Combined uncertainty estimation for the determination of the dissolved iron amount content in seawater using flow injection with chemiluminescence detection

This work assesses the components contributing to the combined uncertainty budget associated with the measurement of the Fe amount content by flow injection chemiluminescence (FI-CL) in <0.2 μm filtered and acidified seawater samples. Amounts of loaded standard solutions and samples were determined gravimetrically by differential weighing. Up to 5% variations in the loaded masses were observed during measurements, in contradiction to the usual assumptions made when operating under constant loading time conditions. Hence signal intensities (V) were normalised to the loaded mass and plots of average normalized intensities (in V kg-1) versus values of the Fe amount content (in nmol kg-1) added to a ‘low level’ iron seawater matrix were used to produce the calibration graphs. The measurement procedure implemented and the uncertainty estimation process developed were validated from the agreement obtained with consensus values for three SAFe and GEOTRACES reference materials (D2, GS and GD). Relative expanded uncertainties for peak height and peak area based results were estimated to be around 12% and 10% (k=2) respectively. The most important contributory factors were the uncertainty on the sensitivity coefficient (i.e. calibration slope) and within-sequence-stability (i.e. the signal stability measured over several hours of operation; in this case 32 h). Therefore, an uncertainty estimation based on the intensity repeatability alone, as is often done in FI-CL studies, is not a realistic estimation of the overall uncertainty of the procedure.JRC.D.2-Standards for Innovation and sustainable Developmen

Prenatal diagnosis of Caudal Regression Syndrome : a case report

BACKGROUND: Caudal regression is a rare syndrome which has a spectrum of congenital malformations ranging from simple anal atresia to absence of sacral, lumbar and possibly lower thoracic vertebrae, to the most severe form which is known as sirenomelia. Maternal diabetes, genetic predisposition and vascular hypoperfusion have been suggested as possible causative factors. CASE PRESENTATION: We report a case of caudal regression syndrome diagnosed in utero at 22 weeks' of gestation. Prenatal ultrasound examination revealed a sudden interruption of the spine and "frog-like" position of lower limbs. Termination of pregnancy and autopsy findings confirmed the diagnosis. CONCLUSION: Prenatal ultrasonographic diagnosis of caudal regression syndrome is possible at 22 weeks' of gestation by ultrasound examination

Arsenic speciation in shrimp and mussel from the Mid-Atlantic hydrothermal vents

cited By 52International audienceSpecimens of shrimp (Rimicaris exoculata) and mussel (Bathymodiolus puteoserpentis) were collected 3500 m below the ocean surface at the hydrothermal vents of the mid-Atlantic Ridge (TAG and Snake Pit sites, respectively). Arsenic, a potentially toxic element, is among the substances emitted by the hydrothermal vents. The hydrothermal vent shrimp, which are known to be a primary consumer of the primary producing chemolithoautotrophic bacteria, contained arsenic at 13 μg g-1 almost exclusively as arsenobetaine (AsB). Arsenic was present in the soft tissues of the mussel at 40 μg g-1 and the major part of the extractable arsenic species in the adductor muscle/mantle tissues and in the gill were present as dimethylarsinylriboside-derivatives (arsenosugars), while AsB was present at 16 and 3.6%, respectively, in these tissues. In spite of the absence of biosynthetically active algae, the pattern of arsenic species found in the shrimp and mussel species in the deep-sea is similar to that found in their counterparts from the ocean surface. It is concluded that the autotrophic bacteria of the hydrothermal vent ecosystem and the symbiotic bacteria harboured in the mussel species are responsible for the biosynthesis of the organoarsenicals detected in the two hydrothermal vent animal species. It is not known if the formation of the same organoarsenicals in the surface and deep sea ecosystems is primarily a detoxification process of inorganic arsenic, or whether these compounds play a physiological role