Background levels of heavy metals in surficial sediments of the Gulf of Lions (NW Mediterranean): An approach based on 133Cs normalization and lead isotope measurements

This paper presents an attempt to reach natural background levels of heavy metals in surficial sediments of the Gulf of Lions(NW Mediterranean). To correct for the grain-size effect, normalization procedures based on a clay mineral indicator element are commonly used, after a first grain size separation by sieving. In our study, we tested the applicability of this method with respect to commonly used normalizer elements, and found that stable Cs shows the best ability to reflect the fine sediment fraction. Background levels were successfully reached for Co, Cr, Cu, Ni and Pb, compared to various literature references. Nevertheless, in the case of lead, the normalized data depicted a general enrichment in all samples, and the natural levels could only be reached when concentrations were corrected for the atmospheric contribution by analysing lead isotope ratios. Also for Zn, a general enrichment was found in our samples, although less important

Go with the Flow - Design of Cloud Logistics Service Blueprints

By adopting principles of cloud computing to the \ logistics domain the paradigm of Cloud Logistics is derived. It \ appears to be a promising paradigm in order to evolve logistics \ into being more flexible and collaborative. Yet, appropriate \ concepts that enable the cloud logistics paradigm are missing. \ In the paper, existing body of literature is reviewed and a \ definition and a framework of cloud logistics is given. Further, \ service blueprinting is combined with domain engineering and \ general morphological analysis in order to create a suitable \ method for designing cloud oriented service blueprints. Those \ are focusing on domain-specific flows and transformations \ enabling cloud oriented business collaboration. The method \ is applied to the logistics domain and a cloud logistics service \ blueprint is designed. Finally, the concept is evaluated with \ real use cases from logistics service providers

Sources and sinks of sediment-bound contaminants in the Gulf of Lions (NW Mediterranean Sea): A multi-tracer approach

Surficial sediments collected in 2002 throughout the Gulf of Lions continental shelf (NW Mediterranean) were analysed for trace metals (Cd, Co, Cr, Cs, Cu, Ni, Pb, Sr, Zn and Zr), major elements (Al, Ca, Fe, P and Ti) and the sewage marker coprostanol. In addition, particle size distribution, organic carbon (OC) and carbonates were also determined. Results showed that the metal contamination (Cd, P, Cu, Pb and Zn) is mainly introduced by the local rivers and accumulates—via a regulation by OC and silt fraction (2–63 mm)—in the direct vicinity of the mouths, in high shear stress environments. Here also the signal of sewage contamination is the best preserved, especially off the eastern point sources where local sedimentation rates save the faecal marker from biodegradation processes. It is demonstrated that the shallow prodeltas are the first repository areas for land-derived particles, exposing local ecosystems to both inorganic and organic contaminations. When going seaward, however, sediment dilution, particle sorting and biodegradation processes make that most riverborne contaminants rapidly reach natural levels. Only some metals (i.e. Pb and Zn)—closely associated with the clay fraction—still depict anthropogenic enrichment, which seems to be inherited from man-made aerosols

Fate of metals in coastal sediments of a Mediterranean flood-dominated system: An approach based on total and labile fractions

The dynamics of sediment-bound metals (Cs, Cu, Ni, Pb, Ti and Zn) were studied off the Têt River (western Gulf of Lion), a typical Mediterranean coastal river punctuated by short and violent flash-floods. Spatial and temporal sampling strategies were combined to elucidate the fate of these elements in response to both the riverine sediment input and the offshore transport of these sediments through hydrodynamics. Our results show the temporal entrapment of riverborne particles and associated metals, consecutively to a major flood event, in the nearshore sedimentary unit called prodelta. Here, deposition and resuspension mechanisms define a sedimentological cycle that could be followed completely in this study. In terms of speciation between reactive (labile) and residual fractions along the fluvio-deltaic continuum, our results show that Cu, Pb and Zn are the most labile (potentially mobile) metals in the river, in accordance with their contributions from anthropogenic sources. But in the marine surficial sediments, two main behaviours can be discriminated when compared to the riverine suspended particulate matter. While Pb and Zn depict rather a constant labile fraction, Cu is characterized by decreasing levels (up to 50% difference). In terms of environmental impact, these contrasting trends have direct repercussions for the contaminant dispersal in the coastal area. Whereas Pb and Zn conserve their enhanced levels because of their stronger affinity with fine sediments, Cu is marked by the entire loss of its anthropogenic component that is progressively transferred to the dissolved phase, likely mediated by organic ligands. We ascribe these behaviours to different post-depositional partition mechanisms with respect to oxidation of the particulate organic phase at the bottom sediment/water interface. Also, analysis of one sediment core from the prodelta indicates that these early diagenetic processes govern the chemical forms of land-derived contaminants sequestrated in the nearshore sedimentary archives