A Retrospective Isotopic Study of Spruce Decline in the Vosges Mountains (France)

The objective of this study was to assess the time variation of mineral and water stress levels across the life of a declining, Mg-deficient, spruce stand, in order to clarify the factors that caused the decline. Since 1985, strong soil acidification linked to a large leaching of nitrate and base cations was measured at the study site. In 1994, 5 trees were felled and tree rings were measured and analysed for Ca, Mg, K, Sr, ¹³C¹²C and ⁸⁷Sr/⁸⁶Sr isotopic ratios. Strontium pools and fluxes as well as root Sr isotope ratio in relation to depth were also measured. Wood chemical concentrations and isotope ratios were strongly related to the dominance status of each tree. On average during the study period, the ⁸⁷Sr/⁸⁶Sr ratio of spruce wood decreased. Using a mechanistic model computing long term variations of ⁸⁷Sr/⁸⁶Sr ratio in trees and soils, we reproduced the observed trend by simulating soil acidification – increasing Sr drainage from the whole profile, and particularly from the organic horizon –, and root uptake becoming more superficial with time. Between 1952 and 1976, tree ring ¹³C decreased strongly and continuously, which, in addition to other factors, might be related to an increase in water stress. Thus, a decrease in rooting depth, possibly related to soil acidification, appeared as a possible cause for the long term increase in water stress. The extreme drought event of 1976 appears to have revealed and triggered the decline.     

Croissance de la larve de l'oursin Paracentrotus lividus

Paracentrotus lividus (Lamarck) larvae were reared to metamorphosis. The larvae were fed on the haptophycean Hymenomonas elongata Droop (Braarud) at three concentrations: 9 to 14×10⁵, 24 to 37×10⁵, 43 to 61×10⁵ μm³ cells ml^-1 d^-1. Optimum growth took place at a density of 24 to 37×10⁵ μm³ algal cells. Growth of the plutei was estimated in terms of weight increases in protein, carbohydrate and lipid; growth equations are given. The relationship between growth and the food ingested was calculated for the different larval stages. Earlier field data for the bay of Villefranche have shown the mean biovolume of nanoflagellates to be 0.65×10⁵ μm³ ml^-1; at such in situ food concentrations, P. lividus larvae would metamorphose only after one month of planktotrophic life. Chemoreception by larvae could lead to prey selection, thereby altering the amounts of protein, carbohydrate and lipid ingested, and hence the duration of larval life.     

Sterols in sediment samples from Venice Lagoon, Italy

Sterols of different origin were analysed in sediment samples collected in the Venice Lagoon. The purpose of the study was to investigate the degree of sewage contamination within the Lagoon using fecal sterols (coprostanol, epicoprostanol and coprostanone) and to analyse the pattern of the sterols to plot the origin of the organic matter.

Sedimentary coprostanol at Canal Grande within the city of Venice was more than one order of magnitude higher than other stations in the Lagoon and two orders higher than in a sediment sample collected in the open sea. The cholesterol/coprostanol ratio, like the percentage of coprostanol in total sterols at this sample site was very similar to values in sewage sludge. The different pattern of sterols at station 2 which had the largest amount of total sterol indicates a difference in the origin of the organic material. Nevertheless the sterols used as tracer of terrestrial vascular plants did not show any particular trend at this station, receiving fresh water inputs. (3-Sitosterol and cholestanol reached the highest levels at the station within the Chioggia basin.     

Advanced techniques in air pollution†

Specific usage of neutron activation analysis, charged particle analysis, y photons analysis, G.C.M.S. coupling, stable isotope dilution techniques, are discussed.

Dust collected on filters, oxygenated compounds in exhaust gases from car engines, nitrogen oxides, have thus been determined.

Special calibration methods for ozone, and remote detection by Lidar Raman are also described.     

Comprehensive primary particulate organic characterization of vehicular exhaust emissions in France

A study to characterize primary particulate matter (PM_2.5 and PM₁₀) from the French vehicular fleet was conducted during winter 2008, in a tunnel in Marseille, France. The carbonaceous fraction represents 70% of the aerosol mass and elemental carbon fraction (EC) represent 60% of the carbonaceous fraction. The organic carbon OC was characterized in term of its water soluble fraction, functionalization rate and HULIS content. Seventy trace organic compounds including alkanes, polycyclic aromatic hydrocarbons (PAH), petroleum biomarkers and carboxylic acids were also quantified, in order to determine an organic emission profile for chemical mass balance modeling studies. Such source profiles were still missing in Europe and particularly in France. The profile obtained in this study is consistent with profiles determined in tunnel or dynamometer studies performed in other countries during the last ten years. These results suggest that organic compounds profiles from vehicular exhaust emissions are not significantly influenced by the geographic area and are thus suitable for use in aerosol source apportionment modeling applied across extensive regions. The chemical profile determined here is very similar to those obtained for diesel emissions with high concentrations of EC relative to OC (EC/OC = 1.8) and low concentrations of the higher molecular weight PAH. These results are consistent with the high proportion of diesel vehicles in the French fleet (49%).     

Production of zeolitic materials in pilot scale based on coal ash for phosphate and potassium adsorption in order to obtain fertilizer

Environmental Science and Pollution Research - The use of different types of zeolites (X, Na-P1, and 4A) synthesized by different methods and scales were tested in this work to adsorb nutrients...     

Estimating an homogeneous series of a population abundance indicator despite changes in data collection procedure: A hierarchical Bayesian modelling approach

Abundance indicators are required both to assess and to manage wild populations. As new techniques are developed and teams in charge of gathering the data change, data collection procedures (DCPs) can evolve in space and time. How to estimate an homogeneous series of abundance indicator despite changes in DCP? To tackle this question a hierarchical Bayesian modelling (HBM) approach is proposed. It integrates multiple DCPs in order to derive a single abundance indicator that can be compared over space and time irrespective of the DCP used. Compared to single DCP models, it takes further advantage for abundance estimation of the joint treatment of a larger set of spatio-temporal units. After presenting the general formulation of our HBM approach, it is applied to the juvenile Atlantic salmon (Salmo salar L.) population of the River Nivelle (France). Posterior model checking, using χ² discrepancy measure, do not reveal any inadequacy between the model and the data. Despite a change in the DCP used (successive removals to catch-per-unit of effort), a unique abundance indicator for the 425 spatio-temporal units (site × year) sampled over twenty-four years (1985-2008) is estimated. The HBM approach allows the assessment of precision of the abundance estimates and shows variation between DCPs: a reduction in precision is observed during the most recent years (2005-2008) when only the catch-per-unit of effort DCP was used. The merits and generality of our HBM approach are discussed. We contend it extends previous single DCP models or inter-calibration of two DCPs, and it could be applied to a wide range of specific situations (taxon and DCPs).     

A Review of Known and Hypothetical Transmission Routes for Noroviruses

Human noroviruses (NoVs) are considered a worldwide leading cause of acute non-bacterial gastroenteritis. Due to a combination of prolonged shedding of high virus levels in feces, virus particle shedding during asymptomatic infections, and a high environmental persistence, NoVs are easily transmitted pathogens. Norovirus (NoV) outbreaks have often been reported and tend to affect a lot of people. NoV is spread via feces and vomit, but this NoV spread can occur through several transmission routes. While person-to-person transmission is without a doubt the dominant transmission route, human infective NoV outbreaks are often initiated by contaminated food or water. Zoonotic transmission of NoV has been investigated, but has thus far not been demonstrated. The presented review aims to give an overview of these NoV transmission routes. Regarding NoV person-to-person transmission, the NoV GII.4 genotype is discussed in the current review as it has been very successful for several decades but reasons for its success have only recently been suggested. Both pre-harvest and post-harvest contamination of food products can lead to NoV food borne illness. Pre-harvest contamination of food products mainly occurs via contact with polluted irrigation water in case of fresh produce or with contaminated harvesting water in case of bivalve molluscan shellfish. On the other hand, an infected food handler is considered as a major cause of post-harvest contamination of food products. Both transmission routes are reviewed by a summary of described NoV food borne outbreaks between 2000 and 2010. A third NoV transmission route occurs via water and the spread of NoV via river water, ground water, and surface water is reviewed. Finally, although zoonotic transmission remains hypothetical, a summary on the bovine and porcine NoV presence observed in animals is given and the presence of human infective NoV in animals is discussed.