خيارات البحث
النتائج 3051 - 3060 من 4,043
Impact of anti-inflammatories, beta-blockers and antibiotics on leaf litter breakdown in freshwaters النص الكامل
2016
Hughes, S. R. | Kay, P. | Brown, L. E.
Pharmaceuticals are now recognised as important pollutants in freshwater systems, but a shortcoming of effects studies is that they have focused on structural endpoints and impacts on ecosystem functioning are poorly understood. The decomposition of organic matter is an important functional process in aquatic systems, and it is known that this can be impacted by the presence of pollutants. Previous studies on leaf litter breakdown have only considered the effects of antibiotics and not other groups of drugs though. The current study investigated the effects of anti-inflammatories, a beta-blocker and an antibiotic on microbially mediated breakdown of leaf litter in the laboratory; colonisation of leaf packs by benthic macroinvertebrates when placed in a stream; and shredding of leaf litter by these organisms. Furthermore, the effects of single compounds relative to their mixture were assessed. It was found that exposure of leaf litter to the study compounds did not influence its breakdown by microbes in the laboratory or macroinvertebrates in a stream. Exposure of leaf litter to pharmaceuticals also had no effect on its colonisation by macroinvertebrates in this study. Many unknowns remain, however, and further studies of the effects of pharmaceuticals on structural and functional endpoints are needed to aid aquatic conservation.
اظهر المزيد [+] اقل [-]Barium chloride induces redox status unbalance, upregulates cytokine genes expression and confers hepatotoxicity in rats—alleviation by pomegranate peel النص الكامل
2016
Elwej, Awatef | Grojja, Yousri | Ghorbel, Imen | Boudawara, Ons | Jarraya, Raoudha | Boudawara, Tahia | Zeghal, Najiba
The present study was performed to establish the therapeutic efficacy of pomegranate peel against barium chloride induced liver injury. Adult rats were divided into four groups of six animals each: group I, serving as controls, received distilled water; group II received by their drinking water 67 ppm of BaCl₂; group III received both 67 ppm of BaCl₂ by the same way than group II and 5 % of pomegranate peel (PP) via diet; group IV received 5 % of PP. Analysis by HPLC/MS of PP showed its rich composition in flavonoids such as gallic acid, castalin, hyperin, quercitrin, syringic acid, and quercetin. The protective effects of pomegranate peel against hepatotoxicity induced by barium chloride were assessed using biochemical parameters and histological studies. Exposure of rats to barium caused oxidative stress in the liver as evidenced by an increase in malondialdehyde (MDA), lipid hydroperoxides (LOOHs), H₂O₂ and advanced oxidation protein product (AOPP) levels, and lactate dehydrogenase (LDH), gamma glutamyl transpeptidase (GGT), alanine aminotransferase (AST) and aspartate aminotransferase (ALT) activities, a decrease in catalase (CAT) and glutathione peroxidase (GPx) activities, glutathion (GSH), non-protein thiol (NPSH), vitamin C levels, and Mn-SOD gene expression. Liver total MT levels, MT-1, and MT-2 and pro-inflammatory cytokine genes expression like TNF-α, IL-1β and IL-6 were increased. Pomegranate peel, supplemented in the diet of barium-treated rats, showed an improvement of all the parameters indicated above.The present work provided ethnopharmacological relevance of pomegranate peel against the toxic effects of barium, suggesting its beneficial role as a potential antioxidant.
اظهر المزيد [+] اقل [-]Removal efficiency of particulate matters at different underlying surfaces in Beijing النص الكامل
2016
Liu, Jiakai | Mo, Lichun | Zhu, Lijuan | Yang, Yilian | Liu, Jiatong | Qiu, Dongdong | Zhang, Zhenming | Liu, Jinglan
Particulate matter (PM) pollution has been increasingly becoming serious in Beijing and has drawn the attention of the local government and general public. This study was conducted during early spring of 2013 and 2014 to monitor the concentration of PM at three different land surfaces (bare land, urban forest, and lake) in the Olympic Park in Beijing and to analyze its effect on the concentration of meteorological factors and the dry deposition onto different land cover types. The results showed that diurnal variation of PM concentrations at the three different land surfaces had no significant regulations, and sharp short-term increases in PM10 (particulate matter having an aerodynamic diameter <10 μm) occurred occasionally. The concentrations also differed from one land cover type to another at the same time, but the regulation was insignificant. The most important meteorological factor influencing the PM concentration is relative humidity; it is positively correlated with the PM concentration. While in the forests, the wind speed and irradiance also influenced the PM concentration by affecting the capture capacity of trees and dry deposition velocity. Other factors were not correlated with or influenced by the PM concentration. In addition, the hourly dry deposition in unit area (μg/m²) onto the three types of land surfaces and the removal efficiency based on the ratio of dry deposition and PM concentration were calculated. The results showed that the forest has the best removal capacity for both PM2.5 (particulate matter having an aerodynamic diameter <2.5 μm) and PM10 because of the faster deposition velocity and relatively low resuspension rate. The lake’s PM10 removal efficiency is higher than that of the bare land because of the relatively higher PM resuspension rates on the bare land. However, the PM2.5 removal efficiency is lower than that of the bare land because of the significantly lower dry deposition velocity.
اظهر المزيد [+] اقل [-]Representations of pesticides and social practices: the case of French farmers النص الكامل
2016
Zouhri, Bouchra | Feliot-Rippeault, M. | Michel-Guillou, E. | Weiss, K.
Pesticides and their use in agriculture are important social issues. We conducted research to study the construction of this sensitive social object through the lens of social representations (study of the structural organisation of the social representations of pesticides) and their anchoring in three contexts that differ in terms of farming practices (Martinique, Brittany and Southern France). Our research was composed of two phases: hierarchical associations (n = 213) and a context independence test questionnaire (n = 124), conducted among farmers from the three study sites. The results indicate three representational fields that reflect salient issues in each agricultural territory. These illustrate the heuristic nature of social representations in the analysis of agricultural practices and pesticide use among French farmers.
اظهر المزيد [+] اقل [-]A new approach for remediation of As-contaminated soil: ball mill-based technique النص الكامل
2016
Shin, Yeon-Jun | Park, Sang-Min | Yoo, Jong-Chan | Jeon, Chil-Sung | Lee, Seung-Woo | Baek, Kitae
In this study, a physical ball mill process instead of chemical extraction using toxic chemical agents was applied to remove arsenic (As) from contaminated soil. A statistical analysis was carried out to establish the optimal conditions for ball mill processing. As a result of the statistical analysis, approximately 70 % of As was removed from the soil at the following conditions: 5 min, 1.0 cm, 10 rpm, and 5 % of operating time, media size, rotational velocity, and soil loading conditions, respectively. A significant amount of As remained in the grinded fine soil after ball mill processing while more than 90 % of soil has the original properties to be reused or recycled. As a result, the ball mill process could remove the metals bound strongly to the surface of soil by the surface grinding, which could be applied as a pretreatment before application of chemical extraction to reduce the load.
اظهر المزيد [+] اقل [-]Unexpected effects of sublethal doses of insecticide on the peripheral olfactory response and sexual behavior in a pest insect النص الكامل
2016
Lalouette, Lisa | Pottier, Marie-Anne | Wycke, Marie-Anne | Boitard, Constance | Bozzolan, Françoise | Maria, Annick | Demondion, Elodie | Chertemps, Thomas | Lucas, Philippe | Renault, David | Maibeche, Martine | Siaussat, David
Unexpected effects of sublethal doses of insecticide on the peripheral olfactory response and sexual behavior in a pest insect النص الكامل
2016
Lalouette, Lisa | Pottier, Marie-Anne | Wycke, Marie-Anne | Boitard, Constance | Bozzolan, Françoise | Maria, Annick | Demondion, Elodie | Chertemps, Thomas | Lucas, Philippe | Renault, David | Maibeche, Martine | Siaussat, David
Pesticides have long been used as the main solution to limit agricultural pests, but their widespread use resulted in chronic or diffuse environmental pollutions, development of insect resistances, and biodiversity reduction. The effects of low residual doses of these chemical products on organisms that affect both targeted species (crop pests) but also beneficial insects became a major concern, particularly because low doses of pesticides can induce unexpected positive—also called hormetic—effects on insects, leading to surges in pest population growth at greater rate than what would have been observed without pesticide application. The present study aimed to examine the effects of sublethal doses of deltamethrin, one of the most used synthetic pyrethroids, known to present a residual activity and persistence in the environment, on the peripheral olfactory system and sexual behavior of a major pest insect, the cotton leafworm Spodoptera littoralis. We highlighted here a hormetic effect of sublethal dose of deltamethrin on the male responses to sex pheromone, without any modification of their response to host-plant odorants. We also identified several antennal actors potentially involved in this hormetic effect and in the antennal detoxification or antennal stress response of/to deltamethrin exposure.
اظهر المزيد [+] اقل [-]Unexpected effects of sublethal doses of insecticide on the peripheral olfactory response and sexual behavior in a pest insect النص الكامل
2016
Lalouette, Lisa | Pottier, Marie-Anne | Wycke, Marie-Anne | Boitard, Constance | Bozzolan, Françoise | Maria, Annick | Demondion, Elodie | Chertemps, Thomas | Lucas, Philippe | Renault, D | Maïbèche, Martine | Siaussat, David | Institut d'écologie et des sciences de l'environnement de Paris (iEES) ; Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS) | Physiologie de l'Insecte : Signalisation et Communication (PISC) ; Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-AgroParisTech | Ecosystèmes, biodiversité, évolution [Rennes] (ECOBIO) ; Université de Rennes (UR)-Institut Ecologie et Environnement - CNRS Ecologie et Environnement (INEE-CNRS) ; Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des sciences de l'environnement de Rennes (OSERen) ; Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE) | ANR-12-ADAP-0012, ANR PHEROTOX | DIM ASTREA (région Ile de France) | EMERGENCE UPMC | ANR-12-ADAP-0012,PHEROTOX,Perception de la phéromone dans un environnement contaminé en insecticides : info-perturbation ou adaptation?(2012)
International audience | Pesticides have long been used as the main solution to limit agricultural pests, but their widespread use resulted in chronic or diffuse environmental pollutions, development of insect resistances, and biodiversity reduction. The effects of low residual doses of these chemical products on organisms that affect both targeted species (crop pests) but also beneficial insects became a major concern, particularly because low doses of pesticides can induce unexpected positive-also called hormetic-effects on insects, leading to surges in pest population growth at greater rate than what would have been observed without pesticide application. The present study aimed to examine the effects of sublethal doses of deltamethrin, one of the most used synthetic pyrethroids, known to present a residual activity and persistence in the environment, on the peripheral olfactory system and sexual behavior of a major pest insect, the cotton leafworm Spodoptera littoralis. We highlighted here a hormetic effect of sublethal dose of deltamethrin on the male responses to sex pheromone, without any modification of their response to host-plant odorants. We also identified several antennal actors potentially involved in this hormetic effect and in the antennal detoxification or antennal stress response of/to deltamethrin exposure
اظهر المزيد [+] اقل [-]Root morphological responses of five soybean [Glycine max (L.) Merr] cultivars to cadmium stress at young seedlings النص الكامل
2016
Wang, Peng | Deng, Xiaojuan | Huang, Yian | Fang, Xiaolong | Zhang, Jie | Wan, Haibo | Yang, Cunyi
To examine the differences in root morphological responses of soybean cultivars with different cadmium (Cd) tolerance and accumulation to Cd stress, the biomass, Cd concentration, and root morphological features of five soybean cultivars were determined under 0, 9, 23, 45, and 90 μM Cd stress via hydroponic experiments. Significantly genotypic differences in Cd tolerance and Cd concentration were observed between five soybean cultivars at four Cd levels. For Cd tolerance, HX3 showed a strong Cd tolerance with tolerance indexes of shoot biomass at 92.49, 76.44, 60.21, and 46.45 % after 18 days at four Cd levels, and others had similar weak tolerance at young seedling. For Cd accumulation, Cd concentration in roots showed far higher than that in shoots. The different accumulation features in roots and shoots among five cultivars were found at four Cd levels. Comparing with the control, the total root length (RL), root surface area (SA), and root volume (RV) of all cultivars were decreased significantly at four Cd levels. Tolerant cultivar HX3 had the largest root system and sensitive cultivar BX10 had the smallest root system at young seedling stage. Correlation analysis indicated that RL, SA, and RV were positively correlated with root biomass and shoot biomass under 9 and 23 μM Cd treatments, but root average diameter (RD) was negatively correlated with shoot biomass and root biomass only under 9 μM Cd treatments, while RL and SA were negatively correlated with root Cd concentration under 23 and 45 μM Cd treatments. The results suggested that root morphological traits were closely related to Cd tolerance at young seedlings under Cd treatments.
اظهر المزيد [+] اقل [-]Investigating the environmental Kuznets curve hypothesis: the role of tourism and ecological footprint النص الكامل
2016
Ozturk, Ilhan | Al-Mulali, Usama | Saboori, Behnaz
The main objective of this study is to examine the environmental Kuznets curve (EKC) hypothesis by utilizing the ecological footprint as an environment indicator and GDP from tourism as the economic indicator. To achieve this goal, an environmental degradation model is established during the period of 1988–2008 for 144 countries. The results from the time series generalized method of moments (GMM) and the system panel GMM revealed that the number of countries that have a negative relationship between the ecological footprint and its determinants (GDP growth from tourism, energy consumption, trade openness, and urbanization) is more existent in the upper middle- and high-income countries. Moreover, the EKC hypothesis is more present in the upper middle- and high-income countries than the other income countries. From the outcome of this research, a number of policy recommendations were provided for the investigated countries.
اظهر المزيد [+] اقل [-]The effect of the UV photon flux on the photoelectrocatalytic degradation of endocrine-disrupting alkylphenolic chemicals النص الكامل
2016
da Silva, Salatiel Wohlmuth | Viegas, Cheila | Ferreira, Jane Zoppas | Rodrigues, Marco Antônio Siqueira | Bernardes, Andréa Moura
The photoelectrocatalytic (PEC) degradation of 4-nonylphenol ethoxylate (NP₄EO) using a low, moderate, or high UV photon flux in different treatment times was investigated. The byproducts were verified using gas chromatography with flame ionization detection (GC-FID) and gas chromatography with quadrupole mass analyzer (GC-qMS). The GC results showed that the use of a low (2.89 μmol m⁻²s⁻¹) or a high (36.16 μmol m⁻²s⁻¹) UV photon flux reaching the anode surface was associated to the production of alcohols and the toxic byproduct nonylphenol (NP), leading to the same degradation pathway. Meanwhile, the use of a moderate UV photon flux (14.19 μmol m⁻²s⁻¹) reaching the anode surface did not produce alcohols or the NP toxic byproduct. This study demonstrates that different UV photon fluxes will have an influence in the degradation of NP₄EO with or without generation of toxic byproducts. Furthermore, it is concluded that, after the determination of the UV photon flux able to degrade NP₄EO without NP formation, the treatment time is essential in removal of NP₄EO, since increasing the treatment time of 4 to 10 h, when using the PEC best conditions (moderate UV photon flux), implies in a higher treatment efficiency.
اظهر المزيد [+] اقل [-]Occurrence and fate of PBDEs and novel brominated flame retardants in a wastewater treatment plant in Harbin, China النص الكامل
2016
Li, Bo | Sun, Shao-Jing | Huo, Chun-Yan | Li, Wen-Long | Zhu, Ning-Zheng | Qi, Hong | Kong, Ling-Jun | Li, Yi-Fan | Ma, Wanli
Wastewater treatment plant (WWTP) is considered to be an important medium for the transport and transformation of organic pollutants. This study attempted to comprehensively investigate polybrominated diphenyl ethers (PBDEs) and novel brominated flame retardants (NBFRs) in a WWTP in Harbin, one of the main “Old Industrial Base” in China. The mean concentrations of the total PBDEs in the influent, effluent, and sludge were 152 ng/L, 16.2 ng/L, and 503 g/g dw, respectively, which were at the low end of the global range. BDE-209 was the most abundant congener, with contributions to the total PBDE ranging from 90.5 to 98.5 %. The level of the total NBFRs ranged from 24.5 to 107 ng/L, 0.95 to 20.3 ng/L, and 305 to 1202 ng/g dw in the influent, effluent, and sludge, respectively. For NBFRs, DBDPE was the most abundant congener (38.8–50.5 %), followed by BEHTBP (11.0–35.0 %). The ratio for DBDPE/BDE-209 (0.62 ± 0.42) was found less than 1 in sludge, which indicated that Deca-BDE is still the major BFR product in this city. Source identification suggested that indoor dust should be an important source of BFRs in the WWTP. Approximately 20.8 and 7.79 kg of PBDEs and NBFRs on annual basis were removed with the sludge. Biodegradation could play an important role on the fate of BFRs in the WWTP, which is required for future research.
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