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891.
A Regional Analysis of Lake Acidification Trends for the Northeastern U.S., 1982-1994 总被引:1,自引:0,他引:1
John L. Stoddard Charles T. Driscoll Jeffrey S. Kahl James H. Kellogg 《Environmental monitoring and assessment》1998,51(1-2):399-413
Acidic deposition is a regional phenomenon, but its effects have traditionally been studied using site-specific, intensive monitoring. We present trends information for 36 lakes of high-to-moderate acid sensitivity (defined as acid neutralizing capacity [ANC] < 100 eq L-1), and 15 deposition monitoring stations, in the northeastern U.S. for the period 1982-1994. Trends at each site were assessed through use of the Seasonal Kendall tau test; the resulting statistics were combined, through a technique analogous to analysis of variance, to produce quasi-regional estimates of change for key chemical variables. Rates of sulfate deposition declined significantly across all of the northeastern region during this time period, while rates of nitrate and ammonium deposition were unchanged. All lakes exhibited strong decreases in sulfate concentrations
in response to declining sulfate deposition, but there was a strong contrast in the response of acid/base status between lakes in New England and lakes in the Adirondacks. As a group, the New England lakes exhibited recovery (ANC = +0.8 eq L-1yr-1, p<0.001), while the Adirondack lakes exhibited either no trend or further acidification (as a group, ANC = -0.5 eq L-1yr-1, p<0.01). This contrast can be attributed to changes in base cation concentrations: New England lakes exhibited base cations declines that were smaller in magnitude than declines in sulfate, producing the observed recovery in ANC; Adirondack lakes showed base cation declines that were very similar to those of sulfate, and no recovery was evident. 相似文献
892.
Charles F. Mason 《Environmental Modeling and Assessment》2006,11(2):131-143
Firms would like to capitalize on consumers' willingness to pay more for goods that use environmentally friendly production techniques, but have difficulty credibly conveying their environmental friendliness. One possible remedy is “ecolabeling,” where a third party certifies firms' products. To model this phenomenon, I analyzed a market characterized by asymmetric information in which firms decide whether to seek an ecolabel. Market equilibrium is discussed in three settings: where both technologies and outputs are fixed (so the only choice is whether to seek certification), where technologies are fixed but outputs are not, and where firms can choose both technology and output. 相似文献
893.
Inventory compilation and distribution of heavy metals in wastewater from small-scale industrial areas of Delhi, India 总被引:1,自引:0,他引:1
Delhi has the highest cluster of small-scale industries (SSI) in India. There are generally less stringent rules for the treatment of waste in SSI due to less waste generation within each individual industry. This results in SSI disposing of their wastewater untreated into drains and subsequently into the river Yamuna, which is a major source of potable water in Delhi, thus posing a potential health and environmental risk to the people living in Delhi and downstream. To study the quantity, quality and distribution of heavy metals in liquid waste from industrial areas, wastewater, suspended materials and bed sediments were collected from industrial areas and from the river Yamuna in Delhi. This study has also focused on the efficiency of production processes in small-scale industries in India. Heavy metals such as Fe, Mn, Cu, Zn, Ni, Cr, Cd, Co and Pb were detected using a GBC 902 atomic absorption spectrometer. The concentration of heavy metals observed was as follows: Fe 2-212, Mn 0.3-39, Cu 0.2-20, Zn 0.2-5, Ni 0.6-6, Cr 0.2-53, Cd 0.08-0.2, Co 0.013-0.55, Pb 0.3-0.7 mg L(-1) in wastewater; Fe 5842-78 000, Mn 585-10 889, Cu 206-7201, Zn 406-9000, Ni 22-3621, Cr 178-10 533, Co 17-114, Cd 13-141, Pb 67-50 171 mg kg(-1) in suspended material; and Fe 3000-84000, Mn 479-1230, Cu 378-8127, Zn 647-4010, Ni 164-1582, Cr 139-3281, Co 20-54, Cd 37-65, Pb 228-293 mg kg(-1) in bed residues. This indicates that SSI could be one of the point sources of metals pollution in the river system. 相似文献
894.
Environmental Monotoring and Assessment Program: Current Status of Virginian Province (U.S.) Estuaries 总被引:1,自引:0,他引:1
Charles J. Strobel Henry W. Buffum Sandra J. Benyi John F. Paul 《Environmental monitoring and assessment》1999,56(1):1-25
Monitoring of indicators of the ecological condition of bays, tidal rivers, and estuaries within the Virginian Biogeographic Province (Cape Cod, Massachusetts to Cape Henry, Virginia) was conducted annually by the U.S. EPA's Environmental Monitoring and Assessment Program (EMAP) during the summer months of 1990 to 1993. Data were collected at 425 probability-based stations within the Province. Indicators monitored included water quality (temperature, salinity, water clarity, and dissolved oxygen concentration), sediment contamination, sediment toxicity, benthic community structure, fish community structure, and fish gross external pathology. Data were used to estimate the current status of the ecological condition of Virginian Province estuarine resources, and provide a baseline for identifying possible future changes. Estimates, with 95% confidence limits, of the areal extent of impacted resources within the Province are provided. Data are also presented by estuarine class (large estuaries, small estuarine systems, and large tidal rivers). Results show that, overall, approximately half of the estuarine waters of the Virginian Province can be classified as impacted based on multiple indicators, with hypoxia being the major stressor. 相似文献
895.
Tang KM Nace CG Maddaloni MA Harkay JD Graham DR Koustas RN Rotola JD LaPosta D Callahan KC 《Journal of the Air & Waste Management Association (1995)》2004,54(10):1293-1298
The destruction of the buildings at the World Trade Center (WTC) complex dispersed dust and debris into the surrounding area. Pulverized building material made up most of the fallout and was intermixed with combustion byproducts of the aircraft and building contents. A study was conducted to confirm the effectiveness of several cleaning procedures in removing WTC-related contamination from lower Manhattan residences. The contaminants included asbestos, lead, dioxin/furans, synthetic vitreous fibers (fibrous glass), and crystalline silica. All cleaning procedures included the common elements of vacuuming and wet wiping with soap and water. This cleaning procedure combination is effective in reducing WTC-related contamination to below health-based benchmarks. Post-cleaning environmental test results suggested that airborne asbestos measurements can be used as a surrogate parameter in clearance determinations. 相似文献
896.
897.
Mass spectrometry/mass spectrometry (MS/MS) has been demonstrated to be a valuable technique in the analysis of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs, PCDFs). In this study, we demonstrate both the value and limitations of high-resolution mass spectrometry (HRMS) and MS/MS in the analysis of PCDDs and PCDFs. We have found that in certain cases, MS/MS can solve analytical problems that cannot be solved by high-resolution mass spectrometry and we demonstrate the reliability and reproducibility of MS/MS in the analysis of PCDDs and PCDFs in environmental matrices. 相似文献
898.
Measurements from sites of the Southeastern Aerosol Research and Characterization (SEARCH) program, made from 1998 to 2001, are used with a thermodynamic equilibrium model, Simulating Composition of Atmospheric Particles at Equilbrium (SCAPE2), to extend an earlier investigation of the responses of fine particulate nitrate (NO3-) and fine particulate matter (PM2.5) mass concentrations to changes in concentrations of nitric acid (HNO3) and sulfate (SO42-). The responses were determined for a projected range of variations of SO42- and HNO3 concentrations resulting from adopted and proposed regulatory initiatives. The predicted PM2.5 mass concentration decreases averaged 1.8-3.9 microg/m3 for SO42- decreases of 46-63% from current concentrations. Combining the S042- decrease with a 40% HNO3 decrease from current concentrations (approximating expected mobile-source oxides of nitrogen [NOx] reductions by 2020) yielded additional incremental reductions of mean predicted PM2.5 mass concentration of 0.2 microg/m3 for three nonurban sites and 0.8-1 microg/m3 for one nonurban and two urban sites. Increasing the HNO3 reduction to 55% (an estimate of adding Clear Skies Phase II NOx reductions) yielded additional incremental reductions of mean predicted PM2.5 mass concentration of 0-0.4 microg/m3. Because of the well-documented losses of particulate NO3- from Federal Reference Method (FRM) filters, only a fraction of these incremental changes would be observed. 相似文献
899.
/ Contemporary trends in natural resource management are reviewed, with specific reference to the shift in conservation management strategies away from law enforcement-based strategies towards strategies aimed at facilitating local community participation in the management of natural resources. This review lays a foundation for the presentation of a conceptual framework, the partnership forum framework, for the planning, implementation, and evaluationof protected area outreach programmes. The framework proposes that protected areas should function as integral components of the local social, economic, and environmental systems and that the integration of the protected area into these systems should be managed through comanagement institutions. The establishment of such institutions is discussed, and it is argued that the development of comanagement institutions can be characterized into four progressive phases: a preliminary communication phase, a problem-solving phase, a pilot project phase, and a comanagement phase. The framework proposes that during the three initial phases the partnership forum members will develop management procedures that they will use during the comanagement phase. The framework is presented as a design skeleton around which the site-specific characteristics of specific protected area outreach programs will combine to form an outreach program, i.e., the framework is process rather than project based.KEY WORDS: Sub-Saharan Africa; Integrated conservation and development 相似文献
900.
Yury Verlinsky Svetlana Rechitsky Serge Evsikov Melody White Jeanine Cieslak Aaron Lifchez Jorge Valle Jacob Moise Charles M. Strom 《黑龙江环境通报》1992,12(2):103-110
Preimplantation diagnosis provides couples at high genetic risk the possibility of avoiding genetic disease without the need for prenatal diagnosis and selective abortion of the affected pregnancy. Following extensive background work on the reliability of genetic diagnosis in a single cell, we offered on a research basis preimplantation diagnosis to five couples at risk for offspring with the delta-F508 mutation (the major mutation causing cystic fibrosis). There was no detrimental effect from polar body removal on either fertilization or preimplantation development. Genetic analysis, undertaken in 22 polar bodies and 15 corresponding blastomeres, identified 21 embryos of which ten were transferred. 相似文献