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1.
Abstract

During the 1950s and 1960s, hundreds of thousands of underground storage tanks (and above-ground storage tanks) containing petroleum products and hazardous chemicals were installed. Many of these tanks either have been abandoned or have exceeded their useful lives and are leaking, thereby posing a serious threat to the nation’s surface and groundwater supplies, as well as to public health. Cleaning up releases of petroleum hydrocarbons or other organic chemicals in the subsurface environment is a real-world problem,

Biological treatment of hydrocarbon-contaminated soil is considered to be a relatively low-cost and safe technology; however, its potential for effectively treating recalcitrant wastes has not been fully explored. For millions of years, microorganisms such as bacteria, fungi, actinomycete, protozoa, and others have performed the function of recycling organic matter from which new plant life can grow.

This paper examines the biological treatment technology for cleaning up petroleum product-contaminated soils, with special emphasis on microbial enzyme systems for enhancing the rate of biodegradation of petroleum hydrocarbons. Classifications and functions of enzymes, as well as the microbes, in degrading the organic contaminants are discussed. In addition, the weathering effect on biodegradation, types of hydrocarbon degraders, advantages associated with enzyme use, methods of enzyme extraction, and future research needs for development and evaluation of enzyme-assisted bioremediation are examined.  相似文献   

2.
The extensive application of 2,4-D herbicides to wheat and other agricultural crops in the states of Washington and Oregon can produce "off-target" damage when the 2,4-D formulations are transported by the atmosphere to sensitive crops, such as grapes. During May-June of 1973 and April-June of 1974, a 2,4-D monitoring network in south-central Washington collected samples for subsequent herbicide analysis. The daily, 24 hr field samples were collected with differential Impactor-impinger air samplers and were routinely analyzed in the analytical laboratory by electron-capture gas chromatography. In addition, gas chromatography/mass spec-trometry was employed for positive identification of the 2,4-D esters and for comparative quantitative analysis. The complete sampling and analytical methodology, the 2,4-D concentration data for 1973 and 1974, the agricultural 2,4-D application records and crop Injury reports, and the concomitant meteorological data are described in this paper.  相似文献   

3.
The proportions of manganese to other metals in samples of airborne fine particles taken at some sites in California have increased greatly since the beginning of 1985. Here, data are presented which indicate that the addition of manganese to leaded gasoline is largely responsible for this increase. Concentrations of manganese, silicon, titanium, iron, lead and other elements in airborne particles were measured using energy-dispersive X-ray fluorescence analysis. Coefficients of correlation among levels of manganese, iron and lead measured at twenty sites in California were calculated. Levels of manganese and iron are generally highly correlated because of the presence of large amounts of these elements in the earth’s crust. Levels of airborne manganese and lead at sites In Southern California are often highly correlated, suggesting a vehicular source of manganese. Observed manganese concentrations are apportioned into two major sources: the earth’s crust and motor vehicles. The apportionment indicates that vehicular emissions of manganese may account for a significant part of the total at urban sites in Southern California. At most other sites, the contribution from vehicles is found to be far smaller than that from the earth’s crust.  相似文献   

4.
This paper describes a method for establishing a priority list of airborne carcinogens within a state Jurisdiction. In this case it was necessary to identify, from among hundreds of potential candidates, the five to ten materials of greatest potential concern in California as airborne carcinogens.

Because no previous inventory of carcinogens in California existed, published lists, rankings, and assessments of national scope were used to identify candidates. By systematic manipulation and comparison of these data sources, 47 materials of some notoriety were chosen for closer scrutiny. This selection was pared to 22 candidates largely by eliminating those which had very little production and use in California. (Substances primarily used as pesticides were excluded from the scope of this study.) The remaining candidates were then ranked by additive . and multiplicative algorithms and by a panel of experts. The results of these rankings were combined to produce a single selection of 11 priority candidates. In alphabetical order, they are arsenic, asbestos, benzene, cadmium, carbon tetrachloride, chloroform, ethylene dibromide, ethylene dichloride, N-nitrosoamines, perchloroethylene, and polycyclic aromatic hydrocarbons. In continuing studies, a baseline emissions inventory is being prepared, and a source testing program is being designed.  相似文献   

5.
Air quality standards have existed in California for almost six years. They have become an important part of the State’s air pollution control program.

The two principal uses of the standards have been to establish the goals for controlling motor vehicle emissions and to provide a basis for evaluating air quality throughout the State. The standards have also proved to be valuable as a means of communicating on air pollution problems with legislators, administrators, the press, the public, and dischargers of pollutants.

Lack of adequate data on the effects of varying concentrations of contaminants of concern in air pollution is a serious limitation in any effort to establish air quality standards.It is important that this data be obtained.

The concept of employing air quality standards as administrative goals is not unique to the air pollution field but is part of a broad trend to utilize standards for insuring a satisfactory environment. Those engaged in the air pollution field can expect to see increasing emphasis on such standards.

Air quality standards do not provide a magic formula for eliminating air pollution; they are but one element in a comprehensive program. They have limitations and are no better than the data upon which they are based. The standards, however, can play an important role in preserving satisfactory air quality and protecting man’s health.

In using air quality standards, one should keep in mind the comments of H. W. Streeter5 on water quality standards—“Let us devise them, try them, revise them, and apply them, but also remember that they are but ’feeble instruments of the human will’ and like all other such tools are made to be discarded for better ones when they become worn out.“  相似文献   

6.
Pollution prevention/waste minimization is a win-win-win situation for government, industry, and the public, which offers more than just protection of the environment for all. Industry gains from reduced capital and operating costs, reduced liabilities, cleaner and safer working conditions, conservation of energy and material resources, and the opportunity for government and industry to work together in a cooperative manner. However, a number of regulatory barriers exist which discourage pollution prevention/waste minimization. This paper provides examples from the aluminum, chemical, petroleum, and wood treating industries of how these regulatory barriers become disincentives. To promote pollution prevention/waste minimization, Congress and the U.S. EPA need to reexamine those RCRA provisions which support a command and control strategy that creates the barriers. The barriers include the distinction between value and valueless materials, offsite storage requirements prior to reuse/recycle, the “Derived from Rule”, the “Burning for Fuel Rule”, land ban technology standards, and RD&;D restrictions. A new RCRA Pollution Prevention/Waste Minimization subtitle is proposed to eliminate or minimize these barriers.  相似文献   

7.
On June 18, 19, and 20, 1970, two aircraft, a rawinsonde, two pibal stations, and four ground stations provided simultaneous samples of total oxidant, temperature, and winds up to 8000 ft in an area extending from Santa Monica, Calif., east to Redlands and north across the San Bernardino Mountains. It was shown that photochemical oxidant formed in the marine layer is vented up the slopes and over the crest of the San Bernardino Mountains during the day. Layers of high oxidant concentrations were detected above the inversion base, suggesting that some pollution is vented up the slopes and subsequently advected back to the south. The diurnal changes in the temperature inversion also contribute to the high concentration found above the inversion base. These processes result in multi-layers of pollution. The study suggests that oxidant air pollution is transported up to 80 mi to forested mountains, where severe damage to conifer species has been documented.  相似文献   

8.
The air basin between the Mississippi River and the bluff in Illinois is of particular interest for this report. The autumnal temperature profiles were measured by a wiresonde. Each day through September and October had an inversion at dawn and/or dusk. During the entire three months, inversions 5° or more occurred at dawn 64% of the mornings, those 10° or more occurred 45% of the mornings; and those 15° occurred 23% of the mornings. Under intense inversions, the topography holds cool air in the basin like water in a saucer, and currents within this 200-ft air layer comprise a quasi-closed circulation system. A frequent pattern of air circulation involves a northwestward surface drift in the basin, with a southwest wind aloft and an updraft over St. Louis. This forms a horizontal semi-vortex along the river, concentrating the heavier particulates near East St. Louis and Granite City. Multiple evidence showed this pattern to exist one morning among four. Business interests would use the basin for industrial expansion, but air resource planners prefer to keep new air pollution sources out of this low land.  相似文献   

9.
10.
Abstract

Ambient air quality data were analyzed to empirically evaluate the effects of reductions of volatile organic compounds (VOCs) and oxides of nitrogen (NOx) emissions on weekday and weekend levels of ozone (O3; 1991–1998) and particulate NO3 - (1980–1999) in southern California. Despite significantly lower O3 precursor levels on weekends, 20 of 28 South Coast Air Basin (SoCAB) sites (28 of all 78 southern California sites) showed statistically significant higher mean O3 levels on Sundays than on weekdays (p < 0.01); 49 of the remaining 50 sites showed no significant differences between mean weekday and Sunday peak O3 levels. We also observed no statistically significant differences between mean weekday and weekend concentrations of particulate NO3 - or nitric acid (HNO3, the precursor of particulate NO3 -). Averaged over sites, the mean Sunday NOx and nonmethane hydrocarbon concentrations were 25–41% and 16–30% lower, respectively, than on weekdays. Site-to-site differences between weekend and weekday mean peak hourly O3 levels were related to whether O3 formation was limited by the availability of NOx. A thermodynamic equilibrium model predicts that particulate NO3 - levels would decrease in response to a reduction of HNO3, and that particulate ammonium NO3 - formation was not limited by the availability of ammonia. The similarity of mean weekday and weekend levels of NO3 - therefore did not result from limitations on the formation of particulate NO3 - from its precursor, HNO3.  相似文献   

11.
The trends in oxidant air quality in the South Coast Air Basin of California are of great interest because of the high oxidant levels in the region. In this work, we have updated the trends for daily peak oxidant levels in the entire Basin and at two sites, Azusa and San Bernardino. Since the daily oxidant levels are highly dependent on the local meteorology, we have determined trends under fixed meteorological conditions. We previously applied this approach to data from the 1971 to 1979 period. In the present work, we found that, for the 1971–1981 period, the oxidant trends basinwide and in Azusa are downward while the trend in San Bernardino is flat. An additional finding of this study is that in recent years the basinwide daily peak oxidant concentration has been occurring in San Bernardino with increasing frequency. The overall decrease in and eastward movement of the basinwide maxima are discussed in relation to the trends in the emissions of reactive hydrocarbons and nitrogen oxides over the time period as well as the predictions of smog chamber experiments.  相似文献   

12.
Abstract

The purpose of this study was to assess the effectiveness of a new generation of high-volume, ceiling-mounted high-efficiency particulate air (HEPA)-ultraviolet (UV) air filters (HUVAFs) for their ability to remove or inactivate bacterial aerosol. In an environmentally controlled full-scale laboratory chamber (87 m3), and an indoor therapy pool building, the mitigation ability of air filters was assessed by comparing concentrations of total bacteria, culturable bacteria, and airborne endotoxin with and without the air filters operating under otherwise similar conditions. Controlled chamber tests with pure cultures of aerosolized Mycobacterium parafortuitum cells showed that the HUVAF unit tested provided an equivalent air-exchange rate of 11 hr?1. Using this equivalent air-exchange rate as a design basis, three HUVAFs were installed in an indoor therapy pool building for bioaerosol mitigation, and their effectiveness was studied over a 2-year period. The HUVAFs reduced concentrations of culturable bacteria by 69 and 80% during monitoring periods executed in respective years. The HUVAFs reduced concentrations of total bacteria by 12 and 76% during the same monitoring period, respectively. Airborne endotoxin concentrations were not affected by the HUVAF operation.  相似文献   

13.
The purpose of this investigation was to determine the effects of meteorological conditions and specific air pollutants on the viability of airborne algae and protozoa. Such investigations will be of interest to medical researchers because these organisms are the source of many allergies. The three air pollutants that were continuously measured and recorded were sulfur, hydrocarbons, and particulate maiter. During the experiment, 25 different species of algae and 19 species of protozoa were collected from the atmosphere and cultured at the Westinghouse Environmental Station Laboratory in Raleigh, North Carolina. The algae and protozoa were collected over a one-year period (Jan-Dec 1971) by using a sequential sampler that moved air through a membrane filter at the rate of 15 ft3/hr. Every two hours a new filter was sequentially moved in to replace the old one. The results indicated a relationship between wind speed, wind direction, temperature, dew-point, particulate matter, barometric pressure, and rainfall to the percent frequency of positive culture tubes and number of cells/ft3 of air. Further studies are necessary to determine the interrelationships between the physical and chemical character of various air masses and their effect on the survival of algae and protozoa.  相似文献   

14.
15.
Numerous oxidant-injured ponderosa pine and other tree species have been detected in the lower elevation forests of the southern Sierra Nevada mountain range of California in the Sequoia National Forest, Sequoia-Kings Canyon National Parks, and on state and private lands. Affected pines were observed in a broad band following the many ridges that rise above the Central Valley floor to the 1900-2600 m elevation. Slight symptoms of ozone chlorotic mottle on ponderosa pine appeared from about 1000 m altitude, increased in severity as elevation increased and then diminished in severity above 2600 m. An apparent east to west gradient of disease was discovered; severity lessened as distance from the Central Valley increased. Atmospheric monitoring in three forested sites suggests that ozone occurs in doses sufficient to elicit symptoms of this widespread disease.  相似文献   

16.
17.
Data obtained by the Continuous Air Monitoring Program (CAMP) in six cities during two years are summarized. Six gaseous pollutants were monitored in Cincinnati, Chicago, New Orleans, Philadelphia, San Francisco, and Washington, D. C. during 1962 and 1963. The data serve as a basis for describing several contrasts and similarities in the nature of air pollution experienced in six cities, which represent a broad geographical and climatological range of urbayi environments. Specific topics covered are: typical pollutant levels, patterns of daily and seasonal variations, and unusual phenomena such as atmospheric stagnation periods and photochemical smog formation.  相似文献   

18.
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20.
Airborne lidar (light detection and ranging) data were collected during two field programs in 1989 in the border metropolitan area comprising El Paso (U.S.) and Ciudad Juarez (Mexico). These data were utilized to provide estimates of suspended particulate distributions in the presence of historical data with limited spatial and temporal density in the U.S. and almost no historical data in Mexico. The resulting information was used to help ascertain the magnitude and spatial extent of the particulate air quality problem and to help determine the number and disposition of recommended permanent particulate monitors in the area. The results support the hypothesis that, given a few representative measurements for calibration, airborne lidar might be used in specific situations to develop detailed concentration patterns and to provide useful estimates of pollutant flux, when combined with appropriate measurements of wind velocity profiles. Such information, in turn, should be useful for the development of control strategies for potential alleviation of particulate air quality problems.  相似文献   

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