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91.
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93.
Summary This paper describes the rising tide of environmentalism in contemporary culture. It is accepted that this represents a fragile advance in our sensibilities about nature and one another. It has impacted the embodied practices of everyday affairs in decision-making. The sense of environmental risk factors may have contributed to this evolving sensibility towards nature. The rising environmental concern converges with the practices of democracy in the development and expansion of right-to-know laws, both locally and globally. In concert with the right-to-know laws are concepts and practices of sustainable development and the merging of social and environmental justice.Dr Jay Schulkin is a Research Associate at the Wharton Risk Management and Decision Process Center, University of Pennsylvania, and Director of Research at the American College of Obstetricians and Gynecologists in Washington DC. David Sarokin is Director of the Special Projects Office at the US Environmental Protection Agency, 401 M Street SW, Washington DC 20460, USA. The views in this paper are those of the authors, and not the institutions with which they are affiliated. 相似文献
94.
Jay R. Stauffer Kenneth L. Dickson John Cairns 《Journal of the American Water Resources Association》1974,10(5):860-876
ABSTRACT. Studies were conducted to determine the distribution of fish in the New and East Rivers in relation to thermal discharges from Appalachian Power Company's fossil fuel plant at Glen Lyn, Virginia. Over 15,300 specimens representing 41 species were collected with seines, electrogear and rotenone at six sampling locations from February, 1973 to October 1973. Sampling frequency was designed to evaluate the effects of ambient temperature upon preferred temperature. Diversity indices were calculated for each location. There was a slight decrease in the diversity indices for those stations located in the thermal discharge. Condition coefficients calculated for Notropis albeolus Jordan, Notropis rubellus Aqasaiz, Notropis spilopterus Cope, Ictalurus punctatus Rafinesque, and Etheostoma blennioides Rafuesque were found to be significantly (p =.05) lower in the thermal discharge for all species tested except E. blennioides. Temperatures were plotted against frequency of capture to determine a particular species temperature selection from field data and indicated that: (1) Some species avoided high temperatures (i.e., Curnpostoma anomalum Rafuesque). (2) Some species were attracted to high temperatures (i.e., Ictalurus punctatus). (3) Some species distribution was not effected by temperatures (i.e., Notropis spilopterus). 相似文献
95.
Agricultural lands have the potential to contribute to greenhouse gas mitigation by sequestering organic carbon within the soil. Credible and consistent estimates will be necessary to design programs and policies to encourage management practices that increase carbon sequestration. Because a nationwide survey of soil carbon by the wide range of natural resources and management conditions of the United States is prohibitively expensive, a simulation modeling approach must be used. The National Nutrient Loss Database (NNLD) is a modeling and database system designed and built jointly by the USDA– Natural Resources Conservation Service (NRCS) and Texas A&M University to provide science-based inferences on environmental impacts from changes in agricultural management practices and programs at the regional and national level. Currently, the NNLD simulates 16 crops and covers 1.35 × 108 ha. For estimating soil carbon sequestration, the database will be populated with 1.5 × 106 field-level model runs using the EPIC (Environmental Policy Impact Calculator) model, which includes newly incorporated carbon equations consistent with those in the Century model. Each run will represent a unique situation defined by state, crop, climate, soil, irrigation type, conservation practice, tillage system, and nutrient management treatment (nutrient rate, application frequency, application timing, and manure category). Results are to be assigned to specific National Resource Inventory points (NRI) to simulate regional and national baselines. In this article we present the modeling approach and discuss the strengths and limitations.
Published online 相似文献
96.
Gaseous emissions from animal manure storage facilities can contribute to global greenhouse gas inventories. Biogas fluxes were measured for one year from a 2-ha anaerobic lagoon that received waste from a 10500-head swine (Sus scrofa) finishing operation in southwestern Kansas. During 2001, ebullition of biogas was measured continuously by using floating platforms equipped with gas-collection domes. Periodically, the composition of the biogas was determined by using gas chromatography. Detailed records of feed quality and quantity and animal weights and gains also were obtained to determine the carbon budget of the facility (barns and lagoon). Flux of biogas was very seasonal, with peak emission (18.7 mol m(-2) d(-1)) occurring in early June. Nearly 50% of the annual biogas losses occurred during a 30-d period beginning on day of year (DOY) 146. Flux patterns suggest that the start of the high biogas production period was governed by temperature, while the decline in production in mid-June was caused by substrate limitations. Average biogas composition was 0.71 L CH4 L(-1). The quantity of CH4 released from the lagoon was 86.3 Mg yr(-1), which represents about 38 g of CH4 per kg of animal weight gain. The average flux density of biogas from the lagoon was 382 mol m(-2) yr(-1) or 728 mol yr(-1) per resident animal where the resident animal population was 10500. Flux rates of CH4 were 1.7 to 3.4 times less than predictions made with Intergovernmental Panel on Climate Change (IPCC) models. Additional research is needed on the carbon budgets of other animal feeding operations so that better estimates of greenhouse gas emissions can be determined. 相似文献
97.
Ray Jay Davis George William Sherk Donald Phelps 《Journal of the American Water Resources Association》1995,31(4):583-588
ABSTRACT: Whomever would affect water policy development must influence the water legislative process. This paper discusses in the context of the Model State Water Allocation Code the following ten ideas about doing that: (1) seek the right timing for enactment; (2) set modest goals; (3) prepare a well-drafted proposal; (4) recognize diversity by offering legislative choices; (5) consider the impacts of adoption; (6) make alliances; (7) respect executive influence; (8) become involved in legislative interaction; (9) be flexible; and (10) persist. Heeding these ideas, although not guaranteeing enactment, is sure to be educational for participants and useful to legislators. 相似文献
98.
Morville S Scheyer A Mirabel P Millet M 《Journal of environmental monitoring : JEM》2004,6(12):963-966
A method using GC-MS and derivatization with N-(t-butyldimethylsilyl)-N-methyltrifluoroacetamide (MTBSTFA) was developed for the analysis of 20 phenolic compounds in atmospheric samples (gas and particles). Air sampling was carried out using a Hi-Vol sampler with glass fibre filter and XAD-2 resin at a flow rate of 60 m(3) h(-1). The particle and gas phases were collected separately over a period of 4 h. Samples were Soxhlet extracted, evaporated to dryness under nitrogen and refilled with acetonitrile. 100 microl of these extracts were derivatized with 100 microl of MTBSTFA at 80 degrees C for 1 h under strong stirring. Phenolic compounds were injected into a GC-MS in splitless mode and quantified as their TBDMS derivatives in the SIM mode. Mass spectral analysis of the derivatives of the 20 compounds studied indicates that the spectra are highly specific showing an ion at [M - 57]+ which is useful for structure confirmation or analysis at low levels using selected ion monitoring. Quantification limits varied between 5 microg l(-1) and 10 microg l(-1) which correspond to 20 pg m(-3) and 40 pg m(-3) for 250 m(3) of air sampled. This method was successfully applied to atmospheric samples. 相似文献
99.
Hashem A. Faidi Luis A. Garcia Maurice M. Albertson 《Environmental Modeling and Assessment》2002,7(3):191-206
A model for simulation of solute transport in a dynamic stream–aquifer system is developed by integrating four existing sub-models. Interface packages are created to link the sub-models. The developed model is successfully used to simulate chloride transport in the stream–aquifer system of the Arkansas River and the Equus Beds Aquifer in Kansas and demonstrates that chloride concentration in the aquifer decreases in the vicinity of the simulated channel over time. 相似文献
100.
A holistic approach towards assessment of severity of land degradation along the Great Wall in northern Shaanxi Province,China 总被引:26,自引:0,他引:26
The farming and grazing interlocked transitional zone along theGreat Wall in northern Shaanxi Province is particularly vulnerable to desertification due to its fragile ecosystem and intensive human activity. Studies reveal that desertification isboth a natural and anthropogenic process. Four desertificationindicators (vegetative cover, proportion of drifting sand area, desertification rate, and population pressure) were used to assess the severity of desertification in a GIS. The first threefactors were derived from multitemporal remote sensing and landinventory data. The last factor was calculated from census data.It was found that the overall severity of land degradation in thestudy area has worsened during the last two decades with severely, highly and moderately degraded land accounting for 84.2% of the total area in 1998. While the area affected by desertification has increased, the rate of desertification has also accelerated from 0.74 to 0.87%. Risk of land degradation in the study area has increased, on an average, by 155% since 1985. Incorporation of both natural and anthropogenic factors inthe analysis provides realistic assessment of risk of desertification. 相似文献