خيارات البحث
النتائج 2321 - 2330 من 4,044
Chemical assessment of lead, cadmium, nitrate, and nitrite intakes with daily diets of children and adolescents from orphanages in Krakow, Poland النص الكامل
2016
Pysz, Katarzyna | Leszczyńska, Teresa | Bieżanowska-Kopeć, Renata | Kopeć, Aneta
The aim of this study has been to measure the level of lead, cadmium, nitrates, and nitrites in the daily diets of children and adolescents from orphanages located in Krakow (Poland). Diets were collected over four seasons of 2009. The content of cadmium and lead was measured with flameless atomic absorption spectrometry. Nitrates and nitrites in diets were measured using the Griess colorimetric method. In all orphanages, the average intake of lead with daily diets, regardless of the season, ranged from 1.11 ± 0.15 to 22.59 ± 0.07 μg/kg bw/week. The average cadmium intake by children and adolescents ranged between 3.09 ± 0.21 and 20.36 ± 2.21 μg/kg bw/week and, for all orphanages, exceeded the tolerable weekly intake (TWI) level. Daily intake of nitrates and nitrites ranged respectively from 27 to 289 % and from 9 to 99 % of the acceptable daily intake (ADI). The youngest children, with lower body mass, were particularly sensitive to the excessive intakes of cadmium and nitrates.
اظهر المزيد [+] اقل [-]Impact of untreated urban waste on the prevalence and antibiotic resistance profiles of human opportunistic pathogens in agricultural soils from Burkina Faso النص الكامل
2016
Youenou, Benjamin | Hien, Edmond | Deredjian, Amélie | Brothier, Elisabeth | Favre-Bonté, Sabine | Nazaret, Sylvie
This study examined the long-term effects of the landfill disposal of untreated urban waste for soil fertilization on the prevalence and antibiotic resistance profiles of various human opportunistic pathogens in soils from Burkina Faso. Samples were collected at three sites in the periphery of Ouagadougou during two campaigns in 2008 and 2011. At each site, amendment led to changes in physico-chemical characteristics as shown by the increase in pH, CEC, total C, total N, and metal contents. Similarly, the numbers of total heterotrophic bacteria were higher in the amended fields than in the control ones. No sanitation indicators, i.e., coliforms, Staphylococci, and Enterococci, were detected. Pseudomonas aeruginosa and Burkholderia cepacia complex (Bcc) were detected at a low level in one amended field. Stenotrophomonas maltophilia was detected from both campaigns at the three sites in the amended fields and only once in an unamended field. Diversity analysis showed some opportunistic pathogen isolates to be closely related to reference clinical strains responsible for nosocomial- or community-acquired infections in Northern countries. Antibiotic resistance tests showed that P. aeruginosa and Bcc isolates had a wild-type phenotype and that most S. maltophilia isolates had a multi-drug resistance profile with resistance to 7 to 15 antibiotics. Then we were able to show that amendment led to an increase of some human opportunistic pathogens including multi-drug resistant isolates. Although the application of untreated urban waste increases both soil organic matter content and therefore soil fertility, the consequences of this practice on human health should be considered.
اظهر المزيد [+] اقل [-]Status of hormones and painkillers in wastewater effluents across several European states—considerations for the EU watch list concerning estradiols and diclofenac النص الكامل
2016
Schröder, P. | Helmreich, B. | Škrbić, B. | Carballa, M. | Papa, M. | Pastore, C. | Emre, Z. | Oehmen, A. | Langenhoff, A. | Molinos, M. | Dvarioniene, J. | Huber, C. | Tsagarakis, Konstantinos P. | Martinez-Lopez, E. | Pagano, S Meric | Vogelsang, C. | Mascolo, G.
Present technologies for wastewater treatment do not sufficiently address the increasing pollution situation of receiving water bodies, especially with the growing use of personal care products and pharmaceuticals (PPCP) in the private household and health sector. The relevance of addressing this problem of organic pollutants was taken into account by the Directive 2013/39/EU that introduced (i) the quality evaluation of aquatic compartments, (ii) the polluter pays principle, (iii) the need for innovative and affordable wastewater treatment technologies, and (iv) the identification of pollution causes including a list of principal compounds to be monitored. In addition, a watch list of 10 other substances was recently defined by Decision 2015/495 on March 20, 2015. This list contains, among several recalcitrant chemicals, the painkiller diclofenac and the hormones 17β-estradiol and 17α-ethinylestradiol. Although some modern approaches for their removal exist, such as advanced oxidation processes (AOPs), retrofitting most wastewater treatment plants with AOPs will not be acceptable as consistent investment at reasonable operational cost. Additionally, by-product and transformation product formation has to be considered. The same is true for membrane-based technologies (nanofiltration, reversed osmosis) despite of the incredible progress that has been made during recent years, because these systems lead to higher operation costs (mainly due to higher energy consumption) so that the majority of communities will not easily accept them. Advanced technologies in wastewater treatment like membrane bioreactors (MBR) that integrate biological degradation of organic matter with membrane filtration have proven a more complete elimination of emerging pollutants in a rather cost- and labor-intensive technology. Still, most of the presently applied methods are incapable of removing critical compounds completely. In this opinion paper, the state of the art of European WWTPs is reflected, and capacities of single methods are described. Furthermore, the need for analytical standards, risk assessment, and economic planning is stressed. The survey results in the conclusion that combinations of different conventional and advanced technologies including biological and plant-based strategies seem to be most promising to solve the burning problem of polluting our environment with hazardous emerging xenobiotics.
اظهر المزيد [+] اقل [-]Improved traceability of Shiga-toxin-producing Escherichia coli using CRISPRs for detection and typing النص الكامل
2016
Delannoy, Sabine | Beutin, Lothar | Fach, Patrick
Among strains of Shiga-toxin-producing Escherichia coli (STEC), seven serogroups (O26, O45, O103, O111, O121, O145, and O157) are frequently associated with severe clinical illness in humans. The development of methods for their reliable detection from complex samples such as food has been challenging thus far, and is currently based on the PCR detection of the major virulence genes stx1, stx2, and eae, and O-serogroup-specific genes. However, this approach lacks resolution. Moreover, new STEC serotypes are continuously emerging worldwide. For example, in May 2011, strains belonging to the hitherto rarely detected STEC serotype O104:H4 were identified as causative agents of one of the world’s largest outbreak of disease with a high incidence of hemorrhagic colitis and hemolytic uremic syndrome in the infected patients. Discriminant typing of pathogens is crucial for epidemiological surveillance and investigations of outbreaks, and especially for tracking and tracing in case of accidental and deliberate contamination of food and water samples. Clustered regularly interspaced short palindromic repeats (CRISPRs) are composed of short, highly conserved DNA repeats separated by unique sequences of similar length. This distinctive sequence signature of CRISPRs can be used for strain typing in several bacterial species including STEC. This review discusses how CRISPRs have recently been used for STEC identification and typing.
اظهر المزيد [+] اقل [-]Repellent and mosquitocidal effects of leaf extracts of Clausena anisata against the Aedes aegypti mosquito (Diptera: Culicidae) النص الكامل
2016
Mukandiwa, Lillian | Eloff, J. N. (Jacobus Nicolaas) | Naidoo, Vinny
Mosquitoes are rapidly developing resistance to insecticides that millions of people relied on to protect themselves from the diseases they carry, thereby creating a need to develop new insecticides. Clausena anisata is used traditionally as an insect repellent by various communities in Africa and Asia. For this study, the repellency and adulticidal activities of leaf extracts and compounds isolated from this plant species were evaluated against the yellow fever mosquito, Aedes aegypti. In the topical application assays, using total bites as an indicator, repellency was dose dependent, with the acetone crude extract (15 %) having 93 % repellence and the hexane fraction (7.5 %) 67 % repellence after 3 h. Fractionation resulted in a loss of total repellence. As mosquito-net treating agents, the acetone and hexane extracts of C. anisata, both at 15 %, had average repellences of 46.89 ± 2.95 and 50.13 ± 2.02 %, respectively, 3 h after exposure. The C. anisata acetone extract and its hexane fraction caused mosquito knockdown and eventually death when nebulised into the testing chamber, with an EC₅₀ of 78.9 mg/ml (7.89 %) and 71.6 mg/ml (7.16 %) in the first 15 min after spraying. C. anisata leaf extracts have potential to be included in protection products against mosquitoes due to the repellent and cidal compounds contained therein.
اظهر المزيد [+] اقل [-]Assessment of trace metal air pollution in Paris using slurry-TXRF analysis on cemetery mosses النص الكامل
2016
Natali, Marco | Zanella, Augusto | Rankovic, Aleksandar | Banas, Damien | Cantaluppi, Chiara | Abbadie, Luc | Lata, Jean -Christophe
Mosses are useful, ubiquitous accumulation biomonitors and as such can be used for biomonitoring surveys. However, the biomonitoring of atmospheric pollution can be compromised in urban contexts if the targeted biomonitors are regularly disturbed, irregularly distributed, or are difficult to access. Here, we test the hypothesis that cemeteries are appropriate moss sampling sites for the evaluation of air pollution in urban areas. We sampled mosses growing on gravestones in 21 urban and peri-urban cemeteries in the Paris metropolitan area. We focused on Grimmia pulvinata (Hedwig) Smith, a species abundantly found in all studied cemeteries and very common in Europe. The concentration of Al, As, Br, Ca, Ce, Cl, Cr, Cu, Fe, K, Mn, Ni, V, P, Pb, Rb, S, Sr, Ti, and Zn was determined by a total reflection X-ray fluorescence technique coupled with a slurry sampling method (slurry-TXRF). This method avoids a digestion step, reduces the risk of sample contamination, and works even at low sample quantities. Elemental markers of road traffic indicated that the highest polluted cemeteries were located near the highly frequented Parisian ring road and under the influence of prevailing winds. The sites with the lowest pollution were found not only in the peri-urban cemeteries, adjoining forest or farming landscapes, but also in the large and relatively wooded cemeteries located in the center of Paris. Our results suggest that (1) slurry-TXRF might be successfully used with moss material, (2) G. pulvinata might be a good biomonitor of trace metals air pollution in urban context, and (3) cemetery moss sampling could be a useful complement for monitoring urban areas. Graphical abstract We tested the hypothesis that cemeteries are appropriate moss sampling sites for the evaluation of air pollution in urban areas. We sampled 110 moss cushions (Grimmia pulvinata) growing on gravestones in 21 urban and peri-urban cemeteries in the Paris metropolitan area. The concentration of 20 elements in mosses was determined by a total reflection X-ray fluorescence technique coupled with a slurry sampling method. Statistical analysis revealed that: - Urbanized Parisian areas crossed by traffic roads have the highest polluted cemeteries with a strong influence of main wind direction on the distribution of air pollutants - As expected, small cemeteries with low tree density were heavily polluted - Less obvious, large green spaces such as large cemeteries (Père Lachaise, Montmartre, Montparnasse) in the center of a dense metropolis like Paris present the same level of atmospheric trace metal pollution as cemeteries in less urbanized areas or nearing a very large forest. This suggests that even in densely urbanized areas, there is more spatial variability in pollution distribution than usually assumed and that large urban areas with low traffic and green filters such as trees are likely to intercept air pollutants
اظهر المزيد [+] اقل [-]Potential of barrage fish ponds for the mitigation of pesticide pollution in streams النص الكامل
2016
Gaillard, Juliette | Thomas, Marielle | Lazartigues, Angélique | Bonnefille, Bénilde | Pallez, Christelle | Dauchy, Xavier | Feidt, Cyril | Banas, Damien
Barrage fishponds may represent a significant surface water area in some French regions. Knowledge on their effect on water resources is therefore necessary for the development of appropriate water quality management plans at the regional scale. Although there is much information on the nutrient removal capacity of these water bodies, little attention has been paid to other agricultural contaminants such as pesticides. The present paper reports the results of a 1-year field monitoring of pesticide concentrations and water flows measured upstream and downstream from a fishpond in North East France to evaluate its capacity in reducing pesticide loads. Among the 42 active substances that had been applied on the fishpond’s catchment, seven pesticides (five herbicides, two fungicides) were studied. The highest concentration in the inflow to the pond was 26.5 μg/L (MCPA), while the highest concentration in pond outflow was 0.54 μg/L (prosulfocarb). Removal rates of dissolved pesticides in the fishpond ranged from 0-8 % (prosulfocarb) to 100 % (clopyralid). Although not primarily designed for the treatment of diffuse sources of pesticides, the studied fishpond had the potential to do so.
اظهر المزيد [+] اقل [-]Oxidative stress in two tropical species after exposure to diesel oil النص الكامل
2016
Sardi, Adriana E. | Sandrini-Neto, Leonardo | da S. Pereira, Leticia | Silva de Assis, Helena | Martins, Cesar C. | Lana, Paulo da Cunha | Camus, Lionel
Recent offshore petroleum exploration has increased the risks of oil spills worldwide. We investigated biomarker responses to diesel oil exposure in two tropical and subtropical species, the clam Anomalocardia flexuosa and the polychaete Laeonereis culveri. Animals were exposed to oil-spiked sediment at two different concentrations (0.5 L and 1.0 L m⁻²). Activities of antioxidant enzymes catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx); glutathione transferase (GST); and lipid peroxides (LPO) were assessed in bivalve digestive glands and polychaete whole-body homogenates at 36 and 60 h of exposure. Significant variation in enzymatic antioxidant activity depended on the sampling time after exposure. No similar response patterns, either increases or decreases, were detected for the two target species, and biomarker responses were species-specific. L. culveri showed clearer patterns in its antioxidant response and should be prioritized over other species in biomonitoring studies involving oil exposure. Understanding the temporal variability of these biomarkers is a necessary action before implementing them as indicators measures in oil contamination biomonitoring programs. Our results provide a better understanding of biomarker responses in subtropical species, evidencing their potential use as sentinels of oil contamination.
اظهر المزيد [+] اقل [-]Effects of an environmentally relevant concentration of diuron on oyster genitors during gametogenesis: responses of early molecular and cellular markers and physiological impacts النص الكامل
2016
Akcha, F. | Barranger, A. | Bachère, E. | Berthelin, C Heude | Piquemal, D. | Alonso, P. | Sallan, R Rondon | Dimastrogiovanni, G. | Porte, C. | Menard, D. | Szczybelski, A. | Benabdelmouna, A. | Auffret, M. | Rouxel, J. | Burgeot, T.
Genitors of the Pacific oyster Crassostrea gigas were submitted during gametogenesis to a short pulse exposure to the herbicide diuron at a realistic environmental concentration. Histological analysis showed no effect of diuron on gametogenesis course, sex ratio and reproductive effort. A non-significant increase in testosterone and progesterone levels was observed in genitors exposed to the herbicide. At cell level, diuron exposure was shown to modulate the phagocytic activity of circulating hemocytes. The results of a transcriptional analysis showed that diuron affected the expression of genes belonging to functions known to play a major role during oyster gametogenesis such as gene transcription regulation, DNA replication and repair, DNA methylation and cytokinesis. Taking into account the results we previously obtained on the same genitors, this study showed a negative effect of diuron on oyster reproduction by inducing both structural and functional modifications of the DNA.
اظهر المزيد [+] اقل [-]Side effects of Bacillus thuringiensis var. kurstaki on the hymenopterous parasitic wasp Trichogramma chilonis النص الكامل
2016
Amichot, Marcel | Curty, Christine | Benguettat-Magliano, Olivia | Gallet, Armel | Wajnberg, E.
Most of the detrimental effects of using conventional insecticides to control crop pests are now well identified and are nowadays major arguments for replacing such compounds by the use of biological control agents. In this respect, the bacterium Bacillus thuringiensis var. kurstaki and Trichogramma (Hymenoptera: Trichogrammatidae) parasitic wasp species are both effective against lepidopterous pests and can actually be used concomitantly. In this work, we studied the potential side effects of B. thuringiensis var. kurstaki on Trichogramma chilonis females. We first evidenced an acute toxicity of B. thuringiensis on T. chilonis. Then, after ingestion of B. thuringiensis at sublethal doses, we focused on life history traits of T. chilonis such as longevity, reproductive success and the time spent on host eggs patches. The reproductive success of T. chilonis was not modified by B. thuringiensis while a significant effect was observed on longevity and the time spent on host eggs patches. The physiological and ecological meanings of the results obtained are discussed.
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