A Rating of the Major Air Pollutants and Their Sources by Effect

The available national annual air pollution emissions are based on mass. Different air pollutants have greatly different toxicities per unit mass, hence the emissions should be rated by effect, not by mass, so that more sensible priorities can be set in control research and regulation. Effect factors are derived from the health effect literature indirectly by using the national ambient air quality standards. The resulting analysis by effects shows transportation to be still the largest source as it is in the mass analysis while hydrocarbons become the largest pollutants by effect compared to carbon monoxide being the largest pollutant by mass.     

Desulfurization of Flue Gases in A Fluidized Bed of Modified Limestone

This publication concerns the dry removal of SO₂ from gases using limestone absorbents. It reports bench-scale experiments made with commercial samples of powdered limestone (CaCO₃) activated by addition of a cheap substance, namely CaCl₂. The absorption was carried out in a fluidized bed traversed by the flue gases, between 600° and 900° C. The degree and rate of transformation of CaCO₃ to CaSO₄ in the presence of SO₂ and air have been compared for unmodified and modified absorbents. Initial rates of reaction, and the variation of the rate of absorption with time have been measured. The influence of the SO₂ content of the gas has been assessed. At 700° C, the maximum degree of transformation of activated limestone to sulfate exceeds 90%, whereas untreated CaCO₃ transforms only to 16–20%. At the same temperature, more than 90% of SO₂ contained In a gas carrying 0.35% SO₂ is removed. Because of the much smaller quantity of solid absorbent required, dry absorption processes based on the modified absorbents might get renewed interest. The modified absorbents might also be used for in situ absorption in fluidized bed combustion, in which the temperatures are in the range studied in the present paper.     

Prediction of thermal hazards from fireballs

Various models of fireball diameter have been evaluated by statistical techniques. The model of Gayle for fireball diameter estimation showed good agreement between the predicted and experimental data. The models relating to fireball duration, transmissivity and view factor have been selected based on their relative merits. A user interactive computer program has been developed to predict thermal hazards from fireballs in chemical process industries.     

Disposal of contaminated sediments/soils in MSW landfills: Need to consider the true cost

A disturbing trend among governmental agencies is the remediation of so‐called “nonhazardous” contaminated sediments/soils by deposition in minimum‐design Subtitle D municipal solid waste (MSW) landfills or landfills with equivalent design. This is done despite the fact that, in terms of protection of public health and environmental quality, the designation “nonhazardous” is misleading at best, and the fact that minimum‐design Subtitle D landfills as being allowed will not ensure protection of groundwater quality for as long as the buried wastes remain a threat. Although acknowledged in the regulatory documentation and exposed in the writings of a few in the scientific/engineering community, the environmental and public health issues that will inevitably be faced at minimum‐design Subtitle D landfills are underplayed, and even misrepresented, to the public. Discussion of relevant issues, as well as remarkable omissions, characterized the October 2004 United States Army Corps of Engineers (US ACE)/United States Environmental Protection Agency (US EPA)/Sediment Management Work Group (SMWG) conference,” Addressing Uncertainty and Managing Risk at Contaminated Sediment Sites.” This article addresses many of those neglected issues. © 2005 Wiley Periodicals, Inc.     

Industrial facility deactivation: A proactive approach for reducing costs and liabilities

For both private corporations and military branches, downsizing and consolidation are becoming more commonplace. A range of environmental concerns must be addressed to effectively implement a consolidation program. A facility deactivation program can often become a minefield for an organization. Responsible personnel are typically inexperienced with the process, and this can lead to costly mistakes. This article provides insight into this topic based on experience gained with a multifacility program and related environmental issues. It emphasizes the importance of detailed, up-front, proactive project planning; a solid program management system; and accurate identification of project objectives and deliverables.     

IMPACTS OF CLIMATE CHANGE ON MISSOURI RWER BASIN WATER YIELD1

ABSTRACT: Water from the Missouri River Basin is used for multiple purposes. The climatic change of doubling the atmospheric carbon dioxide may produce dramatic water yield changes across the basin. Estimated changes in basin water yield from doubled CO₂ climate were simulated using a Regional Climate Model (RegCM) and a physically based rainfall‐runoff model. RegCM output from a five‐year, equilibrium climate simulation at twice present CO₂ levels was compared to a similar present‐day climate run to extract monthly changes in meteorologic variables needed by the hydrologic model. These changes, simulated on a 50‐km grid, were matched at a commensurate scale to the 310 subbasin in the rainfall‐runoff model climate change impact analysis. The Soil and Water Assessment Tool (SWAT) rainfall‐runoff model was used in this study. The climate changes were applied to the 1965 to 1989 historic period. Overall water yield at the mouth of the Basin decreased by 10 to 20 percent during spring and summer months, but increased during fall and winter. Yields generally decreased in the southern portions of the basin but increased in the northern reaches. Northern subbasin yields increased up to 80 percent: equivalent to 1.3 cm of runoff on an annual basis.     

THE IMPACT OF URBANIZATION ON THE DISTRIBUTION OF HEAVY METALS IN BOTTOM SEDIMENTS OF THE SADDLE RIVER1

ABSTRACT: A three-year study has been conducted on a 4.6 mile stretch of the Saddle River near Lodi, New Jersey. The primary objectives of this investigation were (1) to provide baseline information on the concentration and distribution of heavy metals in bottom sediments of the Saddle River; (2) to qualitatively evaluate which parameters affect this distribution; and (3) to determine the effect of urbanization on the concentration and distribution of these materials. Significant enrichments of several heavy metals were observed in bottom sediments of the lower Saddle River near Lodi, New Jersey, as compared to the upper Saddle River. Attempts to correlate metal concentrations in bottom sediments with chemical-oxygen demand were not successful in demonstrating a relationship between these two factors. Metal concentrations were found to be strongly dependent upon particle size. In general, metal concentrations in bottom sediments increased with decreasing partical diameter. However, metals enrichment was observed to be considerably greater in the larger sediment fractions studied (>420μ) than the smaller sediment fractions as one proceeded downstream through the urban area. Since the larger sediment fractions are least effected by scour and transport they may best reflect the effect of urbanization on the distribution of heavy metals over an extended period of time at a given location.     

Improvements in the two-dimensional nuclear magnetic resonance spectroscopy of humic substances

Understanding pollutant sorption, bioremediation of these pollutants, and their interactions with humic substances requires knowledge of molecular-level processes. New developments with nuclear magnetic resonance (NMR) experiments and labeled compounds have improved the overall understanding of these mechanisms. The advancements made with two-dimensional NMR show great promise, as structural information and hydrogen-carbon bond connectivity can be discerned. This communication presents the application of improved two-dimensional NMR methods, the double quantum filtered (DQF) correlation spectroscopy (COSY) and echo/anti-echo heteronuclear single quantum coherence (HSQC) experiments, for use in structural studies of humic substances. Both experiments were found to produce significant improvements over the conventional COSY and heteronuclear multiple quantum coherence (HMQC) experiments that have been previously employed in similar studies. The more sensitive echo/anti-echo HSQC experiment produced more cross-peaks with higher resolution when compared with the HMQC spectra. The DQF-COSY significantly suppressed the diagonal signals and allowed numerous signals previously hidden in the standard COSY experiment to be observed. These improvements will aid current characterization strategies of humic substances from soils, sediments, and water and their subsequent reactions with pollutants and microorganisms.