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981.
This article Introduces a technology for the simultaneous control of the emissions of PCDD/ PCDF, hydrochloric acid (HCI) and nitrogen oxides (NOx) from municipal solid waste (MSW) Incinerators. The technology uses ammonia as the control medium for all three pollutants. In this paper, the theoretical basis of the technology Is discussed. In addition, a bench-scale experiment proving the theory Is described and the practical application of the theory Is presented. Finally, further steps which are being taken to develop the technology for commercial application are detailed.  相似文献   
982.
An overview of the methods used for the isolation and characterization of organic matter in natural waters is presented. Commonly used techniques for the concentration and isolation of organic matter from water, such as preparative chromatography, ultrafiltration and reverse osmosis, and the methods used to analyze the organic matter obtained by these methods are reviewed. the development of methods to obtain organic matter that is associated with fractions of the dissolved organic carbon other than humic substances, such as organic bases, hydrophilic organic acids and colloidal organic matter are discussed. Methods specifically used to study dissolved organic nitrogen and dissolved organic phosphorous are also discussed.  相似文献   
983.
Methods are discussed for describing patterns of current wet and dry deposition under various scenarios. It is proposed that total deposition data across an area of interest are the most relevant in the context of critical loads of acidic deposition, and that the total (i.e., wet plus dry) deposition will vary greatly with the location, the season, and the characteristics of individual subregions. Wet and dry deposition are proposed to differ in such fundamental ways that they must be considered separately. Both wet and dry deposition rates are controlled by the presence of the chemical species in question in the air (at altitudes of typically several kilometers in the case of wet deposition, and in air near the surface for dry). The great differences in the processes involved lead to the conclusion that it is better to measure wet and dry deposition separately and combine these quantifications to produce “total deposition” estimates than to attempt to derive total deposition directly. A number of options for making estimates of total deposition to be used in critical loads assessment scenarios are discussed for wet deposition (buckets and source receptor models) and for dry deposition (throughfall, micrometeorology, surrogate surfaces and collection vessels, inference from concentrations, dry-wet ratios, and source-receptor models). The research described in this article has been funded by the US Environmental Protection Agency. This document has been prepared at the EPA Environmental Research Laboratory in Corvallis, Oregon, through contract #68-C8-0006 with ManTech Environmental Technology, Inc., and Interagency Agreement #1824-B014-A7 with the U.S. Department of Energy and at Oak Ridge National Laboratory managed by Martin Marietta Energy Systems, Inc., under Contract DE-AC05-84OR21400 with the US Department of Energy. Environmental Sciences Division Publication No. 3905. It has been subjected to the Agency’s peer and administrative review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.  相似文献   
984.
A field study was conducted on a Lowell silty loam soil of 2.7% organic matter at the Kentucky State University Research Farm, Franklin County, Kentucky. Eighteen universal soil loss equation (USLE) standard plots (22 x 3.7 m each) were established on a 10% slope. Three soil management practices were used: (i) class-A biosolids (sewage sludge), (ii) yard waste compost, each mixed with native soil at a rate of 50 ton acre(-1) on a dry-weight basis, and (iii) a no-mulch (NM) treatment (rototilled bare soil), used for comparison purposes. Devrinol 50-DF "napropamide" [N,N-diethyl-2-(1-naphthyloxy) propionamide] was applied as a preemergent herbicide, incorporated into the soil surface, and the plots were planted with 60-day-old sweet bell pepper seedlings. Napropamide residues one hour following spraying averaged 0.8, 0.4, and 0.3 microg g(-1) dry soil in sewage sludge, yard waste compost, and no-mulch treatments, respectively. Surface runoff water, runoff sediment, and napropamide residues in runoff were significantly reduced by the compost and biosolid treatments. Yard waste compost treatments increased water infiltration and napropamide residues in the vadose zone compared to sewage sludge and NM treatments. Total pepper yields from yard waste compost amended soils (9187 lbs acre(-1)) was significantly higher (P < 0.05) than yield from either the soil amended with class-A biosolids (6984 lbs acre(-1)) or the no-mulch soil (7162 lbs acre(-1)).  相似文献   
985.
Abandoned‐mine drainage (AMD) is drainage flowing from or caused by surface mining, deep mining, or coal refuse piles that is typically highly acidic with elevated levels of dissolved metals. AMD results from the interactions of certain sulfide minerals with oxygen, water, and bacteria. Passive treatment systems have been used to remediate AMD at numerous sites throughout the United States. The theory behind passive treatment is to allow naturally occurring chemical, biological, and physical reactions that aid in AMD treatment to occur in the controlled environment of the system, not in the receiving water body. The advantages of passive treatment over active treatment include lower operation and maintenance costs, virtually no use of chemicals, and minimal energy consumption. The disadvantages are that smaller volumes of water are treated than with active systems, and discharges with high concentrations of dissolved metals and extremes of pH may have to be treated several times within one system to treat the discharge. AMD passive treatment systems include aerobic treatment systems and anaerobic treatment systems. It is estimated that it will take 50 years and between $5 billion and $15 billion to remediate all AMD problems in Pennsylvania. © 2001 John Wiley & Sons, Inc.  相似文献   
986.
The main objective of this investigation was to monitor concentrations of seven metals (Cd, Pb, Ni, Mo, Cu, Zn, and Cr) in the fruits, leaves, stem, and roots of Capsicum annuum L. (cv. Xcatic) plants grown under four soil management practices: yard waste (YW), sewage sludge (SS), chicken manure (CM), and no-much (NM) bare soil. Elemental analyses were conducted using inductively coupled plasma mass spectrometer. Pb and Cd concentrations in soil amended with YW, SS, and CM were not significantly different (P < 0.05) compared to NM soil, whereas Mo and Cu concentrations were significantly greater in YW compared to SS, CM, and NM treatments. Concentrations of Cd in the fruits of plants grown in NM soil were greater compared to the fruits of plants grown in other treatments. Total Ni concentration (sum of Ni in all plant parts) in plants grown in NM bare soil was greater than in plants grown in SS-, YW-, and CM-amended soils. Values of the bioaccumulation factor indicated that pepper fruits of plants grown in YW, SS, and CM did not show any tendency to accumulate Pb, Cr, and Ni in their edible fruits.  相似文献   
987.
988.
Jharia (India) a coal mining town has been affected by the consequences of mining and associated activities. Samples of outdoor fallen dust were collected at different locations of Jharia covering four different zones: commercial, petrol pump, high traffic, and residential areas. The dust samples were analysed for different trace elements (As, Cd, Co, Cr, Cu, Mn, Ni, Pb, Se, and Zn). The highest concentration of the elements in the dust samples are Mn (658 mg/kg), Zn (163.6 mg/kg), Cr (75.4 mg/kg), Pb (67.8 mg/kg), Ni (66 mg/kg), Cu (56.8 mg/kg), Co (16.9 mg/kg), As (4.1 mg/kg), and Cd (0.78 mg/kg). The concentration of selenium was below detection limit. Except Cd, contents of all the other elements in the dust samples were significantly lower in the residential area. High amount of Ni (145 mg/kg) and Pb (102 mg/kg) was observed in the high traffic and petrol pump areas, respectively. The exposure risk assessment strategies are helpful in predicting the potential health risk of the trace elements in the street dust. Selected receptors for risk assessment were infants, toddlers, children, teens, and adults. The calculated hazard quotient (HQ) for lifetime exposure was <1.0 for all the elements studied, indicating no risks from these elements for adults Among the receptors, toddlers were found to be more vulnerable, with HQ for Co, Cr, and Pb > 0.1. The finding predicts potential health risk to toddlers and children.  相似文献   
989.
Tertiary-butyl acetate (TBAC) (CAS No. 540-88-5) is an organic solvent with a potential for occupational and environmental exposure as a result of its use in industrial coatings, adhesives, inks, and degreasers. The objective of these studies was to extend the toxicological database upon which health hazard and risk assessments of TBAC can be made. The metabolism of TBAC was studied in rats exposed by inhalation for 6?h to concentrations of 100 or 1000?ppm. There was an evidence of partial saturation of TBAC absorption and metabolism at some concentration below 1000?ppm. Approximately 5% of the low dose and 26% of the high dose was expired without change within 12?h, while the retained material was rapidly metabolised and excreted, mostly in the urine, within 24?h. Very little radioactivity remained in the tissues after day 7. The metabolism of TBAC appears to follow two major routes: hydroxylation of the tertiary-butyl moiety to form 2-hydroxymethylisopropyl acetate and ester hydrolysis to form tertiary-butyl alcohol (TBA). A minor route involves oxidation of the acetate moiety. Based on the proportion of metabolites that can clearly be assigned to one or the other major pathway, hydroxylation of the tertiary-butyl moiety prevails at 100?ppm, while hydrolysis of the ester bond predominates at 1000?ppm.

Based on nose-only inhalation exposure of rats to TBAC for 6?h, the LC50 for males and females combined is approximately 4200?ppm. Clinical signs included exaggerated breathing, staggering, tremors, and lethargy approximately 1?h after the exposure, but all surviving rats appeared normal from 24?h until the end of the 14?day observation period. An LC50 was not identified for mice. After exposure of whole body for 6?h to 3000?ppm, the highest concentration tested, all mice were prostrate for most of the exposure time, but there were no deaths.

Groups of five male and five female Sprague-Dawley rats were exposed nose-only to 0, 100, 400, or 1600?ppm TBAC 6?h?day?1 5 days?wk?1 for 2?weeks. There were no effects on body weight, feed or water consumption, or necropsy findings. Male rats exposed to 1600?ppm had increased liver weights and hypertrophy of centrilobular hepatocytes. An increased proportion of cortical tubule cells with hyaline droplet accumulation was observed in all treated groups of males. Groups of five male and five female CD-1 mice were exposed whole body to 0, 190, 375, 750, or 1500?ppm TBAC 6?h?day?1 for 14 consecutive days. There were no effects on body weight, feed consumption, or necropsy findings. Liver weights were increased in female mice at 750 and 1500?ppm. Minimal hypertrophy of centrilobular hepatocytes was found in female mice at 375, 750, and 1500?ppm and in male mice at 1500?ppm TBAC.

TBAC did not induce gene mutations in bacterial tests with strains of S. typhimurium and E. coli. Further, there was no evidence of clastogenic activity from tests either for the induction of chromosomal aberrations in human lymphocytes in vitro in the presence or absence of S9 mix or for the induction of micronuclei in bone marrow cells of rats exposed by inhalation for 6?h to 1600?ppm TBAC.

These results are relevant to human health risk assessment and are discussed in the context of previous studies. The weight of the scientific evidence supports the conclusion that TBAC has lower acute toxicity than previously suggested, that it is rapidly excreted when inhaled, and that neither TBAC nor its TBA metabolite are genotoxic or potential human carcinogens.  相似文献   
990.
Increasing demand for water in domestic, agricultural, and industrial sectors necessitates exploitation of water either in the form of groundwater or from natural resources. To safeguard the long-term sustainability of water resources and their utilization, the quality of water has to be periodically monitored and determined for various characteristics, especially when the sources are polluted, such as Damodar river. Central Institute of Mining and Fuel Research (CIMFR), Dhanbad, is carrying out research work on coal and its utilization and associated environmental concerns. The blood stream of life for the whole Jharia Coalfield is none other than the river Damodar. CIMFR's campus also depends exclusively on river Damodar for meeting its demand of drinking water. This study is a general survey toward the characteristics of Damodar river water, with special emphasis on the pollutant parameters, and evaluation of the treatment process being carried out at the institute for potability. Damodar river water is indeed affected by the disposal of the wastes without any pre-treatment by different coal-based industries established in its basin. The quantity of dissolved and suspended solids, total hardness, chemical oxygen demand, and coliform bacterial count are higher in Damodar water due to the disposal of the waste/effluents from coal-washing plants, coke ovens, cement, and other industries, but well within the permissible limit which is probably attributable to the high-carrying capacity of the river. The river is still not that much affected as it is usually apprehended, and it can be well utilized for potable and domestic purposes after simple treatment.  相似文献   
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