[Departement_IRSTEA]Eaux [TR1_IRSTEA]QUASARE | Dans cette étude, nous avons comparé l'évolution de trois grandes villes,

Oil spills pose a threat to aquatic organisms. However, the physiological effects of crude oil on cardiac function and on thermal tolerance of juvenile fish are still poorly understood. Consequently, in this paper, we will present results of two separate experiments where we exposed juvenile rainbow trout and European sea bass to crude oil and made cardiac thermal tolerances and maximum heart rate (fHmax) measurements after 1 week (rainbow trout) and 6-month recovery (sea bass). In both species, the fHmax was lower in crude oil-exposed fish than in the control ones at temperatures below the optimum but this difference disappeared at higher temperatures. More importantly, the oil-exposed fish had significantly higher Arrhenius break point temperature for fHmax, which gave an estimate for optimum temperature, than the control fish in both species even though the exposure conditions and recovery times differed between species. The results indicated that exposure of juvenile fish to crude oil did not have a significant negative impact upon their cardiac performance in high temperatures and upper thermal tolerance increased when the fish were tested 1 week or 6 months after the exposure. Our findings suggest that the cardiac function and thermal tolerance of juvenile fish are relatively resistant to a crude oil exposure.

We demonstrated the use of a new organometallic nanoprobe for competitive surface-enhanced Raman scattering (SERS) immunoassay devoted to the detection of polycyclic aromatic hydrocarbons (PAH) such as benzo[a]pyrene (BaP) in seawater. The nanoprobes are gold nanoparticles (GNPs) labeled by a Raman reporter, the 5,5'-dithiobis(succinimidyl-2-nitrobenzoate) (DSNB) and functionalized with monoclonal antibodies anti-BaP. The antibodies are bound with a high specificity to the analyte while the GNPs enhanced the Raman scattering of the DSNB. This type of immunoassay involved the grafting of BaP onto a sensing surface. Thus, NH2-terminated self-assembled monolayer is formed on the surface of gold substrate using cysteamine. Amines finally reacted with 6-formylbenzo[a]pyrene. So, this SERS detection involves four steps: (i) the nanoprobes are incubated with the sample; (ii) a drop of the mixture is then put onto the substrate; (iii) the surface is rinsed; and (iv) the surface is analyzed by Raman spectroscopy. To synthesize the nanoprobes, firstly, we prepared GNPs according to Frens' method. Then, GNPs were spontaneously labeled by the DSNB Raman reporter, thanks to a strong gold-sulfur interaction. Thereafter, BaP antibodies were cross-linked to the DSNB labeled GNPs by reaction of proteins primary amino groups with N-hydroxyl succinimide (NHS). Before use in SERS detection, their activity was controlled by surface plasmon resonance technique. The present method allows us to detect BaP at trace concentration (2 nmol/L). The results demonstrate that the proposed method has a great potential for application in the monitoring of seawater.

Among various cavitand molecules, cyclodextrins are extensively studied due to their ability to form host-guest complexes with small hydrophobic molecules. Aiming to explore cyclodextrin implementation on the scopes related to the environmental pollution monitoring or remediation, extensive studies for understanding the cyclodextrin-based host-guest complex formation with selected targeted substances are conducted. In this context, two polycyclic aromatic hydrocarbons, naphthalene and fluoranthene as well as toluene as a member of volatile organic compounds, were studied regarding their ability to encapsulate into cyclodextrin cavities. Synthesised complexes were examined by thermogravimetric analysis combined with Raman spectroscopy. The obtained results demonstrated that the size between targeted molecules and the cyclodextrin cavities strongly correlates with its ability to engage in complexation. Thus, this latter parameter plays an important role in the inclusion complex formation as well as in the strength of the interaction between the molecules.

This paper presents the characterization and modeling of exhaust emissions released from the passenger cars on urban roads under heterogeneous traffic conditions. Onboard exhaust emissions measurement were made at selected corridors in a populous urban area of India. Exhaust emissions were characterized for different driving modes classified according to vehicle specific power (VSP). Results indicated that emissions at VSP modes under cruising speeds were 10–12 times less than idling (which is the mode used for emission standard certification), braking and accelerating conditions. Also it has been found that more than 20% of time vehicles were in idling conditions at most of the roads.Real-time exhaust emission prediction models for heterogeneous traffic conditions were developed using artificial neural network (ANN) technique. The vehicle characteristics such as revolutions per minute (RPM), speed, acceleration and VSP were used as input to the model. The onboard measurements of CO, HC and NOx concentrations were used to train the ANN based exhaust emission prediction models. Result showed good agreement with onboard measured emissions data (index of agreement = 0.9) of all driving modes. Further, ANN model's emissions were compared with emissions estimated from the COPERT model and emission factors recommended by the Automotive Research Association of India (ARAI). It was found that the ANN model emissions were edge over the ARAI and COPERT model emissions and useful for urban air quality management and traffic planning.

Atmospheric PM1 (particulate matter with aerodynamic diameter ≤ 1 μm) samples have been collected during foggy (n = 17) and non-foggy nights (n = 19) in wintertime at Kanpur in central Indo-Gangetic Plain (IGP) to assess light absorption characteristics and direct radiative forcing of water-extractable brown carbon (BrC). We have observed a significant enhancement (two-tailed t-test: t = 2.2; at significance level: p < 0.05) in the absorption coefficient of water-extractable BrC at 365 nm (babs-BrC-365) from non-foggy (Avg.: 53.5 Mm⁻¹) to foggy episodes (69.3 Mm⁻¹). Enhancement in mass absorption efficiency (MAE) of BrC (1.8 m²/g C) during foggy episodes is consistent with that of babs-BrC-365. Absorption Ångström exponent (AAE) remained similar (2.8) during foggy and non-foggy episodes. Significantly lower value of AAE (2.8) at Kanpur compared to other places in IGP (∼5) highlights more light absorbing potential of atmospheric BrC over central IGP. Furthermore, MAE of EC at 660 nm during foggy period (8.5 m²/g) is relatively high as compared to that during the non-foggy episode (7.0 m²/g). The MAE of BrC and EC exhibited enhancement by ∼15% and 20%, respectively during foggy events. These observations are also reflected by an increase (t = 11.1; p < 0.05) in direct radiative forcing of water-extractable BrC (relative to EC) in the atmosphere: from 23.7 ± 10.8% during non-foggy to 54.3 ± 16.5% during foggy episodes. Differences in chemical composition, loading, absorption properties and direct radiative forcing (DRF) of carbonaceous aerosols during non-foggy and foggy episodes indicate predominant influence of fog-processing.

Whether considered as a risk for human health or as ecological tracers, contaminants' concentrations measured in fish muscles are commonly expressed relative to wet or dry mass. Comparison of results required conversion factors (CF) but accurate values are scarce and case-specific. The present paper is aimed at investigating errors linked with the use of the theoretical value. Muscles dry and wet masses were measured in 15 fish species to determine the actual CF. Most CF were lower than the theoretical wet:dry ratio of 5 classically used, with variations at individual and species level. Muscle lipid content (inferred by C/N ratios) was a crucial factor explaining discrepancies, claiming for caution when working with lipid-rich species. The observed variability demonstrated that using the theoretical CF may be inaccurate, when actual CF largely differs from the theoretical value. Dedicated measurement is the better approach when accuracy is required.

Trace metal concentrations in muscle and liver tissues from two offshore species of skate were examined. Concentrations of mercury in muscle of Leucoraja circularis (n = 20; 23–110.5 cm total length, 157–490 m water depth) and L. fullonica (n = 24; 28.5–100 cm total length, 130–426 m water depth) were 0.02–1.8 and 0.04–0.61 mg kg− 1, respectively. Concentrations of both As and Hg increased with total length. Only the largest specimen had a concentration of Hg in muscle > 1.0 mg kg− 1. Data were limited for specimens > 90 cm long, and further studies on contaminants in larger-bodied skates could usefully be undertaken.

In June 2015, an individual of Diretmichthys parini (Post and Quero, 1981) was trawled at 530 m depth, in the North Sea off Norway and donated to research. This capture, the first for this species in the North Sea was the northernmost recorded so far, and provided an opportunity to document some aspects of the biology and ecology of this data-poor species. This individual was a female, 331 mm total length of 33 years old, with low mercury content in muscle and liver (~ 0.2 μg g− 1 wet mass). Stable isotope ratios (C and N) in muscle and liver were consistent with the planktonic diet expected for this species. The capture of this fish at the northern latitude known so far would be consistent with the extension of the home range and the latitudinal shift hypothesized for this species in the 1990′s.

This study was designed to identify in the pearl oyster Pinctada margaritifera, used as a bio-accumulator, molecular biomarkers for the presence of heavy metals in the lagoon environment. Pearl oysters were exposed to 2 concentrations (1 and 10 μg L− 1) of cadmium (Cd) and chromium (Cr) compared to a control. Twelve target genes encoding proteins potentially involved in the response to heavy metal contamination with antioxidant, detoxification or apoptosis activities were selected. P. margaritifera accumulated Cd but not Cr, and mortality was related to the amount of Cd accumulated in tissues. In response to Cd-Cr contamination, metallothionein (MT) was significantly up-regulated by Cd-Cr at both concentrations, while 7 others (SOD, CAT, GPX, GSTO, GSTM, CASP, MDR) were down-regulated. Based on the development of these molecular tools, we propose that the pearl oyster, P. margaritifera, could be used as a sentinel species for heavy metal contamination in the lagoons of tropical ecosystems.