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221.
George R. Southworth Ralph R. Turner Mark J. Peterson Mary Anna Bogle Michael G. Ryon 《Environmental monitoring and assessment》2000,63(3):481-494
Approximately 250 000 kg of mercury was lost towater and soils at the U.S. Dept. of Energy Y-12 Plantin Oak Ridge, Tennessee in the 1950s and early 1960s. A creek originating within the plant receivedcontinuous inputs of waterborne mercury, predominantlyas dissolved inorganic mercury, from groundwater,streambed contamination, and sump and process waterdischarges to the contaminated storm sewer network.These produce aqueous total mercury concentrations of1–2 g L-1 in the upper reaches of the stream,decreasing to about 0.1–0.2 g L-1 in its lowerreaches. A program to reduce mercury concentrationsin the creek identified specific sources (buildingsumps, contaminated springwater seeps, foundationdrains, and contaminated piping) and rerouted wateraround contaminated portions of the drain system orcollected and treated mercury-contaminated waterbefore discharging it. As a result, waterbornemercury concentrations in the creek and total mercuryloading were reduced from 1.8 g L-1 to0.6 g L-1 and 100 to 20 g d-1, respectively, in the last 5 yr.Mean mercury concentrations in fish nearest sourceareas in the creek headwaters decreased at roughly thesame rate as waterborne total mercury concentrationsover the past five years, but at the facility boundarydownstream the decline in mercury bioaccumulation wasmuch less. At sites 5–15 km farther downstream, nodecrease was evident. Dissolved methylmercury tendedto increase with distance downstream in a patterninverse to that noted for its dissolved inorganicmercury precursor.Improvements in water quality and modification ofweirs to allow the passage of fish have resulted inthe establishment of large populations of fish inmercury-contaminated headwater areas previously devoidof fish. It may be that the accumulation, retention,and eventual downstream transport of this reservoir ofbiologically incorporated methylmercury has acted tobuffer against expected reductions in mercury in fishat downstream sites. 相似文献
222.
J T Peterson 《Atmospheric environment(England)》1972,6(7):433-442
223.
James O. Peterson Stephen M. Born Russel C. Dunst 《Journal of the American Water Resources Association》1974,10(6):1228-1245
ABSTRACT: The degradation of many lakes is the result of aging processes which have been accelerated by the activities of man. Where it is too late to prevent sedimentation and eutrophication problems, lake rehabilitation and protection comprise a resource management option warranting serious consideration. A Wisconsin Lake Renewal Demonstration Project has been evaluating several rehabilitation schemes for the past five years. A selected summary of Project lake rehabilitation activities, including nutrient inactivation, dilution, aeration, and several types of aquatic plant management, suggests the present status of lake rehabilitation. 相似文献
224.
Spencer A. Peterson David P. Larsen Steven G. Paulsen N. Scott Urquhart 《Environmental management》1998,22(5):789-801
N = 11,076). Results were compared to a large, nonrandomly sampled data set for the same area compiled by Rohm and others and
contrasted with lake trophic state information published in the National Water Quality Inventory: 1994 Report to Congress
[305(b) report. Lakes across the entire Northeast were identified by EMAP data as 37.9% (±8.4%) oligotrophic, 40.1% (±9.7%)
mesotrophic, 12.6% (±7.9%) eutrophic, and 9.3% (±6.3%) hypereutrophic. Lakes in the ADI and NEU generally are at a low, nearly
identical trophic state (96% oligotrophic/mesotrophic), while those in the CLP are much richer (45% eutrophic). EMAP results
are similar to results of the Rohm data set across the entire region. In the CLP, however, EMAP identified approximately 45%
of the lakes as eutrophic/hypereutrophic, while the Rohm data set identified only 21% in these categories. Across the entire
Northeast, the 305(b) report identified a much higher proportion (32.2%) of lakes in eutrophic condition and a much smaller
proportion (19.8%) in oligotrophic condition than did the EMAP survey data (12.5% ± 7.9% and 37.9% ± 8.5%, respectively).
Probability sampling has several advantages over nonrandom sampling when regional resource condition assessment is the goal. 相似文献
225.
A scanning electron microscope study of the mandibular morphology of boreal copepods 总被引:2,自引:0,他引:2
Morphological details of the mandibular blades of 11 species of copepods were examined with scanning electron microscopy. The micrographs improved our understanding of the complex toothed edge of the mandibular blade, which in turn aids in identification of the copepod prey of chaetognaths by gut-content analysis. Beklemishev's discovery of siliceous tooth crowns in calanoid copepods was confirmed for most of the species examined. Long, sharp projections on the crowns of herbivorous species, and the deep grooves into which they fit on the teeth of the opposite mandible, suggest a cracking rather than a grinding function for these teeth. 相似文献
226.
Theodore Panayotou Jeffrey D. Sachs Alix Peterson Zwane 《Journal of Environmental Economics and Management》2002,43(3):437
The debate over an international climate change regime has thus far focused primarily on efficiency concerns in developed countries. This paper suggests a means by which equity concerns may be addressed in the ongoing negotiations. A system of transfers is developed that is motivated by the difference between the damage caused by a country and the damage suffered by that country as a result of climate change. Illustrative calculations of the magnitude and direction of these transfers are made. We find that in general transfers flow from temperate to tropical countries but that the degree of uncertainty associated with these calculations is very large. 相似文献
227.
MOVEMENT WAYFINDING IN THE KING SAUD UNIVERSITY BUILT ENVIRONMENT: A LOOK AT FRESHMAN ORIENTATION ENVIRONMENTAL INFORMATION 《Journal of environmental psychology》1996,16(4):303-318
One potentially significant, yet hardly investigated, criterion for postoccupancy evaluation is the legibility of a setting—the degree to which a building or group of buildings facilitate the ability of users to find their way around. Legibility is one of the foundation concepts of environmental psychology, yet it has not often been considered enough as a guiding principle in design. The purpose of this paper is to analyse spatial orientation and wayfinding problems encountered by newcomers (freshman students) at the King Saud University (KSU) campus, Saudi Arabia, and to test/relate this to Lynch's elements of the image of cities. The analysis draws on previous research findings, theories, and more general observations, as well as observations made of wayfinding performance and map sketching by 30 high-school students likely to soon enroll at the university. Many specific problems with orientation and the architectural legibility of the buildings are identified and discussed. Emphasis is placed upon physical-setting variables that are likely to affect the ease with which spatial orientation and wayfinding are accomplished. These include the following facets of the KSU built environment: degree of differentiation; degree of visual access; and complexity of spatial layout.Legible buildings within which people can effectively maintain their orientation and find their way, according to this research, are in no way simplistic, dull, or boring; on the contrary, settings must possess distinctive landmarks and regions which, along with understandable path networks, allow users to know where they are and how to make their way to desired destinations. Coherent and legible environments are important in the lives of the people who use them. The movement of people through buildings and the factors that influence whether or not they are able to find their way need to continue to be of significance to both researchers and practitioners. 相似文献
228.
229.
Each National Park Service unit in the United States produces a resources management plan (RMP) every four years or less.
The plans commit budgets and personnel to specific projects for four years, but they are prepared with little quantitative
and analytical rigor and without formal decision-making tools. We have previously described a multiple objective planning
process for inventory and monitoring programs (Schmoldt and others 1994). To test the applicability of that process for the
more general needs of resources management planning, we conducted an exercise on the Olympic National Park (NP) in Washington
State, USA. Eight projects were selected as typical of those considered in RMPs and five members of the Olympic NP staff used
the analytic hierarchy process (AHP) to prioritize the eight projects with respect to their implicit management objectives.
By altering management priorities for the park, three scenarios were generated. All three contained some similarities in rankings
for the eight projects, as well as some differences. Mathematical allocations of money and people differed among these scenarios
and differed substantially from what the actual 1990 Olympic NP RMP contains. Combining subjective priority measures with
budget dollars and personnel time into an objective function creates a subjective economic metric for comparing different
RMP’s. By applying this planning procedure, actual expenditures of budget and personnel in Olympic NP can agree more closely
with the staff’s management objectives for the park. 相似文献
230.
We determined the association between radionuclide deposition levels from nuclear testing at the Nevada Test Site (NTS) and
cancer mortality rates in 513 counties of the Midwestern states of Iowa, Illinois, Kansas, Missouri, and Nebraska. The 10-day
cumulative deposition for 54 radionuclides and 1-year cumulative deposition for 19 radionuclides were determined with isotope
ratios based on each test and 131I levels in the 513 counties obtained from the US National Cancer Institute’s 131I fallout study. Deposition calculations were done for each test and each radionuclide. Age-adjusted cancer mortality rates
for 84 organ-gender combinations for the periods 1950–1959, 1960–1969, 1970–1979, and 1979–1995 were used. Analyses included
permutation-based randomization tests for Spearman rank correlation (adjusted for multiple testing). Age-adjusted cancer mortality
rates for connective and soft tissue sarcoma, thymus, and female lymphosarcoma and cancer of the colon, brain, thyroid, and
uterus were significantly correlated with total fallout and total precipitation during 1951–1957 and 1962. 187W had the highest cumulative deposition density at 10 days postshot (2783 MBq/m2) among the NTS radionuclides considered. The most significant correlations were observed for 10-day cumulative deposition
density of 181W, 185W, 54Mn, 187W, 24Na, 185W, 199Au, 7Be, 60Co, and deposition density of 185W, 54Mn, 7Be, and 60Co present at 1-year with mortality for cancers such as female connective and soft tissue sarcoma, male and female thymus,
female colon, male and female thyroid, female brain, male multiple myeloma, female breast, and uterine cancer. Significant
correlations included isotopic forms of mutagenic metals such as antimony, beryllium, cadmium, cobalt, cesium, manganese,
rhodium, selenium, tellurium, and tungsten. The large number of significant correlation tests beyond expectation warrants
deeper questions related to the toxicology of fission products and induced radionuclides, validity of kriging procedures,
and new studies on core sampling of watersheds and trees in regions assumed to receive the greatest levels of environmental
radiocontamination.
The text was submitted by the authors in English. 相似文献