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Genetic and physiological responses of three freshwater diatoms to realistic diuron exposures | Réponses génétiques et physiologiques de 3 espèces de diatomées d'eau douce à des expositions réalistes au diuron
2015
Moisset, S. | Kim Tiam, S. | Feurtet Mazel, A. | Morin, Soizic | Delmas, François | Mazzella, Nicolas | Gonzalez, P. | Environnements et Paléoenvironnements OCéaniques (EPOC) ; Observatoire aquitain des sciences de l'univers (OASU) ; Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Pratique des Hautes Études (EPHE) ; Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS) | Ecosystèmes aquatiques et changements globaux (UR EABX) ; Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)
[Departement_IRSTEA]Eaux [TR1_IRSTEA]BELCA | International audience | This study examined the effects of diuron on strains of three major freshwater diatom species, Eolimna minima, Nitzschia palea and Planothidium lanceolatum. These species are frequently recorded in the Morcille river, where diuron runs off during phytosanitary treatments of the vineyards around. Here, there were three diatom exposure groups for each species: 0, 1 and 10µg/L diuron during a fourteen-day laboratory assessment. Diuron water concentration, cell number, photosynthetic activity and gene expression were assessed at 6h, 2, 7 and 14 days after contamination. Diuron exposure altered photosynthetic activity in that the optimal quantum yield of photosystem II (PSII) decreased between 40 and 50% and, for Planothidium lanceolatum at 10µg/L, there was complete inhibition. Genetic responses indicated diuron effects on both photosystem II and mitochondrial metabolism in all three species at both diuron exposure levels. Thus, analysis of the expression of psaA, d1, cox1, nad5 and 12s could be an early biomarker to detect pesticide pollution. Overall, this study revealed differences in diuron sensitivity among the three species: Eolimna minima and Nitzschia palea appeared to be more tolerant than Planothidium lanceolatum. These results suggest that the development of molecular tools, and more precisely of biomarkers, will aid in early assessment of contamination and water quality.
Afficher plus [+] Moins [-]Effects of cyanobacterial extracellular polymeric substances on the stability of ZnO nanoparticles in eutrophic shallow lakes
2015
Xu, Huacheng | Jiang, Helong
Extracellular polymeric substances (EPS) from bloom-forming cyanobacteria exist ubiquitously in eutrophic waters, while their effects on the aggregation/stabilization of nanoparticles remain unknown. In this study, the stability of ZnO nanoparticles (ZNPs) upon adsorption of cyanobacterial EPS was investigated by using two dimensional ATR-FTIR correlation spectroscopy, XPS and DLVO theory. Results showed that the adsorption process followed the Langmuir isotherm and pseudo-second-order kinetics both for the total organic contents as well as the individual parallel factor-derived components. The physicochemical and spectroscopic techniques revealed the mechanism of both electrostatic attraction and surface complexation in EPS adsorption. Further analysis showed increased absorbance and turbidity of ZNPs solutions with EPS addition, demonstrating the enhanced colloidal stability. The DLVO theory explained that the increased energy barriers and values of second energy maximum were responsible for the stability enhancement. This study facilitates a deeper insight into the environmental behavior of nanoparticles in eutrophic algae-rich waters.
Afficher plus [+] Moins [-]Surface–rain interactions: Differences in copper runoff for copper sheet of different inclination, orientation, and atmospheric exposure conditions
2015
Hedberg, Yolanda S. | Goidanich, Sara | Herting, Gunilla | Odnevall Wallinder, Inger
Predictions of the diffuse dispersion of metals from outdoor constructions such as roofs and facades are necessary for environmental risk assessment and management. An existing predictive model has been compared with measured data of copper runoff from copper sheets exposed at four different inclinations facing four orientations at two different urban sites (Stockholm, Sweden, and Milan, Italy) during a 4-year period. Its applicability has also been investigated for copper sheet exposed at two marine sites (Cadiz, Spain, for 5 years, and Brest, France, for 9 years). Generally the model can be used for all given conditions. However, vertical surfaces should be considered as surfaces inclined 60–80° due to wind-driven effects. The most important parameters that influence copper runoff, and not already included in the model, are the wind and rain characteristics that influence the actual rainfall volume impinging the surface of interest.
Afficher plus [+] Moins [-]Potential environmental factors that influence the nitrogen concentration and δ15N values in the moss Hypnum cupressiforme collected inside and outside canopy drip lines
2015
Skudnik, Mitja | Jeran, Z. (Zvonka) | Batič, Franc | Simoncic, Primoz | Kastelec, Damijana
Samples of the moss Hypnum cupressiforme were collected at 103 locations in forests of Slovenia. At each location, samples were taken at two types of sites: under tree canopies and in adjacent forest openings. The results show that the moss collected in the forest openings reflects the surrounding land-use characteristics and, consequently, the main N emission sources. For moss sampled under canopies, the characteristics of the forest at the moss-sampling locations are more important than the main emission sources outside the forest. A regression model was used to provide the nitrogen (N) concentration in moss from the forest openings in relation to the N concentration in moss under canopies and other environmental variables. The spatial distribution of the locations of the N concentrations and δ15N values in moss collected in the forest openings and under the canopies in relation to main N deposition sources is discussed.
Afficher plus [+] Moins [-]Chronic bisphenol A exposure alters behaviors of zebrafish (Danio rerio)
2015
Wang, Ju | Wang, Xia | Xiong, Can | Liu, Jian | Hu, Bing | Zheng, Lei
The adult zebrafish (Danio rerio) were exposed to treated-effluent concentration of bisphenol A (BPA) or 17β-estradiol (E2) for 6 months to evaluate their effects on behavioral characteristics: motor behavior, aggression, group preference, novel tank test and light/dark preference. E2 exposure evidently dampened fish locomotor activity, while BPA exposure had no marked effect. Interestingly, BPA-exposed fish reduced their aggressive behavior compared with control or E2. Both BPA and E2 exposure induced a significant decrease in group preference, as well as a weaker adaptability to new environment, exhibiting lower latency to reach the top, more entries to the top, longer time spent in the top, fewer frequent freezing, and fewer erratic movements. Furthermore, the circadian rhythmicity of light/dark preference was altered by either BPA or E2 exposure. Our results suggest that chronic exposure of treated-effluent concentration BPA or E2 induced various behavioral anomalies in adult fish and enhanced ecological risk to wildlife.
Afficher plus [+] Moins [-]Urban metabolism: Measuring the city's contribution to sustainable development
2015
Conke, Leonardo S. | Ferreira, Tainá L.
Urban metabolism refers to the assessment of the amount of resources produced and consumed by urban ecosystems. It has become an important tool to understand how the development of one city causes impacts to the local and regional environment and to support a more sustainable urban design and planning. Therefore, the purpose of this paper was to measure the changes in material and energy use occurred in the city of Curitiba (Brazil) between the years of 2000 and 2010. Results reveal better living conditions and socioeconomic improvements derived from higher resource throughput but without complete disregard to environmental issues. Food intake, water consumption and air emissions remained at similar levels; energy use, construction materials and recycled waste were increased. The paper helps illustrate why it seems more adequate to assess the contribution a city makes to sustainable development than to evaluate if one single city is sustainable or not.
Afficher plus [+] Moins [-]Organochlorine pesticides accumulated by SPMD-based virtual organisms and feral fish in Three Gorges Reservoir, China
2015
Wang, Jingxian | Liang, Wei | Henkelmann, Bernhard | Pfister, Gerd | Schramm, Karl-Werner
Organochlorine pesticides (OCPs) accumulated by semipermeable membrane device (SPMD) -based virtual organisms (VOs) and local feral fish were studied in Three Gorges Reservoir (TGR), China. VOs were deployed at seven sites in TGR for two periods in 2009 and 5 species of fish with different living habitats and feeding habits collected in the same periods from two counties in TGR. 28 OCPs were analyzed and the concentration and profile of OCPs in fish were quite different from those in VOs. The lipid-based concentrations of OCPs in fish ranged from 225.7 ng/g lw to 1996.4 ng/g lw which were much higher than those in VOs which ranged from 17.3 to 112.4 ng/g lw. Dichlorodiphenyltrichloroethanes (DDTs) were the prevalent OCPs in the investigated fish, while hexachlorobenzene (HCB) was the dominant compound in VOs. DDT in the few fish sample analyzed was not of concern based on chemical contaminant limits of non-carcinogenic effect.
Afficher plus [+] Moins [-]Sources, occurrence and predicted aquatic impact of legacy and contemporary pesticides in streams
2015
McKnight, Ursula S. | Rasmussen, Jes J. | Kronvang, Brian | Binning, Philip J. | Bjerg, Poul L.
We couple current findings of pesticides in surface and groundwater to the history of pesticide usage, focusing on the potential contribution of legacy pesticides to the predicted ecotoxicological impact on benthic macroinvertebrates in headwater streams. Results suggest that groundwater, in addition to precipitation and surface runoff, is an important source of pesticides (particularly legacy herbicides) entering surface water. In addition to current-use active ingredients, legacy pesticides, metabolites and impurities are important for explaining the estimated total toxicity attributable to pesticides. Sediment-bound insecticides were identified as the primary source for predicted ecotoxicity. Our results support recent studies indicating that highly sorbing chemicals contribute and even drive impacts on aquatic ecosystems. They further indicate that groundwater contaminated by legacy and contemporary pesticides may impact adjoining streams. Stream observations of soluble and sediment-bound pesticides are valuable for understanding the long-term fate of pesticides in aquifers, and should be included in stream monitoring programs.
Afficher plus [+] Moins [-]Influences of ambient air PM2.5 concentration and meteorological condition on the indoor PM2.5 concentrations in a residential apartment in Beijing using a new approach
2015
Han, Yang | Qi, Meng | Chen, Yilin | Shen, Huizhong | Liu, Jing | Huang, Ye | Chen, Han | Liu, Wenxin | Wang, Xilong | Liu, Junfeng | Xing, Baoshan | Tao, Shu
PM2.5 concentrations in a typical residential apartment in Beijing and immediately outside of the building were measured simultaneously during heating and non-heating periods. The objective was to quantitatively explore the relationship between indoor and outdoor PM2.5 concentrations. A statistical method for predicting indoor PM2.5 concentrations was proposed. Ambient PM2.5 concentrations were strongly affected by meteorological conditions, especially wind directions. A bimodal distribution was identified during the heating season due to the frequent and rapid transition between severe pollution events and clean days. Indoor PM2.5 concentrations were significantly correlated with outdoor PM2.5 concentrations but with 1–2 h delay, and the differences can be explained by ambient meteorological features, such as temperature, humidity, and wind direction. These results indicate the potential to incorporate indoor exposure features to the regional air quality model framework and to more accurately estimate the epidemiological relationship between human mortality and air pollution exposure.
Afficher plus [+] Moins [-]Trends of deposition fluxes and loadings of sulfur dioxide and nitrogen oxides in the artificial Three Northern Regions Shelter Forest across northern China
2015
Zhang, Xiaodong | Huang, Tao | Zhang, Leiming | Gao, Hong | Shen, Yanjie | Ma, Jianmin
This study provides the first estimate of dry deposition fluxes of criteria air pollutants (SO2 and NOx) across the Three Northern Regions Shelter Forest (TNRSF) region in Northern China and their long-term trends from 1982 to 2010 using the inferential method. Dry deposition velocities of SO2 and NOx increased in many places of the TNRSF up to 118.2% for SO2 and 112.1% for NOx over the last three decades due to the increased vegetation coverage over the TNRSF. The highest atmospheric deposition fluxes of SO2 and NOx were found in the Central-North China region, followed by the Northeast and the Northwest China regions of the TNRSF. A total of 820,000 t SO2 and 218,000 t NOx was estimated to be removed from the atmosphere through dry deposition process over the TNRSF from 1982 to 2010. About 50% of the total removal occurred in the Central-North China region. The estimated total SO2 and NOx dry deposition fluxes from 1982 to 2010 between a TNRSF site in this region and an adjacent farmland outside the TNRSF showed that the fluxes of these two chemicals at the TNRSF site were the factors of 2–3 greater than their fluxes in the farmland.
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