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171.
Indicators for sustainable energy development in Mexico   总被引:1,自引:0,他引:1  
This article presents a summary of a study on the application to the Mexican energy sector of a core set of indicators for sustainable energy development (ISED), developed by the International Atomic Energy Agency (IAEA). The study focused on the elaboration of socio‐economic and environmental indicators related to energy production and use, and was aimed at assessing Mexico's existing energy policies and identifying strategies and possible policies that could bring about improvements in major priority areas: energy intensity, atmospheric emissions, energy import dependency and use of renewables. While positive trends have been observed in relation to energy intensity and atmospheric emissions, Mexico is becoming more dependent on imports of gasoline, natural gas and other high‐value secondary energy sources, while exporting significant amounts of primary fuels, such as crude oil. Also, no significant increase has been observed in the use of renewable sources of energy. Social, economic and environmental policies need to be formulated for the energy sector and related investments (public and private) reinforced so that all economic sectors have access to energy from cleaner and more diverse sources.  相似文献   
172.
Epiphytic lichens, collected from 119 sampling sites grown over “Roistonea Royal Palm” trees, were used to assess the spatial distribution pattern of lead (Pb) and identify possible pollution sources in Havana (Cuba). Lead concentrations in lichens and topsoils were determined by flame atomic absorption spectrophotometry and inductively coupled plasma (ICP) atomic emission spectrometry, respectively, while Pb in crude oils and gasoline samples were measured by ICP-time of flight mass spectrometry (ICP-ToF-MS). Lead isotopic ratios measurements for lichens, soils, and crude oils were obtained by ICP-ToF-MS. We found that enrichment factors (EF) reflected a moderate contamination for 71% of the samples (EF > 10). The 206Pb/207Pb ratio values for lichens ranged from 1.17 to 1.20 and were a mixture of natural radiogenic and industrial activities (e.g., crude oils and fire plants). The low concentration of Pb found in gasoline (<7.0 μg L?1) confirms the official statement that leaded gasoline is no longer used in Cuba.  相似文献   
173.
Arsenic oxidation (As(III) to As(V)) and As(V) removal from water were assessed by using TiO2 immobilized in PET (polyethylene terephthalate) bottles in the presence of natural sunlight and iron salts. The effect of many parameters was sequentially studied: TiO2 concentration of the coating solution, Fe(II) concentration, pH, solar irradiation time; dissolved organic carbon concentration. The final conditions (TiO2 concentration of the coating solution: 10%; Fe(II): 7.0 mg l−1; solar exposure time: 120 min) were applied to natural water samples spiked with 500 μg l−1 As(III) in order to verify the influence of natural water matrix. After treatment, As(III) and total As concentrations were lower than the limit of quantitation (2 μg l−1) of the voltammetric method used, showing a removal over 99%, and giving evidence that As(III) was effectively oxidized to As(V). The results obtained demonstrated that TiO2 can be easily immobilized on a PET surface in order to perform As(III) oxidation in water and that this TiO2 immobilization, combined with coprecipitation of arsenic on Fe(III) hydroxides(oxides) could be an efficient way for inorganic arsenic removal from groundwaters.  相似文献   
174.
We analyzed polychlorobiphenyls (PCBs), perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) in the edible part of farmed sea bass reared in two fish farms in Liguria (Northern Italy). The aim was to determine the contamination levels and human exposure to these chemicals through fish consumption. Concentrations of “dioxin-like” PCBs (DL-PCBs) ranged from 0.033 to 0.759 pg ΣTEQ-PCB g−1 whole weight (w.w.) in fish farm 1 and from 0.032 to 1.60 pg ΣTEQ-PCB g−1 w.w. in fish farm 2, and the six indicators of “non-dioxin-like” (NDL-PCBs) from 0.538 to 9.33 ng Σ6PCB g−1 w.w. and from 1.62 to 27.6 ng Σ6PCB g−1 w.w. Concentrations were generally lower in farm 1 than in farm 2. One reason for this difference might be the proximity of farm 2 to the seaport of La Spezia, which could be a punctual source of pollutants influencing the contamination of the water in the farm. Principal component analysis (PCA) showed differences also in the congeners profiles for the two sites, with higher-chlorinated PCBs more abundant in farm 1, and lower-chlorinated PCBs were more abundant in farm 2. Most of the concentrations of PFOS and PFOA were below the limit of detection (LOD 0.05 ng g−1 w.w.). Only about 10% of the samples analyzed had levels slightly higher than the LOD. Assessments of exposure using these data showed that consumption of farmed fish may contribute significantly to PCBs through the diet, whereas the contribution of PFOS and PFOA seems to be low.  相似文献   
175.
Environmental Science and Pollution Research - The excessive use of pesticides is posing major threats to humans and the environment. However, the environmental exposure and impact of pesticides in...  相似文献   
176.
Environmental Science and Pollution Research - It is well known that airborne transmission of COVID-19 in indoor spaces occurs through various respiratory activities: breathing, vocalizing,...  相似文献   
177.
178.
An approach to transportation risk analysis for road and rail transport of dangerous goods is proposed, which is based on the use of geographic information systems (GIS) to manage territorial information, coupled with a product data bank in a risk evaluation tool. Such an approach enables to accurately take into account the local data affecting risk analysis, such as population, accident rate, and weather conditions along all the route, by means of a system which can be easily updated. The resulting risk evaluation tool assists in the step of route identification and allows to rapidly perform an accurate transportation risk analysis, for a single transportation event as well as for multiple substances, trips and itineraries.  相似文献   
179.
The aim of this study was to evaluate the concentration of CA 125 in second trimester amniotic fluid from Down syndrome pregnancies. CA 125 was measured in stored amniotic fluid samples from pregnancies of 14–19 weeks' gestation with and without Down syndrome fetuses. CA 125 levels were expressed in multiples of the median (MOM) for normal pregnancies of the same gestational age. Twenty-one pregnancies with Down syndrome fetuses and 63 unaffected controls matched for maternal age, gestational age, and duration of storage were studied. The median MOM values of the affected pregnancies were significantly higher than those of the controls (1·41 MOM versus 0·99 MOM). These findings show that there is an increased concentration of CA 125 in second-trimester amniotic fluid from Down syndrome pregnancies.  相似文献   
180.
Future conservation efforts will need to transcend geopolitical boundaries in efforts to protect entire landscapes and ecosystems. Neotropical migratory birds are as a group a useful conservation tool for linking diverse landscapes and people due to their dependence on multiple habitats, sensitivity to habitat changes, and universal public appeal. The conservation of neotropical migrants can therefore function as a powerful hemispheric umbrella for ecosystem protection. Efforts to protect neotropical migratory birds on their nonbreeding grounds have traditionally been focused on Mexico, Central America, and the Caribbean. To assess the importance of South America to neotropical migrants, an ecoregional classification system was used to determine species distributions in the Andean/Southern Cone Region (Bolivia, Colombia, Ecuador, Paraguay, Peru, and Venezuela). The occurrence of migrants in protected areas that are part of The Nature Conservancy's Parks in Peril program was also assessed. Of the 406 neotropical migrant species, nearly one third (132) occur as regular nonbreeding residents in the region and for almost half of these species (53), South America is their main nonbreeding ground. All Parks in Peril sites were found to harbor neotropical migrants. Forty-eight species (36%) have declining longterm North American Breeding Bird Survey population trends and/or high Partners in Flight concern scores and thus are of significant conservation concern. Most importantly, 29 species (22%) of conservation concern use South America as their primary nonbreeding ground, indicating a need for focused conservation action. The nature of the ecoregional approach used in this endeavor makes future prioritization of ecoregions and conservation strategies for neotropical migrants across national boundaries possible. The ability to link diverse landscapes using a common element such as migratory birds allows for unique transboundary partnerships and opportunities for habitat conservation, which support the goal of the Conservancy's new Migratory Bird Initiative.  相似文献   
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