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91.
In this study, long-term aerosol particle total number concentration measurements in five metropolitan areas across Europe are presented. The measurements have been carried out in Augsburg, Barcelona, Helsinki, Rome, and Stockholm using the same instrument, a condensation particle counter (TSI model 3022). The results show that in all of the studied cities, the winter concentrations are higher than the summer concentrations. In Helsinki and in Stockholm, winter concentrations are higher by a factor of two and in Augsburg almost by a factor of three compared with summer months. The winter maximum of the monthly average concentrations in these cities is between 10,000 cm(-3) and 20,000 cm(-3), whereas the summer min is approximately 5000-6000 cm(-3). In Rome and in Barcelona, the winters are more polluted compared with summers by as much as a factor of 4-10. The winter maximum in both Rome and Barcelona is close to 100,000 cm(-3), whereas the summer minimum is > 10,000 cm(-3). During the weekdays the maximum of the hourly average concentrations in all of the cities is detected during the morning hours between 7 and 10 a.m. The evening maxima were present in Barcelona, Rome, and Augsburg, but these were not as pronounced as the morning ones. The daily maxima in Helsinki and Stockholm are close or even lower than the daily minima in the more polluted cities. The concentrations between these two groups of cities are different with a factor of about five during the whole day. The study pointed out the influence of the selection of the measurement site and the configuration of the sampling line on the observed concentrations.  相似文献   
92.
Summary. The first identification of a sex pheromone of a pine sawfly (Hymenoptera, Diprionidae) dates back almost thirty years. Since then, female-produced pheromones of over twenty diprionid species have been investigated by solvent extraction followed by separation and identification. However, no study has shown what the females actually release. Collection of airborne compounds using absorbtion on charcoal filter as well as solid phase microextraction (SPME) followed by analysis employing gas chromatography combined with mass spectrometry (GC-MS), revealed an unusual system in Diprion pini, in which the pheromone precursor alcohol, 3,7-dimethyl-2-tridecanol, is released together with acetic, propionic, butyric and isobutyric acids. The corresponding acetate, propionate and butyrate esters of 3,7-dimethyl-2-tridecanol were also found in the samples. All esters were electrophysiologically active, and the propionate and isobutyrate were attractive in trapping experiments. Based on these and earlier reported results, it seems that at least in part of its range, the pheromone response of D. pini is not very specific with regard to the functional group, as long as this is an ester.  相似文献   
93.

Background, aim and scope  

Chlormequat (Cq) is a plant growth regulator used throughout the world. Despite indications of possible effects of Cq on mammalian health and fertility, little is known about its fate and transport in subsurface environments. The aim of this study was to determine the fate of Cq in three Danish subsurface environments, in particular with respect to retardation of Cq in the A and B horizons and the risk of leaching to the aquatic environment. The study combines laboratory fate studies of Cq sorption and dissipation with field scale monitoring of the concentration of Cq in the subsurface environment, including artificial drains.  相似文献   
94.

Aim and Background

Varying interpretations of the hazard potential of native oils and fats for aquatic ecosystems have led to conflicting international and national regulations. Background is the different consideration of physical effects. This study aimed at compiling published data on behaviour and effects of native oils and fats in water, hereby providing a basis for discussion on adequate classification of these substances.

Results

According to scientific data, physical effects may significantly contribute to the hazard potential of native oils and fats. This is especially important in risk assessment of spills, e.g. in the case of accidents. Basically, these effects are the same in marine and freshwater environments; the latter may even be regarded as worst-case situations with respect to physical effects.

Recommendations

Based on these facts, the German classification of native oils and their derivates as ‘not hazardous to waters’ according e.g. to § 19g of the Water Resources Act and § 4 of the Ordinance of Hazardous Substances should be revised. New criteria need to be incorporated into the evaluation procedure to allow an adequate assessment of these substances regarding physical effects.  相似文献   
95.
Contamination profiles of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) were determined in six fish species from three selected regions along coastal waters off Savannah, GA, USA. Concentrations of PCBs were predominant (12–493 ng g?1 lw) followed by PBDEs (10–337 ng g?1 lw), OCPs such as DDTs (2.7–153 ng g?1 lw), chlordanes (3.8–34 ng g?1 lw), cyclodienes (<0.1–35 ng g?1 lw), mirex (<0.1–8.6 ng g?1 lw), γ-hexachlorocyclohexane (<0.1–1.4 ng g?1 lw), and hexachlorobenzene (<0.1–0.68 ng g?1 lw). The results indicated no region-specific difference in the contaminants however inter-species as well as intra-species differences were evident. Comparison of DDTs, PCBs, and PBDEs profiles in fish with those from other countries revealed that fish from coastal waters off Savannah contained relatively less concentrations of PCBs and chlorinated pesticides, while PBDE concentrations were comparable or even higher than fish samples from other regions. Polychlorinated biphenyl congeners and chlorinated pesticide tempoal trend data exhibited no increase of contamination levels. The levels of PCBs and chlorinated pesticides in fish from Savannah coastal waters were below the Food and Drug Administrations (FDA) established limits for human consumption.  相似文献   
96.
  1. No binding of chromium was detected after incubation of calf thymus nuclei with hexavalent chromium up to 0.5 mM.

  2. Chromium was readily taken up and tightly bound after incubation with trivalent chromium.

  3. In a DNA‐filter binding assay, increasing amounts of chromium and DNA were bound with increasing chromium trichloride concentrations incubated with the nuclei.

  4. Treatment with proteinase K abolished the increase in DNA retention induced by trivalent chromium.

  5. It is concluded that trivalent chromium is the ultimate genetoxic agent after chromate uptake by living cells.

  相似文献   
97.
Urban green spaces provide important recreational services for urban residents. In general, when park visitors enjoy “the green,” they are in actuality appreciating a mix of biotic, abiotic, and man-made park infrastructure elements and qualities. We argue that these three dimensions of structural diversity have an influence on how people use and value urban parks. We present a straightforward approach for assessing urban parks that combines multi-dimensional landscape mapping and questionnaire surveys. We discuss the method as well the results from its application to differently sized parks in Berlin and Salzburg.  相似文献   
98.
Communicating the topic of conservation to the public and encouraging proenvironmental behaviors can mitigate loss of biodiversity. Thus, the evaluation of educational efforts is important to ascertain the educational effects and provide high-quality conservation education. The learning outcomes of conservation education are diverse (e.g., attitudes, knowledge, and behavior). Considering the specific characteristics of these different outcomes and the factors that influence them is crucial to delivering successful conservation education. We reviewed 29 peer-reviewed articles published in English from January 2011 to April 2020 on empirical studies of learning outcomes of on-site conservation education in zoos and aquaria, institutions that seek to educate the public about conservation. We examined the range of learning outcomes, their definitions, and factors that influenced them. Cognitive outcomes were most frequently investigated (37%) in comparison with other outcomes (e.g., affective outcomes, 31%). The articles did not use explicit definitions for learning outcomes, and implicit or explorative definitions provided were inconsistent. Outcomes were influenced by various factors (e.g., prior experiences, staff interaction, animal behavior). Our results suggest the agenda of conservation education research should be broadened by examining all learning outcomes relevant to behavior change. Educational and behavior change theories should be used as a background for conservation education research to ensure clear and consistent definitions, derive appropriate instruments to measure learning outcomes, and relate learning outcomes to influencing factors. We recommend conservation education researchers and practitioners to treat conservation education holistically and acknowledge its learning outcomes’ full complexity.  相似文献   
99.
The study of mechanisms controlling preferential flow and transport in variably saturated fractured clayey till is often hindered by insufficient spatial resolution or unknown measuring volume. With the objective to study these mechanisms while circumventing the obstacles, tracer experiments with two fluorescent tracers Acid Yellow 7 (AY7) and Sulforhodamine B (SB) were performed at three different rain events for a fall and a summer season. Irrigated areas were excavated down to depths of 2.8 m and the movement of both tracers in the exposed profiles was delineated simultaneously by high spatial resolution apparent concentration maps (pixel approximately 1 mm(2)) obtained with an imaging device. The device consists of a light source and a CCD camera, both equipped with tracer-specific-filters for fluorescent light. The fluorescence images were corrected for nonuniform lighting, changing surface roughness, and varying optical properties of the soil profile. The resulting two-dimensional apparent concentration distribution profiles of the tracers showed that: (i) relative low water content in the upper 10 cm of the irrigated till in summer had a pronounced retardation effect on the AY7-migration and no effect on the SB-migration; (ii) the dead-end biopores were not activated in the fall season; (iii) only 3D fracture-plans connected to hydraulically active 1D-biopores contributed to the leaching; (iv) the tracer migration primary followed macropores during both seasons, though AY7 also followed a topsoil piston transport in summer; (v) the highest tracer pixel apparent concentrations were often found in macropores and most pronounced in the summer season; and (vi) 3D-dilution in fractures seems to play a dominating role in AY7-migration in the fall season.  相似文献   
100.
Increasing human impact on stream ecosystems has resulted in a growing need for tools helping managers to develop conservations strategies, and environmental monitoring is crucial for this development. This paper describes the development of models predicting the presence of fish assemblages in lowland streams using solely cost-effective GIS-derived land use variables. Three hundred thirty-five stream sites were separated into two groups based on size. Within each group, fish abundance data and cluster analysis were used to determine the composition of fish assemblages. The occurrence of assemblages was predicted using a dataset containing land use variables at three spatial scales (50 m riparian corridor, 500 m riparian corridor and the entire catchment) supplemented by a dataset on in-stream variables. The overall classification success varied between 66.1–81.1% and was only marginally better when using in-stream variables than when applying only GIS variables. Also, the prediction power of a model combining GIS and in-stream variables was only slightly better than prediction based solely on GIS variables. The possibility of obtaining precise predictions without using costly in-stream variables offers great potential in the design of monitoring programmes as the distribution of monitoring sites along a gradient in ecological quality can be done at a low cost.  相似文献   
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