排序方式: 共有25条查询结果,搜索用时 31 毫秒
1.
L.-W. Antony Chen Judith C. Chow Bruce G. Doddridge Russell R. Dickerson William F. Ryan Peter K. Mueller 《Journal of the Air & Waste Management Association (1995)》2013,63(8):946-956
Abstract Observations of the mass and chemical composition of particles less than 2.5 μm in aerodynamic diameter (PM2.5), light extinction, and meteorology in the urban Baltimore-Washington corridor during July 1999 and July 2000 are presented and analyzed to study summertime haze formation in the mid-Atlantic region. The mass fraction of ammoniated sulfate (SO4 2-) and carbonaceous material in PM2.5 were each ~50% for cleaner air (PM2.5 < 10 μg/m3) but changed to ~60% and ~20%, respectively, for more polluted air (PM2.5 > 30 μg/m3). This signifies the role of SO4 2- in haze formation. Comparisons of data from this study with the Interagency Monitoring of Protected Visual Environments network suggest that SO4 2? is more regional than carbonaceous material and originates in part from upwind source regions. The light extinction coefficient is well correlated to PM2.5 mass plus water associated with inorganic salt, leading to a mass extinction efficiency of 7.6 ± 1.7 m2/g for hydrated aerosol. The most serious haze episode occurring between July 15 and 19, 1999, was characterized by westerly transport and recirculation slowing removal of pollutants. At the peak of this episode, 1-hr PM2.5 concentration reached ~45 μg/m3, visual range dropped to ~5 km, and aerosol water likely contributed to ~40% of the light extinction coefficient. 相似文献
2.
3.
Contamination of aquatic ecosystems with heavy metals has been receiving increased worldwide attention due to their harmful e ects
on human health and other organisms in the environment. Most of the studies dealing with toxic e ects of metals deal with single
metal species, while the aquatic organisms are typically exposed to mixtures of metals. Hence, in order to provide data supporting
the usefulness of freshwater fish as indicators of heavy metal pollution, it has been proposed in the present study to investigate the
bioaccumulation and depuration of chromium in the selected organs of freshwater fingerlings Cirrhinus mrigala, individually and in
binary solutions with nickel. The results show that the kidney is a target organ for chromium accumulation, which implies that it is also
the “critical” organ for toxic symptoms. The results further show that accumulation of nickel in all the tissues of C. mrigala is higher
than that of chromium. In addition, the metal accumulations of the binary mixtures of chromium and nickel are substantially higher
than those of the individual metals, indicating synergistic interactions between the two metals. Theoretically the simplest explanation
for an additive joint action of toxicants in a mixture is that they act in a qualitatively similar way. The observed data suggest that C.
mrigala could be suitable monitoring organisms to study the bioavailability of water-bound metals in freshwater habitats. 相似文献
4.
RM. Thirupathi R. Ben Ruben Jiju Antony 《International Journal of Sustainable Engineering》2019,12(2):95-107
Application of appropriate environmentally conscious manufacturing strategies enables the sustainable development of products and processes. Automotive component manufacturers recognise the potential of applying appropriate strategies for attaining Triple Bottom Line benefits. In this context, three strategies such as eco-efficiency, waste minimisation and material efficiency are being applied to minimise environmental impacts associated with the manufacture of automotive products and its associated processes. A case study of an automotive component manufacturing firm has been exemplified. After conducting the study, the potential environmental impact was reduced by 20% and eco-efficiency was improved by 13%. Further, improvements have been observed in terms of overall resource consumption and material efficiency. The overall power consumption was reduced by 18% and weight of the component was reduced by 11%. The study aimed at improving the sustainable performance of product by incorporating green and environmentally friendlier manufacturing practices.
Abbreviations: USEPA: United Nations Environmental Protection Agency; OECD: Organisation for Economic Co-operation and Development; WBCSD: World Business Council for Sustainable Development; Eco-QFD: Environmental Quality Function Deployment; WCED: World Commission on Environment and Development; LCA: Life Cycle Assessment 相似文献
5.
Lead is a widespread element and one of the persistent and cumulative pollutants of the environment. The present study deals with the bioaccumulation of lead and the influence of chelating agents, meso 2,3-dimercaptosuccinic acid (DMSA), D-Penicillamine and CaNa2EDTA in reducing the concentration of lead on the selected organs of Catla catla fingerlings for both acute and chronic exposures by using ICP-AES. It is inferred from the present findings that there was a correlation between environmental conditions and the heavy metal contents of the fish. The highest concentration of lead is found in kidney tissues and the lowest in muscle tissues. The accumulation pattern of lead in the selected organs of Catla catla is: kidney > liver > gill > brain > muscle. Also, it has been found that the treatment of chelating agents, DMSA, D-Penicillamine and CaNa2EDTA reduces the concentration of lead significantly for both acute and chronic exposures. The results also show that DMSA is the most effective chelator of lead in reducing the body burden of C. catla fingerlings. The observed data further indicate that C. catla could be suitable for monitoring organisms to study the bioavailability of water-bound metals in freshwater habitats. 相似文献
6.
7.
Stefaniak AB Hoover MD Day GA Dickerson RM Peterson EJ Kent MS Schuler CR Breysse PN Scripsick RC 《Journal of environmental monitoring : JEM》2004,6(6):523-532
Little is known about the physicochemical properties of beryllium aerosols associated with increased risk of beryllium sensitization and chronic beryllium disease (CBD). Such information is needed to evaluate whether airborne mass of beryllium is the appropriate metric of exposure or alternatively to provide a scientific basis for using information on particle size, surface area, and chemistry to support an improved exposure limit based on bioavailability through the inhalation and dermal routes of exposure. Thus, we used a suite of analytical techniques to characterize aerodynamically size-fractionated beryllium particles and powders that have been associated in epidemiological studies with higher prevalence of CBD. Aerosol particles were sampled from the ventilation systems of production lines for powders of beryllium metal and beryllium oxide and for ingots of copper-beryllium alloy. End product powders from the metal and oxide production lines were also collected.Particles released during production of beryllium metal were found to be complex, having heterogeneous composition, including reactive species such as fluorine. Powders from beryllium metal production were of high purity with only a minor component of beryllium oxide. Both particles and powders from oxide production were high-purity oxide. Particles released during production of copper-beryllium alloy were heterogeneous, being predominantly copper oxides. Thus, all particles and powders contain at least some beryllium in the form of beryllium oxide.These data justify efforts to thoroughly characterize beryllium aerosol properties when performing exposure assessments. The data also suggest that differences in particle chemical composition, size, number, and surface area may influence bioavailability of beryllium and contribute to risk of CBD. However, a scientific basis does not yet exist to replace mass as the current metric of exposure. 相似文献
8.
Donald M. Keagy William W. Stalker Charles E. Zimmer Richard C. Dickerson 《Journal of the Air & Waste Management Association (1995)》2013,63(6):270-280
A diffusion flame burner was operated to determine the effect of several parameters on the quantity of NOx and unburned hydrocarbons produced. The statistical analysis indicated the unburned hydrocarbon emissions to be dependent upon the rate of heat release in the system, the amount of excess combustion air, the fuel molecular structure, and the interaction between the fuel structure and the amount of excess air. Analysis of the NOx emissions, after an adjustment to a common temperature to eliminate the temperature effect, showed them to be dependent upon the fuel molecular structure and the amount of excess air. The NOx emissions reached a maximum at the conditions which yielded minimum unburned hydrocarbon emissions. Multiple regressions were made which yielded predicting equations for both the unburned hydrocarbon and the NOx for the apparatus used. 相似文献
9.
PL. RM. Palaniappan K. S. Pramod V. Vijayasundaram 《Environmental Chemistry Letters》2009,7(4):313-319
Heavy metal discharges to aquatic environment are of great concern due to their toxicity and accumulative behavior. Zinc is
an essential trace element required for different physiological functions and plays important role in cellular metabolism.
However, it becomes toxic when elevated concentrations are introduced into the environment. The aim of this work is to analyze
zinc induced biochemical changes in the brain tissues of Labeo rohita fingerlings using Fourier Transformation Infrared Spectroscopy. Several important features have been observed in the zinc
intoxicated brain tissues, namely, altered membrane lipid, altered protein profile and decreased glycogen content, indicating
an alteration in the lipid and protein profiles leading to modification in membrane composition. Further, it is observed that
the acute exposure to zinc causes some alteration in protein profile with a decrease in α-helix and an increase in random
coil structures. 相似文献
10.
Environmental Monitoring Of Remedial Dredging At The New Bedford Harbor, Ma, Superfund Site 总被引:1,自引:0,他引:1
Bergen BJ Nelson WG Mackay J Dickerson D Jayaraman S 《Environmental monitoring and assessment》2005,111(1-3):257-275
New Bedford Harbor (NBH), MA, is a Superfund site because of high polychlorinated biphenyl (PCB) concentrations in the sediment.
From April 1994 to September 1995, a remedial dredging operation (termed the “Hot Spot”) removed the most contaminated sediments
(PCB concentrations greater than 4000μg/g) from the upper harbor. During remediation, a monitoring program assessed the potential
environmental impacts to NBH and adjacent Buzzards Bay. The monitoring program was developed with input from federal, state,
and local authorities. Site-specific decision criteria were established to assess net PCB transport, water column toxicity,
and PCB bioaccumulation in blue and ribbed mussels (Mytilus edulis and Geukensia demissa, respectively). The remediation was completed without exceeding PCB net transport or acute toxicity effects specified in
the decision criteria. In addition, PCB bioaccumulation in mussels during this time period was not significantly greater than
pre- or post-operational measurements. The results indicated that approximately 14000 cubic yards of highly PCB contaminated
sediment were permanently removed with minimal environmental effects. The lessons learned during this operation, as well as
previous pilot studies at the site, will be used to make full-scale remedial efforts in NBH more efficient and environmentally
protective. 相似文献