Chemical contamination in fish species from rivers in the North of Luxembourg: Potential impact on the Eurasian otter (Lutra lutra).

Contamination levels of PCBs, and of the heavy metals cadmium (Cd), lead (Pb) and mercury (Hg) were analyzed in four fish species from seven rivers in the North of Luxembourg. During August and September 2007, 85 samples of fish were collected belonging to four species: the stone loach (Barbatula barbatula, n = 12 pools), the chub (Squalius cephalus, n = 36), the barbel (Barbus barbus, n = 23) and eel (Anguilla anguilla, n = 14). The concentration of seven indicator PCBs (P7PCBs) reached a mean of 39 ng g 1 and varied between 4.0 and 346.2 ng g 1 (wet wt) depending on the site and species. Fish collected at Wal- lendorf on the Our River and sites on the Wiltz and the Clerve rivers showed the highest concentrations for PCBs. In comparison with 1994, PCB levels in fish decreased strongly during the last decade in these rivers. Lead was detected at low levels (0–181.4 ng g 1 wet wt). Mercury concentrations ranged between 10.3 and 534.5ngg 1 (wet wt) exceeding maximum tolerable levels for human consumption of 500 ng g 1 in two fish out of 85. Chubs and eels from the Sûre River were the most contaminated by mer- cury. Cadmium levels varied between 4.0 and 103.9 ng g 1 (wet wt). In addition to mercury in fish, cad- mium was the most problematic pollutant on the Our, the Wiltz, the Clerve and the Troine Rivers, because values found in 20% of fish exceeded the threshold of about 10–50 ng g 1 (wet wt) recommended for human health. The total PCB level predicted to accumulate in livers from otter potentially feeding on these fish based on a previously published mathematical model is 37.7 lg g 1 (lipid wt), which is between a proposed ‘‘safe level” and a ‘‘critical level” for otters. Rivers in the North of Luxembourg are thus to some extent polluted, and the establishment of otter populations could be affected by current levels of contamination.Peer reviewe

Versailles project on advanced materials and standards (VAMAS) interlaboratory study on measuring the number concentration of colloidal gold nanoparticles

We describe the outcome of a large international interlaboratory study of the measurement of particle number concentration of colloidal nanoparticles, project 10 of the technical working area 34, "Nanoparticle Populations" of the Versailles Project on Advanced Materials and Standards (VAMAS). A total of 50 laboratories delivered results for the number concentration of 30 nm gold colloidal nanoparticles measured using particle tracking analysis (PTA), single particle inductively coupled plasma mass spectrometry (spICP-MS), ultraviolet-visible (UV-Vis) light spectroscopy, centrifugal liquid sedimentation (CLS) and small angle X-ray scattering (SAXS). The study provides quantitative data to evaluate the repeatability of these methods and their reproducibility in the measurement of number concentration of model nanoparticle systems following a common measurement protocol. We find that the population-averaging methods of SAXS, CLS and UV-Vis have high measurement repeatability and reproducibility, with between-labs variability of 2.6%, 11% and 1.4% respectively. However, results may be significantly biased for reasons including inaccurate material properties whose values are used to compute the number concentration. Particle-counting method results are less reproducibile than population-averaging methods, with measured between-labs variability of 68% and 46% for PTA and spICP-MS respectively. This study provides the stakeholder community with important comparative data to underpin measurement reproducibility and method validation for number concentration of nanoparticles

Versailles project on advanced materials and standards (VAMAS) interlaboratory study on measuring the number concentration of colloidal gold nanoparticles

We describe the outcome of a large international interlaboratory study of the measurement of particle number concentration of colloidal nanoparticles, project 10 of the technical working area 34, "Nanoparticle Populations" of the Versailles Project on Advanced Materials and Standards (VAMAS). A total of 50 laboratories delivered results for the number concentration of 30 nm gold colloidal nanoparticles measured using particle tracking analysis (PTA), single particle inductively coupled plasma mass spectrometry (spICP-MS), ultraviolet-visible (UV-Vis) light spectroscopy, centrifugal liquid sedimentation (CLS) and small angle X-ray scattering (SAXS). The study provides quantitative data to evaluate the repeatability of these methods and their reproducibility in the measurement of number concentration of model nanoparticle systems following a common measurement protocol. We find that the population-averaging methods of SAXS, CLS and UV-Vis have high measurement repeatability and reproducibility, with between-labs variability of 2.6%, 11% and 1.4% respectively. However, results may be significantly biased for reasons including inaccurate material properties whose values are used to compute the number concentration. Particle-counting method results are less reproducibile than population-averaging methods, with measured between-labs variability of 68% and 46% for PTA and spICP-MS respectively. This study provides the stakeholder community with important comparative data to underpin measurement reproducibility and method validation for number concentration of nanoparticles

Versailles project on advanced materials and standards (VAMAS) interlaboratory study on measuring the number concentration of colloidal gold nanoparticles

We describe the outcome of a large international interlaboratory study of the measurement of particle number concentration of colloidal nanoparticles, project 10 of the technical working area 34, "Nanoparticle Populations" of the Versailles Project on Advanced Materials and Standards (VAMAS). A total of 50 laboratories delivered results for the number concentration of 30 nm gold colloidal nanoparticles measured using particle tracking analysis (PTA), single particle inductively coupled plasma mass spectrometry (spICP-MS), ultraviolet-visible (UV-Vis) light spectroscopy, centrifugal liquid sedimentation (CLS) and small angle X-ray scattering (SAXS). The study provides quantitative data to evaluate the repeatability of these methods and their reproducibility in the measurement of number concentration of model nanoparticle systems following a common measurement protocol. We find that the population-averaging methods of SAXS, CLS and UV-Vis have high measurement repeatability and reproducibility, with between-labs variability of 2.6%, 11% and 1.4% respectively. However, results may be significantly biased for reasons including inaccurate material properties whose values are used to compute the number concentration. Particle-counting method results are less reproducibile than population-averaging methods, with measured between-labs variability of 68% and 46% for PTA and spICP-MS respectively. This study provides the stakeholder community with important comparative data to underpin measurement reproducibility and method validation for number concentration of nanoparticles

Dynamics of rare earth elements and associated major and trace elements during Douglas-fir (Pseudotsuga menziesii) and European beech (Fagus sylvatica L.) litter degradation

Given the diverse physico-chemical properties of elements, we hypothesize that their incoherent distribution across the leaf tissues, combined with the distinct resistance to degradation that each tissue exhibits, leads to different turnover rates among elements. Moreover, litter layers of varying ages produce diverse chemical signatures in solution during the wet degradation. To verify our hypothesis, Na, K, Mg, Mn, Ca, Pb, Al and Fe were analysed together with the rare earth elements (REE) in the solid fractions and in the respective leachates of fresh leaves and different litter layers of two forested soils developed under Pseudotsuga menziesii and Fagus sylvatica L. trees. The results from the leaching experiment were also compared with the in situ REE composition of the soil solutions to clarify the impact that the litter degradation processes may have on soil solution chemical composition. Both tree species showed similar biogeochemical processes dominating the element dynamics during litter degradation. REE, Al, Fe and Pb were preferentially retained in the solid litter material, in comparison with the other cations, and their concentrations increased over time during the degradation. Accordingly, different litter fractions produced different yields of elements and REE patterns in the leachates, indicating that the tree species and the age of the litter play a role in the chemical release during degradation. In particular, the evolution of the REE patterns, relative to the age of the litter layers, allowed us to deliver new findings on REE fractionation and mobilization during litter decay. Specifically, the degradation of the litter was characterized by a decrease in the Y/Ho ratio and an increase in the LaN/YbN ratio. The relationship between these ratios provided information on the litter species-specific resistance to degradation, with Douglas-fir litter material showing a lower resistance. During the litter degradation of the two tree species, two main differences were highlighted with the help of the REE: (i) in Pseudotsuga menziesii the behaviour of Eu appeared to be linked to Ca during leaf senescence and (ii) species-specific release of organic acids during litter degradation leads to a more pronounced middle REE (MREE) enrichment in the Fagus sylvatica leachates. Finally, we showed the primary control effect that white fungi may have in Ce enrichment of soil solutions, which appears to be associated with the dissolution and/or direct transport of Ce-enriched MnO2 accumulated on the surface of the old litter due to the metabolic functioning of these microorganisms. Similar MREE and heavy REE (HREE) enrichments were also found in the leachates and the soil solutions, probably due to the higher affinity of these elements for the organic acids, which represent the primary products of organic matter degradation

Soluble silver ions from silver nanoparticles induce a polarised secretion of interleukin-8 in differentiated Caco-2 cells

Because of their antimicrobial properties, silver nanoparticles are increasingly incorporated in food-related and hygiene products, which thereby could lead to their ingestion. Although their cytotoxicity mediated by oxidative stress has been largely studied, their effects on inflammation remain controversial. Moreover, the involvement of silver ions (originating from Ag0 oxidation) in their mode of action is still unclear. In this context, the present study aims at assessing the impact of silver nanoparticles on the secretion of the pro-inflammatory chemokine interleukin-8 by Caco-2 cells forming an in vitro model of the intestinal mucosal barrier. Silver nanoparticles induced a vectorized secretion of interleukin-8 towards the apical compartment, which is found in the medium 21 h after the incubation. This secretion seems mediated by Nrf2 signalling pathway that orchestrates cellular defense against oxidative stress. The soluble silver fraction of silver nanoparticles suspensions led to a similar amount of secreted interleukin-8 than silver nanoparticles, suggesting an involvement of silver ions in this interleukin-8 secretion

Comparative study of the ecotoxicological effects of different sizes of silver nanoparticles on physiological and behavioural responses of Gammarus sp

International audienc

The Potato in the Human Diet: a Complex Matrix with Potential Health Benefits

Beyond providing energy through its high starch content, the potato tuber can make a significant contribution to the dietary intake of certain minerals including potassium, phosphorous, magnesium and iron, as well as of vitamin C, dietary fibres and phenolic compounds. While some animal and human studies have shown beneficial associations between the consumption of potato, or some of its components, and health, some other studies could not confirm these positive effects. Numerous factors may indeed influence (i) the composition of the potato tuber itself, i.e. genotype, environmental conditions during growth, post-harvest storage conditions, cooking and processing, and (ii) the bioaccessibility and bioavailability of its components, affecting the final bioactivity. The purpose of this paper is to provide a brief overview of potato composition variability followed by an analysis of potential health-promoting effects and bioavailability of specific components including iron and phenolic compounds. It appeared that the various components of the potato matrix might interact with each other at the intestinal level, leading to favourable or detrimental effects on their bioavailability. The consumption of a potato cultivar with a high level of phenolic compounds may improve the health status of an individual regarding its risk of developing chronic diseases on the one hand, but may reduce iron absorption on the other hand, putting an individual at risk of micronutrient deficiency. Tailoring potato varieties or products to match the population nutritional needs appears therefore of major importance. © 2015 European Association for Potato Researc

Evaluation and comparison of nutritional quality and bioactive compounds of berry fruits from Lonicera caerulea, Ribes L. species and Rubus idaeus grown in Russia

The fruits of three berry species cultivated in Russia, Rubus idaeus, Ribes L. species (R. nigrum and R. nigrum × R. 12 dikuscha) and the less common Lonicera caerulea, were investigated for their minerals and phytochemical compounds. Under the 13 same environmental conditions, differences in contents of nutrients and bioactive compounds among species were found. Lonicera 14 caerulea contained the highest level of K, Ribes L. presented the highest content of Ca, while R. idaeus displayed the highest 15 content of Mg and different micro-elements (Fe, Mn, Zn and Mo). Lonicera caerulea and Ribes L. displayed the highest content 16 of sugars, but the profile of individual sugars differed among each species, with a probable influence on the fruit’s organoleptic 17 quality. The most striking result was the polyphenolic contents of L. caerulea which was significantly higher than that of Ribes 18 L. and R. idaeus, two species already known to contain large amounts of these antioxidant compounds. This difference was 19 much higher when the subclass of anthocyanins is considered. These results revealed L. caerulea as a promising species from a 20 nutritional perspective