Temporal changes in nickel and vanadium concentrations and in condition index and metallothionein levels in three species of molluscs following the “

The petroleum spilt by the tanker “Erika” contained environmentally high concentrations of nickel (45 mg kg−1) and vanadium (83 mg kg−1). Our aim was to show that nickel and vanadium concentrations in marine organisms could be used as tracers of their exposure to oil deposits along the coast. Two biomarkers were determined, condition index (CI) and metallothionein levels. Samples were collected monthly from January to May 2000 from five sites along the coast of Vendée and Loire Atlantique: (1) Lérat, (2) La Govelle, (3) Saint Gildas, (4) La Bernerie and (5) La Fosse. Among benthic invertebrates, mussels Mytilus edulis (filter-feeders), periwinkles Littorina littorea (grazing-feeders) and dogwhelks Nucella lapillus (carnivora, bivalve predators) were selected. In addition, mussels were collected from a control site, Fier d'Ars (Ré Island). The species chosen as bioindicators have responded to the presence of oil in their environment by accumulating nickel and vanadium. The bioaccumulation of vanadium occurred early one month after oil spill whereas nickel bioaccumulation was deferred, probably as a consequence of a lower stability of vanadylporphyrins compared to nickelporphyrins which are known in particular for their role in stabilizing emulsions (film at the water/oil interface). Interspecific differences may be explained by different food habits: periwinkles grazed contaminated algae; mussels as filter-feeders retained particles and colloids from the water column; dogwhelks fed on mussels. Spatio-temporal changes of nickel and vanadium concentrations may result from (i) the arrival of new oil slicks, (ii) the action of cleaning of the coasts contributing to the re-suspension of petroleum. In all of the three species, few changes of the CI were observed from site to site. CI variations were linked to sexual ripening in mussels. Mussels originating from the control site showed MT concentrations significantly lower than those in specimens from impacted sites. The highest MT concentrations were observed in January and February, and then a consistent decrease was registered in March and May. MT concentrations in periwinkles increased very significantly in March and May. An increase in MT concentrations was also shown at this period in dogwhelks. Depending on the species, positive correlations were shown between MT and nickel and/or vanadium concentrations

A new combination of microbial indicators for monitoring composting bioaerosols

International audienceBioaerosols emitted from composting plants are a cause of concern because of their potential impact on occupational health and neighboring residential areas. The aim of this study was to identify microbial indicators that are most useful for monitoring bioaerosol emittance and dispersal by industrial composting plants. Seven microbial indicators were measured in air collected outdoors in natural environments and at eleven composting plants. The indicators were: cultivable bacteria and fungi, total bacteria (epifluorescent microscopy), viable bacteria (solid-phase cytometry) and quantification by qPCR of three microbial indicators which had been previously shown as strongly associated with composting. For each indicator, the increase in concentrations due to the turning of composting piles as compared to the background concentration obtained in natural environments and upwind of composting plants was determined. Based on these results, the most effective combination of three indicators was selected for monitoring composting bioaerosol emissions: viable bacteria as one general indicator of bioaerosol emission and two bacterial phylotypes specific to composting bioaerosol: NA07, affiliated to Saccharopolyspora sp. and NC38, affiliated to the Thermoactinomycetaceae. This set of indicator was then quantified on-site and at increasing distances downwind during the turning of compost windrows in thermophilic phase. Composting activity was considered to affect bioaerosol emission when the concentrations of the three indicators were higher than their respective background levels. For all the composting sites studied, an impact was measureable up to distances of 100 m. Further away, the impact was not systematically observed as it depended on meteorological conditions (wind speed) and on levels of bioaerosol emissions

Long-term effects of urban waste composts on soil carbon and nitrogen dynamics in an agroecosystem: application of the NCSOIL/CERES-EGC coupled model

INRA EGC et PESSAC, Véolia EnvironnementLong-term effects of urban waste composts on soil carbon and nitrogen dynamics in an agroecosystem: application of the NCSOIL/CERES-EGC coupled model. 15. International Conferences of RAMIRAN (Network on Recycling of Agricultural, Municipal and Industrial Residues in Agriculture

SOERE PRO: Long term field experiment network for research on the recycling of organic matters issued of wastes in agriculture

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