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191.
Jin‐Yong Choi Bernard A. Engel Suresh Muthukrishnan Jon Harbor 《Journal of the American Water Resources Association》2003,39(3):623-635
ABSTRACT: To adequately manage impacts of ongoing or future land use changes in a watershed, the magnitude of their hydrologic impacts needs to be assessed. A grid based daily streamflow model was calibrated with two years of observed streamflow data, using time periods when land use data are available and verified by comparison of model predictions with observed streamflow data. Streamflow data were separated into direct runoff and baseflow to estimate the impacts of urbanization on each hydrologic component. Analysis of the ratio between direct runoff and total runoff from 30 years of simulation results and the change in these ratios with urbanization shows that estimated annual direct runoff increased from 49.2 percent (1973) to 63.1 percent (1984) and 65.0 percent (1991), indicating the effects of urbanization are greater on direct runoff than on total runoff. The direct runoff ratio also varies with annual rainfall, with dry year ratios larger than those for wet years. This suggests that the impact of urbanization on areas that are sensitive to runoff ratios, such as stream ecosystems, might be more serious during drier years than in wetter years in terms of water quality and water yield. This indicates that sustainable base‐flow is important to maintaining sound stream ecosystems. 相似文献
192.
Jon Birger Skjærseth 《环境政策》2018,27(3):498-518
European Union (EU) climate/energy targets and policies are poised for the first full climate policy cycle – from adoption and implementation of the policy package for 2020, to reform for 2030. A dynamic approach to the ways in which EU policies affect policy development is developed by applying theories of domestic implementation, policy feedback and integration. Implementation experiences in Poland – the ‘least climate ambitious’ EU member state – affected Polish preferences for reformed EU policies. Existing EU policies, their ‘fit’ with Poland’s energy interests and change in anticipation of future EU policies explain much of the variation in preferences. Second, policy feedback from Poland significantly affected the EU 2030 climate and energy framework. As yet, the EU has succeeded only partly in gathering momentum through a ‘snowball’ effect whereby positive policy feedback from implementation generates further steps. 相似文献
193.
This paper addresses how risks to the environment in the Arctic are handled in decisions regarding the exploration for petroleum resources. An exploration well in the Norwegian Barents Sea is used as a case to demonstrate how environmental risks are assessed together with technical and economic considerations in the Oil Company’s decisions to enter into a new area and drill a well. The paper outlines environmental challenges in petroleum activities in the Arctic, the different roles of the Authorities and Oil Companies in decisions about petroleum activities, and the Oil Company’s tools and decision criteria used in addressing risks in the decision making.It is concluded that environmental and associated reputation risks are not a major issue at the strategic level in the Oil Company, since the most controversial areas in the Norwegian Arctic offshore have already been kept out of the exploration acreage by the authorities. Risks and uncertainties penetrate every aspect of the exploration of petroleum resources, and environmental risks are not unique in this sense. The Oil Company has established technical and economic tools and decision criteria to address them, and the mitigation of environmental risks becomes an element in the technical and economic analyses that affect detailed design and operational procedures. Mitigation measures such as the minimization of discharges to the sea (the so-called “zero-discharge” policy) and oil spill contingency planning are dimensioned to meet authority requirements and expectations rather than on strict risk acceptance considerations. A significant concern is to avoid delays in the permit granting process. 相似文献
194.
Christine L. Goldstein Karl W.J. Williard Jon E. Schoonover 《Journal of the American Water Resources Association》2009,45(3):664-672
Abstract: Autumn‐olive (Elaeagnus umbellata Thunb.) is an invasive, exotic shrub that has become naturalized in the eastern United States. Autumn‐olive fixes nitrogen (N) via a symbiotic relationship with the actinomycete Frankia. At the plot scale, the presence of autumn‐olive has been related to elevated soil water nitrate‐N (NO3?‐N) concentrations. This study examined the relationship between autumn‐olive cover in a watershed and stream water quality. Stream water nitrate‐N (NO3?‐N) and ammonium‐N (NH4+‐N) concentrations were measured in 12 first order ephemeral streams draining watersheds with mixed forest cover and a range of 0‐35% autumn‐olive cover. Percent autumn‐olive cover was positively correlated with mean stream NO3?‐N concentrations, but was not correlated with mean stream NH4+‐N concentrations. While other studies have demonstrated a significant relationship between native N‐fixers and stream NO3?‐N, this is the first study to document a relationship for an invasive, exotic N‐fixing species. Results suggest that this exotic species can be an additional source of NO3? in local and regional water bodies and demonstrates an additional negative ecosystem consequence of invasion beyond losses in biodiversity. 相似文献
195.
A. H. Sweet B. J. Steigerwald J. H. Ludwig 《Journal of the Air & Waste Management Association (1995)》2013,63(2):111-113
The immediacy of the need for pollution-free vehicles is investigated by projecting to 2010 vehicle emission densities for eight urban areas and measures of population exposure to pollution for four cities. Three degrees of emission control are applied. Application of 50% control to 1968 automobiles maintains emission densities below present levels for the next 20 years, but is less effective in reducing population exposure to pollution, in some cases only slowing the rate of growth. Application of 50% control in 1968 and 80% in 1973 fails to reduce emission densities below 50% of the present. Reduction below 50% will eventually require an essentially pollution-free vehicle in many areas. 相似文献
196.
William M. Cox Jon Clark 《Journal of the Air & Waste Management Association (1995)》2013,63(7):762-766
Data on dally maximum ozone concentrations measured at ambient air monitoring stations operated by state and local air pollution control agencies in the Eastern United States were analyzed using principal factor analysis. Four orthogonal factors representing O3 formation potentials were derived using the statistical package SPSS; these factors accounted for over two-thirds of the variations in 1978 summer O3 levels at 21 urban-oriented stations. The analysis confirmed that O3 variations are similar among stations within defined geographical areas; this confirmation supports the widely held theory that ambient O3 formations are reglonwlde. The analysis suggested that trends analysis for determining general progress in improving O3 air quality should be based on aggregate statistics from clusters of monitors rather than from a single monitoring station within areas associated with the derived factors. 相似文献
197.
Jon M. Heuss 《Journal of the Air & Waste Management Association (1995)》2013,63(11):1152-1153
Abstract A mathematical model is proposed for assessing health risk rates of fluctuating concentrations. Each time-averaged concentration may be regarded as a dose that, when applied to the dose-response curve, produces a risk of an adverse effect. A theoretical derivation shows that the dose-response pattern is a cumulative lognormal curve because of the diversity of the individuals in the exposed population. Similarly, the concentration pattern is a log-normal distribution because of the diversity of emission sources and dispersive processes. The health risk is produced by the overlapping of the right tail of the concentration distribution and the left tail of the dose-response curve. The evaluation of the joint probability in this region has been performed by numerical integration by computer in terms of two generalized parameters. One represents the geometric standard deviation of the concentration distribution relative to that of the dose-response curve, and the other represents the distance between the geometric mean concentration and the concentration producing an adverse response in 50% of the exposed population. These results are presented graphically and in tabular form. If the two parameters of the dose-response curve are known, the health risk of the concentration pattern may be calculated conveniently for any geometric mean and geometric standard deviation values. 相似文献
198.
Jon B. Manchester-Neesvig Glen R. Cass 《Journal of the Air & Waste Management Association (1995)》2013,63(9):1065-1079
Abstract Atmospheric particulate matter (PM) samples from 12 sites in southern California, collected as part of the Southern California Children’s Health Study (SCCHS), were analyzed using gas chromatography/mass spectrometry (GC/MS) techniques. Ninety-four organic compounds were quantified in these samples, including n-alkanes, fatty acids, polycyclic aromatic hydrocarbons (PAH), ho-panes, steranes, aromatic diacids, aliphatic diacids, resin acids, methoxyphenols, and levoglucosan. Annual average concentrations of all detected compounds, as well as average concentrations for three seasonal periods, were determined at all 12 sites for the calendar year of 1995. These measurements provide important information about the seasonal and spatial distribution of particle-phase organic compounds in southern California. Also, co-located samples from one site were analyzed to assess precision of measurement. Excellent agreement was observed between annual average concentrations for the broad range of organic compounds measured in this study. Measured concentrations from the 12 sampling sites were used in a previously developed molecular-marker source apportionment model to quantify the primary source contributions to the PM10 organic carbon and mass concentrations at these 12 sites. Source contributions to atmospheric PM from six important air pollution sources were quantified: gasoline-powered motor vehicle exhaust, diesel vehicle exhaust, wood smoke, vegetative detritus, tire wear, and natural gas combustion. Important trends in the seasonal and spatial patterns of the impact of these six sources were observed. In addition, contributions from meat smoke were detected in selected samples. 相似文献
199.
Jon Leonard R. Del Delumyea 《Journal of the Air & Waste Management Association (1995)》2013,63(6):804-806
Elemental carbon (EC) particles have been found in the lungs of dolphins. The question arose as to whether these particles originated over land or water. This project determined the amount of EC particulate found in terrestrial air. Portions of paniculate filters and associated data collected during the period from January 1990 through December 1991 were provided by the Florida Department of Environmental Regulation. Using reflectance spectroscopy and laboratory-generated standards, atmospheric concentrations of EC and TSP were determined. This paper addresses the data from those counties which surround Tampa Bay. In the spring of 1992, a television news station reported that researchers at Mote Marine Institute had found black carbon particulates in the lungs of dolphins (reported as “...dolphins with Black Lung Disease..."). The dolphins were found in the Gulf of Mexico off the coast of Florida.1 In discussions with a principal investigator of the dolphin study, the question arose as to whether these particulates came from urban or marine sources. No comprehensive investigation of soot concentrations in the air over Florida had been made. This study reports the elemental carbon (EC) content of urban particulate matter in the Tampa Bay region, where the affected dolphins were discovered between 1988 and 1990 (Sarasota County). This is the first step toward answering whether urban concentrations of EC were sufficient to contribute measurably to the EC found in the marine environment. Future efforts will address marine concentrations and sources of EC. Elemental carbon, commonly termed “soot,” is a product of incomplete combustion. Common urban sources of EC in particulate matter include both mobile sources (diesel-powered buses, cars, and trucks) and point sources (incinerators, power plants and home heating units). The State of Florida operates environmental monitoring stations in selected municipalities around the state. At these stations, which were sited according to EPA requirements2, Total Suspended Particulate (TSP) samples were collected using the accepted methods.3 These samples were suitable for EC analysis. Samples collected in the Tampa Bay region in 199b and 1991 were analyzed for EC content using reflectance spectroscopy. EC concentrations were calculated in micrograms per cubic meter (μg/m3). 相似文献
200.
McKinney MA Letcher RJ Aars J Born EW Branigan M Dietz R Evans TJ Gabrielsen GW Peacock E Sonne C 《Environment international》2011,37(2):365-374
Flame retardants and legacy contaminants were analyzed in adipose tissue from 11 circumpolar polar bear (Ursus maritimus) subpopulations in 2005-2008 spanning Alaska east to Svalbard. Although 37 polybrominated diphenyl ethers (PBDEs), total-(α)-hexabromocyclododecane (HBCD), 2 polybrominated biphenyls (PBBs), pentabromotoluene, pentabromoethylbenzene, hexabromobenzene, 1,2-bis(2,4,6-tribromophenoxy(ethane) and decabromodiphenyl ethane were screened, only 4 PBDEs, total-(α-)HBCD and BB153 were consistently found. Geometric mean ΣPBDE (4.6-78.4 ng/g lipid weight (lw)) and BB153 (2.5-81.1 ng/g lw) levels were highest in East Greenland (43.2 and 39.2 ng/g lipid weight (lw), respectively), Svalbard (44.4 and 20.9 ng/g lw) and western (38.6 and 30.1 ng/g lw) and southern Hudson Bay (78.4 and 81.1 ng/g lw). Total-(α)-HBCD levels (<0.3-41.1 ng/g lw) were lower than ΣPBDE levels in all subpopulations except in Svalbard, consistent with greater European HBCD use versus North American pentaBDE product use. ΣPCB levels were high relative to flame retardants as well as other legacy contaminants and increased from west to east (1797-10,537 ng/g lw). ΣCHL levels were highest among legacy organochlorine pesticides and relatively spatially uniform (765-3477 ng/g lw). ΣDDT levels were relatively low and spatially variable (31.5-206 ng/g lw). However, elevated proportions of p,p'-DDT to ΣDDT in Alaska and Beaufort Sea relative to other subpopulations suggested fresh inputs from vector control use in Asia and/or Africa. Comparing earlier circumpolar polar bear studies, ΣPBDE, total-(α)-HBCD, p,p'-DDE and ΣCHL levels consistently declined, whereas levels of other legacy contaminants did not. International regulations have clearly been effective in reducing levels of several legacy contaminants in polar bears relative to historical levels. However, slow or stalling declines of certain historic pollutants like PCBs and a complex mixture of "new" chemicals continue to be of concern to polar bear health and that of their arctic marine ecosystems. 相似文献