Remediation of metal-contaminated urban soil using flotation technique

A soil washing process using froth flotation technique was evaluated for the removal of arsenic, cadmium, copper, lead, and zinc from a highly contaminated urban soil (brownfield) after crushing of the particle-size fractions >250microm. The metal contaminants were in particulate forms and distributed in all the particle-size fractions. The particle-by-particle study with SEM-EDS showed that Zn was mainly present as sphalerite (ZnS), whereas Cu and Pb were mainly speciated as various oxide/carbonate compounds. The influence of surfactant collector type (non-ionic and anionic), collector dosage, pulp pH, a chemical activation step (sulfidization), particle size, and process time on metal removal efficiency and flotation selectivity was studied. Satisfactory results in metal recovery (42-52%), flotation selectivity (concentration factor>2.5), and volume reduction (>80%) were obtained with anionic collector (potassium amyl xanthate). The transportation mechanisms involved in the separation process (i.e., the true flotation and the mechanical entrainment) were evaluated by the pulp chemistry, the metal speciation, the metal distribution in the particle-size fractions, and the separation selectivity indices of Zn/Ca and Zn/Fe. The investigations showed that a great proportion of metal-containing particles were recovered in the froth layer by entrainment mechanism rather than by true flotation process. The non-selective entrainment mechanism of the fine particles (<20 microm) caused a flotation selectivity drop, especially with a long flotation time (>5 min) and when a high collector dose is used. The intermediate particle-size fraction (20-125 microm) showed the best flotation selectivity.

Fluorodeoxyglucose-positron-emission tomography imaging of head and neck squamous cell cancer

The hybrid technique of PET/CT has significantly impacted the imaging and management of HNSCC since its introduction in 2001 and has become the technique of choice for imaging of this cancer. Diagnostic FDG-PET/CT is useful for identification of an unknown primary tumor, delineation of extent of primary tumor, detection of regional lymph node involvement even in a normal-sized node, detection of distant metastases and occasional synchronous primary tumor, assessment of therapy response, and long-term surveillance for recurrence and metastases. The role of PET/CT is evolving in radiation therapy planning. Combined diagnostic PET/CT provides the best anatomic and metabolic in vivo information for the comprehensive management of HNSCC.

Full-length cytokeratin-19 is released by human tumor cells: a potential role in metastatic progression of breast cancer

Introduction

We evaluated whether CK19, one of the main cytoskeleton proteins of epithelial cells, is released as full-length protein from viable tumor cells and whether this property is relevant for metastatic progression in breast cancer patients.

Methods

EPISPOT (EPithelial ImmunoSPOT) assays were performed to analyze the release of full-length CK19 by carcinoma cells of various origins, and the sequence of CK19 was analyzed with mass spectrometry. Additional functional experiments with cycloheximide, Brefeldin A, or vincristine were done to analyze the biology of the CK19-release. CK19-EPISPOT was used to detect disseminated tumor cells in bone marrow (BM) of 45 breast cancer patients who were then followed up over a median of 6 years.

Results

CK19 was expressed and released by colorectal (HT-29, HCT116, Caco-2) and breast (MCF-7, SKBR3, and MDA-MB-231) cancer cell lines. The CK19-EPISPOT was more sensitive than the CK19-ELISA. Dual fluorescent EPISPOT with antibodies against different CK19 epitopes showed the release of the full-length CK19, which was confirmed by mass spectrometry. Functional experiments indicated that CK19 release was an active process and not simply the consequence of cell death. CK19-releasing cells (RCs) were detectable in BM of 44% to 70% of breast cancer patients. This incidence and the number of CK19-RCs were correlated to the presence of overt metastases, and patients with CK19-RCs had a reduced survival as compared with patients without these cells (P = 0.025, log-rank test; P = 0.0019, hazard ratio, 4.7; multivariate analysis).

Conclusions

Full-length CK19 is released by viable epithelial tumor cells, and CK19-RCs might constitute a biologically active subset of breast cancer cells with high metastatic properties.

[Treatment of PAH-contaminated aluminium wastes by flotation using amphoteric surfactants]

The aluminium industry produces wastes polluted with polycyclic aromatic hydrocarbons (PAH). The most important PAH found in these wastes is benzo(b,j,k)fluoranthene (BJK) at concentrations exceeding the permitted levels (>1000 mg kg(-1)). The objective of this research was to compare the performances of amphoteric (BW and CAS) and non-ionic surfactants (Triton X-100 and Tween 80), at a concentration of 0.5% (w w(-1)), for PAH removal (and particularly for BJK) during washing treatment of aluminium industry wastes. The best removal yield of BJK (35%) has been measured during treatment with CAS. The efficiency of this surfactant has been further improved by using a flotation process. Flotation tests have also been realized at different CAS concentrations (0.1, 0.2, 0.25 and 0.5% w w(-1)) and using different total solids (7, 10, 15 and 20% w v(-1)). The highest BJK removal yield (68%) has been obtained using 0.5% CAS and a total solids concentration of 15%. The rate of hazardous wastes produced in these conditions represents 10% of the initial weight of aluminium wastes treated.

Soil washing for metal removal: a review of physical/chemical technologies and field applications

Soil washing is one of the few permanent treatment alternatives to remove metal contaminants from soils. This paper reviews the various technology types and pilot/full-scale field applications of soil washing applicable to soils highly contaminated with heavy metals. The physical separation technologies, the chemical extraction processes and the integrated processes that combine both physical and chemical methods are discussed separately. This paper reviews basic principles, applicability, advantages and limitations, methods of predicting and improving performance of each physical/chemical technology. The discussion is based on a review of 30 recent laboratory investigations and 37 field applications of soil washing systems which have been undertaken, mostly in the US, for the period 1990-2007. This paper also examines and compares the status of soil washing technology for remediation of soils contaminated with metals in the US, in Canada and in Europe.

Fécondation in vitro et tabac: intérêt de la cotininurie et de l'analyseur de monoxyde de carbone expiré

OBJECTIVE

To study the correlation between expired air carbon (EACO) and urinary cotinine, and to determine the impact of tobacco smoking on in vitro fertilization (IVF) results.

PATIENTS AND METHODS

We studied prospectively 221 patients in our ART center from October 2002 to October 2004: 51 active smokers, 85 passive smokers, and 85 non-smokers. Patients were classified into active, passive smokers, or non-smokers, based on a questionnaire. We measured urinary cotinine and EACO on the embryo transfer day and we recorded the IVF parameters.

RESULTS

Two hundred and twenty-one patients were included. We observed a 17.2% reduction of estradiolemy (P=0.05), a 1.5% reduction of pregnancies (NS), a 7.8% reduction of infants born alive (NS), a 28.5% reduction of twin pregnancies (P=0.06), as well as a 10% increase of miscarriages (NS) in the active smokers in comparison with non-smokers (the same trends were observed between active and passive smokers). EACO and urinary cotinine were well correlated. There was a negative correlation between estradiolemy and urinary cotinine (R=-0.15, P=0.02).

DISCUSSION AND CONCLUSION

Tobacco smoking intensity may be dilatory on IVF results. There is a high correlation between EACO and urinary cotinine. Other larger studies would probably obtain results more statistically significant.

[PAH removal from black sludge from aluminium industry by flotation using non-ionic surfactants]

The valorization of black sludge is an environmental problem of the aluminium industry because of Polycyclic Aromatic Hydrocarbon (PAH), fluoride and alumina contents. A soil washing operated in a cell flotation with non-ionic surfactants (Brij 35, Igepal CA-720, Triton X-100, Tween 80) at different concentrations has been tested in order to remove the PAH (benzo(a)anthracene, benzo(a)pyrene, benzo(b)fluoranthene, benzo(j)fluoranthene, benzo(k)fluoranthene, fluoranthene) detected in black sludge. The Tween 80 at 0.5% gave the best results with PAH removal rates between 35 and 50%. These percentages remain low due to the presence in large quantity of fine solid particles (45%) in the PAH concentrate produced by the flotation process. The substitution of the cell flotation by a column flotation allowed the reduction of this problem. Thus, the PAH removal rates reached 60%. This removal yield has been obtained with the lowest wash water flow-rate (150 ml min(-1)) and pulp total solids (10% p p(-1)) tested.

Transcriptional disruptions in Down syndrome: a case study in the Ts1Cje mouse cerebellum during post-natal development

To understand the aetiology and the phenotypic severity of Down syndrome, we searched for transcriptional signatures in a substructure of the brain (cerebellum) during post-natal development in a segmental trisomy 16 model, the Ts1Cje mouse. The goal of this study was to investigate the effects of trisomy on changes in gene expression across development time. The primary gene-dosage effect on triplicated genes (approximately 1.5) was observed at birth [post-natal day 0 (P0)], at P15 and P30. About 5% of the non-triplicated genes were significantly differentially expressed between trisomic and control cerebellum, while 25% of the transcriptome was modified during post-natal development of the cerebellum. Indeed, only 165, 171 and 115 genes were dysregulated in trisomic cerebellum at P0, P15 and P30, respectively. Surprisingly, there were only three genes dysregulated in development and in trisomic animals in a similar or opposite direction. These three genes (Dscr1, Son and Hmg14) were, quite unexpectedly, triplicated in the Ts1Cje model and should be candidate genes for understanding the aetiology of the phenotype observed in the cerebellum.

[General practitioners' and intensivists' relationships: intensivists' point of view from eight French southern regional areas]

OBJECTIVES

Assessment of relationship between general practitioners and intensivists.

STUDY DESIGN

Intensivists were questioned by phone from June 14th to September 28th 2004.

METHODS

245 out of 264 intensivists from 8 French Southern regional areas were questioned concerning their relationship with critically ill patients' general practitioner.

RESULTS

Patients were mainly admitted into Intensive care Unit (ICU) from the Emergency Department (55%). An information letter from the general practitioner was reported for 20% of admitted patients but 50% of these letters was assumed as not informative. The informations concerning the patient's medical history, therapies, and disease leading to admission and the patient's status were assessed with 6.5, 7.0, 6.0 and 2.0, respectively (maximal note=10). The intensivists contacted the general practitioner for 30% of admitted patients. During the stay in ICU, 33% general practitioners were reported to request informations by phone or visit in ICU. When the stay in ICU was>10 days, the general practitioner was nearly never regularly informed about patient's status. When the patient was discharged from the ICU, 80% of intensivists used an exhaustive typed report to inform the general practitioner. The overall relationship between the general practitioner and the intensivist was assessed as 5.5/10. Insufficient information in the general practitioner's letter at admission, the lack of request for information during the stay in ICU, the lack of contact with the general practitioner by the intensivist and an intensivist's age between 46 and 55 were associated with a relationship assessment<4/10).

A haploid-specific transcriptional response to irradiation in Saccharomyces cerevisiae

Eukaryotic cells respond to DNA damage by arresting the cell cycle and modulating gene expression to ensure efficient DNA repair. We used global transcriptome analysis to investigate the role of ploidy and mating-type in inducing the response to damage in various Saccharomyces cerevisiae strains. We observed a response to DNA damage specific to haploid strains that seemed to be controlled by chromatin regulatory proteins. Consistent with these microarray data, we found that mating-type factors controlled the chromatin-dependent silencing of a reporter gene. Both these analyses demonstrate the existence of an irradiation-specific response in strains (haploid or diploid) with only one mating-type factor. This response depends on the activities of Hdf1 and Sir2. Overall, our results suggest the existence of a new regulation pathway dependent on mating-type factors, chromatin structure remodeling, Sir2 and Hdf1 and independent of Mec1 kinase.

État du développement technologique en matière d'enlèvement des métaux des effluents industriels

Cette étude trace un profil des diverses technologies utilisées et en développement pour la séparation et/ou la récupération des métaux dans les effluents industriels. Les principes de fonctionnement de ces technologies sont abordés, ainsi que leurs avantages et limites d'utilisation. Les procédés d'enlèvement et de récupération des métaux comprennent les techniques de précipitation (formation d'hydroxydes, de carbonates, de sulfures, etc.) et coprécipitation (sels de fer et d'aluminium, etc.), d'adsorption (sable, cellulose, charbon activé, pyrite, ciment, lignite, mousse de tourbe, sciure de bois, etc.) et de biosorption (bactéries, levures, moisissures, algues marines et d'eaux douces), d'électrodéposition et d'électrocoagulation, de cémentation, de séparation par membranes (osmose inverse et électrodialyse), d'extraction par solvant (acides carboxyliques, amines aliphatiques ou aromatiques, acides aminés, composés phénoliques, phosphates alkyl, etc.), et d'échange d'ions (résines naturelles et synthétiques). La précipitation ou la coprécipitation représentent les procédés les plus largement utilisés et étudiés pour l'enlèvement des métaux des effluents industriels, suivis des techniques d'adsorption. Les procédés plus sophistiqués tels que l'électrodéposition, l'extraction par solvant, la séparation par membranes et l'échange d'ions, bien que largement utilisés dans les procédés métallurgiques, sont relativement peu employés et examinés pour le traitement des effluents industriels. La biosorption a fait l'objet de plusieurs travaux de recherche au cours des dernières années et représente une option intéressante pour le traitement de divers types d'effluents contenant de faibles concentrations en métaux. Finalement, le recyclage et la gestion optimale des effluents constitue une avenue de plus en plus suivie par les industries soucieuses de satisfaire aux nouvelles réglementations et législations.

Étude de l'enlèvement du Cd, Cu, Mn et Zn par solubilisation biologique dans les sédiments lacustres fortement contaminés

Des essais en erlenmeyers de 0,5 L ont été faits afin d'évaluer les possibilités d'application d'un procédé de solubilisation biologique aux sédiments. Ce procédé utilise la capacité des thiobacilles de lixivier les métaux en milieu acide. Au cours des essais, l'influence, sur la solubilisation des métaux, de la quantité de substrat (FeSO4 × 7H2O), du pourcentage d'inoculum et de la teneur en solides totaux a été suivie. La concentration de substrat n'a pas d'effet sur l'enlèvement du Cd, du Zn, du Mn et du Cu. Les taux d'enlèvement moyens pour le Cd, Zn et Mn, sont, après 46 heures, de 70 à 90 %, 90 à 100 % et 64 à 72 % pour des concentrations de substrat variant de 0 à 30 % FeSO4 × 7H2O (poids sec/poids sec). A 29 et 46 heures, des coefficients de détermination (r2) de 0,46 et 0,59 entre le pH et la concentration de FeSO4 × 7H2O, et de 0,92 et 0,55 entre le POR et la concentration de FeSO4 × 7H2O ont été trouvés. A plus forte teneur en FeSO4 × 7H2O, le POR est moins élevé, surtout au début des essais. La présence des ions ferreux en plus grande quantité expliquerait les plus faibles valeurs du potentiel-rédox.

A 20 % d'inoculum, la solubilisation des métaux est optimale avec une solubili- sation de 86 % pour le Cd et 73 % pour le Cu et le Mn. La forte corrélation entre le POR, le pH et le pourcentage d'inoculum (r2 à 29, 46 et 70 heures de 0,94, 0,94 et 0,63 pour le POR et le pourcentage d'inoculum et de 0,80, 0,69 et 0,60 pour le pH et le pourcentage d'inoculum), a permis d'établir une corrélation entre le POR, le pH et la solubilisation du Cu. Les seuils trouvés permettant une solubilisation du Cu supérieure à 10 % sont un pH de 3,75 et un POR de 260 mV.

L'augmentation des solides totaux (ST) semble limiter le développement des thiobacilles et diminue les rendements de solubilisation du Cd (à 21 heures) et du Zn (à 45 heures). Ainsi, pour le Cd, les pourcentages de solubilisation passent de 71 % à 24 % pour 3 et 15 % ST, alors que dans le cas du Zn, ils diminuent de 94 % à 81 % pour 3 et 15 % ST. La solubilisation du Mn serait, pour sa part, plutôt de type chimique.

[Study of the metal precipitation from decontamination leachates of municipal wastes fly ash incinerators]

This research work focuses on the development of a new process for the decontamination of municipal wastes incinerators fly ashes. The objective of this study was to evaluate different total and selective precipitation methods for metals removal from ash decontamination leachates. The tested options include 1) use of hydrated lime and caustic soda for selective (pH 5.0) and total (pH 8.5) metal precipitation; 2) addition of different chemicals (H3PO4, Na2S and FeCl3) in a pH range from 6.0 to 9.0. Fly ash decontamination assays using alkaline and acid washing steps were initially performed using optimal conditions previously established. Treated fly ashes respected the standards based on the TCLP leaching test for all studied metals and SPLP. Total metal precipitation tests carried out at pH 8.5 achieve removal yields for all metals > or = 90% using hydrated lime and > or = 83% using caustic soda. Selective precipitation tests alone at pH 5.0 show removal yields > or = 97% for Cr and between 75 and 87% for Al and Pb. Moreover, assays carried out using a stoechiometric addition of Na2S have allowed the separation of Cd (> or = 99%) and Zn (> or = 71%) as metal sulphides (CdS and ZnS). From an economical point of view, the most interesting option seems to be the leachates neutralization at pH 7.0 using Ca(OH)2 combined with the reuse of the treated leachates in the fly ash leaching steps. Metal precipitation cost at pH 7.0 has been estimated to be 22.7 CAN dollars tct-1 using Ca(OH)2, and 26.7 CAN dollars tct-1 using NaOH.