dans le sol. La fertilisation azotée ne devrait donc être utilisée qu’en cas de forte carence azotée.Ce travail a permis de démontrer qu’une culture de N. caerulescens pouvait extraire jusqu’à 18 % du Cd total (CAL-SF) et 10 % du Zn total (NMET) dans les 20 premiers cm de sols modérément contaminés (jusqu’à 10 mg Cd kg-1 et 1000 mg Zn kg-1). À condition d’augmenter et de stabiliser les rendements de biomasse aérienne, la phytoextraction du Cd avec N. caerulescens pourrait donc être une technique pour décontaminer des sols modérément contaminés en Cd tels que les sols agricoles ou les sols urbains., Doctorat en Sciences agronomiques et ingénierie biologique, info:eu-repo/semantics/nonPublished

International audience; Some volcanic soils like andosols contain short-range order nanoclays (allophane) which build aggregates with a tortuous and fractal microstructure. The aim of the work was to study the influence of the microstructure and mesoporosity of the allophane aggregates on the pesticide chlordecone retention in soils. Our study shows that the allo-phane microstructure favors pollutants accumulation and se-questration in soils. We put forth the importance of the meso-porous microstructure of the allophane aggregates for pollutant trapping in andosols. We show that the soil contamination increases with the allophane content but also with the mesopore volume, the tortuosity, and the size of the fractal aggregate. Moreover, the pore structure of the allophane aggregates at nanoscale favors the pesticide retention. The fractal and tortuous aggregates of nanoparticles play the role of nanolabyrinths. It is suggested that chlordecone storage in allophanic soils could be the result of the low transport properties (permeability and diffusion) in the allophane aggregates. The poor accessibility to the pesticide trapped in the mesopore of allophane aggregates could explain the lower pollutant release in the environment.

Located in the Bekaa valley in Lebanon, The Litani River is exposed to agricultural, industrial, domestic and urban wastewaters. Through the irrigation of agricultural soils, the river's water contributes to soil and culture contamination and represents a risk for human health and environment. Amongst the emergent sustainable remediation methods, there is arbuscular mycorrhizal fungi (AMF) assisted-phytoremediation. However, one of the limitation in using phytoremediation as depollution method is its socio-economic profitability. Among the eco-innovative valorization processes with high profitability, the cultivation of aromatic and medicinal plants producing essential oils (EO) with biological activities has been suggested as a promising option. Thus, this thesis work aims firstly at characterizing the soil of an experimental site located at Marj-Bekaa and directly irrigated by the Litani's water and secondly at proposing a mode of management of the contaminated soil based on the production of EO that can meet environmental, economic and social expectations. Our findings showed that the soil sampled in Marj-Bekaa is mainly contamined by metal trace elements [Ni (88 mg.Kgˉ ¹), Cr (122 mg.Kgˉ ¹), V (170 mg.Kgˉ ¹) and Mn (551 mg.Kgˉ ¹) and alkanes (2.5 g.Kgˉ ¹ of soil). This contamination is causing (i) cytotoxicity against both bronchial and hepatic human cells revealed by the evaluation of two enzyme activities, extracellular lactate dehydrogenase and mitochondrial dehydrogenase, as well as (2) ecotoxicity pointed out by the reduction of (i) seed germination (wheat, clover, alfalfa, ryegrass and tall fescue), (ii) soil microbial biomass [Gram-positive and Gram-negative bacteria, arbuscular mycorrhizal fungal (AMF), ectomycorrhizal and saprotrophic fungi], (iii) abundance and diversity of AMF spores as well as (iv) the plant diversity and richness. The AMF-assisted phytoremediation of the Bekaa experimental site was evaluated both in microcosms and in situ experiments using an aromatic plant producing EO, oregano (Origanum syriacum L.). Our results revealed that oregano plant possess an alkane's dissipation potential and no polluant transfer is detected in EO. Moreover, the mycorrhization modified the EO composition. On the over hand, our study evaluated several biological (antifungal, antioxidant and anti-inflammatory) activities of a range of EO extracted from many plant species including oregano, in the presence and the absence of cyclodextrines (HP-β-CD), cyclic oligosaccharides that encapsulate EO and enhance their bioavailabilities.; Situé au sein de la plaine de la Bekaa au Liban, le fleuve du Litani est sujet à divers rejets agricoles, industriels, domestiques et urbain. Lors de l'irrigation des parcelles agricoles, les eaux du fleuve contaminent le sol et les cultures présentant ainsi un risque pour la santé de l'Homme et l’environnement. Parmi les méthodes de remédiation émergentes et en adéquation avec le développement durable figure la phytoremédiation assistée par les champignons mycorhiziens arbusculaires (CMA). Cependant, la rentabilité de ce mode de gestion constitue l'un des principaux freins à son développement et la valorisation de produits biosourcés, à hautes valeurs ajoutées, issus de la biomasse végétale produite sur ces sols contaminés permettrait d'abaisser les coûts globaux de gestion et de requalification de ces sols pollués. Parmi les filières de valorisation éco-innovantes, la culture de plantes à parfums aromatiques et médicinales (PPAM) productrices d'huiles essentielles (HE) à activités biologiques peut être suggérée comme une option prometteuse. Ainsi, l'objectif de ce travail de thèse a consisté tout d'abord à caractériser le sol d'une parcelle expérimentale située à Marj-Bekaa et directement irriguée par les eaux du Litani, puis à proposer un mode de gestion basé sur la production d'HE pouvant ainsi répondre aux attentes environnementales, économiques et sociales. Nos résultats montrent que la parcelle expérimentale, située à Marj-Bekaa et directement irriguée par les eaux du Litani, est principalement contaminée par des éléments traces métalliques [Ni (88 mg.Kgˉ ¹), Cr (122 mg.Kgˉ ¹), V (170 mg.Kgˉ ¹) et Mn (551 mg.Kgˉ ¹) et des polluants organiques [les alcanes (2.5 g.Kgˉ ¹ du sol)]. Cette contamination est à l'origine d'une (1) cytotoxicité vis-à-vis des cellules pulmonaires et hépatiques mise en évidence grâce au dosage de deux activités enzymatiques, la lactate déshydorgénase et la déshydorgénase mithochondriale mais aussi d'une (2) écotoxicité révélée par la réduction (i) des taux de germination des graines (blé, trèfle, luzerne, ray-grass et fétuque), (ii) de la biomasse microbienne du sol [bactéries Gram-positive et Gram-négative, champignons mychoriziens à arbuscules (CMA), champignons saprotrophes et ectomycorhiziens], (iii) de l'abondance et de la diversité des spores de CMA et (iv) de la richesse et de la diversité végétales. Cependant, toutes les plantes indigènes étaient mycorhizées. C'est pourquoi, la faisabilité de la phytoremédiation assistée par les CMA du site expérimental de la Bekaa, a été testée à la fois en microcosmes et in situ en utilisant une plante aromatique productrice d'HE, l'origan (Origanum syriacum L.). Nos résultats ont montré que non seulement l'origan possède un potentiel de dissipation des alcanes mais en plus cette plante ne transfère pas ces polluants dans les HE extraites à partir de sa biomasse aérienne. Par ailleurs, il a été constaté que la mycorhization a une influence sur la composition des HE. En outre, notre étude a permis l'évaluation de diverses activités biologiques (antifongiques, antioxydante et anti-inflammatoire) d'une gamme d'HE extraites de différentes espèces végétales dont l'origan et ce en présence et en absence des cyclodextrines (HP-β-CD), oligosaccharides cycliques qui complexent les HE et augmentent leurs biodisponibilités.

Located in the Bekaa valley in Lebanon, The Litani River is exposed to agricultural, industrial, domestic and urban wastewaters. Through the irrigation of agricultural soils, the river's water contributes to soil and culture contamination and represents a risk for human health and environment. Amongst the emergent sustainable remediation methods, there is arbuscular mycorrhizal fungi (AMF) assisted-phytoremediation. However, one of the limitation in using phytoremediation as depollution method is its socio-economic profitability. Among the eco-innovative valorization processes with high profitability, the cultivation of aromatic and medicinal plants producing essential oils (EO) with biological activities has been suggested as a promising option. Thus, this thesis work aims firstly at characterizing the soil of an experimental site located at Marj-Bekaa and directly irrigated by the Litani's water and secondly at proposing a mode of management of the contaminated soil based on the production of EO that can meet environmental, economic and social expectations. Our findings showed that the soil sampled in Marj-Bekaa is mainly contamined by metal trace elements [Ni (88 mg.Kgˉ ¹), Cr (122 mg.Kgˉ ¹), V (170 mg.Kgˉ ¹) and Mn (551 mg.Kgˉ ¹) and alkanes (2.5 g.Kgˉ ¹ of soil). This contamination is causing (i) cytotoxicity against both bronchial and hepatic human cells revealed by the evaluation of two enzyme activities, extracellular lactate dehydrogenase and mitochondrial dehydrogenase, as well as (2) ecotoxicity pointed out by the reduction of (i) seed germination (wheat, clover, alfalfa, ryegrass and tall fescue), (ii) soil microbial biomass [Gram-positive and Gram-negative bacteria, arbuscular mycorrhizal fungal (AMF), ectomycorrhizal and saprotrophic fungi], (iii) abundance and diversity of AMF spores as well as (iv) the plant diversity and richness. The AMF-assisted phytoremediation of the Bekaa experimental site was evaluated both in microcosms and in situ experiments using an aromatic plant producing EO, oregano (Origanum syriacum L.). Our results revealed that oregano plant possess an alkane's dissipation potential and no polluant transfer is detected in EO. Moreover, the mycorrhization modified the EO composition. On the over hand, our study evaluated several biological (antifungal, antioxidant and anti-inflammatory) activities of a range of EO extracted from many plant species including oregano, in the presence and the absence of cyclodextrines (HP-β-CD), cyclic oligosaccharides that encapsulate EO and enhance their bioavailabilities., Situé au sein de la plaine de la Bekaa au Liban, le fleuve du Litani est sujet à divers rejets agricoles, industriels, domestiques et urbain. Lors de l'irrigation des parcelles agricoles, les eaux du fleuve contaminent le sol et les cultures présentant ainsi un risque pour la santé de l'Homme et l’environnement. Parmi les méthodes de remédiation émergentes et en adéquation avec le développement durable figure la phytoremédiation assistée par les champignons mycorhiziens arbusculaires (CMA). Cependant, la rentabilité de ce mode de gestion constitue l'un des principaux freins à son développement et la valorisation de produits biosourcés, à hautes valeurs ajoutées, issus de la biomasse végétale produite sur ces sols contaminés permettrait d'abaisser les coûts globaux de gestion et de requalification de ces sols pollués. Parmi les filières de valorisation éco-innovantes, la culture de plantes à parfums aromatiques et médicinales (PPAM) productrices d'huiles essentielles (HE) à activités biologiques peut être suggérée comme une option prometteuse. Ainsi, l'objectif de ce travail de thèse a consisté tout d'abord à caractériser le sol d'une parcelle expérimentale située à Marj-Bekaa et directement irriguée par les eaux du Litani, puis à proposer un mode de gestion basé sur la production d'HE pouvant ainsi répondre aux attentes environnementales, économiques et sociales. Nos résultats montrent que la parcelle expérimentale, située à Marj-Bekaa et directement irriguée par les eaux du Litani, est principalement contaminée par des éléments traces métalliques [Ni (88 mg.Kgˉ ¹), Cr (122 mg.Kgˉ ¹), V (170 mg.Kgˉ ¹) et Mn (551 mg.Kgˉ ¹) et des polluants organiques [les alcanes (2.5 g.Kgˉ ¹ du sol)]. Cette contamination est à l'origine d'une (1) cytotoxicité vis-à-vis des cellules pulmonaires et hépatiques mise en évidence grâce au dosage de deux activités enzymatiques, la lactate déshydorgénase et la déshydorgénase mithochondriale mais aussi d'une (2) écotoxicité révélée par la réduction (i) des taux de germination des graines (blé, trèfle, luzerne, ray-grass et fétuque), (ii) de la biomasse microbienne du sol [bactéries Gram-positive et Gram-négative, champignons mychoriziens à arbuscules (CMA), champignons saprotrophes et ectomycorhiziens], (iii) de l'abondance et de la diversité des spores de CMA et (iv) de la richesse et de la diversité végétales. Cependant, toutes les plantes indigènes étaient mycorhizées. C'est pourquoi, la faisabilité de la phytoremédiation assistée par les CMA du site expérimental de la Bekaa, a été testée à la fois en microcosmes et in situ en utilisant une plante aromatique productrice d'HE, l'origan (Origanum syriacum L.). Nos résultats ont montré que non seulement l'origan possède un potentiel de dissipation des alcanes mais en plus cette plante ne transfère pas ces polluants dans les HE extraites à partir de sa biomasse aérienne. Par ailleurs, il a été constaté que la mycorhization a une influence sur la composition des HE. En outre, notre étude a permis l'évaluation de diverses activités biologiques (antifongiques, antioxydante et anti-inflammatoire) d'une gamme d'HE extraites de différentes espèces végétales dont l'origan et ce en présence et en absence des cyclodextrines (HP-β-CD), oligosaccharides cycliques qui complexent les HE et augmentent leurs biodisponibilités.

National audience

A post Ferro-nickel mining land management needs to recognize the physical, chemical characteristics of soil and plants that grow naturally by tolerating the levels of heavy metals. The objective of this study were to: i) investigate and evaluate the natural process of plant colonization on abandoned ferro-nickel mining sites located on ultramafic substrate; to ii) understand the relationship between soil properties and species distribution and to iii) assess the potential of hyperaccumulator plants for the soil phytoremediation. This area was divided into five 100 m(2) plots that were representatives of the variability of the site, based on localization, land use and total vegetative cover. For each plot, the physicochemical characteristics of the soils, the inventory of plant species and the accumulation of Ni by all plant taxa were determined. The soils in the ex-mining area of Perrenjas appeared highly polluted by Ni, Co and Cr compared to the natural levels of the surrounding ultramafic soils. The toxic levels of trace metals and the deficiency of organic matter appeared as major constraints for plant colonization. In total, 96 plant species belonging to 26 families in the studied mining sites of Perrenjas were recorded. Several plants show the ability to tolerate and accumulate metals and may be useful for phyto-stabilization. Alyssum murale was the best candidate for Ni phyto-extraction technologies, with concentrations above 1000 mg/kg Ni in plant tissues.

International audience; The root system anchors the plant to the soil and contributes to plant autotrophy by taking up nutrients and water. In relation with this nutritional function, root development is largely impacted by availability of nutrients and water. Due to human activity, plants, in particular crops, can also be exposed to pollutants which can be absorbed and incorporated into the food chain. Cesium in soils is present at non-toxic concentrations for the plant (micromolar or less), even in soils highly polluted with radioactive cesium due to nuclear accidents. Here, we report on the morphological response of rice roots to Cs+ at micromolar concentrations. It is shown that Cs+ reduces root elongation without affecting root dry weight. Noteworthy, inactivation of the Cs+-permeable K+ transporter OsHAK1 prevents such effect of Cs+, suggesting that internal Cs+ triggers the modification of the root system.

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.

Subcellular fractionation of metals in organisms was proposed as a better way to characterize metal bioaccumulation. Here we report the impact of a laboratory exposure to a wide range of field-metal contaminated soils on the subcellular partitioning of metals in the earthworm Aporrectodea caliginosa. Soils moderately contaminated were chosen to create a gradient of soil metal availability; covering ranges of both soil metal contents and of several soil parameters. Following exposure, Cd, Pb and Zn concentrations were determined both in total earthworm body and in three subcellular compartments: cytosolic, granular and debris fractions. Three distinct proxies of soil metal availability were investigated: CaCl2-extractable content dissolved content predicted by a semi-mechanistic model and free ion concentration predicted by a geochemical speciation model. Subcellular partitionings of Cd and Pb were modified along the gradient of metal exposure, while stable Zn partitioning reflected regulation processes. Cd subcellular distribution responded more strongly to increasing soil Cd concentration than the total internal content, when Pb subcellular distribution and total internal content were similarly affected. Free ion concentrations were better descriptors of Cd and Pb subcellular distribution than CaCl2 extractable and dissolved metal concentrations. However, free ion concentrations and soil total metal contents were equivalent descriptors of the subcellular partitioning of Cd and Pb because they were highly correlated. Considering lowly contaminated soils, our results raise the question of the added value of three proxies of metal availability compared to soil total metal content in the assessment of metal bioavailability to earthworm.

Chlordecone, an organochlorine insecticide, continues to pollute soils in the French West Indies. The main source of human exposure to this pollutant is food. Root vegetables, which are staple foods in tropical regions, can be highly contaminated and are thus a very effective lever for action to reduce consumer exposure. We analyzed chlordecone contamination in three root vegetables, yam, dasheen and sweet potato, which are among the main sources of chlordecone exposure in food in the French West Indies. All soil types do not have the same potential for the contamination of root vegetables, allophanic andosols being two to ten times less contaminating than non-allophanic nitisols and ferralsols. This difference was only partially explained by the higher OC content in allophanic soils. Dasheen corms were shown to accumulate more chlordecone than yam and sweet potato tubers. The physiological nature of the root vegetable may explain this difference. Our results are in good agreement with the hypothesis that chlordecone uptake by root vegetables is based on passive and diffusive processes and limited by transport and dilution during growth.

Les données sol comme support d’innovation. Salon International de l'Agriculture (SIA) 2017

Impacts des pratiques sur la contamination environnementale aux produits phytosanitaires. Colloque Exposition des populations aux produits phytosanitaires et risques sanitaires

International audience; Nickel (Ni), an essential micronutrient, is toxic to plants and animals at elevated levels. Fewer data are available on the dynamics of Ni than for trace metals such as Cu and Zn. Dietary intake is the major source of Ni, but almost no information is available on dietary intake for Asian populations whose diet contains much less animal products and processed foods than in Western countries. In south-eastern China, most food is grown on peri-urban agricultural land and thus, food crops from these areas should be the major source of dietary Ni. A large-scale survey of Ni in soils and edible crops, including 515 sites and 24 crop species from 10 crop groups, was conducted in Fujian Province, SE China, to assess Ni intake for a typical SE Asian diet. Correlation, principal component analysis (PCA) and data mining were used to identify soil and plant factors that determine Ni accumulation in crops. Both soil Ni content and plant species contributed to Ni accumulation. Crop Ni (Ni-crop) was positively correlated with soil Ni DTPA-extractible (diethylenetriaminepentaacetic acid) (Ni-DTPA) for many crops. PCA did not identify strong relations between soil-to-crop transfer factors and any soil properties. Stepwise linear correlations found positive correlations between Ni-crop and Ni-DTPA; however, relationships between Ni-crop and both silt content and pH varied between crops. Dietary intake of foods containing mean Ni content could lead to health risks, especially for children. It was concluded that sandy soils, rich in organic matter with a large Ni content, are unsuitable for the production of rice and legumes.

The former use of chlordecone (CLD) in the French West Indies has resulted in long-term pollution of soils. CLD is known to be potentially transferred towards animal products of animals reared outdoors, mainly through accidental soil ingestion. Several studies indicate that soil bound CLD is bioavailable when administered to farm animals. Currently there is a need to quantify the level of CLD absorption and its toxicokinetic characteristics in the ruminant and particularly in the goat. These are considered as important farm species in the French West Indies. The objective of this study was to evaluate the absorption rate and the half-life of CLD in the non-lactating goat. The goats were administered either intravenously (i.v., n = 6) or orally (p.o., n = 6) one dose (1 mg kg −1 body weight) of CLD. Blood samples were collected at defined times up to 160 days post-dosing. CLD was analyzed in serum by high-resolution gas chromatography. A comparison of the area under the serum concentration-time curves (AUC) showed that the i.v. route is equivalent to the oral route. Thus, CLD is considered almost completely absorbed after p.o. administration, as shown by the mean absolute bioavailability. The comparison between the pharmacokinetic profiles of CLD following oral and intravenous dose showed a difference during the first 14 days and a similar kinetic after this period. The half-life of CLD in serum was close to 20 days. These results highlight a possible strategy of decontamination due to the short half-life of CLD, obtained in dry goats that did not excrete fat matter.

Evaluate the efficiency of Populus alba clone Villafranca in the uptake and translocation of Zn from contaminated soils. The effects of 48 days of zinc treatment (Zn t ) on the growth and the photosynthetic activities of P. alba L. clone Villafranca were studied using ZnSO4 (375 ppm per unit of soil dry weight) added in sand and peat moss substrate at the beginning of the treatment (T 0) and again after 30 days (T 1) in order to reach a target Zn concentration of 375 ppm at T 0 and 750 ppm at T 1 per unit of soil dry weight. Zn uptake in the different organs was analyzed after 30 (T 1) and 48 days (T 2) from the beginning of treatment, showing the following order: root ≫ leaves ≥ woody cutting = stem. The leaf area increased by 12 % in comparison to control plants at the end of second treatment (48 days). Cutting radial growth showed a high synchronicity in the growth rate fluctuation among control and Zn t plants, but a higher increase in radial diameter of Zn t cutting was observed starting from day 38 (after 8 days of second Zn t ) reaching after 48 days 38 % higher than control plants. Although our data of leaf Zn concentration were in the range usually reported as toxic for plants, Villafranca clone in Zn t substrate were unaffected in terms of net CO2 assimilation and stomatal conductance to water vapor.

International audience; Due to diffuse atmospheric fallouts of process particles enriched by metals and metalloids, polluted soils concern large areas at the global scale. Useful tools to assess ecotoxicity induced by these polluted soils are therefore needed. Earthworms are currently used as biotest, however the influence of specie and earthworm behaviour, soil characteristics are poorly highlighted. Our aim was therefore to assess the toxicity of various polluted soils with process particles enriches by metals and metalloids (Pb, Cd, Cu, Zn, As and Sb) collected from a lead recycling facility on two earthworm species belonging to different ecological types and thus likely to have contrasted behavioural responses (Eiseina hortensis and Lum-bricus terrestris). The combination of behavioural factors measurements (cast production and biomass) and physico-chemical parameters such as metal absorption, bioaccumulation by earthworms and their localization in invertebrate tissues provided a valuable indication of pollutant bioavailability and ecotoxicity. Soil characteristics influenced ecotoxicity and metal uptake by earthworms, as well as their soil bioturbation.

Les hydrocarbures aromatiques polycycliques (HAP) sont des polluants organiques persistants largement répandus dans l’environnement en particulier dans les sols. La gestion des sols industriels contaminés par ces molécules est à la fois un enjeu environnemental, sanitaire et scientifique. Des modes de gestion basés sur la nature, comme la phytoremédiation, généralement plus économiques et respectueux de l’environnement, sont à privilégier. Toutefois la phytoremédiation des HAP des sols industriels pour lesquels la rhizodégradation est souhaitée, s’avère souvent limitée par la disponibilité de ces polluants, héritage du vieillissement de la contamination et de sa forte interaction avec les matières organiques d’origine fossiles majoritairement présentes dans ces sols particuliers. L’autre enjeu majeur auquel il convient de faire face est la culture d’espèces végétales d’intérêt, rendue délicate par la faible fertilité de ces sols d’une part et la toxicité des HAP pour les plantes d’autre part. Une meilleure compréhension des mécanismes d’action des HAP sur la plante permet d’envisager des modes de gestion permettant de pallier les effets délétères observés. Il s’agit alors de faire évoluer le concept du traitement de phytoremédiation du paradigme de rhizodégradation, ou dégradation assistée par les plantes, vers celui rhizoatténuation, diminution de la disponibilité et donc du risque., Polycyclic aromatic hydrocarbons (PAH) are persistent organic pollutant widely dispersed in the environment but they accumulate more specifically in soils. Management of these contaminated soils is an environmental and sanitary concern as well as a scientific challenge. Nature-based solutions, such as phytoremediation, are to be privileged being cheaper more environmental friendly. However, rhizodegradation is limited by PAH low bioavailability. Indeed in these old contaminated soils, the pollutants have aged and are strongly sorbed to the anthropic organic matter. Plant growth may also prove difficult due to limited soil fertility combined to phytotoxicty of the pollutants. These difficulties may be overcome with a better knowledge of the mechanisms involved in plant-PAH interaction. In that respect, soil treatment goals should rather move from rhizodegradation to rhizoattenuation, aiming at limiting PAH availability, and thus reduce risk.

Dynamics of trace element accumulation at the plant communauty level along mediterranean roadside secondary succession. 10th ISEB conference

Background: Chemical soil factors play an important role in generating and maintaining plant diversity. Naturally metal-enriched habitats support highly distinctive plant communities consisting of many rare and endemic species. Species of these plant communities possess remarkable physiological adaptations and are now being considered key elements in the implementation of green technologies aimed at phytoremediation of contaminated soils and post-mined soils. Several studies have emphasised that industrial mineral extraction results in serious damage to ecosystems and serious threats to human health and leads to the extinction of metallophyte species. In the southeastern Democratic Republic of the Congo (DRC), mining activities represent a threat to the long-term persistence of communities located on metalliferous copper and cobalt outcrops and their associated endemic metallophytes, which are currently considered some of the most critically endangered plants in the world. Scope: Plant diversity conservation of metal-rich soils must assess soil-plant relationships at different scales (ecosystems, communities, and populations) to define in-situ and ex-situ conservation and restoration projects. This paper proposes a review of soil-plant relationships involved in plant diversity and endemism and their implications for biodiversity conservation and restoration., SCOPUS: ar.j, info:eu-repo/semantics/published

The use of insecticidal proteins known as Cry or Bt, either as biopesticides used in agriculture or as vector control or originating from commercial genetically modified crops (GM), is increasing rapidly. The fate of these proteins in the environment depends strongly on their adsorption on the organo–mineral complexes of soil. Environmental monitoring requires the quantification of the proteins and this entails their chemical extraction from soil. Three Cry proteins, Cry1Ac, Cry1C and Cry2A, present in commercial biopesticide formulations or synthesized by GM plants or both were studied. The adsorption of trace amounts of Cry proteins on over 40 types of soil with contrasting properties was measured in dilute suspension. After a short incubation the extraction yield was measured with a previously tested alkaline solution that contained surfactant and another protein. Each of the proteins had a strong affinity for soil. No soil property was observed to determine either the affinity for soil or the extraction yield. There was no simple relation between the affinity (assessed from the distribution coefficient, Kd) and the extraction yield, although there was a significant inverse relation (P < 0.05) for two of the proteins, Cry1Ac and Cry2A. The proteins differ in both their affinity for soil and their extraction yields. We conclude that these insecticidal proteins will be largely immobile in soil, but that routine environmental monitoring can give only semi-quantitative values for protein in soil.

Insecticidal Cry, or Bt, proteins are produced by the soil-endemic bacterium, Bacillus thuringiensis and some genetically modified crops. Their environmental fate depends on interactions with soil. Little is known about the toxicity of adsorbed proteins and the change in toxicity over time. We incubated Cry1Ac and Cry2A in contrasting soils subjected to different treatments to inhibit microbial activity. The toxin was chemically extracted and immunoassayed. Manduca sexta was the target insect for biotests. Extractable toxin decreased during incubation for up to four weeks. Toxicity of Cry1Ac was maintained in the adsorbed state, but lost after 2 weeks incubation at 25 °C. The decline in extractable protein and toxicity were much slower at 4 °C with no significant effect of soil sterilization. The major driving force for decline may be time-dependent fixation of adsorbed protein, leading to a decrease in the extraction yield in vitro, paralleled by decreasing solubilisation in the larval gut.