خيارات البحث
النتائج 1171 - 1180 من 4,044
Features of the annual evolution of CO2 and CH4 in the atmosphere of a Mediterranean climate site studied using a nonparametric and a harmonic function النص الكامل
2016
Pérez, Isidro A. | Sánchez, M Luisa | García, M Ángeles | Pardo, Nuria
Concentrations of CO2 and CH4 measured over 3 years at a rural site in the Spanish northern plateau were investigated together with vegetation and meteorological variables. Two procedures were implemented to study the annual evolution. Kernel estimation provided a detailed time description, and the harmonic model may be fitted easily. The site was characterised by grass from autumn to spring. However, vigorous growth was observed during the latter season due to the biological cycle of plants under favourable meteorological conditions. A CO2 peak was observed a fortnight before the time of maximum NDVI, and was attributed to the prevalence of respiration over photosynthesis. A pronounced trough was apparent in summer and was explained by the death of vegetation and active dispersion in a highly developed boundary layer. CH4 evolution was characterised by a deficit period from May to October, indicating that meteorological evolution played a key role. The harmonic model showed that annual and half-annual cycles evidenced a similar contribution for CO2, whereas said weight for the half-annual cycle was considerably smaller for CH4.
اظهر المزيد [+] اقل [-]Organochlorines and polychlorinated biphenyl environmental pollution in south coast of Rio De Janeiro state النص الكامل
2016
da Silva, Ana Maria Ferreira | Pavesi, Thelma | Rosa, Ana Cristina Simões | Santos, Tatyane Pereira dos | de Medeiros Tabalipa, Marianne | Lemes, Vera Regina Rossi | Alves, Sergio Rabello | de Novaes Sarcinelli, Paula
The objective of this study was to evaluate the burden of environmental pollution by Polychlorinated Biphenyls (PCBs) and Organochlorine Pesticides (OCs) in two localities of Rio de Janeiro coast, through the determination of these levels in specimens of mullets and croakers collected from May to August 2008, at Guanabara Bay (GB) and from Araújo Island (AI), at Paraty Bay. Twenty three organochlorine pollutants were detected in croakers at GB and twenty in mullets and all PCBs congeners investigated in the study were present in the two species. Ratio ∑DDT/∑PCB of 1.4 shows an important contribution of agricultural residues in GB and p,p′-DDE/∑DDT of 0.1 demonstrates a reintroduction of DDT. Consumption of mullet may represent a risk to the health of fishermen families from GB, with average and maximum estimated daily intake of ∑DDT of 9.012μg/kg p.c. and 26,174μg/kg p.c., representing 45% and 131% of ADI established by WHO.
اظهر المزيد [+] اقل [-]Occurrence and distribution of antibiotic resistance genes in the coastal area of the Bohai Bay, China النص الكامل
2016
Niu, Zhi-Guang | Zhang, Kai | Zhang, Ying
Considering the abuse of antibiotics worldwide, we investigated the abundance of three classes of antibiotic resistance genes (ARGs) and the concentrations of corresponding antibiotics in water and sediments of Bohai Bay. The results showed that sulI and sulII were detected in all samples, and their abundance range was 10−5–10−2/16S gene copies. The abundance of tetM and ermB were relatively higher than the other genes of tet-ARGs and erm-ARGs. Sulfonamides were the most prevalent antibiotics, and the concentrations of antibiotic in sediments were higher than those in water. The correlation analysis revealed that antibiotics had pertinence with corresponding ARGs, indicating that antibiotics play an important role in the creation and transfer of ARGs. The results of regression analysis indicated that the propagation and maintenance of sulI and sulII were facilitated by class I integrons.
اظهر المزيد [+] اقل [-]Is climate change an unforeseen, irresistible and external factor – A force majeure in marine environmental law? النص الكامل
2016
Saul, Roxanne | Barnes, Richard | Elliott, Michael
Several environmental laws include provisions on natural causes or force majeure, which except States from their commitments if it can be proven that the failure to meet the commitment is due to factors outside their control. The European Union Marine Strategy Framework Directive (MSFD) has a pivotal role in managing EU marine waters. This paper analyses natural causes and force majeure provisions of the MFSD and other marine legislation, and addresses their interaction with climate change and its consequences, especially the effect on the obligation of ensuring seas are in Good Environmental Status. Climate change is an exogenic unmanaged pressure in that it emanates from outside the area being managed but in which the management authority has to respond to the consequences of climate change, such as sea level rise and temperature elevation, rather than its causes. It is suggested that a defence by a Member State of force majeure may be accepted if an event was proven to be due to an externality of control, irresistible and unforeseeable. The analysis contends that countering such a legal defence would centre on the fact that climate change is a well-accepted phenomenon, is foreseen with an accepted level of confidence and probability and is due to human actions. However, as yet, this has not been legally tested.
اظهر المزيد [+] اقل [-]Spatial–temporal trend and health implications of polycyclic aromatic hydrocarbons (PAHs) in resident oysters, South China Sea: A case study of Eastern Guangdong coast النص الكامل
2016
Yu, Zi-Ling | Lin, Qin | Gu, Yang-Guang | Ke, Chang-Liang | Sun, Run-Xia
Spatial and temporal distributions of polycyclic aromatic hydrocarbons (PAHs) were investigated in Eastern Guangdong coast, China. Total PAH concentrations in oysters ranged from 231 to 1178ng/g with a mean concentration of 622ng/g dry weight. Compared with other bays and estuaries, PAH levels in oysters were moderate. Spatial distribution of PAHs was site specific, with relatively high PAH concentrations observed in Zhelin Bay and Kaozhouyang Bay. Based on the Spearman test analysis, only PAH concentration in oysters from Jiazi Harbor showed a significant increasing trend (P<0.05). Three-ring PAHs were the most abundant, accounting for 54.2%–88.4% of total PAHs. Diagnostic ratios suggested that PAHs were derived mainly from petroleum origin. BaP and ∑4PAH concentrations were well within the European Union limits (5ng/g and 30ng/g wet weight, respectively). The incremental lifetime cancer risks (ILCR) for PAHs were <10−5, indicating that the adverse health risks associated with oyster consumption in this area were minimal.
اظهر المزيد [+] اقل [-]Development of a solid-phase extraction system modified for preconcentration of emerging contaminants in large sample volumes from rivers of the lagoon system in the city of Rio de Janeiro, Brazil النص الكامل
2016
Lopes, Vitor Sergio Almeida | Riente, Roselene Ribeiro | da Silva, Alexsandro Araújo | Torquilho, Delma Falcão | Carreira, Renato da Silva | Marques, Mônica Regina da Costa
A single method modified for monitoring of emerging contaminants in river water was developed for large sample volumes. Water samples from rivers of the lagoon system in the city of Rio de Janeiro (Brazil) were analyzed by the SPE-HPLC-MS-TOF analytical method. Acetaminophen was detected in four rivers in the concentration range of 0.09μgL−1 to 0.14μgL−1. Salicylic acid was also found in the four rivers in the concentration range of 1.65μgL−1 to 4.81μgL−1. Bisphenol-A was detected in all rivers in the concentration range of 1.37μgL−1 to 39.86μgL−1. Diclofenac was found in only one river, with concentration of 0.22μgL−1. The levels of emerging organic pollutants in the water samples of the Jacarepaguá hydrographical basin are significant. The compounds are not routinely monitored and present potential risks to environmental health.
اظهر المزيد [+] اقل [-]Sensitivity of online coupled model to extreme pollution event over a mega city Delhi النص الكامل
2016
Srinivas, Reka | Panicker, Abhilash S. | Parkhi, Neha S. | Peshin, Sunil K. | Beig, Gufran
Sensitivity of interactive Weather-Chemistry model has been examined to predict the air quality (1 and 3 days in advance) of Indian mega city Delhi during two identical extreme events of Diwali in 2012 and 2013. Analysis is conducted 3 days prior to 3 days later of Diwali day for both events to verify the rapid changes in fine particulate matter (PM2.5) due to widespread display of Diwali fireworks. The model successfully predicted the variability in PM2.5 during 2012 for the entire period of analysis with reasonable accuracy. Although model performed reasonably well until Diwali day in 2013 but it was unable to simulate rapid built up of PM2.5 (1500 μg−3 hourly average) during post Diwali day as it failed to capture unusual mid-night steep temperature gradient followed by a record lowering of boundary layer height. The predictability of the model and its limitation to micrometeorological processes are discussed in detail.
اظهر المزيد [+] اقل [-]OC/EC from PM10 in the vicinity of Turów lignite open-pit mine (SW Poland): Carbon isotopic approach النص الكامل
2016
Kosztowniak, Elżbieta | Ciężka, Monika | Zwoździak, Anna | Górka, Maciej
Concentrations of PM10 (particulate matter less than 10 μm in diameter) were measured at sampling points located in the vicinity of the Turów open-pit mine, southwest Poland, in April 2008. The samples were analysed by isotope ratio mass spectrometry (IR-MS) to determine the stable carbon isotope compositions of organic carbon (δ13COC) and elemental carbon (δ13CEC). The daily PM10 concentrations ranged from 15 to 99 μg m−3 with an average value of 50 ± 24 μg m−3. The analysed δ13COC values ranged from −25.1 to −19.9‰ with an average value of −23.1 ± 1.9‰, and the values of δ13CEC ranged from −25.6 to −24.1‰ with an average value of −25.0 ± 0.5‰. Additionally, the average δ13CTC value of lignite from the open-pit mine reached −25.8‰, and calculated δ13COC of lignite using an isotopic mass balance (IMB) value reaches −25.7 ± 0.1‰, whereas lignite δ13CEC value reaches −25.9 ± 0.2‰. The calculated major possible sources indicated that organic carbon (OC) in PM10 are represented probably by primary OC originated from the local lignite open-pit mine, whereas elemental carbon (EC) in PM10 are probably derived from local coal/lignite combustion products. If a data base of δ13COC and δ13CEC values from other possible “pure” sources (coal/gasoline/diesel/biomass/etc) is created, it will be possible to calculate individual isotopic mass balances for OC and for EC, which would yield more information than was obtained for total carbon (TC). The method could be a new and very helpful tool for calculating the percentage input of possible sources of OC and EC in atmospheric particles, and it can be applied to data from locations throughout the whole world.
اظهر المزيد [+] اقل [-]Distribution and contamination assessment of heavy metals in surface sediments of the Luanhe River Estuary, northwest of the Bohai Sea النص الكامل
2016
Liu, Jinqing | Yin, Ping | Chen, Bin | Gao, Fei | Song, Hongying | Li, Meina
33 surface sediment samples from the Luanhe River Estuary have been analyzed for heavy metals to evaluate the spatial distribution pattern and their potential ecological risk. Higher metal concentrations were found in the river mouth and southern areas where being covered by fine particulate matters. In comparison with the threshold effect level and the probable effect level, Cu, Pb, Cr, Ni, and As had occasionally adverse biological effects on the aquatic ecosystems. Both the enrichment factor and geoaccumulation index values show that all the regions have been weakly polluted by Pb, Hg, As, and Cd with an exception of being moderately to strongly polluted by Hg in the river mouth and southern areas. The sources of Zn, Ni, Cd, Hg, and Cr were mainly from the river input and coastal discharge, whereas Cu, Pb, and As were mainly derived from vehicle emissions, coal and oil combustion.
اظهر المزيد [+] اقل [-]The role of social marketing, marine turtles and sustainable tourism in reducing plastic pollution النص الكامل
2016
Eagle, Lynne | Hamann, Mark | Low, David R.
Environmental plastic pollution constitutes a significant hazard to marine turtles, human health and well-being. We describe a transdisciplinary approach to draw together findings from diverse disciplines in order to highlight key environmental pollution problems and their consequences, together with social marketing-based strategies to address the problems. The example of plastic pollution and impacts to marine turtles illustrates the severity of the problem. Wildlife tourism and sustainable tourism activity have not focussed on specific behaviours to change and have had minimal impact on subsequent human behaviour regarding environmental issues, indicating the need for new strategies. Social marketing principles offer promise, but there is a need to investigate the utility of various theoretical foundations to aid the design and implementation of interventions. We offer insight towards using sophisticated multi-method research to develop insights into behaviours and segmentation-based strategies, that can aid the identification of barriers to, and enablers of, sustained behaviour change.
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