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Sensitivity of the deep-sea amphipod Eurythenes gryllus to chemically dispersed oil Texte intégral
2016
Olsen, Gro Harlaug | Coquillé, Nathalie | Le Floch, Stephane | Geraudie, Perrine | Dussauze, Matthieu | Lemaire, Philippe | Camus, Lionel
In the context of an oil spill accident and the following oil spill response, much attention is given to the use of dispersants. Dispersants are used to disperse an oil slick from the sea surface into the water column generating a cloud of dispersed oil droplets. The main consequence is an increasing of the sea water–oil interface which induces an increase of the oil biodegradation. Hence, the use of dispersants can be effective in preventing oiling of sensitive coastal environments. Also, in case of an oil blowout from the seabed, subsea injection of dispersants may offer some benefits compared to containment and recovery of the oil or in situ burning operation at the sea surface. However, biological effects of dispersed oil are poorly understood for deep-sea species. Most effects studies on dispersed oil and also other oil-related compounds have been focusing on more shallow water species. This is the first approach to assess the sensitivity of a macro-benthic deep-sea organism to dispersed oil. This paper describes a toxicity test which was performed on the macro-benthic deep-sea amphipod (Eurythenes gryllus) to determine the concentration causing lethality to 50 % of test individuals (LC₅₀) after an exposure to dispersed Brut Arabian Light (BAL) oil. The LC₅₀ (24 h) was 101 and 24 mg L⁻¹ after 72 h and 12 mg L⁻¹ at 96 h. Based on EPA scale of toxicity categories to aquatic organisms, an LC₅₀ (96 h) of 12 mg L⁻¹ indicates that the dispersed oil was slightly to moderately toxic to E. gryllus. As an attempt to compare our results to others, a literature study was performed. Due to limited amount of data available for dispersed oil and amphipods, information on other crustacean species and other oil-related compounds was also collected. Only one study on dispersed oil and amphipods was found, the LC₅₀ value in this study was similar to the LC₅₀ value of E. gryllus in our study. Since toxicity data are important input to risk assessment and net environmental benefit analyses, and since such data are generally lacking on deep-sea species, the data set produced in this study is of interest to the industry, stakeholders, environmental management, and ecotoxicologists. However, studies including more deep-sea species covering different functional groups are needed to evaluate the sensitivity of the deep-sea compartments to dispersed oil relative to other environmental compartments.
Afficher plus [+] Moins [-]The effect of dispersed Petrobaltic oil droplet size on photosynthetically active radiation in marine environment Texte intégral
2016
Haule, Kamila | Freda, Włodzimierz
Oil pollution in seawater, primarily visible on sea surface, becomes dispersed as an effect of wave mixing as well as chemical dispersant treatment, and forms spherical oil droplets. In this study, we examined the influence of oil droplet size of highly dispersed Petrobaltic crude on the underwater visible light flux and the inherent optical properties (IOPs) of seawater, including absorption, scattering, backscattering and attenuation coefficients. On the basis of measured data and Mie theory, we calculated the IOPs of dispersed Petrobaltic crude oil in constant concentration, but different log-normal size distributions. We also performed a radiative transfer analysis, in order to evaluate the influence on the downwelling irradiance E d , remote sensing reflectance R ᵣₛ and diffuse reflectance R, using in situ data from the Baltic Sea. We found that during dispersion, there occurs a boundary size distribution characterized by a peak diameter d ₀ = 0.3 μm causing a maximum E d increase of 40 % within 0.5-m depth, and the maximum E d decrease of 100 % at depths below 5 m. Moreover, we showed that the impact of size distribution on the “blue to green” ratios of R ᵣₛ and R varies from 24 % increase to 27 % decrease at the same crude oil concentration.
Afficher plus [+] Moins [-]Hydrochemistry and coal mining activity induced karst water quality degradation in the Niangziguan karst water system, China Texte intégral
2016
Zhang, Xiaobo | Li, Xue | Gao, Xubo
Hydrogeochemical analysis, statistical analysis, and geochemical modeling were employed to evaluate the impacts of coal mining activities on karst water chemistry in Niangziguan spring catchment, one of the largest karst springs in Northern China. Significant water quality deterioration was observed along the flow path, evidenced from the increasing sulfate, nitrate, and TDS content in karst water. Karst water samples are Ca-Mg-HCO₃ type in the recharge areas, Ca-Mg-HCO₃-SO₄ type in the coal mining areas, and Ca-Mg-SO₄-HCO₃/HCO₃-SO₄ type in the rural areas and discharge areas. A four-factor principal component analysis (PCA) model is conducted which explains over 82.9 % of the total variation. Factor 1, which explained the largest portion (45.33 %) of the total variance, reveals that coal mining activities and natural water-rock interaction as the primary factors controlling karst water quality. Anthropogenic effects were recognized as the secondary factor with high positive loadings for NO₃⁻ and Cl⁻ in the model. The other two factors are co-precipitation removal of trace elements and silicate mineral dissolution, which explained 20.96 % of the total variance. A two-end mixing modeling was proposed to estimate the percentage of coal wastewater giving on karst water chemistry, based on the groundwater sulfate chemistry constrains rather than sulfur isotopes. Uncertainty of sulfur isotope sources led to an overestimation of coal mining water contribution. According to the results of the modeling, the contribution of coal mining waste on karst water chemistry was quantified to be from 27.05 to 1.11 % which is ca. three times lower than the values suggested using a sulfur isotope method.
Afficher plus [+] Moins [-]Relationships of physiologically equivalent temperature and hospital admissions due to I30–I51 other forms of heart disease in Germany in 2009–2011 Texte intégral
2016
Shiue, Ivy | Perkins, David R. | Bearman, Nick
We aimed to understand relationships of the weather as biometeorological and hospital admissions due to other forms of heart disease by subtypes, which have been paid less attention, in a national setting in recent years. This is an ecological study. Ten percent of daily hospital admissions of the included hospitals (n = 1618) across Germany that were available between 1 January 2009 and 31 December 2011 (n = 5,235,600) were extracted from Statistisches Bundesamt, Germany. We identified I30–I51 other forms of heart disease by the International Classification of Diseases version 10 as the study outcomes. Daily weather data from 64 weather stations that have covered 13 German states, including air temperature, humidity, wind speed, cloud cover, radiation flux and vapour pressure, were obtained and generated into physiologically equivalent temperature (PET). Admissions due to other diseases of pericardium, nonrheumatic mitral valve disorders, nonrheumatic aortic valve disorders, cardiomyopathy, atrioventricular and left bundle-branch block, other conduction disorders, atrial fibrillation and flutter, and other cardiac arrhythmias peaked when PET was between 0 and 10 °C. Complications and ill-defined descriptions of heart disease admissions peaked at PET 0 °C. Cardiac arrest and heart failure admissions peaked when PET was between 0 and −10 °C while the rest did not vary significantly. A common drop of admissions was found when PET was above 10 °C. More medical resources could have been needed for heart health on days when PETs were <10 °C than on other days. Adaptation to such weather change for medical professionals and the general public would seem to be imperative.
Afficher plus [+] Moins [-]Stress tolerance and biocontrol performance of the yeast antagonist, Candida diversa, change with morphology transition Texte intégral
2016
Li, Guangkun | Chi, Mengshan | Chen, Huizhen | Sui, Yuan | Li, Yan | Liu, Yongsheng | Zhang, Xiaojing | Sun, Zhiqiang | Liu, Guoqing | Wang, Qi | Liu, Jia
As an eco-friendly management method, biological control of postharvest diseases, utilizing antagonistic yeasts, is a research topic receiving considerable attention. Detailed knowledge on the biology of yeast antagonists is crucial when considering their potential application and development as biocontrol products. Changes in the growth form, such as single-cell to pseudohyphae, have been associated with the mode of action in postharvest biocontrol yeasts. In this study, the antagonistic yeast, Candida diversa, reversibly shifted from a single-cell morphology on yeast peptone dextrose (YPD) medium with 2 % agar to a pseudohyphal morphology on YPD with 0.3 % agar. The tolerance of the pseudohyphal form to heat and oxidative stresses, as well as the biocontrol efficacy against Botrytis cinerea on apple and kiwifruit stored at 25 and 4 °C, was significantly higher as compared to the single-cell form. This study provides new information on the ability of C. diversa to change its morphology and the impact of the morphology shift on stress tolerance and biocontrol performance.
Afficher plus [+] Moins [-]Isobolographic analysis of the interaction between cadmium (II) and sodium sulphate: toxicological consequences Texte intégral
2016
Mera, Roi | Torres, Enrique | Abalde Alonso, Julio
Sulphate is an essential nutrient for autotrophic organisms and has been shown to have important implications in certain processes of tolerance to cadmium toxicity. Sodium sulphate is the main salt of sulphate in the natural environments. The concentration of this salt is increasing in the aquatic environments due to environmental pollution. The aim of this study was to investigate, using an analysis of isobolograms, the type and the degree of the interaction between Cd(II) and sodium sulphate in the freshwater microalga Chlamydomonas moewusii. Two blocks of experiments were performed, one at sub-optimal sodium sulphate concentrations (<14.2 mg/L) and the other at supra-optimal concentrations (>14.2 mg/L). Three fixed ratios (2:1, 1:1, and 1:2) of the individual EC₅₀ for cadmium and sodium sulphate were used within each block. The isobolographic analysis of interaction at sub-optimal concentrations showed a stronger antagonistic effect with values of interaction index (γ) between 1.46 and 3.4. However, the isobologram with sodium sulphate at supra-optimal concentrations revealed a slight but significant synergistic effect between both chemicals with an interaction index between 0.54 and 0.64. This synergic effect resulted in the potentiation of the toxic effects of cadmium, synergy that was related to the increase of the ionic strength and of two species of cadmium, CdSO₄ (aq), and Cd(SO₄) ₂ ² ⁻ , in the medium. Results of the current study suggest that sodium sulphate is able to perform a dual antagonist/synergist effect on cadmium toxicity. This role was concentration dependent.
Afficher plus [+] Moins [-]Mercury contamination from historical mining territory at Malachov Hg-deposit (Central Slovakia) Texte intégral
2016
Dadová, Jana | Andras, Peter | Kupka, Jiří | Krnáč, Jozef | Andráš, Peter, Jr | Hroncová, Emília | Midula, Pavol
Environmental contamination caused by mercury is a serious problem worldwide. The study was conducted in order to identify Hg contamination in soil, technosoil from dumps, groundwater, and surface water in the surroundings of the abandoned Hg deposit of Malachov in Central Slovakia. Soil from the Malachovský brook valley was classified as cambi-soil (rendzina). The highest Hg concentrations (44.24 mg kg⁻¹) were described in the soil from the mining area at the Veľká Studňa locality. In the groundwater, the maximal Hg content is 0.84 μg L⁻¹, and in the surface water it is 394 μg L⁻¹. The speciation study proved that in most samples, Hg occurs in the form of cinnabarite. The release of Hg into the environment as a consequence of weathering is limited.
Afficher plus [+] Moins [-]Effect of activated carbon and biochars on the bioavailability of polycyclic aromatic hydrocarbons in different industrially contaminated soils Texte intégral
2016
Kołtowski, Michał | Hilber, Isabel | Bucheli, Thomas D. | Oleszczuk, Patryk
Coal production negatively affects the environment by the emission of polycyclic aromatic hydrocarbons (PAHs). Two soils (KOK and KB) from a coking plant area was investigated and their total PAH concentration was 40 and 17 mg/kg for the sum (∑) 16 US EPA PAHs, respectively. A third soil was sampled from a bitumen plant area and was characterized by 9 mg/kg ∑16 US EPA PAHs. To reduce the freely dissolved concentration (Cfᵣₑₑ) of the PAHs in the soil pore water, active carbon (AC) and two biochars pyrolysed from wheat straw (biochar-S) and willow (biochar-W) were added to the soils at 0.5–5 % (w/w), each. The AC performed best and reduced the Cfᵣₑₑ by 51–98 % already at the lowest dose. The biochars needed doses up to 2.5 % to significantly reduce the Cfᵣₑₑ by 44–86 % in the biochar-S and by 37–68 % in the biochar-W amended soils. The high black carbon (BC) content of up to 2.3 % in the Silesian soils competed with the sorption sites of the carbon amendments and the performance of the remediation was a consequence of the contaminant’s source and the distribution between the BC and the AC/biochars. In contrast, the carbon amendment could best reduce the Cfᵣₑₑ in the Lublin soil where the BC content was normal (0.05 %). It is therefore crucial to know the contaminant’s source and history of a sample/site to choose the appropriate carbon amendment not only for remediation success but also for economic reasons.
Afficher plus [+] Moins [-]Exploitation of subabul stem lignin as a matrix in controlled release agrochemical nanoformulations: a case study with herbicide diuron Texte intégral
2016
Yearla, Srinivasa Rao | Padmasree, Kollipara
The utilization of nanomaterials in the domain of agriculture is at an inception, especially in the development of controlled release agrochemical nanoformulations. The present study demonstrated the potential of subabul stem lignin as a matrix material in agrochemical formulations using nanotechnology. In this study, “nanoprecipitation” method was employed and “optimized” to fabricate a stable herbicide, “diuron nanoformulation” (DNF). “Optimized DNF” (ODNF) has 5.17 ± 0.49 % diuron loading efficiency (DLE) and 74.3 ± 4 % encapsulation efficiency (EE). The size of nanoparticles in ODNF was 166 ± 68 nm as revealed by FESEM/TEM studies. Physicochemical characterization of ODNF by UV, FT-IR, and DSC studies revealed the successful loading of diuron within the lignin matrix. The ODNF exhibited nonlinear biphasic release profile for diuron. Further, the bioefficacy of diuron released from ODNF was tested using canola (Brassica rapa). B. rapa seedlings grown in the soil supplemented with ODNF showed early signs of leaf chlorosis and mortality when compared with seedlings grown in the presence of commercial diuron formulation (CDF) or bulk diuron (BD), respectively. This study not only revealed the exploitation of subabul stem lignin as a “matrix” in the controlled release nanoformulation of diuron but also opened up new avenues for utilizing it as matrix for several other agrochemicals associated with the growth and development of the plant.
Afficher plus [+] Moins [-]Core-shell Fe3O4@MIL-101(Fe) composites as heterogeneous catalysts of persulfate activation for the removal of Acid Orange 7 Texte intégral
2016
Yue, Xinxin | Guo, Weilin | Li, Xianghui | Zhou, Haihong | Wang, Ruiqin
In this study, a novel core-shell Fe₃O₄@MIL-101 (MIL stands for Materials of Institute Lavoisier) composite was successfully synthesized by hydrothermal method and was fully characterized by X-ray diffraction, transmission electron microscopy, Fourier-transform infrared spectra, and X-ray photoelectron spectroscopy. The composite was introduced as a catalyst to generate powerful radicals from persulfate for the removal of Acid Orange 7 in an aqueous solution. Effects of the central metal ions of MIL-101, amino group content of MIL-101, and pH were evaluated in batch experiments. It was found that both hydroxyl and sulfate radicals were generated; importantly, sulfate radicals were speculated to serve as the dominant active species in the catalytic oxidation of Acid Orange 7. In addition, a possible mechanism was proposed. This study provides new physical insights for the rational design of advanced metal-organic frameworks (MOF)-based catalysts for improved environmental remediation.
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