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561.
The crisis in the early 1990s over conservation of biodiversity in the forests of the Pacific Northwest caused an upheaval in forest policies for public and private landowners. These events led to the development of the Coastal Landscape Assessment and Modeling Study (CLAMS) for the Coast Range Physiographic Province of Oregon, a province containing over two million hectares of forest with a complex mixture of public and private ownership. Over a decade, CLAMS scientists developed regional data bases and tools to enable assessments of the implications of current policies for biodiversity and have begun using these data and tools to test ideas for solving policy problems. We summarize here four main lessons from our work: (1) Regional ecosystem perspectives, while rewarding, are difficult to achieve. Helping policy makers and the public understand biodiversity policies for an entire province can assist in developing more reasoned policies. However, this result is difficult to achieve because needed scientific building blocks generally do not exist, few policy institutions address regional cross-ownership issues, people can find it difficult to take a regional view, and the appropriate region for analysis changes with the policy problem. (2) Interest in environmental policy analysis may come as much from a pursuit of power as a pursuit of understanding. Biodiversity policy analyses are often viewed as weapons in an ongoing political battle. Also, results that might destabilize existing policies generally will not be well received by those in power. (3) The relationship of regional analyses to civic processes remains challenging and unsettled. Communication between citizens and scientists takes real effort. Also, collaborative processes both inspire and constrain regional policy analysis, and scientific work often proceeds at a different pace than these processes. In the end, CLAMS's most important effect on the civic dialogue may be to change how people think about the Coast Range. (4) An important role exists for anticipatory assessments done independently by scientists. Independent review will be especially important as policy analyses shift to management of nonfederal forests. Our future efforts in CLAMS will focus on evaluating ideas for fundamental changes in forest management. 相似文献
562.
M Deshusses C T Johnson G Leson 《Journal of the Air & Waste Management Association (1995)》1999,49(8):973-979
To date, biofilters have been used primarily to control dilute, usually odorous, off-gases with relatively low volatile organic compound (VOC) concentrations (< 1 g m-3) and VOC loads (< 50 g m-3 hr-1). Recently, however, U.S. industry has shown an interest in applying biofilters to higher concentrations of VOCs and hazardous air pollutants (HAPs). In this study, the behavior of biofilters under high loads of binary VOC mixtures was studied. Two bench-scale biofilters were operated using a commercially available medium and a mixture of wood chips and compost. Both were exposed to varying mixtures of ethyl acetate and toluene. Concentration profiles and the corresponding removal efficiencies as a function of VOC loading were determined through frequent grab-sampling and GC analysis. Biofilter response to two frequently encountered operating problems--media dry-out and operating temperatures exceeding 40 degrees C--was also evaluated under controlled conditions. Microbial populations were also monitored to confirm the presence of organisms capable of degrading both major off-gas constituents. The results demonstrated several characteristics of biofilters operating under high VOC load conditions. Maximum elimination capacities for ethyl acetate were typically in the range of 200 g m-3 hr-1. Despite the presence of toluene degraders, the removal of toluene was inhibited by high loads of ethyl acetate. Several byproducts, particularly ethanol, were formed. Short-term dry-out and temperature excursions resulted in reduced performance. 相似文献
563.
Methyl bromide (MeBr) is one of the most widely used soil fumigants. Human exposure to MeBr above threshold values can cause serious health problems. The exposure assessment of MeBr depends on estimation or measurement of its air concentrations. This study proposed a methodology for systematically exploring the empirical relationship between MeBr use intensity and ambient air concentrations. Monitored air concentrations were regressed to MeBr use over various spatiotemporal scales that step-wise increased around the monitoring site and monitoring period. The results showed that the goodness-of-fit varied with the spatiotemporal scale of MeBr use. The best fit was Y = 0.46 + 0.00120X (R2 = 0.95, n = 11), where Y was the 8-wk average ambient air concentration (microg/m3), and X was the weekly average use (kg/wk) over an area of 11.3 x 11.3 km (7 x 7 mi). The model was calibrated with air-monitoring data and use data of 2000, and verified with the same type data of 2001. The model estimated subchronic air concentration with reasonable accuracy. 相似文献
564.
Crystal Lesmeister Larry Pochop Greg Kerr Shaun S. Wulff Drew Johnson 《Journal of the American Water Resources Association》2007,43(4):938-946
Abstract: The effectiveness of measuring lawn sprinkler application rates using the catch‐can test was evaluated. A survey of sources recommending the catch‐can test for measuring application rates show that catch‐can test procedures differ in the collector type, collector placement, number of collectors, and test duration. Analyses of catch‐can tests were performed to address these procedural differences, with emphasis on the type and number of collectors required to provide a reasonable level of confidence in test results. The accuracy of the catch‐can test generally improves as the number of randomly placed collectors increases. In order to achieve an accuracy of ±25% for 90 out of 100 catch‐can tests, the number of randomly placed collectors required ranged from 6 to over 50 for hand‐move systems, while for in‐ground systems, the number of randomly placed collectors required ranged from 2 to 8, depending on the pressure and percent overlap of the water distribution pattern. As long as a reasonable number of collectors were used when performing a catch‐can test, no consistent differences were observed in catch‐can test results due to type of collectors when using tuna fish cans, soup cans, or coffee mugs. 相似文献
565.
Jeffrey Lee Robbins Church Duane Lammers Leon Liegel Mark Johnson Deborah Coffey Richard Holdren Donald Stevens Robert Turner Louis Blume 《Environmental management》1989,13(1):95-108
Through the Direct/Delayed Response Project (DDRP), the United States Environmental Protection Agency is attempting to assess the risk to surface waters from acidic deposition in three regions of the eastern United States: the Northeast Region, the Southern Blue Ridge Province, and the Mid-Appalachian Region. The central policy question being addressed by the DDRP is: Within the regions of concern, how many surface water systems (lakes, streams) will become acidic due to current or altered levels of acidic sulfur deposition, and on what time scales? The approach taken by the DDRP is to select a statistically representative set of watersheds in each region of concern and to project the future response of each watershed to various assumed levels of acidic deposition. The probability structure will then be used to extrapolate the watershed-specific results to each region. The data will be used also for statistical investigation of hypothesized relationships between current surface water chemistry and watershed characteristics. Because the needed terrestrial data base was not available, regional watershed surveys were conducted to meet the specific data needs of the DDRP. Maps (1∶24,000) of soils, vegetation, land use, depth to bedrock, and bedrock geology were made for each watershed. The soils were grouped into sampling classes based on their hypothesized response to acidic deposition. Randomized sampling of these classes provided regional means and variances of soil properties that can be applied to individual watersheds. Because of DDRP's need for consistency within and among regions, unique quality control/quality assurance activities were developed and implemented. After verification and validation, the DDRP data base will be made publicly available. This will be a unique and useful resource for others investigating watershed relationships on a regional scale. The results of these surveys and the conclusions of the DDRP will be presented in several future papers. The current paper gives an overview of the context, rationale, logistical considerations, and implementation of these surveys, with special emphasis on the field activities of watershed mapping and soil sampling. This discussion should be useful to those planning, implementing, and managing survey activities in support of regional assessments of other environmental concerns, who are likely to face similar choices and constraints. 相似文献
566.
Leah RT Ma ZY Evans SJ Johnson MS 《Environmental pollution (Barking, Essex : 1987)》1991,72(2):117-126
A study of mercury concentrations in the stomach contents of fish from the north-east Irish Sea and Mersey Estuary has been shown to provide a means for surveillance of geographical and time-based changes in environmental exposure of fish biota to mercury in marine and estuarine ecosystems. This paper describes data for the flatfish dab (Limanda limanda), caught during the period 1986-1988. The low degree of variability in the data enables confirmation of clear trends in mercury concentration in stomach contents over time. As the inputs of mercury to the sewage sludge dumping ground in Liverpool Bay have decreased, there has been a corresponding decrease in mercury in fish food items. The mean mercury value in stomach contents around the dump site has declined to 100 microg kg(-1) (wet weight) which now predominates over the whole of Liverpool Bay. In 1986, mercury concentrations in stomach contents of fish ranged to over 750 microg kg(-1) although the majority of values were below 200 microg kg(-1). Most of the sites within the Mersey Estuary produced mean concentrations which were similar to those in the open sea, except for Garston which is the site closest to an inland, and principal alternative, source of mercury. 相似文献
567.
H. C. Johnson H. A. James 《Journal of the Air & Waste Management Association (1995)》2013,63(8):530-533
Intermingled land usage in the 3900 square mile Bay Area Air Pollution Control District presented special problems in curtailing open burning. Regulation 1, adopted in 1957, prohibited most types of open burning, with exceptions for public safety, instruction in fire fighting, flood control, agricultural burning and one- and two-family dwellings.Variances for open burning could be granted by the District’s Hearing Board.The need was established for utilizing the services of professional meteorologists for planning and carrying out open burns.Their proposals to limit adverse effects were : (1) Select a day of no inversion, with wind direction to carry pollutants away from local targets; and, (2) a day of low velocity at ground level, high velocity at high altitudes. Predicted meteorological conditions have been met for up to eight hours in a high percentage of cases. Experience has proven the need for proper stacking and drying of the wood waste to assure high temperature burning, and completion of the burn as scheduled. Even though the cost of hauling to landfills may be substantially more than the cost of burning under a variance, hauling is often selected because of the time required for stacking, drying, and waiting for designated meteorological conditions. Substantial progress has been made in curtailing agricultural burning. Burning of greenhouse waste has been stopped.on emissions from orchard heaters has resulted in replacement with new smokeless heaters.Orchard brush can be burned only on “burn days” designated in the winter when the inversion is predicted to be above 2500 ft. Stubble burning has continued due to the lack of a feasible alternative. Range brush burning also continues, mostly in remote areas of high elevation. Lumbering slash is burned at the insistence of forestry officials. The above burning could be limited to designated burn days, as is successfully being applied to orchard brush. Research on alternatives to agricultural burning is being spearheaded by the University of California, and its agricultural extension service. Each project usually requires several years to carry out and evaluate. Closer cooperation by all involved in agriculture and air pollution control is necessary to develop feasible alternatives to open burning. 相似文献
568.
Zachary T. Kalinoski Debra Steele‐Johnson Elizabeth J. Peyton Keith A. Leas Julie Steinke Nathan A. Bowling 《组织行为杂志》2013,34(8):1076-1104
The purpose of this meta‐analysis was to use theory and research on diversity, attitudes, and training to examine potential differential effects on affective‐based, cognitive‐based, and skill‐based outcomes, to examine potential moderators of those effects with a focus on affective‐based outcomes, and finally, to provide quantitative estimates of these posited relationships. Results from 65 studies (N = 8465) revealed sizable effects on affective‐based, cognitive‐based, and skill‐based outcomes as well as interesting boundary conditions for these effects on affective‐based outcomes. This study provides practical value to human resources managers and trainers wishing to implement diversity training within organizations as well as interesting theoretical advances for researchers. Practitioners have quantitative evidence that diversity training changes affective‐based, cognitive‐based, and skill‐based trainee outcomes. This study also supports and addresses future research needs. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
569.
570.
Michael A. Mallin Virginia L. Johnson Scott H. Ensign 《Environmental monitoring and assessment》2009,159(1-4):475-491
Water quality data at 12 sites within an urban, a suburban, and a rural stream were collected contemporaneously during four wet and eight dry periods. The urban stream yielded the highest biochemical oxygen demand (BOD), orthophosphate, total suspended sediment (TSS), and surfactant concentrations, while the most rural stream yielded the highest total organic carbon concentrations. Percent watershed development and percent impervious surface coverage were strongly correlated with BOD (biochemical oxygen demand), orthophosphate, and surfactant concentrations but negatively with total organic carbon. Excessive fecal coliform abundance most frequently occurred in the most urbanized catchments. Fecal coliform bacteria, TSS, turbidity, orthophosphate, total phosphorus, and BOD were significantly higher during rain events compared to nonrain periods. Total rainfall preceding sampling was positively correlated with turbidity, TSS, BOD, total phosphorus, and fecal coliform bacteria concentrations. Turbidity and TSS were positively correlated with phosphorus, fecal coliform bacteria, BOD, and chlorophyll a, which argues for better sedimentation controls under all landscape types. 相似文献