Agénésie de la vésicule biliaire: à propos de trois cas

L’agénésie de la vésicule biliaire est une anomalie congénitale rare. Le but de ce travail est d’étudier, à travers trois cas que nous rapportons, les aspects épidémiologiques de cette affection ainsi que les particularités de diagnostic et de prise en charge thérapeutique. Les 2 adultes ont été admis pour coliques hépatiques et troubles dyspeptiques avec à l’échographie une vésicule scléroatrophique multilithiasique. L’un des deux a eu un scanner qui a objectivé l’aspect d’un calcul au niveau d’une vésicule scléroatrophique. Ces 2 malades ont été opéréspar voie classique à tort pour lithiase vésiculaire. L’absence de vésicule biliaire a été découverte en per opératoire. Afin de confirmer le diagnostic en post opératoire, on a pratiqué une bili-IRM pour la 1ère patiente. L’autre malade a été perdu de vue. Notre 3ème cas, une enfant de 13 ans, hospitalisée pour pancréatite aigüe et l’agénésie vésiculaire a été suspectée devant l’aspect scannographique, puis confirmée par la Bili-IRM et elle n’a pas été opérée

Chemical speciation of Fe, Mn, Pb, Zn, Cd, Cu, Co, Ni and Cr in the suspended particulate matter off the Mejerda River Delta (Gulf of Tunis, Tunisia)

International audienceFluxes of suspended particulate matter (SPM) and their associated metals were performed off the Mejerda River Delta during both the wet (March) and the dry (July) seasons in 2012, using sediment traps at study stations at depths of 10, 20 and 40 m. Fluxes nearest to the Mejerda outlet were more significant, especially during winter (36 g m−2 day−1), but dissipated further offshore, 24.5–6 g m−2 day−1 at the 20 m and 21.8–4.8 g m−2 day−1 at the 40 m stations. Many variations observed in seasonal and spatial metal fluxes are similar to those of SPM, in particular Pb and Zn, probably because they are associated with the mining activity characteristic of the Mejerda catchment. Chemical speciation reveals that most of the metals (20–100%) are bound to the residual fraction. The most toxic metals (Pb, Zn) are bound in part to the exchangeable fraction (20–50% for Pb and 5–15% for Zn) making them relatively bioavailable and therefore potentially toxic. While Cu and Cd fluxes are not always clearly established according to season, both metals are apparently sequestered deep in the sediment, bound especially to clays (40–80% for Cd and up to 100% for Cu)

Diagenetic processes and sediment-water exchanges of heavy metals in the Mejerda River Delta (Gulf of Tunis)

International audienc

Bioavailability and assessment of heavy metal pollution in sediment cores off the Mejerda River Delta (Gulf of Tunis): How useful is a multiproxy approach ?

International audienceThree core samples were taken from zones offshore from the Mejerda River Delta (Tunisia) and analyzed formajor and trace elements to assess their relationships with organic matter, monosulfides and carbonates, aswell as for pollution and bioavailability. Chemical speciation,ΣSEM/AVS, the enrichment factor (EF) and thegeo-accumulation index (I-geo) were used. Iron, cadmium, lead and zinc – the most frequently mined metalsin the Mejerda catchment – were found as contaminants in the offshore areas. Estimations of trace elementaccumulation using the EF and the I-geo index show that lead, and to a lesser extent zinc, are the most pollutingmetals off the Mejerda outlet. According to their bioavailability, these metals are also the most toxic. Only cadmiumis heavily present in delta sediment (EF N 100) though deeply sequestrated (100% bound to the residualfraction) and thus presents no toxicity

Suspended particulate matter fluxes along with their associated metals, organic matter and carbonates in a coastal Mediterranean area affected by mining activities

International audienceA study of suspended particulate matter (SPM) fluxes along with their associated metals, organic matter and carbonates, was conducted off the Mejerda River outlet in May 2011 and in March and July 2012 at depths of 10, 20 and 40 m using sediment traps. SPM fluxes are more significant near the Mejerda outlet, especially in winter, but dissipate further offshore. Normalization reveals that the Mejerda is a major source of Pb, Zn, Cd, Cu, Ni, and Co, all of which are the result of human activities. In contrast, Fe, Mn and N are of authigenic origin. The enrichment factor shows that Pb, Zn and especially Cd are the most highly polluting metals off the Mejerda outlet. This confirms the trend observed on the shores of the Mejerda prodelta and is consistent with the type of mining activities conducted in the Mejerda catchment

Nutrient exchange and oxygen demand at the sediment–water interface during dry and wet seasons off the Medjerda River Delta (Tunis Gulf, Tunisia)

International audienc

Metal transfer budgets in a Mediterranean marine environment subjected to natural and anthropogenic inputs: case of the Mejerda River Delta (Gulf of Tunis, northern Tunisia)

International audienceDeltaic sediments are important for biogeochemical metal cycling since they are hotspots for metal inputs. In addition, they are potential sites for diagenetic processes leading to either the burial of inorganic contaminants or their release. Diffusive fluxes of certain metals (Fe, Mn, Pb, Zn, Cu and Cd) in the sediments of the Mejerda River Delta (MRD) (Gulf of Tunis, Tunisia) were quantified by modeling the available concentration profiles in the pore water. The metals’ burial and sedimentation fluxes were also calculated using both the asymptotic concentrations of available metal profiles and sediment trap results. These fluxes were assembled with the exchange fluxes at the sedimentwater interface in order to develop complete metal transfer budgets. The results showed that budgets of Cu and Zn are almost neutral. The sediment appears tobe a good trap for iron since its average burial flux at the three studied stations is about 332.6 g m−2 year−1. Organic matter degradation, carbonate dissolution, and oxyhydroxide reduction are the main mechanisms which accelerate the release of metals associated with the suspended particle matter once they reach the pore water in the seabed

Sulfide influence on metal behavior in a polluted southern Mediterranean lagoon: implications for management

International audienc

Distribution and assessment of heavy metal toxicityin sediment cores from Bizerte Lagoon, Tunisia

International audienceTo examine the state of pollution of Bizerte Lagoon which is exposed to intense anthropogenic pressure, two sediment cores were taken at two sites, one undergoes the dual effects of both marine waters arriving from the Mediterranean Sea through the Channel, and also of freshwater from the Tinja River; the other core is located at the center of the lagoon where water depth is maximal (12 m). Heavy metal concentrations in the two cores were assessed, with calculated enrichment factors and geo-accumulation indexes. Core sediments were also studied for chemical speciation and their monosulfide contents were measured. Results from enrichment factors and geo-accumulation indexes show an accumulation of Cd, Zn, Cr, and Pb, while chemical speciation revealed a risk only from Cd and Mn. Comparison of sequential extraction values with those of acid volatile sulfides revealed that non-toxic effects may be caused by any of the studied metals in the sediment