International audience | This study addressed the relative importance of particle coating, sewage sludge amendment, and aging on aggregation and dissolution of manufactured Ag nanoparticles (Ag MNPs) in soil pore water. Ag MNPs with citrate (CIT) or polyvinylpyrrolidone (PVP) coatings were incubated with soil or municipal sewage sludge which was then amended to soil (1% or 3% sludge (w/w)). Pore waters were extracted after 1 week and 2 and 6 months and analyzed for chemical speciation, aggregation state and dissolution. Ag MNP coating had profound effects on aggregation state and partitioning to pore water in the absence of sewage sludge, but pre-incubation with sewage sludge negated these effects. This suggests that Ag MNP coating does not need to be taken into account to understand fate of AgMNPs applied to soil through biosolids amendment. Aging of soil also had profound effects that depended on Ag MNP coating and sludge amendment. (C) 2013 Elsevier Ltd. All rights reserved.

[Departement_IRSTEA]Eaux [TR1_IRSTEA]GEUSI | Many articles have dealt with the advantages of spatially discriminating the abatement effort when the pollution is non-uniformly mixed. However, few authors have attempted to identify the impact of certain model parameters on the advantage of this discrimination. These parameters are the transfer coefficients, the parameters of the abatement cost function or the level of the quality standard. In this article, we studied the role of the slope of the environmental benefit function on the advantages of spatially discriminating pollution abatement efforts. It appears that the relative increase in the net social benefit between a uniform and a perfectly discriminated control is not affected by this slope. However, in the case of partial discrimination, a steeper benefit slope increases the optimal number of zones.

PM2.5 and PM10 samples were collected at 4 and 14 sampling sites, respectively, located in the Metropolitan area of Costa Rica (MACR), during 2010-2011. These sites were representative of commercial, industrial and residential zones of this region. Concentrations of elemental carbon (EC) and organic carbon (OC) were analyzed using the IMPROVE thermal-optical reflectance (TOR) method. OC and EC concentrations were higher in commercial and industrial sites and showed clear seasonal variations with higher concentrations observed in the rainy season (May-November) than in the dry season (December-April), due to wind patterns in the study area. Total carbonaceous aerosol accounted for 35% of PM10 and 56% of PM2.5 mass. Good correlation between OC and EC in PM10 (R=0.89-0.75) and PM2.5 (R=0.79-0.64) indicated that they had common dominant sources of combustion such as industrial activities and traffic emissions. The annual average concentrations of estimated SOC (Secondary Organic Carbon) in the MACR PM10 samples showed values between 0.65-8.49 mg/m3, accounting for 48% and 56% of the OC in PM10 and PM2.5 respectively. Positive Matrix Factorization (PMF) identified five principal sources for OC and EC in particles: gasoline vehicles, diesel vehicles, on road traffic, wood smoke and industrial combustion. The contribution of each of the source varied between the PM10 and PM2.5 size fractions. | Se recolectaron muestras de PM2.5 y PM10 en 4 y 14 sitios de muestreo, respectivamente, ubicados en el Área Metropolitana de Costa Rica (MACR), durante 2010-2011. Estos sitios eran representativos de zonas comerciales, industriales y residenciales de esta región. Las concentraciones de carbono elemental (CE) y carbono orgánico (OC) se analizaron utilizando el método IMPROVE termoóptica reflectancia (TOR). Las concentraciones de OC y CE fueron mayores en los sitios comerciales e industriales y mostraron claras variaciones estacionales con concentraciones más altas observadas en la temporada de lluvias (mayo-noviembre) que en la estación seca (diciembre-abril), debido a los patrones de viento en el área de estudio. El aerosol carbonoso total representó el 35% de PM10 y el 56% de la masa de PM2.5. La buena correlación entre OC y EC en PM10 (R = 0,89-0,75) y PM2,5 (R = 0,79-0,64) indicó que tenían fuentes de combustión dominantes comunes como las actividades industriales y las emisiones de tráfico. Las concentraciones medias anuales de SOC (Carbono Orgánico Secundario) estimado en las muestras MACR PM10 mostraron valores entre 0.65-8.49 mg / m3, representando el 48% y 56% de la OC en PM10 y PM2.5 respectivamente. La Factorización de Matriz Positiva (PMF) identificó cinco fuentes principales de OC y EC en partículas: vehículos de gasolina, vehículos diesel, en el tráfico rodado, humo de leña y combustión industrial. La contribución de cada una de las fuentes varió entre las fracciones de tamaño PM10 y PM2.5. | As amostras de PM2.5 e PM10 foram coletadas em 4 e 14 locais de amostragem, respectivamente, localizados na área metropolitana da Costa Rica (MACR), durante 2010-2011. Esses locais eram representativos das zonas comerciais, industriais e residenciais desta região. As concentrações de carbono elementar (CE) e carbono orgânico (OC) foram analisadas usando o método IMPROVE de refletância ótica-térmica (TOR). As concentrações de OC e EC foram maiores nos locais comerciais e industriais e mostraram claras variações sazonais com maiores concentrações observadas na estação chuvosa (maio-novembro) do que na estação seca (dezembro-abril), devido aos padrões de vento na área de estudo. O aerossol carbonáceo total foi responsável por 35% da massa de PM10 e 56% da massa de PM2,5. A boa correlação entre OC e EC em PM10 (R = 0,89-0,75) e PM2,5 (R = 0,79-0,64) indicou que eles tinham fontes dominantes comuns de combustão, como atividades industriais e emissões de tráfego. As concentrações médias anuais estimadas de SOC (Carbono Orgânico Secundário) nas amostras MACR PM10 apresentaram valores entre 0,65-8,49 mg / m3, representando 48% e 56% do OC em PM10 e PM2,5 respectivamente. A Fatoração de Matriz Positiva (PMF) identificou cinco fontes principais de CO e CE em partículas: veículos a gasolina, veículos a diesel, no tráfego rodoviário, fumaça de lenha e combustão industrial. A contribuição de cada uma das fontes variou entre as frações de tamanho PM10 e PM2,5. | Universidad Nacional, Costa Rica | Universidad de Costa Rica | Instituto Nacional de Ecología, Mexico | Universidad Nacional Autónoma de México, México | Escuela de Ciencias Ambientales

International audience | The concentrations of polychlorinated biphenyls (PCB), hexachlorobenzene (HCB), pentachlorobenzene (PeCB) and polybrominated diphenylethers (PBDE) were described in benthic and pelagic species collected off Adélie Land, Antarctica. Strong differences were observed among species, with reduced PeCB and HCB levels in benthic species, and elevated PCB levels in the Antarctic yellowbelly rockcod, the Antarctic sea urchin and the snow petrel. Lower-chlorinated congeners were predominant in krill; penta-PCBs in benthic organisms; hexa- and hepta-PCBs in seabirds and cryopelagic fish. This segregation may result from sedimentation process, specific accumulation and excretion, and/or biotransformation processes. The presence of PBDEs in Antarctic coastal organisms may originate from atmospheric transport and partly from a contamination by local sources. Although POP levels in Antarctic marine organisms were substantially lower than in Arctic and temperate organisms, very little is known about their toxic effects on these cold-adapted species, with high degree of endemism.

The AZTI’s marine biotic index (AMBI), an ecological indicator for managing estuarine and coastal waters worldwide, was tested in two fjords in Chilean Patagonia. The Aysen Fjord (42° Lat. S) supports intensive salmon farming in coastal ecosystems, while the Baker Fjord (48° Lat. S) is currently just beyond the limit of the southern expansion of salmon concessions. The ecological status of the Aysen Fjord was classified as good, while the status of the Baker Fjord was classified as high and unbalanced. These differences were consistent with our expectations, illustrating the effect of local environmental conditions and human activities, combined with river inputs into semi-confined fjords. This method is appropriate for the evaluation of the ecological status of the fjords, but requires a sufficient amount of data for the robust environmental assessment as proposed by the Water Framework Directive (WFD).

International audience | Calcium dissolved deposition shows an unusual spatial structure in France, probably due to the contribution of southern air masses from Mediterranean Sea and Saharan desert. These masses are often loaded with terrigenous particles that contain carbonates. However, no precise relationship has been quantified between dissolved Ca and mineral dust deposition (MDD). The database of the French network RENECOFOR, gathering atmospheric deposition <0.45 mu m in 27 sites near forests during 18 years, was used to determine the non-sea-salt atmospheric deposition over France. This study (1) explores the relationship between dissolved components to decipher their origin in atmospheric deposition nearby forests and (2) tests the use of dissolved Ca and Mg as proxies for MDD. In the RENECOFOR database, non-sea-salt Ca (nssCa) preferentially deposited between May and August. MDD observed in RENECOFOR was synchronic with high nssCa deposition, particularly in June 2008, when air mass highly loaded with Saharan dust covered France. The dissolution of this mineral dust likely contributed to the nssCa deposition of this period and suggested a relationship between the depositions of nssCa and MDD. Then, MDD was specifically sampled with dissolved deposition in four sampling sites. Encouraging relationships were found between MDD and the depositions of nssMg and nssCa, suggesting that the latter could be used as a proxy for MDD in regions where it is not monitored, and in a retrospective approach in order to calculate nutrient fluxes.