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61.
Surface water methane (CH4) and nitrous oxide (N2O) concentrations and fluxes were investigated in two subtropical coastal embayments (Bramble Bay and Deception Bay, which are part of the greater Moreton Bay, Australia). Measurements were done at 23 stations in seven campaigns covering different seasons during 2010–2012. Water–air fluxes were estimated using the Thin Boundary Layer approach with a combination of wind and currents-based models for the estimation of the gas transfer velocities. The two bays were strong sources of both CH4 and N2O with no significant differences in the degree of saturation of both gases between them during all measurement campaigns. Both CH4 and N2O concentrations had strong temporal but minimal spatial variability in both bays. During the seven seasons, CH4 varied between 500% and 4000% saturation while N2O varied between 128 and 255% in the two bays. Average seasonal CH4 fluxes for the two bays varied between 0.5 ± 0.2 and 6.0 ± 1.5 mg CH4/(m2·day) while N2O varied between 0.4 ± 0.1 and 1.6 ± 0.6 mg N2O/(m2·day). Weighted emissions (t CO2-e) were 63%–90% N2O dominated implying that a reduction in N2O inputs and/or nitrogen availability in the bays may significantly reduce the bays' greenhouse gas (GHG) budget. Emissions data for tropical and subtropical systems is still scarce. This work found subtropical bays to be significant aquatic sources of both CH4 and N2O and puts the estimated fluxes into the global context with measurements done from other climatic regions. 相似文献
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Two‐Stage Ditch Floodplains Enhance N‐Removal Capacity and Reduce Turbidity and Dissolved P in Agricultural Streams
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Ursula H. Mahl Jennifer L. Tank Sarah S. Roley Robert T. Davis 《Journal of the American Water Resources Association》2015,51(4):923-940
Two‐stage ditches represent an emerging management strategy in artificially drained agricultural landscapes that mimics natural floodplains and has the potential to improve water quality. We assessed the potential for the two‐stage ditch to reduce sediment and nutrient export by measuring water column turbidity, nitrate (NO3?), ammonium (NH4+), and soluble reactive phosphorus (SRP) concentrations, and denitrification rates. During 2009‐2010, we compared reaches with two‐stage floodplains to upstream reaches with conventional trapezoid design in six agricultural streams. At base flow, these short two‐stage reaches (<600 m) reduced SRP concentrations by 3‐53%, but did not significantly reduce NO3? concentrations due to very high NO3? loads. The two‐stage also decreased turbidity by 15‐82%, suggesting reduced suspended sediment export during floodplain inundation. Reach‐scale N‐removal increased 3‐24 fold during inundation due to increased bioreactive surface area with high floodplain denitrification rates. Inundation frequency varied with bench height, with lower benches being flooded more frequently, resulting in higher annual N‐removal. We also found both soil organic matter and denitrification rates were higher on older floodplains. Finally, influence of the two‐stage varied among streams and years due to variation in stream discharge, nutrient loads, and denitrification rates, which should be considered during implementation to optimize potential water quality benefits. 相似文献
63.
Occurrences and potential risks of 16 fragrances in five German sewage treatment plants and their receiving waters 总被引:1,自引:1,他引:0
Ursula Klaschka Peter Carsten von der Ohe Anne Bschorer Sonja Krezmer Manfred Sengl Marion Letzel 《Environmental science and pollution research international》2013,20(4):2456-2471
Fragrances are used in a wide array of everyday products and enter the aquatic environment via wastewater. While several musk compounds have been studied in detail, little is known about the occurrence and fate of other fragrances. We selected 16 fragrance compounds and scrutinized their presence in Bavarian sewage treatment plants (STP) influents and effluents and discussed their ecological risks for the receiving surface waters. Moreover, we followed their concentrations along the path in one STP by corresponding time-related water sampling and derived the respective elimination rates in the purification process. Six fragrance substances (OTNE, HHCB, lilial, acetyl cedrene, menthol, and, in some grab samples, also methyl-dihydrojasmonate) could be detected in the effluents of the investigated sewage treatment plants. The other fragrances under scrutiny were only found in the inflow and were eliminated in the purification process. Only OTNE and HHCB were found in the receiving surface waters of the STP in congruent concentrations, which exceeded the preliminary derived environmental thresholds by a factor of 1.15 and 1.12, respectively, indicating potential risks. OTNE was also detected in similar concentration ranges as HHCB in muscles and livers of fish from surface waters and from ponds that are supplied with purified wastewater. The findings show that some fragrance compounds undergo high elimination rates, whereas others—not only musks—are present in receiving surface water and biota and may present a risk to local aquatic biota. Hence, our results suggest that the fate and potential effects of fragrance compounds in the aquatic environment deserve more attention. 相似文献
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Ursula Stephan Ute Strobel Philip Weller Jasmine Bachmann Renate Klaß 《Environmental Sciences Europe》1999,11(6):313-320
10 years ago, the WWF (World Wide Fund for Nature) began to support the work of environmental protection in the countries of Eastern Europe. A main topic is the Danube-Carpathian Program. With the beginning of the bombardements, connected with great amounts of chemicals released directly and as clouds from the fires and explosions, the question raises: What are the consequences for mankind and nature? Is there a risk for the Danube-Carpathian Program? The WWF feels responsible for reporting about these consequences. In July 1999, a group of two Oil Experts and two scientists (each a chemist and a toxicologist) visited Belgrad, Pan?evo and Novi Sad, took samples of soil and water, and estimated the contents of dangerous substances. The first findings and the first consequences for nature and human health are described. 相似文献
66.
Klaschka Ursula Kolossa-Gehring Marike 《Environmental science and pollution research international》2007,14(1):44-52
Goal, Scope and Background Fragrance preparations or perfumes are used in an increasing variety of applications, as for example washing, cleansing, personal
care products, consumer goods or in applications to modify indoor air. However, up to now, little is known to the general
or scientific public about their chemical identity and the use pattern of single substances, not even for high production
volume chemicals. Some toxicological data are published for a comparatively small number of substances with a focus on sensitisation
and dermal effects, while other effects are neglected. Information on ecotoxicity and environmental fate are rare, especially
for long-term exposure. Data for a detailed hazard and risk analysis are available in exceptional cases only. According to
the current legal situation, fragrance industry is self-regulated, which means that pre-market risk evaluation is not required
for most fragrances.
Odour and the ability to smell play a major role for wildlife for all taxonomic groups. Reproductive and social behaviour,
defence, communication and orientation depend on volatile compounds which can be identical to those used in fragrance preparations.
Our interdisciplinary approach leads to the question of whether and, if so, to what extent anthropogenic fragrances may influence
life and reproduction of organisms in the environment.
Main Features Information from literature on use, exposure and biological effects was combined to analyse the state of knowledge. Following
an overview of the amounts of fragrances used in different consumer products and their release into the environment, the roles
of odours in nature are shown for a selection of compounds. Existing regulation was analysed to describe the data basis for
environmental risk evaluation. Finally, recommendations for further action are derived from these findings.
Results Three main results were elaborated: First, fragrance substances are continuously discharged in large amounts into the environment,
especially via the waste water. Second, there are some indications of negative effects on human health or the environment,
although the data basis is very thin due to the self regulation of the fragrance industry and the regulatory situation of
fragrance substances. Third, many odoriferous substances used by man are identical to those which are signal substances of
environmental organisms at very low concentrations, thus giving rise to specific mode of actions in the ecosystem.
Recommendations For the adequate risk assessments of fragrances, test results on their unspecific as well as their specific effects as signal
substances are needed. This would imply prioritisation methods and development of useful test methods for specific endpoints
for appropriate risk assessments. Before a comprehensive testing and evaluation of results has been finished, a minimization
of exposure should be envisaged. Eco-labelling of products containing acceptable fragrance ingredients could be a first step
and provide consumers with the respective information. Transparency concerning the fragrance ingredients used and their biological
potency will help to build up confidence between producers and consumers.
Conclusions and Perspectives The interdisciplinary approach, bringing together chemical, biological, toxicological and ecotoxicological data with information
provided by manufacturers and with legal and consumer aspects, offers new insights into the field of fragrance substances
used in consumer products. The amounts and application fields of fragrance substances increases while fate and effects in
the environment are hardly known. The current legal situation is not suited to elucidate the effects of fragrances on human
health and the environment sufficiently, especially as it was shown that fragrances may play a considerable role in the ecosystem
on the behaviour of organisms. According to the precautionary principle, the lack of knowledge should best be tackled by reducing
exposure, especially for compounds such as fragrance substances where no ethical reasons object a substitution by less hazardous
chemicals.
ESS-Submission Editor: Dr. Thomas Knacker (th-knacker@ect.de) 相似文献
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Thomas Knacker Hans-Joachim Schallnaß Ursula Klaschka Jan Ahlers 《Environmental science and pollution research international》1995,2(3):179-187
The criteria for classification and labelling of substances as “dangerous for the environment” agreed upon within the European
Union (EU) were applied to two sets of existing chemicals. One set (sample A) consisted of 41 randomly selected compounds
listed in the European Inventory of Existing Chemical Substances (EINECS). The other set (sample B) comprised 115 substances
listed in Annex I of Directive 67/548/EEC which were classified by the EU Working Group on Classification and Labelling of
Existing Chemicals. The aquatic toxicity (fish mortality,Daphnia immobilisation, algal growth inhibition), ready biodegradability and n-octanol/water partition coefficient were measured
for sample A by one and the same laboratory. For sample B, the available ecotoxicological data originated from many different
sources and therefore was rather heterogeneous. In both samples, algal toxicity was the most sensitive effect parameter for
most substances. Furthermore, it was found that, classification based on a single aquatic test result differs in many cases
from classification based on a complete data set, although a correlation exists between the biological end-points of the aquatic
toxicity test systems. 相似文献
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