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241.

Background, aim, and scope  

The widespread use of some platinum group elements as catalysts to minimize emission of pollutants from combustion engines produced a constantly growing increase of the concentration of these elements in the environment; their potential toxicological properties explain the increasing interest in routine easy monitoring. We have found that leaves of Prunus laurus cerasus are efficient collectors of particulate with a dimension <60–80 μm, and a simple and reliable procedure was developed to reveal traces of platinum, palladium, and rhodium released from automotive catalysts. The analysis of the dust deposited on the foliage is a direct indicator of traffic pollution.  相似文献   
242.
According to the European Landfill Directive 1999/31/EC and the related Italian Legislation (“D. Lgs. No. 36/2003”), monitoring and control procedures of landfill gas emissions, migration and external dispersions are clearly requested. These procedures could be particularly interesting in the operational circumstance of implementing a temporary cover, as for instance permitted by the Italian legislation over worked-out landfill sections, awaiting the evaluation of expected waste settlements.A possible quantitative approach for field measurement and consequential evaluation of landfill CO2, CH4 emission rates in pairs consists of the static, non-stationary accumulation chamber technique. At the Italian level, a significant and recent situation of periodical landfill gas emission monitoring is represented by the sanitary landfill for non-hazardous waste of the “Fano” town district, where monitoring campaigns with the static chamber have been annually conducted during the last 5 years (2005-2009). For the entire multiyear monitoring period, the resulting CO2, CH4 emission rates varied on the whole up to about 13,100 g CO2 m−2 d−1 and 3800 g CH4 m−2 d−1, respectively.The elaboration of these landfill gas emission data collected at the “Fano” case-study site during the monitoring campaigns, presented and discussed in the paper, gives rise to a certain scientific evidence of the possible negative effects derivable from the implementation of a temporary HDPE cover over a worked-out landfill section, notably: the lateral migration and concentration of landfill gas emissions through adjacent, active landfill sections when hydraulically connected; and consequently, the increase of landfill gas flux velocities throughout the reduced overall soil cover surface, giving rise to a flowing through of CH4 emissions without a significant oxidation. Thus, these circumstances are expected to cause a certain increase of the overall GHG emissions from the given landfill site.  相似文献   
243.
Self-purification ability of a resurgence stream   总被引:14,自引:0,他引:14  
Vagnetti R  Miana P  Fabris M  Pavoni B 《Chemosphere》2003,52(10):1781-1795
The self-purification ability of a resurgence stream has been investigated by taking samples along the course of a channeled tract made up of a first part in beaten soil (3.3 km) and a second in concrete (7.2 km). The study has been conducted by statistically processing pre-existent data, acquired monthly by analyzing waters at the beginning and at the end of the whole canal for 6 years, from 1995 to 2000 (historic data), and by performing specific experiments (recent data) to evaluate differently the self-purification capacity of the beaten soil section and that in concrete. A significant abatement of concentrations has been observed from historic data for ammonium, phosphates, turbidity, heavy metals and bacteria. From the recent data, all these parameters seem to decrease in the beaten soil tract. Whereas significant further decreases in the concrete tract were observed only for ammonium, phosphates and bacteria. For other parameters, e.g. pH, dissolved oxygen, chlorides, fluorides, sodium, and sulfates, a significant increase was observed from the historic data.  相似文献   
244.
Environmental Science and Pollution Research - The growing use of pharmaceutical drugs has become a major environmental issue considering that these substances (or their metabolites) end up...  相似文献   
245.
Environmental Science and Pollution Research - Pharmaceuticals are significant environmental stressors, since they are utilized around the world; they are usually released in to the aquatic system...  相似文献   
246.
247.
The quahog Mercenaria mercenaria has been introduced repeatedly to the Pacific coast of North America, but only one population is known to have become established. In the 1970s, the population of M. mercenaria at Colorado Lagoon, in Los Angeles County, California (33o46′16″N, 118o08′05″W), was estimated at more than 300,000 individuals. To determine the current status of this non-indigenous species (NIS), in 2009, we sampled 57 intertidal and 20 shallow subtidal plots, identifying and quantifying collected bivalves. No quahogs were found among the 2,490 living bivalves in our plots, though two were found intertidally outside of our plots. The M. mercenaria population has thus collapsed since 1980, but the native community has not recovered. Six of the fourteen living bivalve species we encountered were NIS; three are new records for the location, including the clam Venerupis philippinarum, which made up 87.6% of collected individuals. Though M. mercenaria is likely on its way to extinction on the US Pacific coast, the bivalve assemblage at this location remains heavily dominated by NIS.  相似文献   
248.
Initiated in 1992, air monitoring of organic pollutants in the Canadian Arctic provided spatial and temporal trends in support of Canada's participation in the Stockholm Convention of Persistent Organic Pollutants. The specific analytical laboratory charged with this task was changed in 2002 while field sampling protocols remained unchanged. Three rounds of intensive comparison studies were conducted in 2004, 2005, and 2008 to assess data comparability between the two laboratories. Analysis was compared for organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) in standards, blind samples of mixed standards and extracts of real air samples. Good measurement accuracy was achieved for both laboratories when standards were analyzed. Variation of measurement accuracy over time was found for some OCPs and PCBs in standards on a random and non-systematic manner. Relatively low accuracy in analyzing blind samples was likely related to the process of sample purification. Inter-laboratory measurement differences for standards (<30%) and samples (<70%) were generally less than or comparable to those reported in a previous inter-laboratory study with 21 participating laboratories. Regression analysis showed inconsistent data comparability between the two laboratories during the initial stages of the study. These inter-laboratory differences can complicate abilities to discern long-term trends of pollutants in a given sampling site. It is advisable to maintain long-term measurements with minimal changes in sample analysis.  相似文献   
249.
Exposed limestone cliffs in central Europe harbor a highly divers flora with many rare and endangered species. During the past few decades, there has been increasing recreational use of these cliffs, which has caused local environmental disturbances. Successful restoration strategies hinge on identifying critical limitations. We examined the composition of aboveground forest vegetation and density and species composition of seeds in the soil seed bank at the base of four limestone cliffs in mixed deciduous forests that are intensively disturbed by human trampling and at four undisturbed cliffs in the Jura Mountains in northwestern Switzerland. We found that long-term human trampling reduced total aboveground vegetation cover at the base of cliffs and caused a significant shift in the plant-species composition. Compared with undisturbed cliffs, total seed density was lower in disturbed cliffs. Human trampling also altered the species composition of seeds in the soil seed bank. Seeds of unintentionally introduced, stress-tolerant, and ruderal species dominated the soil seed bank at the base of disturbed cliffs. Our findings indicate that a restoration of degraded cliff bases from the existing soil seed bank would result in a substantial change of the original unique plant composition. Active seed transfer, or seed flux from adjacent undisturbed forest areas, is essential for restoration success.  相似文献   
250.
Journal of Polymers and the Environment - Lignocellulosic composites are biodegradable, have low cost, neutrality to CO2 emission, easily processed, easily available and pause no health risks,...  相似文献   
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