20 research outputs found
Enhanced pilot bioremediation of oily sludge from petroleum refinery disposal under hot-summer Mediterranean climate
Large pilot scale bioremediation approaches were implemented for the treatments of oily sludge (OS) characterised by alkaline pH (pH > 9), high concentration of metals (3% dry weight) and high total petroleum hydrocarbons content (TPH) rangingbetween 22,000 and 67,300 mg kg â1 from a Tunisian petroleum refinery. The treatments included bioaugmentation and biostimulation approaches with autochthonous isolated bacterial strains and consortia. Chemical, microbial, and ecotoxicological analyses were performed over a period of 180 days incubation. The bioremediation treatments favoured the development of Proteobacteria, Firmicutes and Bacteroidetes following an ecological succession of specialist bacterial groups, first associated to hydrocarbon degradation (e.g. Marinobacter and Alcanivorax) that resulted in a greater extent of TPH-degradation (up to 80%), and the selection of metal resistant bacteria including Hyphomonas, Phaeobacter, and Desulfuromusa. The best performances were obtained when bioaugmentation and biostimulation were combined. Over 90% of the TPH initial concentration was degraded over 180 days, which was accompanied with a 3-fold reduction of ecotoxicity. Our study demonstrates the efficacy of large pilot scale bioremediation of highly contaminated oily sludge, providing the evidence that the management of autochthonous microbial communities is of paramount importance for the success of the bioremediation process
Ătude expĂ©rimentale de lâĂ©volution en microcosme du chrome (VI) dans lâeau de mer et de ses effets sur la macrofaune et les bactĂ©ries indigĂšnes de la Lagune de Bizerte (Tunisie)
La prĂ©sente Ă©tude vise Ă comparer au laboratoire lâimpact biologique du chrome hexavalent (Cr (VI)) prĂ©sent dans le ciment non dĂ©chromĂ©, et celui du chrome prĂ©sent dans le ciment dĂ©chromĂ© en considĂ©rant deux Ă©chelons trophiques de la lagune de Bizerte : les bactĂ©ries indigĂšnes et la macrofaune reprĂ©sentĂ©e par la palourde Ruditapes decussatus.Dans deux types de microcosmes, lâun contenant de lâeau de mer seulement et lâautre contenant de lâeau de mer et du sĂ©diment, la palourde europĂ©enne Ruditapes decussatus a Ă©tĂ© introduite Ă raison de 20 individus par aquarium. Quatre types dâaquarium ont Ă©tĂ© mis en place : un tĂ©moin (T), un aquarium contaminĂ© par du ciment non dĂ©chromĂ© (0,16 mgâąL-1 de Cr (VI)), un contaminĂ© par du ciment dĂ©chromĂ© (0,05 mgâąL-1 de Cr (VI)) et un contaminĂ© par le dichromate de potassium (0,16 mgâąL-1 de Cr (VI)). Deux replicats ont Ă©tĂ© rĂ©alisĂ©s pour chaque type de microcosme.La concentration du Cr (VI) dans lâeau a Ă©tĂ© mesurĂ©e par un dosage colorimĂ©trique au dĂ©but et aprĂšs 96 heures dâexpĂ©rimentation. La quantification des bactĂ©ries hĂ©tĂ©rotrophes a Ă©tĂ© Ă©valuĂ©e par la mĂ©thode du Nombre le Plus Probable.Environ 80 % de la quantitĂ© du Cr (VI) prĂ©sente dans le milieu ont Ă©tĂ© piĂ©gĂ©s dans les sĂ©diments. Les ciments dĂ©chromĂ©s et non dĂ©chromĂ©s ont provoquĂ© 100 % de mortalitĂ© chez les palourdes au bout de trois jours. Cependant, il nâa Ă©tĂ© observĂ© que 40 % de mortalitĂ© dans le microcosme contaminĂ© par le K2Cr2O7. Une diminution de la charge bactĂ©rienne totale a Ă©tĂ© observĂ©e au niveau des sĂ©diments pour tous les traitements.On peut dire que la prĂ©sence du sĂ©diment a entraĂźnĂ© la diminution de la teneur du Cr (VI) dans lâeau et que malgrĂ© le dĂ©chromage du ciment, les deux types de ciment prĂ©sentent un effet nĂ©gatif sur les palourdes et les bactĂ©ries indigĂšnes qui est plus marquĂ© pour le ciment non dĂ©chromĂ©.This laboratory study aimed to compare the biological impact of hexavalent chromium (Cr (VI)) present in chromium-containing treated cement and in chromium-free treated cement, by considering two trophic levels: the indigenous bacteria and macrofauna represented by the clam Ruditapes decussatus.In both types of microcosms, one containing only seawater and the other containing seawater and sediment, European clams Ruditapes decussatus were introduced at a density of 20 individuals per aquarium. Four types of aquariums were used: control (T), contaminated with non-dechromated cement (0.16 mgâąL-1 of Cr (VI)), contaminated with dechromated cement (0.05 mgâąL-1 of Cr (VI)), and one contaminated with potassium dichromate (0.16 mgâąL-1 of Cr (VI)). Two replicates were performed for each type of microcosm. The Cr (VI) content of the water was determined with a colorimetric assay at the beginning of the experiment and after 96 h. The quantification of heterotrophic bacteria was performed by the Most Probable Number method.About 80% of the Cr (VI) present in the sediment-water aquarium was trapped in the sediment. Cement, non-dechromated and dechromated, caused 100% clam mortality after three days. However, only 40% clam mortality was observed in aquariums contaminated with K2Cr2O7. A decrease in total bacterial load was observed in the sediment for all treatments.We conclude that the presence of sediment in the aquariums led to a reduction of the Cr (VI) concentration in the overlying water, and that despite the chromium removal treatment effected on one of the cements, both types of cement had a negative impact on clams and indigenous bacteria, the impact being stronger for chromium-containing treated cement
First Report of the Winter Moth Operophtera brumata on Quercus canariensis and Q. afares in North West of Tunisia
Operophtera brumata is a newly detected moth in Tunisia. It is considered the most important leaffeeding
pest infesting fruit trees and deciduous forests in northern Europe. A recent outbreak of the
winter moths was observed between 2009 and 2014 in oak forest in the North West of Tunisia with a
peak density in 2010-2011. O. brumata was observed on totally defoliated Quercus canariensis and Q.
afares. In this paper, we present a first report of this pest
Influence of Bizerte city wastewater treatment plant (WWTP) on abundance and antibioresistance of culturable heterotrophic and fecal indicator bacteria of Bizerte Lagoon (Tunisia)
International audienc
First Report of Anacampsis scintillella on Halimium halimifolium in Sejnane (Bizerte, Tunisia)
At the beginning of April 2010, larvae of Orgyia trigotephras and Anacampsis scintillella caused
severe plant defoliation in the region of Sejnane situated in the north of Tunisia. A. scintillella was
observed on totally defoliated Halimium halimifolium plants. Larvae and pupae of A. scintillela were
protected between two or three leaves of the host plant. Life history of A. scintillella is poorly studied,
so far. In this paper, we presented a first report of this pest in Tunisia
Using Sarcocornia fruticosa and Saccharomyces cerevisiae to remediate metal contaminated sediments of the Ria Formosa lagoon (SE Portugal)
Ria Formosa lagoon is a coastal system in the south of Portugal, characterized by sediments contaminated from urban and industrial pollution emissions. In this study, sediments from two contrasted metal contamination level sites, colonized by Sarcocornia fruticosa were used in an on-site experimentation. The heavy metal removal efficiencies of S. fruticosa with and without bioaugmentation using autochthonous metal resistant isolated yeast (Saccharomyces cerevisiae) were compared. After 15 days of incubation, the total amount of metal concentration (Cd, Pb, Ni, Cr, and Cu) in sediments and plant matter were compared. We found a striking difference between heavily contaminated site and less contaminated site. Metal reductions in heavily contaminated site were generated more by S. fruticosa which was inoculated with S. cerevisiae. In the less contaminated sediments, the higher percentage reductions were achieved with S. fruticosa alone. Our results indicate that despite the phytoremediation potential of S. fruticosa, the addition of S. cerevisiae, increases the plant phytoremediation capacity. (C) 2018 European Regional Centre for Ecohydrology of the Polish Academy of Sciences. Published by Elsevier B.V. All rights reserved.info:eu-repo/semantics/publishedVersio
Tophaceous hip gouty arthritis revealing asymptomatic axial gout
Background: Hip and axial involvement is uncommon during gout and may raise diagnostic challenges. We describe a rare case of tophaceous hip gout which lead to the diagnosis of asymptomatic axial tophaceous gout at a single rheumatology center. Case presentation: A 35-year-old man, diagnosed with tophaceous polyarticular gout 14âŻyears before presentation, consulted for a gout attack with reduced hip rangeâofâmotion on physical examination and an increased serum uric acid level (655âŻÂ”mol/L). He had been regularly taking colchicine, allopurinol (300âŻmg/j), and occasionally non-steroidal antiinflammatory drugs. Plain Radiography of the hips revealed bilateral circumferential joint space narrowing, subchondral erosions of the right acetabular, a calcified soft tissue tophus of the left hip and bilateral sacroiliitis grade IV. Computed tomography (CT) showed total ankylosis of the upper segments of both sacroiliac joints and bilateral hip joint space narrowing, subchondral geode eroding the right acetabulum. Moreover, CT revealed soft-tissue tophi involving the major trochanter of the left acetabulum, the right coxofemoral joint and lowest two levels of lumbar facet joints (L4-L5; L5-S1). A spinal and plevis magnetic resonance imaging (MRI) concluded on a gouty tophi, locolized bilaterally intraarticularly in the coxofemoral joints, gluteus medius bursae, lumbar facet joints (L4-L5; L5-S1), and cofirmed bilateral sacroiliitis. Conclusion: The axial and hip gouty arthritis are exceptionnel localisation. Radiographic imaging tools, mainly CT and MRI, may show the monosodium urate crystals and tophi that can contribute to bone and joint lesions of gout. They also allow the exclusion of other possible etiologies such as spondylodiscitis, infection, and neoplasia. Keywords: Gout, Tophi, Hip, Sacroiliitis, Lumbar spin
Portée pédagogique de Facebook à travers un programme de formation à base de caricatures
Contexteâ: Les technologies de lâinformation et de la communication (TIC) offrent des nouvelles avenues pĂ©dagogiques dont la portĂ©e demeure peu connue. Leur combinaison avec les caricatures, dotĂ©es dâune grande attractivitĂ© humoristique, pourrait favoriser la mĂ©morisation et lâapprentissage. Butâ: Ăvaluer la portĂ©e pĂ©dagogique de Facebook Ă travers un programme de formation basĂ© sur les caricatures. MĂ©thodesâ: Il sâagit dâune Ă©tude interventionnelle prĂ©-expĂ©rimentale rĂ©alisĂ©e sur une pĂ©riode de 3âmois et incluant tous les internes et les rĂ©sidents exerçant dans les services chirurgicaux et de rĂ©animation. AprĂšs une Ă©valuation initiale sur la transfusion sanguine, un groupe a Ă©tĂ© crĂ©Ă© sur «âFacebookâ» incluant tous les participants et via lequel 25âmessages clĂ©s sous forme de caricatures ont Ă©tĂ© diffusĂ©s Ă raison de 3âmessages par jour durant une pĂ©riode dâun mois. Finalement, lâĂ©valuation initiale a Ă©tĂ© refaite. Le critĂšre de jugement principal Ă©tait le taux de bonne rĂ©ponse (TBR) par participant. RĂ©sultatsâ: Le taux de participation Ă©tait de 84,6â% lors de la premiĂšre Ă©valuation et de 80,2â% lors de la deuxiĂšme. Au terme de notre intervention, le TBR par participant a augmentĂ© de façon significative (de 52,3 Ă 66,5â%â; pâ<â0,001. Concernant les questions considĂ©rĂ©es comme dangereuses, le TBR a Ă©galement significativement augmentĂ© passant de 49,5 Ă 65,9â% avec pâ<â0,001. Conclusionâ: Lâutilisation dâun moyen de communication tel que Facebook associĂ© Ă un support dâinformation tel que les caricatures permettraient dâamĂ©liorer significativement les connaissances et constitueraient des outils pĂ©dagogiques intĂ©ressants et efficaces