International audience

Concerns about the use of residues from municipal solid waste incinerators (MSWI) in construction materials usually focus on the potential for heavy metals and organic chemicals to leach into drainage waters under the influence of rain.We hypothesised that high level of salts in the MSWI leachates may cause more of a problem, particularly on soil physico-chemical properties. Both bottom ash (BA) and Solidified Air Pollution Control residue (SAPCr) leachates were added to experimental grassland plots. The amounts of Na+ increased by up to 13% in soils supplemented with each leachate. A decrease of the soil total porosity (−14%) was evidence of a subsequent adverse physical effect of this strong salinity. The potential for the grass cover type (species composition or density) to limit this adverse effect was discussed. Laboratory tests allowed us to determine that undiluted SAPCr induced slaking of aggregates accompanied by a strong decrease of aggregate stability, to 49% of control values. Undiluted BA induced dispersion of clays and others fine particles, which are then dislodged and transported into pores, causing blockage and decreasing total porosity. Clay dispersion followed by aggregate collapse occurred when soil solution contaminated by SAPCr was diluted by rainwater. This work stressed the importance of accounting for mineral contaminants, such as salts, when conducting an assessment of waste reuse scenarios.

Six marine sediment cores from the Gulf of Lions continental slope (700-1700 in water depth) were analyzed for stable lead isotopes and Pb-210 geochronology in order to reconstruct lead atmospheric fallout pattern during the last century. The detrital lead contribution is 25 mu g g(-1) and the mean sediment anthropogenic inventory is 110 +/- 7 mu g cm(-2), a little bit higher than atmospheric deposition estimate. Anthropogenic lead accumulation in sediments peaked in early 1970s (1973 +/- 2) in agreement with lead emissions features. For the period 1986-1997, the sediment signal also reflect the decrease of atmospheric lead described by independent atmospheric fallout investigations. The anthropogenic Pb deposition in the late 1990s was similar to the 1950s deposition, attesting thus of the output of European environmental policies.

International audience | Polycyclic Aromatic Hydrocarbons (PAHs) are known for their adverse and cumulative effects at low concentration. In particular, the PAHs accumulate in sewage sludge during wastewater treatment, and may thereafter contaminate agricultural soils by spreading sludge on land. Therefore, sludge treatment processes constitute the unique opportunity of PAH removal before their release in the environment. In this study, the ability of aerobic microorganisms to degrade light and heavy PAHs was investigated in continuous bioreactors treating trace-level PAH-contaminated sludge.

Les changements de productivité des forêts ont été étudiés intensément à partir des années 1990, à la suite des événements relatifs au dépérissement des forêts européennes. Dans cette contribution, on analyse les problèmes méthodologiques soulevés par ce type d'étude, les sources de données disponibles pour l'analyse, et les éléments de diagnostic acquis sur plusieurs espèces forestières du territoire français. Les implications pour le cadre théorique qui prévalait dans les années 1980 concernant la productivité des peuplements forestiers sont enfin discutées. problèmes méthodologiques, sources de données, cadre théorique, éléments du diagnostic

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