International audience | A climatic classification for Europe suitable for pesticide fate modelling was constructed using a 3-stage process involving the identification of key climatic variables, the extraction of the dominant modes of spatial variability in those variables and the use of k-means clustering to identify regions with similar climates. The procedure identified 16 coherent zones that reflect the variability of climate across Europe whilst maintaining a manageable number of zones for subsequent modelling studies. An analysis of basic climatic parameters for each zone demonstrates the success of the scheme in identifying distinct climatic regions. Objective criteria were used to identify one representative 26-year daily meteorological series from a European dataset for each zone. The representativeness of each series was then verified against the zonal classifications. These new FOOTPRINT climate zones provide a state-of-the-art objective classification of European climate complete with representative daily data that are suitable for use in pesticide fate modelling.

International audience | This paper compares different vegetation types (coniferous and deciduous forest, grassed and pure heathland) in terms of input (throughfall deposition) and output (seepage flux) in a region with intermediate nitrogen load (+/-20 kg N ha(-1) y(-1) via bulk precipitation) in comparable conditions in north Belgium. Coniferous forest (two plots Pinus sylvestris and two plots Pinus nigra) received significantly higher nitrogen and sulphur throughfall deposition than deciduous forest and heathland. Grassed and pure heathland had significantly highest throughfall quantities of Ca2+ and Mg2+, respectively. The observed differences in throughfall deposition between the different vegetation types were not univocally reflected in the ion seepage flux. Considerable seepage fluxes of NO3-, SO42-, Ca2+ and Al(III) were only found under the P. nigra plots. We discuss our hypothesis that the P. nigra forests already evolved to a situation of N saturation, while the other vegetation types did not. (C) 2007 Elsevier Ltd. All rights reserved.

International audience | Five organic matters, three phosphate compounds, zerovalent iron grit (ZVIG, 2% by soil weight), two alkaline compounds, and two commercial formulations were incorporated, singly and some combined with ZVIG, into a highly Cu-contaminated topsoil (Soil P7, 2600 mg Cu kg−1) from a wood treatment facility. Formulations and two composts were also singly incorporated into a slightly Cu-contaminated topsoil (Soil P10, 118 mg Cu kg−1) from the facility surrounding. This aimed to reduce the labile pool of Cu and its accumulation in beans cultivated on potted soils in a climatic chamber. Lowest Cu concentration in soil solution occurred in P7 soils amended with activated carbon (5%) and ZVIG, singly and combined. Basic slag (3.9%) and compost of sewage sludge (5%) combined with ZVIG promoted shoot production and limited foliar Cu accumulation. For amended P10 soils, no changes occurred in soil solution and foliar Cu concentrations, but one compost increased shoot production. Three soil amendments, iron grit with compost, calcium oxide, and basic slags, decreased the phytotoxicity of a Cu-contaminated soil.

The ammonia stomatal compensation point of plants is determined by leaf temperature, ammonium concentration ([NH4+]apo) and pH of the apoplastic solution. The later two depend on the adjacent cells metabolism and on leaf inputs and outputs through the xylem and phloem. Until now only empirical models have been designed to model the ammonia stomatal compensation point, except the model of Riedo et al. (2002. Coupling soil-plant-atmosphere exchange of ammonia with ecosystem functioning in grasslands. Ecological Modelling 158, 83e110), which represents the exchanges between the plant’s nitrogen pools. The first step to model the ammonia stomatal compensation point is to adequately model [NH4+]apo. This [NH4+]apo has been studied experimentally, but there are currently no process-based quantitative models describing its relation to plant metabolism and environmental conditions. This study summarizes the processes involved in determining the ammonia stomatal compensation point at the leaf scale and qualitatively evaluates the ability of existing whole plant N and C models to include a model for [NH4+]apo.

International audience | Expansion of aquaculture has increased concern over its environmental impact. The composition of effluents from intensive aquaculture is well documented, but few data on extensive aquaculture are available. During 12 draining operations, 523 water samples were collected downstream from six extensively-managed fishponds in northeastern France. Study ponds had surface areas of 2–620 ha and were managed for production of Cyprinids and Percids. Concentrations of total suspended solids, total phosphorus, and Kjeldahl nitrogen in effluents from the ponds were greatest during the final stage of draining. Loads of phosphorus were higher than those reported for effluents of more intensive aquaculture ponds in the USA, but the source of the potential pollutants was catchments and sediment rather than feeds and fertilizer. It will be necessary to reduce the water drawdown rate during the fishing stage and possibly implement other best management practices to prevent the TSS concentration from exceeding 1 g/L. Effluent phosphorus loads were higher than those reported for more intensive aquaculture ponds, but the pollutant source was catchments rather than feeds and fertilizers.

peer reviewed | We evaluated the alterations of organochlorinated compounds such as polychlorobiphenyls (PCB), dichloro-diphenyl-dichloroethylene (DDE) and dichloro-diphenyl-trichloroethane (DDT) on the thyroid in wild and cultured sea bass (Dicentrarchus labrax) at environmental concentrations. These compounds influence the endocrine system of many fish species and are qualified as endocrine disruptors. The thyroid seems to be a target organ. Two alteration endpoints: the thyroid histology and the muscular thyroid hormone concentrations, were used simultaneously. High concentrations in PCBs and DDT were detected in muscles, supporting the idea that the Mediterranean fauna could be more polluted than the Atlantic fauna. The high abundance of DDE indicates a progressive degradation of remnant DDT load and the absence of new inputs in this area. Aquaculture sea bass shows a significant higher amount of pollutants on fresh weight basis (especially PCBs) in their muscles compared to the wild sea bass. Those differences may be related mainly to the contaminations of diet. Thyroid parameters vary between wild and aquaculture sea bass, wild sea bass were characterized by higher follicle diameters, epithelial cell heights and muscular T4 concentrations. A significant relationship between persistent organic pollutants (muscular PCBs and DDT concentration) and the different thyroid parameters (diameters of follicles, epithelial cell heights and muscular T4 levels) could be observed, which support the hypothesis that these compounds have an adverse impact on thyroid morphometry and function.

Kinetic EDTA and citrate extractions were used to mimic metal mobilization in a soil contaminated by metallurgical fallout. Modeling of metal removal rates vs. time distinguished two metal pools: readily labile (QM1) and less labile (QM2). In citrate extractions, total extractability (QM1 + QM2) of Zn and Cd was proportionally higher than for Pb and Cu. Proportions of Pb and Cu extracted with EDTA were three times higher than when using citrate. We observed similar QM1/QM2 ratios for Zn and Cu regardless of the extractant, suggesting comparable binding energies to soil constituents. However, for Pb and Cd, more heterogeneous binding energies were hypothesized to explain different kinetic extraction behaviors. Proportions of citrate-labile metals were found consistent with their short-term, in-situ mobility assessed in the studied soil, i.e., metal amount released in the soil solution or extracted by cultivated plants. Kinetic EDTA extractions were hypothesized to be more predictive for long-term metal migration with depth.