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391.
Regional Environmental Change - Local perspectives on changing weather and climate and analyses of meteorological data represent two different but potentially complementary ways of knowing about...  相似文献   
392.
The fundamental data requirements for the authorization of plant protection products and the inclusion of active ingredients in Annex I of Council Directive 91/414/EEC are described in the Annexes II and III of this Directive. Definite instructions with regard to preconditions and for implementation and methodology (guidelines) concerning investigations with terrestrial plants are deficient. In the following, the scientific data requirements are explained for assessing the effects of plant protection products on terrestrial plants.  相似文献   
393.
BackgroundExisting traffic variables used for predicting NO2 in epidemiological studies are either difficult to acquire or explain only a small proportion of the variance. The purpose of this study was to develop and validate a new predictor, weighted road density, which combines the maximum amount of information related to traffic into a single variable without the requirement of obtaining traffic counts for a given area.MethodTwo week NO2 samples were collected using the readings of up to 32 passive samplers on 3 separate rounds between September and December 2006 and again in 2007. Several types of traffic related explanatory variables based on traffic counts, distance to main road and the proposed weighted road density were constructed using GIS software, and tested for association with the NO2 samplers. Assessment of the best model was based on R2 values, as well as leave-one-out cross validation.ResultsThe weighted road density variable and the density variable based on traffic counts resulted in a similar R2 (0.59) for predicting NO2, although weighted road density was much easier to construct and outperformed other variables such as distance to main road.ConclusionAs well as being a powerful predictor for use in a land use regression model, weighted road density can be used as a proxy for exposure to traffic-related pollution, for use in circumstances where direct measurements of pollutant levels are not feasible or are not required.  相似文献   
394.
A regional modeling system was applied with inputs from global climate and chemistry models to quantify the effects of global change on future biogenic emissions and their impacts on ozone and biogenic secondary organic aerosols (BSOA) in the US. Biogenic emissions in the future are influenced by projected changes in global and regional climates and by variations in future land use and land cover (LULC). The modeling system was applied for five summer months for the present-day case (1990–1999, Case 1) and three future cases covering 2045–2054. Individual future cases were: present-day LULC (Case 2); projected-future LULC (Case 3); and future LULC with designated regions of tree planting for carbon sequestration (Case 4). Results showed changing future meteorology with present-day LULC (Case 2) increased average isoprene and monoterpene emission rates by 26% and 20% due to higher temperature and solar insolation. However when LULC was changed together with climate (Case 3), predicted isoprene and monoterpene emissions decreased by 52% and 31%, respectively, due primarily to projected cropland expansion. The reduction was less, at 31% and 14% respectively, when future LULC changes were accompanied by regions of tree planting (Case 4). Despite the large decrease in biogenic emission, future average daily maximum 8-h (DM8H) ozone was found to increase between +8 ppbv and +10 ppbv due to high future anthropogenic emissions and global chemistry conditions. Among the future cases, changing LULC resulted in spatially varying future ozone differences of ?5 ppbv to +5 ppbv when compared with present-day case. Future BSOA changed directly with the estimated monoterpene emissions. BSOA increased by 8% with current LULC (Case 2) but decreased by 45%–28% due to future LULC changes. Overall, the results demonstrated that on a regional basis, changes in LULC can offset temperature driven increases in biogenic emissions, and, thus, LULC projection is an important factor to consider in the study of future regional air quality.  相似文献   
395.
Although a significant fraction of atmospheric particulate mass is organic carbon, the sources of particulate organic carbon (POC) are not always apparent. One potential source of atmospheric POC is biological particles, such as bacteria, pollen, and fungal spores. Measurements of POC and biological particles, including bacteria, fungal spores, and pollen, were made as part of the Storm Peak Aerosol and Cloud Characterization Study in Steamboat Springs, CO in March–April 2008. Biological particles were identified and characterized using several methods. The results suggest that biological particles could account for an average of 40% of the organic carbon mass in particles with aerodynamic diameters less than 10 μm. These estimates of POC mass from biological particles are highly uncertain; however, the results suggest that biological particles could be a significant source of organic aerosol in the background continental atmosphere and further observations are needed to better constrain these estimates.  相似文献   
396.
Qualitative evaluation of the effects of uncertainties originating from scenario development, modeling approaches, and parameter values is an important subject in the area of safety assessment for high-level nuclear waste disposal sites. In this study, regional-scale groundwater flow analyses for the Tono area, Japan were conducted using three continuous models designed to handle heterogeneous porous media. We evaluated the simulation results to quantitatively analyze uncertainties originating from modeling approaches. We found that porous media heterogeneity is the main factor which causes uncertainties. We also found that uncertainties originating from modeling approaches greatly depend on the types of hydrological structures and heterogeneity of hydraulic conductivity values in the domain assigned by modelers. Uncertainties originating from modeling approaches decrease as the amount of labor and time spent increase, and iterations between investigation and analyses increases.  相似文献   
397.
Advanced oxidation technologies such as ozonation have been proposed to improve removal efficiency of micropollutants during wastewater treatment. In a meta-analysis of peer-reviewed literature, we found no ecotoxicological effects of wastewater ozonation on invertebrates (n = 82), but significant adverse effects on bacteria (n = 24) and fish (n = 5). As information on functional endpoints or trophic interactions is lacking, we applied a bioassay relating to leaf litter decomposition to fill this gap. Leaf discs exposed to ozone-treated wastewater with a high (1.04 mg O3 (mg DOC)−1, n = 49) ozone concentration were significantly preferred by an aquatic detritivore, Gammarus fossarum, over discs conditioned in wastewater not treated with ozone. This effect might have been mediated by reduced bacterial and elevated fungal biomass, and appears to be the first demonstration of wastewater ozonation impacts on invertebrates and an associated ecosystem process. In accordance with the food-choice trials, chemical analyses revealed significantly decreased concentrations of organic micropollutants in wastewater treated with ozone at high concentrations. Thus, food-choice trials as applied here hold promise to assess environmental effects of advanced oxidation technologies in wastewater treatment and appear to be a valuable complement to the ecotoxicological toolbox in general.  相似文献   
398.
Elevated mercury concentrations in water were reported in the prairie wetlands at Lostwood National Wildlife Refuge, ND. In order to determine whether wildlife associated with these wetlands was exposed to and then accumulated higher mercury concentrations than wildlife living near more permanent wetlands (e.g. lakes), tree swallow (Tachycineta bicolor) eggs and nestlings were collected from nests near seasonal wetlands, semi-permanent wetlands, and lakes. Mercury concentrations in eggs collected near seasonal wetlands were higher than those collected near semi-permanent wetlands or lakes. In contrast, mercury concentrations in nestling livers did not differ among wetland types. Mercury and other element concentrations in tree swallow eggs and nestlings collected from all wetlands were low. As suspected from these low concentrations, mercury concentrations in sample eggs were not a significant factor explaining the hatching success of the remaining eggs in each clutch.  相似文献   
399.
The capacity to sustainably govern complex socio-ecological systems (SES) has been identified as a necessary but daunting task by SES scholars, resource stewards and stakeholders. This research sought to inform the question: What are determinant capacities and functional linkages that can be incorporated into diagnostic tools for analysts seeking to improve sustainable socio-economic system SES governance? Literature was used to identify and translate determinant capacities and functional linkages into a quantifiable metric of governance quality. The tool was developed from ecological, business, governance and decision science literature. This tool recognizes the dynamic and systemic linkages between the resources and the social systems that use and govern them for improving systems thinking and SES outcomes. The tool was tested to determine its ability to capture perceived characteristics of governance quality and problem management using Michigan’s cleanup and redevelopment program. The results of this research indicated that the exploratory tool was reliable and valid. This research contributes to the evolving body of SES frameworks, specifically the study of individual and organizational capacities for improved SES outcomes. The implications of this research suggest participatory network-based governance with higher levels of resource exchange, in the form of interdependency, trust, diplomacy and reciprocity, aligns with practitioners’ perceptions of improved program performance. Further, while some capacities and related findings of this research may be context specific, concepts associated with the development and testing of this diagnostic tool, such as the use of systems thinking, participatory network-based governance, and related competencies, may have more universal application.  相似文献   
400.
The objective of this paper is to synthesize results from seven published research papers employing different experimental approaches to evaluate the fate of metal-based nanoparticles (Ag NPs, Au NPs, CuO NPs, CdS NPs, ZnO NPs) in the marine environment and their effects on two marine endobenthic species, the bivalve Scrobicularia plana and the ragworm Hediste diversicolor. The experiments were carried out under laboratory (microcosms) conditions or under environmentally realistic conditions in outdoor mesocosms. Based on results from these seven papers, we addressed the following research questions: (1) How did the environment into which nanoparticles were released affect their physicochemical properties?, (2) How did the route of exposure (seawater, food, sediment) influence bioaccumulation and effects?, (3) Which biomarkers were the most responsive? and (4) Which tools were the most efficient to evaluate the fate and effects of NPs in the marine environment? The obtained results showed that metal‐based NPs in general were highly agglomerated/aggregated in seawater. DGT tools could be used to estimate the bioavailability of metals released from NPs under soluble form in the aquatic environment. Both metal forms (nanoparticulate, soluble) were generally bioaccumulated in both species. Among biochemical tools, GST and CAT were the most sensitive revealing the enhancement of anti-oxidant defenses in both species exposed to sub-lethal concentrations of metal-based NPs. Apoptosis and genotoxicity were frequently observed.  相似文献   
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