As transport characterization in the vadose zone of the soil : a combined study between field and laboratory experiments

Heavy metals are major soil pollutants since a lot of former industrial soils are polluted by these contaminants. In the context of risk assessment of contaminated sites, they are of particular concerns because of their toxicity toward human beings. Nevertheless, the vadose zone of the soil is not taken into consideration in this kind of studies though this is where the pollution enters the soil. That is why mechanisms responsible for trace element release in the unsaturated zone of the soil have to be understood. In addition, tools and methods to measure and put forward interactions between contaminants and the solid matrix have to be provided. Thus the aim of this study was to characterize As transport in soils in the field and to put forward mechanisms responsible for its migration in the unsaturated zone of the soil by setting up an original laboratory experiment. The study site was an in-service wood preserving facility site, located in the north east of France. A regulatory monitoring of the groundwater quality was initiated by a prefectural order in 1998 and 4 water wells are monitored. Water samples are taken twice a year. Soils were contaminated with Cr, Cu and As and we were mainly interested in As release since it was the only trace element measured in groundwater at a concentration above the EU guidelines for drinking water quality. Soils were sandy clay loam. On site, the mean depth of the water table was 6 m from the ground surface; the water table level variation was about 1 m over a year. Soils were sampled and analyze for physico-chemical characteristics and total As content and were submitted to a sequential extraction. In addition, two columns (30 cm high and 12 cm in diameter) were filled with 2 sub-samples of the As contaminated soil (202 and 253 mg/kg) and As release was studied as it could occur on site. Two main phenomena were simulated during these experiments: rain water infiltration and an increase in the water table level. Field studies in combination with a statistical analysis showed that As release was highly correlated to the water table level. After the results of the laboratory experiments, it was shown that As concentrations at the outlet of the two columns were constant over time. Given that and the results of the sequential extraction carried out on this soil, As release could mainly occur from the soluble and exchangeable fractions of As. Arsenic transport modeling is in progress in order to confirm this hypothesis

Faisabilité de la phytoremédiation de sols de cokerie contaminés par des HAP

National audienceLa phytoremédiation des contaminants présents dans les sols est une technologie émergeante mettant en jeu les différentes interactions entre la matrice contaminée et l'organisme végétal. Pour les contaminants organiques, tels les HAP, la phytodégradation semble être l'approche la plus prometteuse. Cependant,bien que prouvée en laboratoire, peu d'études prouvant l'efficacité de cette approche sur le terrain ont été menées.Dans le cadre de cette étude, la phytoremédiation des HAP présents dans un sol de cokerie a été mise en oeuvre au cours d'une expérimentation de plein champ sur deux années. Au préalable, le sol a été homogénéisé puis disposé en six parcelles sans connexion hydrologique. Sur quatre de ces parcelles,différentes espèces végétales couramment rencontrées ont été semées : gazon (tonte courte, parcelle 1 ;tonte longue, parcelle 2) ; plantes ornementales (parcelle 3), arbustes (parcelle 4). La cinquième parcelle(P5) a été laissée en friche et la sixième (P6) désherbée manuellement. Au cours des trois années, un échantillonnage représentatif de deux horizons (0-50 cm et 50-100 cm) de sol a été mené sur chaque parcelle pour caractériser l'évolution des teneurs des 16 HAP prioritaires de l'US-EPA dans les sols.L'impact possible de la phytoremédiation sur les écosystèmes a été évalué en pratiquant sur les sols, ainsi que sur les lixiviats, différents tests de toxicité.Sur la durée du traitement, la teneur moyenne en HAP dans les sols décroît légèrement au cours du temps pour trois parcelles de l'essai. Cette diminution varie entre 3% pour P5 et 24% pour P1 de la teneur totale en HAP initialement présents dans le sol. La décroissance moyenne était plus élevée dans l'horizon profond (14%) que dans l'horizon de surface (12%). Pour les trois autres parcelles, une légère augmentation de la teneur moyenne en HAP a été mise en évidence. Celle-ci variait entre 5% pour P3 et 13% pour P6. Statistiquement, en tenant compte de l'hétérogénéité spatiale de la contamination, seule la diminution de la teneur totale en HAP observée sur la parcelle P1 était significative. Pour l'ensemble des parcelles, une diminution significative des HAP à 3 cycles a été observée, alors que les teneurs en HAP à 4 cycles et plus restaient relativement constantes au cours du temps. Durant les deux premières années,aucune toxicité n'a été détectée sur les matrices solides ou sur les lixiviats. Seule une légère toxicité des lixiviats a été observée la dernière année pour un seul des tests réalisés.Cette étude montre que la phytodégradation des HAP, bien que prometteuse à l'échelle de laboratoire,n'est pas facilement transposable en plein champ. Une des raisons peut être liée à l'effet pépite, induisant une incertitude supplémentaire concernant l'homogénéité de l'échantillonnage au cours du temps. En outre, il est possible qu'une légère toxicité apparaisse à moyen terme tel que montré par nos résultats sur les lixiviats

Comparisons of degradation kinetics of chloroethenes in groundwater between microcosms and field scale

International audienceGroundwater pollution by chlorinated solvents is a major concern since several years. It has been demonstrated that in specific physicochemical conditions, microbial processes like direct reductive dechlorination allow contamination reduction at several sites. Therefore, determination of biodegradation kinetics of chloroethenes is crucial in applying Natural Attenuation protocols on contaminated sites and assessing the potential risks for human health and natural media Biodegradation of chlorinated solvents is effective in highly reduced conditions, which rarely concerns the whole contaminant plume. In this study, direct reductive dechlorination of chloroethenes was studied on two different scales, on microcosms in the laboratory and at the real scale that corresponds to the contaminated site Microcosms studies were conducted in three different ways. (1) sediments sampled from the site and mixed with groundwater modified or not by a synthetic electron donor (Na propionate, Na lactate, toluene), (2) composite sediments coming from several places of the site mixed with groundwater modified or not by a synthetic electron donor; (3) autoclaved sediments and groundwater modified or not by synthetic organic matter. Studies on the real scale were conducted by the achievement of a synthesis of historical data (hydrogeological, geological and physicochemical data) of a polluted site. The synthesis of physicochemical data and then modelling the real site revealed the presence of degradation products of chloroethenes in the plume : cis-1,2-DCE and VC The results of comparisons of degradation kinetics obtained on the laboratory and the field under the same physicochemical conditions showed significant differences. Indeed, biodegradation of chlorinated solvents were faster in lab studies than in the field at the global scale. The existence of chlorinated ethenes biotransformation in microcosms confirmed the presence of a bacterial population able to catalyse reductive dechlorination reaction until CV. It is also likely that the bacterial consortium permitted to degrade other species like electron acceptors; detection of sulphide ions and Fe(II) and the presence of a black precipitate of FeS are proofs of sulphate reducing, ferro reducing and dechlorinating activities. The clear difference that there is between kinetics of degradation on microcosms and field scale could be explained by differences in chemical conditions that are not optimal everywhere in the plume of pollutants. The differences of chemical conditions (electron acceptors, type of natural organic matter, pH, redox potential...) are investigated in details to explain the differences in kinetic constant

Chlorinated solvents transport and natural attenuation modeling in groundwater

International audienceThe purpose of this study is to compare natural attenuation models to predict transport and fate of chlorinated solvents in saturated groundwater Systems. This work was realised within the framework of the research program TRANSPOL. This program was created in order to bring a better and common practice of the use of transport models concerning various pollutants the most encountered. Real case study, Real Case 3, concerns chlorinated solvents fate and transport in groundwater

Tissue Factor Expression in Non-small Cell Lung Cancer: Relationship with Vascular Endothelial Growth Factor Expression, Microvascular Density, and K-ras Mutation

IntroductionTissue factor (TF) is the physiological trigger of blood coagulation, but it could also have an important role in cancer by regulating VEGF expression and angiogenesis.MethodsTF expression was studied by real-time PCR in lung tumors of 64 patients with non-small-cell lung cancer (NSCLC) and by immunohistochemical analysis. The gene expression of two VEGF isoforms, VEGF165 and VEGF189, was also evaluated. Microvascular density (MVD) was studied by measuring Von Willebrand Factor (VWF) mRNA levels and by immunohistochemistry using an anti-CD34 antibody.ResultsTF mRNA levels were significantly lower than in corresponding non-affected lung tissues. However, TF expression was higher in T3-T4 tumors and this result was confirmed by immunohistochemistry. VEGF189 mRNA levels were ten times higher than those of VEGF165 and well correlated with TF mRNA levels. MVD was lower in the inner part of tumors than in the adjacent non-affected lung without being related to TF expression. Finally, codon 12 K-ras mutation was found in 8 lung carcinomas, and higher TF and VEGF189 mRNA levels were measured in mutated tissues (p < 0.001).ConclusionThese results suggest that high TF expression in lung tumors may result from K-ras mutation and contribute to NSCLC progression, probably via mechanisms other than angiogenesis

Approche méthodologique de la modélisation du transport des HAP dans les sols et les eaux

Afin de préciser le cadre d'utilisation de codes de transport de polluants dans les sols et les eaux, un programme d'intercomparaison de méthodes et de codes a été mis en oeuvre avec la collaboration de huit équipes appartenant à des instituts de recherche ou des bureaux d'études. Parmi les types de polluants étudiés, les hydrocarbures aromatiques polycycliques (HAP) ont fait l'objet de simulations par deux groupes de travail. Le premier groupe, composé de cinq équipes, s'est intéressé à leur comportement en phase dissoute à partir d'un cas réel de pollution. Disposant des mêmes données d'étude, chaque équipe avait pour mission de concevoir un modèle conceptuel (description géologique, définition de la source, paramètres d'écoulement et de transport) et de simuler la pollution de la nappe avec le code de son choix. Les résultats obtenus montrent des différences significatives qui trouvent leur explication dans les paramètres des modèles conceptuels adoptés plus que dans les simulateurs choisis. Cet exercice a confirmé l'importance des paramètres suivants qui sont souvent incertains mais justifieraient d'être mieux appréciés lors de diagnostics : paramètres hydrodynamiques (détermination du champ de vitesse), coefficient de partition (pour chaque horizon géologique), temps de demi-vie du ou des polluants, extension de la source de pollution. Le second groupe a étudié les écoulements en phase libre (phase liquide non aqueuse) sur un cas théorique inspiré d'un cas réel de déversement massif de naphtalène. La modélisation a été conduite par trois équipes avec trois codes polyphasiques différents (SIMUSCOPP, TOUGH/T2VOC, UTCHEM). Cet exercice comprend le suivi du déversement et de la migration du naphtalène sous formes liquide et dissoute sur une distance de 300 m et une durée de 10 ans. Le naphtalène révèle un comportement d'hydrocarbure " lourd " avec une phase huile (partiellement miscible) qui tend à descendre à travers la nappe. Ce comportement a été reproduit par chacune des équipes, de manière plus ou moins complète en fonction des possibilités de modélisation offertes par les codes. Les résultats obtenus permettent de vérifier la cohérence des différentes approches polyphasiques entre elles. Bien que plus complexe (paramètres plus nombreux, difficulté numérique accrue), l'approche polyphasique se justifie pour mieux comprendre et déterminer la répartition spatiale de HAP en profondeur dans une nappe

Glucocorticoid-related changes in body mass index among children and adolescents with rheumatic diseases

Objective To examine the temporal and dose-related effects of glucocorticoids (GCs) on body mass index (BMI) in children with rheumatic diseases. Methods Children initiating GCs for a rheumatic disease (n = 130) were assessed every 3 months for 18 months. BMI, weight, and height Z score trajectories were described according to GC starting dosage in prednisone equivalents: high (≥1.0 mg/kg/day), low (\u3c0.2 mg/kg/day to a maximum of 7.5 mg/day), and moderate (between high and low) dosage. The impact of GC dosing, underlying diagnosis, pubertal status, physical activity, and disease activity on BMI Z scores and on percent body fat was assessed with longitudinal mixed-effects growth curve models. Results The GC starting dose was high in 59% and moderate in 39% of patients. The peak BMI Z score was +1.29 at 4 months with high-dose GCs and +0.69 at 4.2 months with moderate-dose GCs (P \u3c 0.001). Overall, 50% (95% confidence interval 41-59%) of the children returned to within +0.25 SD of their baseline BMI Z score. Oral GC dose over the preceding 3 months was the most significant determinant of BMI Z score and percent body fat. The proportion of days in receipt of GCs, disease activity, and a diagnosis of systemic-onset juvenile idiopathic arthritis were also associated with BMI Z scores. The correlation between changes in BMI and changes in percent body fat was 0.09. Conclusion In children with rheumatic diseases starting moderate and high doses of GCs, BMI Z scores peaked at 4 months, and only half returned to within +0.25 SD of their baseline BMI Z score after 18 months. Copyright © 2013 by the American College of Rheumatology

Steroid receptor RNA activator protein binds to and counteracts SRA RNA-mediated activation of MyoD and muscle differentiation

The steroid receptor RNA activator (SRA) has the unusual property to function as both a non-coding RNA (ncRNA) and a protein SRAP. SRA ncRNA is known to increase the activity of a range of nuclear receptors as well as the master regulator of muscle differentiation MyoD. The contribution of SRA to either a ncRNA or a protein is influenced by alternative splicing of the first intron, the retention of which disrupts the SRAP open reading frame. We reported here that the ratio between non-coding and coding SRA isoforms increased during myogenic differentiation of human satellite cells but not myotonic dystrophy patient satellite cells, in which differentiation capacity is affected. Using constructs that exclusively produce SRA ncRNA or SRAP, we demonstrated that whereas SRA ncRNA was indeed an enhancer of myogenic differentiation and myogenic conversion of non-muscle cells through the co-activation of MyoD activity, SRAP prevented this SRA RNA-dependant co-activation. Interestingly, the SRAP inhibitory effect is mediated through the interaction of SRAP with its RNA counterpart via its RRM-like domain interacting with the functional sub-structure of SRA RNA, STR7. This study thus provides a new model for SRA-mediated regulation of MyoD transcriptional activity in the promotion of normal muscle differentiation, which takes into account the nature of SRA molecules present

The Intracellular Localization of ID2 Expression Has a Predictive Value in Non Small Cell Lung Cancer

ID2 is a member of a subclass of transcription regulators belonging to the general bHLH (basic-helix-loophelix) family of transcription factors. In normal cells, ID2 is responsible for regulating the balance between proliferation and differentiation. More recent studies have demonstrated that ID2 is involved in tumor progression in several cancer types such as prostate or breast