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21.
Mercury levels in hair of a general population, 237 adults aged between 35-45, in Naples, Italy, were assessed. The subjects were asked to fill in a questionnaire about age, gender, body weight, height, body mass index (BMI), fish consumption, number, surface and area of dental amalgam fillings. Total mercury (THg) concentrations in human hair ranged from 0.221 to 3.402 microg/g and the mean value for the subjects under study was 0.638 microg/g. Study participants were divided into three groups in accordance with fish consumption and dental amalgam: ANF (amalgam and no fish); NAF (no amalgam but with fish) and AAF (amalgam and fish). Significant differences in THg were found in the three groups (p<0.05). A multiple linear regression analysis showed a weak but significant correlation of THg content in hair with respect to gender and age, but almost no association was found between THg and dental fillings. Conversely, a strong correlation was obtained between THg and fish consumption regardless of the group evaluated. Finally, mercury levels in hair exceeded the levels corresponding to the EPA reference dose (RfD) of 0.1 microg Hg/kg body weight per day (1 microg Hg/g hair) in 6% of the population (4% men and 2% women). However, the THg limits in our subjects were not exceeded according to the WHO guidelines, which use a benchmark dose of 0.23 microg Hg/kg bw/day (14 microg Hg/g maternal hair).  相似文献   
22.
Aerosol pollution in urban environments has been recognized to be responsible for important pathologies of the cardiovascular and respiratory systems. In this perspective, great attention has been addressed to Ultra Fine Particles (UFPs?<?100 nm), because they efficiently penetrate into the respiratory system and are capable of translocating from the airways into the blood circulation. This paper describes the aerosol regional doses deposited in the human respiratory system in a high-traffic urban area. The aerosol measurements were carried out on a curbside in downtown Rome, on a street characterized by a high density of autovehicular traffic. Aerosol number-size distributions were measured by means of a Fast Mobility Particle Sizer in the range from 5.6 to 560 nm with a 1 s time resolution. Dosimetry estimates were performed with the Multiple-Path Particle Dosimetry model by means of the stochastic lung model. The exposure scenario close to traffic is represented by a sequence of short-term peak exposures: about 6.6?×?1010 particles are deposited hourly into the respiratory system. After 1 h of exposure in proximity of traffic, 1.29?×?1010, 1.88?×?1010, and 3.45?×?1010 particles are deposited in the head, tracheobronchial, and alveolar regions. More than 95 % of such doses are represented by UFPs. Finally, according to the greater dose estimated, the right lung lobes are expected to be more susceptible to respiratory pathologies than the left lobes.  相似文献   
23.
Environmental and Ecological Statistics - Habitat modifications driven by human impact and climate change may influence species distribution, particularly in aquatic environments. Niche-based...  相似文献   
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25.
Gas- and particle-phase polycyclic aromatic hydrocarbons (PAHs) concentrations evaluated in the exhaust of 10 two-stroke, 50-cm3 mopeds belonging to three different levels of emission legislation (EURO-0, EURO-1 and EURO-2) were used to assess the prevalent mechanism driving the gas/particle partitioning of PAHs in moped exhaust. Sampling was performed on a dynamometer bench both during the “cold-start” and the “hot” phases of the ECE-47 driving cycle. Gas and particulate phase PAHs were collected on polyurethane foam (PUF) plugs and 47-mm Pallflex T60A20 filters, respectively, under isokinetic conditions by using sampling probes inserted into the dilution tunnel of a Constant Volume Sampling – Critical Flow Venturi (CVS–CFV) system.The results show that semi-volatile PAHs were predominantly partitioned to the particle phase. The soluble organic fraction (SOF) of the collected particulates ranged between 72 and 98%. Measured total suspended particulate matter normalized partition coefficients (Kp) were predicted within a factor of 3–5 by assuming absorption into the organic fraction according to a model developed by Harner and Bidleman [Harner, T., Bidleman, T.F., 1998. Octanol–air partition coefficient for describing particle/gas partitioning of aromatic compounds in urban air. Environmental Science & Technology 32, 1494–1502.]. This suggests that the gas/particle partitioning in moped exhaust is mainly driven by the high fraction of organic matter of the emitted particles and that absorption could be the main partitioning mechanism of PAHs.  相似文献   
26.
Climate change effects are noticeably evident above the timberline where glacier and permafrost processes and mass movements drive the surface evolution. In particular, the cryosphere shrinkage is deeply changing the features and characteristics of several glacierized mountain areas of the world, and these modifications can also affect the landscape perception of tourists and mountaineers. On the one hand glacier retreat is increasing the interest of tourists and visitors in areas witnessing clear climate change impacts; on the other hand cryosphere shrinkage can impact the touristic appeal of mountain territories which, diminishing their ice and snow coverage, are also losing part of their aesthetic value. Then, to promote glacierized areas in a changing climate and to prepare exhaustive and actual proposals for sustainable tourism, it is important to deepen our knowledge about landscape perception of tourists and mountaineers and their awareness of the ongoing environmental modifications. Here we present the results from a pilot study we performed in summer 2009 on a representative glacierized area of the Alps, the Forni Valley (Stelvio National Park, Lombardy, Italy), a valley shaped by Forni, the largest Italian valley glacier. During the 2009 summer season we asked tourists visiting the Forni Valley to complete a questionnaire. This study was aimed at both describing the features and characteristics of tourists and mountaineers visiting this Alpine zone in summer and evaluating their landscape perception and their ability to recognize climate change impacts and evidence. Our results suggest that the dissemination strategies in a natural protected area have to take into account not only the main landscape features but also the sites where the information will be given. In particular considering the peculiarities of the huts located in the area, such as their different accessibility and the fact that they are included or not in a mountaineering network like that of the Italian Alpine Club. Both these factors can influence the kind of visitors to the area, thus requiring different dissemination strategies. Moreover, differences in the viewpoints from where visitors could watch and understand landscape also have to be considered. Next, in a protected area where climate change effects are evident, the dissemination strategies should be developed in close cooperation with scientists who are analyzing the area and with the support of periodic interviews which could be very useful to evaluate the effectiveness of the applied dissemination methods. Last but not least, the questionnaire should be standardized and distributed in several protected areas, thus permitting useful comparisons and the identification of common solutions for sharing in a friendly way scientific knowledge about climate change and its effects on the environment and the landscape.  相似文献   
27.
The sorption kinetics of simazine (6-chloro-N,N′-diethyl-1,3,5-triazine-2,4-diamine), imidacloprid (1-(6-chloro-3-pyridylmethyl)-N-nitroimidazolidin-2-ylideneamine), and boscalid (2-chloro-N-(4′-chlorobiphenyl-2-yl)nicotinamide), three pesticides of wide use in agriculture, was determined in five different water/soil systems over a time interval from the initial few seconds to about 1 month. In all the experiments, sorption kinetics showed a biphasic pattern characterized by an initial, relatively short phase with a high sorption rate and a later phase with much a lower sorption rate. Initial sorption capacity increased with soil organic carbon content and with sorbate hydrophobicity. We postulate that the first phase of the process involves a fast second-order sorption reaction on superficial sites of soil particles, whereas the second phase depends on diffusion-controlled migration to internal binding sites. A kinetic equation based on this hybrid model accurately fitted all data sets. Less satisfactory results were obtained employing the pseudo-first order, pseudo-second order, Elovich, two site non-equilibrium, or Weber-Morris equation. The superior performance of the hybrid model for describing boscalid sorption probably reflects the high hydrophobic character and consequent low diffusion rates of this compound. The accuracy of modelling was in any case strongly dependent on the time interval considered.  相似文献   
28.
The effect of four triazinyl-sulfonylurea herbicides (cinosulfuron, prosulfuron, thifensulfuron methyl, triasulfuron) on soil microbial biomass, soil respiration, metabolic activity, metabolic quotient, and some enzymatic activities (acid and alkaline phosphatase, β-glucosidase, arylsulphatase, and fluorescein diacetate hydrolysis) were monitored under controlled conditions over 30 days. The herbicides were applied at the normal field dose (FD) and at ten-fold (10 FD) the field dose, in order to mimic a long term toxic effect. The measured soil microbial parameters showed that the FD had slight effects on soil microflora, while at 10 FD the tested herbicides exerted a stronger detrimental effect on soil microbial biomass and its biochemical activities.  相似文献   
29.
Meeting environmental, economic, and societal targets in energy policy is complex and requires a multicriteria assessment framework capable of exploring trade-offs among alternative energy options. In this study, we integrated economic analysis and biophysical accounting methods to investigate the performance of electricity production in Finland at plant and national level. Economic and environmental costs of electricity generation technologies were assessed by evaluating economic features (direct monetary production cost), direct and indirect use of fossil fuels (GER cost), environmental impact (CO2 emissions), and global environmental support (emergy cost). Three scenarios for Finland's energy future in 2025 and 2050 were also drawn and compared with the reference year 2008. Accounting for an emission permit of 25 €/t CO2, the production costs calculated for CHP, gas, coal, and peat power plants resulted in 42, 67, 68, and 74 €/MWh, respectively. For wind and nuclear power a production cost of 63 and 35 €/MWh were calculated. The sensitivity analysis confirmed wind power's competitiveness when the price of emission permits overcomes 20 €/t CO2. Hydro, wind, and nuclear power were characterized by a minor dependence on fossil fuels, showing a GER cost of 0.04, 0.13, and 0.26 J/Je, and a value of direct and indirect CO2 emissions of 0.01, 0.04, and 0.07 t CO2/MWh. Instead, peat, coal, gas, and CHP plants showed a GER cost of 4.18, 4.00, 2.78, and 2.33 J/Je. At national level, a major economic and environmental load was given by CHP and nuclear power while hydro power showed a minor load in spite of its large production. The scenario analysis raised technological and environmental concerns due to the massive increase of nuclear power and wood biomass exploitation. In conclusion, we addressed the need to further develop an energy policy for Finland's energy future based on a diversified energy mix oriented to the sustainable exploitation of local, renewable, and environmentally friendly energy sources.  相似文献   
30.
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