خيارات البحث
النتائج 3521 - 3530 من 4,308
Field evidence of bird poisonings by imidacloprid-treated seeds: a review of incidents reported by the French SAGIR network from 1995 to 2014 النص الكامل
2017
Millot, Florian | Decors, Anouk | Mastain, Olivier | Quintaine, Thomas | Berny, Philippe | Vey, Danièle | Lasseur, Romain | Bro, Elisabeth
The large-scale use of neonicotinoid insecticides has raised growing concerns about their potential adverse effects on farmland birds, and more generally on biodiversity. Imidacloprid, the first neonicotinoid commercialized, has been identified as posing a risk for seed-eating birds when it is used as seed treatment of some crops since the consumption of a few dressed seeds could cause mortality. But evidence of direct effects in the field is lacking. Here, we reviewed the 103 wildlife mortality incidents reported by the French SAGIR Network from 1995 to 2014, for which toxicological analyses detected imidacloprid residues. One hundred and one incidents totalling at least 734 dead animals were consistent with an agricultural use as seed treatment. Grey partridges (Perdix perdix) and “pigeons” (Columba palumbus, Columba livia and Columba oenas) were the main species found. More than 70% of incidents occurred during autumn cereal sowings. Furthermore, since there is no biomarker for diagnosing neonicotinoid poisonings, we developed a diagnostic approach to estimate the degree of certainty that these mortalities were due to imidacloprid poisoning. By this way, the probability that mortality was due to poisoning by imidacloprid-treated seeds was ranked as at least “likely” in 70% of incidents. As a result, this work provides clear evidence to risk managers that lethal effects due to the consumption by birds of imidacloprid-treated seeds regularly occur in the field. This in turn raises the question of the effectiveness of the two main factors (seed burying and imidacloprid-treated seeds avoidance) that are supposed to make the risk to birds negligible. Risk factors and the relevance of mitigation measures are discussed.
اظهر المزيد [+] اقل [-]Synergistic use of an oil drift model and remote sensing observations for oil spill monitoring النص الكامل
2017
De Padova, Diana | Mossa, Michele | Adamo, Maria | De Carolis, Giacomo | Pasquariello, Guido
In case of oil spills due to disasters, one of the environmental concerns is the oil trajectories and spatial distribution. To meet these new challenges, spill response plans need to be upgraded. An important component of such a plan would be models able to simulate the behaviour of oil in terms of trajectories and spatial distribution, if accidentally released, in deep water. All these models need to be calibrated with independent observations. The aim of the present paper is to demonstrate that significant support to oil slick monitoring can be obtained by the synergistic use of oil drift models and remote sensing observations. Based on transport properties and weathering processes, oil drift models can indeed predict the fate of spilled oil under the action of water current velocity and wind in terms of oil position, concentration and thickness distribution. The oil spill event that occurred on 31 May 2003 in the Baltic Sea offshore the Swedish and Danish coasts is considered a case study with the aim of producing three-dimensional models of sea circulation and oil contaminant transport. The High-Resolution Limited Area Model (HIRLAM) is used for atmospheric forcing. The results of the numerical modelling of current speed and water surface elevation data are validated by measurements carried out in Kalmarsund, Simrishamn and Kungsholmsfort stations over a period of 18 days and 17 h. The oil spill model uses the current field obtained from a circulation model. Near-infrared (NIR) satellite images were compared with numerical simulations. The simulation was able to predict both the oil spill trajectories of the observed slick and thickness distribution. Therefore, this work shows how oil drift modelling and remotely sensed data can provide the right synergy to reproduce the timing and transport of the oil and to get reliable estimates of thicknesses of spilled oil to prepare an emergency plan and to assess the magnitude of risk involved in case of oil spills due to disaster.
اظهر المزيد [+] اقل [-]Zeolitic imidazolate framework-8 for efficient adsorption and removal of Cr(VI) ions from aqueous solution النص الكامل
2017
Niknam Shahrak, Mahdi | Ghahramaninezhad, Mahboube | Eydifarash, Mohsen
Heavy metals are emerging toxic pollutants in which the development of advanced materials for their efficient adsorption and separation is thus of great significance in environmental sciences point of view. In this study, one of the zinc-based zeolitic imidazolate framework materials, known as ZIF-8, has been synthesized and used for chromium(VI) contaminant removal from water for the first time. The as-synthesized ZIF-8 adsorbent was characterized with different methodologies such as powder X-ray diffraction (XRD), thermo-gravimetric analysis, FT-IR, nuclear magnetic resonance spectroscopy, and UV–Vis spectra of solid state. Various factors affecting removal percentage (efficiency) are experimentally investigated including pH of solution, adsorbent dosage, contact time and initial concentration of Cr(VI) to achieve the optimal condition. The obtained results indicate that the ZIF-8 shows good performance for the Cr(VI) removal from aqueous solution so that 60 min mixing of 2 g of ZIF-8 adsorbent with the 2.5 ppm of Cr(VI) solution in a neutral environment will result in the highest separation efficiency around 70%. The time needed to reach the equilibrium (maximum separation efficiency) is only 60 min for a concentration of 5 mg L⁻¹. Structure stability in the presence of water is also carefully examined by XRD determination of ZIF-8 under different contact times in aqueous solution, which suggests that the structure is going to be destructed after 60 min immersed in solution. Electrostatic interaction of Cr(VI) anions by positively charged ZIF-8 is responsible for Cr(VI) adsorption and separation. Moreover, equilibrium adsorption study reveals that the Cr(VI) removal process using ZIF-8 nicely fits the Langmuir and Toth isotherm models which mean the adsorbent has low heterogeneous surface with different distributions of adsorption energies during Cr(VI) adsorption. Equilibrium adsorption capacity is observed around 0.25 for 20 mg L⁻¹ of initial Cr(VI) solutions.
اظهر المزيد [+] اقل [-]Functionalized hydrothermal carbon derived from waste pomelo peel as solid-phase extractant for the removal of uranyl from aqueous solution النص الكامل
2017
Li, Feize | Tang, Yu | Wang, Huilin | Yang, Jijun | Li, Shoujian | Liu, Jun | Tu, Hong | Liao, Jiali | Yang, Yuanyou | Liu, Ning
To develop a high-performance solid-phase extractant for the separation of uranyl f, pomelo peel, a kind of waste biomass, has been employed as carbon source to prepare carbonaceous matrix through low-temperature hydrothermal carbonization (200 °C, 24 h). After being oxidized by Hummers method, the prepared hydrothermal carbon matrix was functionalized with carboxyl and phenolic hydroxyl groups (1.75 mmol g⁻¹). The relevant characterizations and batch studies had demonstrated that the obtained carbon material possessed excellent affinity toward uranyl (436.4 mg g⁻¹) and the sorption process was a spontaneous, endothermic and rapid chemisorption. The selective sorption of U(VI) from the simulated nuclear effluent demonstrated that the sorbent displayed a desirable selectivity (56.14% at pH = 4.5) for the U(VI) ions over the other 11 competitive cations from the simulated industrial nuclear effluent. The proposed synthetic strategy in the present work had turned out to be effective and practical, which provides a novel approach to prepare functional materials for the recovery and separation of uranyl or other heavy metals from aqueous environment.
اظهر المزيد [+] اقل [-]Distribution of serum levels of persistent organic pollutants, heterocyclic aromatic amine theoretical intake and nutritional cofactors in a semi-rural island population النص الكامل
2017
Carrizo, Daniel | Brennan, SarahF. | Chevallier, OlivierP. | Woodside, Jayne | Cooper, KevinM. | Cantwell, MarieM. | Cuskelly, Geraldine | Elliott, ChristopherT.
Persistent organic pollutant (POP) exposure is strongly associated with negative health effects in humans. Heterocyclic aromatic amines (HAAs) are formed during high temperature cooking of foods (i.e. meat and fish). Human exposure to HAA is through food consumption and from similar food groups to POPs. A study of serum samples for POPs in a non-occupational exposed population (n = 149, age range 18–80 years, recruited in 2012) and comparison with estimated HAA daily intake calculations based on food diaries were undertaken. Three different age groups (group 1, 18–29 years; group 2, 30–44 years; and group 3, 45–80 years) were used to explore possible relationships between POP levels present in blood, HAA intake and nutritional cofactors. Significant differences (p < 0.05) between groups (1 and 3) for POP levels were found for p,p′-DDE, polychlorinated biphenyl (PCB) 153, PCB 138 and the sum of PCBs. A similar trend was found between groups 2 and 3 for PCB 153 and sum of PCBs. Significant differences were found between groups 1 and 3 and groups 2 and 3 for HAA intake., i.e. HAA intake was lowest in those of middle age, which may well reflect a different pathway of human exposure between HAA and POPs through the diet preferences.
اظهر المزيد [+] اقل [-]Distribution of As, Cd, and Pb in seafood in Southern China and their oral bioavailability in mice النص الكامل
2017
Zhu, Zhi-Peng | Tong, Yong-Peng | Tang, Wei-Yang | Wu, Zheng-Xin | Wu, Zhi-Bing
The distribution of the toxic elements As, Cd, and Pb in nine different types of seafood from Shenzhen, China, was investigated by using inductively coupled plasma mass spectrometry (ICP-MS). The results revealed that the concentrations of arsenic (As) in fish (Lutjanus erythropterus, Paralichthys olivaceus) and in bivalve (Meretrix meretrix) and cadmium (Cd) in scallop (Argopecten irradians) exceed the limits established by food safety regulations in China and EU (European Union). Furthermore, the bioavailability of As, Cd, and lead (Pb) in mice after 20-day oral ingestion of Crassostrea rivularis was investigated, and the total rate of absorption of toxic elements in samples from the liver and kidney tissues and blood was determined. The results of this in vivo trial indicated that the oral bioavailability of As, Cd, and Pb was approximately 0.33, 0.45, and 0.74%, respectively.
اظهر المزيد [+] اقل [-]Investigation on the removal of H2S from microwave pyrolysis of sewage sludge by an integrated two-stage system النص الكامل
2017
Zhang, Jun | Tian, Yu | Yin, Linlin | Zuo, Wei | Gong, Zhenlong | Zhang, Jie
In this study, an integrated two-stage system, including the in-situ catalytic microwave pyrolysis (ICMP) and subsequent catalytic wet oxidation (CWO) processes, was proposed to remove H₂S released from microwave-induced pyrolysis of sewage sludge. The emission profile and H₂S removal from the pyrolysis of raw sewage sludge (SS) and sewage sludge spiked with conditioner CaO (SS-CaO) were investigated. The results showed that CaO played a positive role on sulfur fixation during the pyrolysis process. It was found that SS-CaO (10 wt.%) contributed to about 35% of H₂S removal at the first stage (ICMP process). Additionally, the CWO process was demonstrated to have promising potential for posttreatment of remaining H₂S gas. At the Fe³⁺ concentration of 30 g/L, the maximum H₂S removal efficiency of 94.8% was obtained for a single Fe³⁺/Cu²⁺ solution. Finally, at the pyrolysis temperature of 800 °C, 99.7% of H₂S was eliminated by the integrated two-stage system meeting the discharge standard of China. Therefore, the integrated two-stage system of ICMP + CWO may provide a promising strategy to remove H₂S dramatically for the biomass pyrolysis industry.
اظهر المزيد [+] اقل [-]Selenium nanoparticles with low-level ionizing radiation exposure ameliorate nicotine-induced inflammatory impairment in rat kidney النص الكامل
2017
Zahran, WalidE. | Elsonbaty, SawsanM. | Moawed, FatmaS. M.
Occupational exposure to low-level ionizing radiation (<1 Gy) was shown to enhance cell protection via attenuating an established inflammatory process. Nicotine, a major toxic component of cigarette smoke, is responsible for smoking-mediated renal dysfunction. The present study was therefore aimed to investigate the protective impact of ginger Zingiber officinale selenium nanoparticles (SeNPs) with whole-body low-dose gamma radiation (γ-R) against nicotine-induced nephrotoxicity in male albino rats. Nicotine intoxication was induced with 0.5 mg/kg BW. Rats received 0.1 mg SeNPs/kg BW by gastric gavage concomitant with 0.5 Gy γ-R over 4 weeks. Characterization studies showed the formation of spherical SeNPs with a size ranged from 10 to 30 nm in diameter with a thin film encapsulating the nanoballs. Our data revealed that nicotine induced renal dysfunction manifested by significant abnormal levels of kidney function markers (creatinine, urea, sodium and potassium) accompanied by increased levels of malondialdehyde along with a reduction in glutathione level, glutathione peroxidase, and glutathione S-transferase activities. It is worthy to note that nicotine toxicity induced significant increments in serum inflammatory markers: tumor necrosis factor-α and vascular cell adhesion protein 1. Western blotting showed marked significant elevation in caspase-3 activities against nicotine. The mRNA gene expression of inducible cyclooxygenase-2 gene was highly increased with nicotine intoxication while that of cyclooxygenase-1 did not show any changes. Interestingly, our data demonstrated that SeNPs in synergistic interaction with γ-R are efficacious control against nicotine-induced nephrotoxicity via anti-oxidant-mediated anti-inflammatory activities. Thus, it is tempting to recommend dietary approaches with ginger SeNPs for smokers at workplaces exposed occupationally and regularly to low-level ionizing radiation.
اظهر المزيد [+] اقل [-]Day-night variability of water-soluble ions in PM10 samples collected at a traffic site in southeastern Spain النص الكامل
2017
Galindo, Nuria | Yubero, Eduardo
The present work reports diurnal and nocturnal concentrations of water-soluble ions associated to PM₁₀ samples collected during the warm and cold seasons in the urban center of Elche (Southeastern Spain). Statistical differences between daytime and nighttime levels of PM₁₀ were only observed during winter. The lower concentrations during the night were most likely the result of a reduction in traffic-induced road dust resuspension, since nocturnal concentrations of calcium also exhibited a significant decrease compared to daytime levels. During the warm season, nitrate was the only component that showed a statistically significant increase from day to night. The lower nocturnal temperatures that prevent the thermal decomposition of ammonium nitrate and the formation of nitric acid favored by the higher relative humidity at night are the most probable reasons for this variation. The close relationship between nitrate formation and relative humidity during nighttime was supported by the results of the correlation analysis. The reaction of sulfuric and nitric acids with CaCO₃ occurred to a greater extent during daytime in summer.
اظهر المزيد [+] اقل [-]Variations of polycyclic aromatic hydrocarbons in ambient air during haze and non-haze episodes in warm seasons in Hangzhou, China النص الكامل
2017
Lu, Hao | Wang, Shengsheng | Wu, Zuliang | Yao, Shuiliang | Han, Jingyi | Tang, Xiujuan | Jiang, Boqiong
To investigate the characteristics of polycyclic aromatic hydrocarbons (PAHs) during haze episodes in warm seasons, daily PM₂.₅ and gaseous samples were collected from March to September 2015 in Hangzhou, China. Daily samples were further divided into four groups by the definition of haze according to visibility and relative humidity (RH), including non-haze (visibility, >10 km), light haze (visibility, 8–10 km, RH <90 %), medium haze (visibility, 5–8 km, RH <90 %), and heavy haze (visibility, <5 km, RH <90 %). Significantly higher concentrations of PM₂.₅-bound PAHs were found in haze days, but the mean PM₂.₅-bound PAH concentrations obviously decreased with the aggravation of haze pollution from light to heavy. The gas/particle partitioning coefficients of PAHs decreased from light-haze to heavy-haze episodes, which indicated that PM₂.₅-bound PAHs were restricted to adhere to the particulate phase with the aggravation of haze pollution. Absorption was considered the main mechanism of gas/particle partitioning of PAHs from gaseous to particulate phase. Analysis of air mass transport indicated that the PM₂.₅-bound PAH pollution in haze days was largely from regional sources but also significantly affected by long-range air mass transport. The inhalation cancer risk associated with PAHs exceeded the acceptable risk level markedly in both haze and non-haze days.
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