Uranium bioaccumulation and biological disorders induced in zebrafish (Danio rerio) after a depleted uranium waterborne exposure

Because of its toxicity and its ubiquity within aquatic compartments, uranium (U) represents a significant hazard to aquatic species such as fish. In a previous study, we investigated some biological responses in zebrafish either exposed to depleted or to enriched U (i.e., to different radiological activities). However, results required further experiments to better understand biological responses. Moreover, we failed to clearly demonstrate a significant relationship between biological effects and U radiological activity. We therefore chose to herein examine U bioaccumulation and induced effects in zebrafish according to a chemical dose-response approach. Results showed that U is highly bioconcentrated in fish, according to a time- and concentration-dependent model. Additionally, hepatic antioxidant defenses, red blood cells DNA integrity and brain acetylcholinesterase activity were found to be significantly altered. Generally, the higher the U concentration, the sooner and/or the greater the effect, suggesting a close relationship between accumulation and effect.     

Relationship between filtration activity and food availability in the Mediterranean mussel <Emphasis Type="Italic">Mytilus galloprovincialis</Emphasis>

The filtration activity of the Mediterranean mussel, Mytilus galloprovincialis, was assessed under different concentrations and compositions of seston by using a new automated image acquisition and analysis system. This approach allowed for frequent and simultaneous measurements of valve gape and exhalant siphon area. Filtration rates were measured through clearance measurements whereas pumping rates were measured using hot-film probes. The average filtration rate (17.5 l g h⁻¹ DW⁻¹ for a 0.36 g DW mussel) recorded during the present study was higher than those available for Mytilus edulis when standardized to flesh dry weight but almost equivalent (17.5 l h⁻¹ g DW⁻¹ for a 53 mm shell length mussel) to those rates when standardized to shell length. Immediately after the addition of algal cells (Isochrysis galbana; 4.5 μm in size), valve gape, exhalant siphon area and filtration rate increased quickly as mussels reached their maximum filtration activity. These three parameters then gradually decreased until complete closure of the shell. The algal cell concentration inducing this transition was close to 800 cells ml⁻¹ and 0.5 μg Chl a l⁻¹. When algal concentration was maintained above this threshold by successive algal additions, both valve gape and exhalant siphon area remained maximal. Temporal changes in the exhalant siphon area were continuous as opposed to those of valve gape. Therefore, despite the significant correlation between these two parameters, valves and siphon were sometimes dissociated due to a reduction of the area or even a closure of the exhalant siphon while the valves remained open. The velocity of exhaled water tended to be constant irrespective of exhalant siphon area and thus pumping rates were a linear function of exhalant siphon area. Consequently, reductions in exhalant siphon area and pumping rate were almost similar in M. galloprovincialis. Our results thus clearly support the hypothesis that exhalant siphon area constitutes a better proxy of pumping rate than valve gape as already suggested for Mytilus edulis. Finally, the high filtration rates measured during the present study together with the high concentrations of inorganic matter (> 40 mg DW l⁻¹) requested to alter those rates suggest that the studied mussels were well adapted to oligotrophic waters featuring strong hydrodynamism and frequent sediment resuspension events.     

The Cost of Co-viability in the Australian Northern Prawn Fishery

Fisheries management must address multiple, often conflicting objectives in a highly uncertain context. In particular, while the bio-economic performance of trawl fisheries is subject to high levels of biological and economic uncertainty, the impact of trawling on broader biodiversity is also a major concern for their management. The purpose of this study is to propose an analytical framework to formally assess the trade-offs associated with balancing biological, economic and non-target species conservation objectives. We use the Australian Northern Prawn Fishery (NPF), which is one of the most valuable federally managed commercial fisheries in Australia, as a case study. We develop a stochastic co-viability assessment of the fishery under multiple management objectives. Results show that, due to the variability in the interactions between the fishery and the ecosystem, current management strategies are characterized by biological and economic risks. Results highlight the trade-offs between respecting biological, economic and non-target species conservation constraints at each point in time with a high probability and maximizing the net present value of the fishery.     

Impact of clay mineral on air oxidation of PAH-contaminated soils

This work investigated the impact of a clay mineral (bentonite) on the air oxidation of the solvent extractable organic matters (EOMs) and the PAHs from contaminated soils. EOMs were isolated from two coking plant soils and mixed with silica sand or bentonite. These samples, as well as raw soils and bentonite/soil mixtures, were oxidized in air at 60 and 100 °C for 160 days. Mineralization was followed by measuring the CO₂ produced over the experiments. EOM, polycyclic aromatic compound (PAC), including PAH, contents were also determined. Oxidation led to a decrease in EOM contents and PAH concentrations, these diminutions were enhanced by the presence of bentonite. Transfer of carbon from EOM to insoluble organic matter pointed out a condensation phenomenon leading to a stabilization of the contamination. Higher mineralization rates, observed during the oxidation of the soil/bentonite mixtures, seem to indicate that this clay mineral had a positive influence on the transformation of PAC into CO₂.     

Evidence for a significant contribution of wood burning aerosols to PM2.5 during the winter season in Paris,France

Although particulate emissions from residential wood burning have become a subject of great scientific concern for a few years, data related to their impact on the air quality of large European urban centres are still missing. In the present study, we investigated the chemical and optical properties of fine (PM_2.5) carbonaceous aerosols in Paris during the 2005 winter season in order to track the presence of wood burning emissions in such a large city. The use of a seven wavelength Aethalometer allowed us to document shortwave light absorption by brown-carbon-containing organic aerosols of biomass burning origin. In particular, a well-marked diurnal pattern of the spectral dependence of light absorption, with maxima during the night, could be observed every day of the campaign and attributed to wood burning emissions. Relatively high absorption Ångstrom exponents and WSOC/OC ratios (respectively 1.25 and 0.35 on average for the period of study) also indicated the importance of biomass burning aerosols in the Paris atmosphere in winter. Finally, a rough estimate of the contribution of wood burning carbonaceous aerosols to PM_2.5 could be achieved. This contribution was found to be as high as 20 ± 10% on average at the Paris background site investigated here.     

The nexus amid foreign direct investment,urbanization, and CO2 emissions: Evidence from energy grouping along the ECOWAS community

Environment, Development and Sustainability - The vision of every country or subregions is to achieve economic growth and sustainable economic growth. Thus, the Economic Community of West African...     

Characterization of particulate polycyclic aromatic hydrocarbons in the east of France urban areas

Background

Air samples collected on three different urban sites in East of France (Strasbourg, Besan?on, and Spicheren), from April 2006 to January 2007, were characterized to measure the concentrations of polycyclic aromatic hydrocarbons (PAHs) in the particulate phase (PM₁₀) and to examine their seasonal variation, diurnal variations, and emission sources.

Results

The average concentrations of ??PAHs were 12.6, 9.5, and 8.9?ng?m^?3 for the Strasbourg, Besan?on, and Spicheren sites, respectively. Strong seasonal variations of individual PAH concentrations were found at the three sampling sites, with higher levels in the winter that gradually decreased to the lowest levels in the summer. The diurnal variations of PAH concentrations in summer presented highest concentrations during the morning (04:00?C10:00) and the evening (16:00?C22:00) times, indicating the important contribution from vehicle emissions, in the three sampling sites. Furthermore, the ratio of BaP/BeP suggests that the photochemical degradation of PAHs can suppress their concentrations in the midday/afternoon (10:00?C16:00), time interval of highest global irradiance. In winter, concentrations of PAH were highest during the evening (16:00?C22:00) time, suggesting that domestic heating can potentially be an important source for particulate PAH, for the three sampling sites.

Conclusion

Diagnostic ratios were used to identify potential sources of PAHs. Results showed that vehicle emissions may be the major source of PAHs, especially in summer, with a prevalent contribution of diesel engines rather than gasoline engines at the three sites studied, independently of the seasons.     

Fog as a Fresh-Water Resource: Overview and Perspectives

The collection of fog water is a simple and sustainable technology to obtain fresh water for afforestation, gardening, and as a drinking water source for human and animal consumption. In regions where fresh water is sparse and fog frequently occurs, it is feasible to set up a passive mesh system for fog water collection. The mesh is directly exposed to the atmosphere, and the foggy air is pushed through the mesh by the wind. Fog droplets are deposited on the mesh, combine to form larger droplets, and run down passing into a storage tank. Fog water collection rates vary dramatically from site to site but yearly averages from 3 to 10 l m⁻² of mesh per day are typical of operational projects. The scope of this article is to review fog collection projects worldwide, to analyze factors of success, and to evaluate the prospects of this technology.     

Optimal feed profile for a second order reaction in a semi-batch reactor under safety constraints: Experimental study

Maximising the yield of the second order reaction (2-butanol+propionic anhydride) by manipulating the inlet flow rate is considered for an isothermal semi-batch process. First a procedure for the determination of the kinetic parameters using coupled spectroscopic and calorimetric methods is presented. Then an optimisation of the reaction system is performed numerically and verified experimentally. Constraints on the amount of heat produced and on the temperature attainable in the case of cooling failure are imposed for safety consideration.