摘要:

ABSTRACTThe high temperature product distributions from reactions of methane and methyl chloride have been measured under pyrolysis, preignition oxidation and flame conditions. For pyrolysis and preignition data, 3% fuel/zero oxygen or stoichiometric oxygen/10% N2/Ar were heated behind reflected shocks to temperatures between 1200-2600 K at a density of approximately 2.5 ± 0.25 × 10−5mol/cm3. Flame studies were conducted at atmospheric pressure for methane/air and methyl chloride/methane/air mixtures with equivalence ratios of 1.15 and 1.35 and for four methyl chloride/methane ratios ranging from pure methane to pure methyl chloride.Methyl chloride is more easily decomposed than methane in either pyrolysis or preignition oxidation. This is because of the lower bond dissociation energy of methyl chloride (Do(CH3-Cl) = 334 kJ/mol) as compared to methane (Do(CH3-H) = 435 kJ/mol). In the flame environment, the methane and methyl chloride disappear at approximately the same rate. The presence of chlorine decreases the measured ethane concentration and promotes the formation of acetylene which may explain the propensity of soot formation from chlorinated hydrocarb

ISSN:0738-6168    

DOI:10.1089/hzw.1984.1.1

年代:1984

数据来源: MAL

摘要:

ABSTRACTThe US Environmental Protection Agency (USEPA) has chosen over 500 hazardous waste disposal sites for the National Priorities List (NPL) under the Comprehensive Environmental Response, Compensation and Liability Act. The priority sites were chosen utilizing the Hazard Response System (HRS) model that was designed to numerically score the relative health and environmental risks at uncontrolled hazardous waste sites.Although the HRS model assigns three scores to a hazardous waste facility (migration, fire and explosion, and direct contact), only the migration hazard mode score was used as a criterion for selection of sites for the NPL. The migration hazard mode score is a composite of separate scores for the potential migration of contaminants by routes involving groundwater, surface water, and air.This paper discusses the details of the HRS, and by way of example some of the methodological limitations and inconsistencies in the model that limit its usefulness. For example, the HRS does not consider hydraulic gradient in determining the groundwater route score. In addition, unlike the groundwater and surface water route scores, the air migration route score does not reflect the potential for release of contaminants to the air if direct evidence of release is lacking.Once sites are targeted for cleanup, decisions on the extent and method of cleanup must be made. USEPA has not yet developed a model similar to the HRS to aid in determining the extent of remediation necessary to protect public health once sites have been chosen for priority attention. The elements that must be considered in the development of such a model are discussed.

ISSN:0738-6168    

DOI:10.1089/hzw.1984.1.19

年代:1984

数据来源: MAL

摘要:

ABSTRACTA possible mechanism by which chemical compounds found in industrial waste products may cause tissue injury is through potentiation of damage by free radical formation. In these studies we have used a model system of rats exposed to normobaric hyperoxia to test for effects of chemical compounds that may potentiate or change fluxes of free radicals on animal survival or lung injury, lung Superoxide dismutase, catalase, glutathione peroxidase, glucose-6-phosphate dehydrogenase and glutathione. The chemical compounds tested, including diethylmaleate (DEM), diethyldithiocarbamate (DDC), disulfiram and nitrofurantoin, all potentiated oxygen toxicity but produced their effects through different mechanisms related to changes in free radical levels. Our model system may be useful to test a variety of chemical compounds of industrial wastes for possible potentiating effects on lung injury caused by free radical generation.

ISSN:0738-6168    

DOI:10.1089/hzw.1984.1.35

年代:1984

数据来源: MAL

摘要:

ABSTRACTFluid bed incinerators have been used to dispose of a wide variety of hazardous wastes including refinery waste streams, surplus explosives, PCB-contaminated transformer oil and oxychlorination process wastes. Both inert and catalytic solids have been employed separately and in mixed beds or sequential reactors. However, in most catalytic processes, the nature of the catalyst and the process operating conditions are proprietary. In this paper, the catalytic oxidation kinetics of three chlorinated hydrocarbons are determined in an externally pumped recycle reactor with a commercially available chromia on alumina catalyst. Conversion of the chlorocarbon species in the reactor effluent are monitored by gas chromatography for temperatures in the range 350 to 550°C. Regression of the measured catalytic oxidation rates yields rate expressions which are first order in the chlorocarbon concentration, between zero and first order in oxygen concentration and exhibit some inhibition by water. Some catalyst poisoning by halogen containing species is observed. However, the poisoning phenomena can be minimized by control of the H/Cl ratio in the mixed waste feed stream

ISSN:0738-6168    

DOI:10.1089/hzw.1984.1.41

年代:1984

数据来源: MAL

摘要:

ABSTRACTFreshly collected waste water from a pulp and paper mill was tested in aSalmonellafluctuation assay before and after secondary treatment (biotreatment) in an aerated lagoon. Dose-related mutagenicity was found for the untreated and unconcentrated sample in the fluctuation assay but not in the standard plate incorporation test, and mutagenic activity was not detected after biotreatment. The fluctuation assays were performed without S9 for metabolic activation.

ISSN:0738-6168    

DOI:10.1089/hzw.1984.1.67

年代:1984

数据来源: MAL

摘要:

ABSTRACTSoft shell clams (Mya arenaria) were collected from tidal flats in southeastern New England, and their heamolymph analyzed for the presence of neoplastic cells. The prevalence of neoplasia varied from 10-90% with the highest prevalence found in New Bedford Harbor, a site containing high levels of pollutants, including PCBs, heavy metals and industrial wastes. Further analyses showed that quantifiable levels of Aroclors 1242 and 1254, congeners of PCB, could be detected in neoplastic cell extracts derived only from clams collected from New Bedford Harbor. These studies suggest an association between the high prevalence of disease and the location of soft shell clams at or near an industrially contaminated site.

ISSN:0738-6168    

DOI:10.1089/hzw.1984.1.73

年代:1984

数据来源: MAL

摘要:

ABSTRACTThis paper describes the philosophy and methodology used by Polaroid Corporation in managing its solvent wastes. The emphasis is on distillation and recycling of solvents via careful process planning and development. Techniques are described which show that a non-chemical company can develop procedures with a small but efficient technical group.

ISSN:0738-6168    

DOI:10.1089/hzw.1984.1.83

年代:1984

数据来源: MAL

摘要:

ABSTRACTOnce appropriate environmental samples have been collected and prepared for genotoxicity bioassay, we recommend a tier/battery structure for evaluating their potential genotoxicity. Tier one is composed of well validated, well establishedin vitrogenotoxicity assays. The assay systems included are: Bacterial Mutation, Mammalian Cell Gene-Point Mutation, Mammalian Cell Cytogenetic Assays and Hepatocyte DNA Repair. Tier two which is intended for confirmation is composed primarily ofin vivobioassays exceptingin vitrocellular transformation. Thein vivobioassays in tier two are: Drosophilia Recessive Lethal, Micronucleus Test, Dominant Lethal Assay, Bone Marrow Sister Chromatid Exchange, Chromosome Aberration andIn Vivo/In VitroHepatocyte DNA Repair. Due to expected limited sample size, we recommend a "priority"in vitrogenotoxicity testing scheme. The priority bioassays are theAmes/SalmonellaMutation Assay, the Chinese Hamster Ovary Sister Chromatid Exchange (CHO/SCE) and Aberration Test and the Primary Hepatocyte DNA Repair Test. Depending upon the outcome of testing in the "priority" genotoxicity assays, additional tests from tiers one and two are recommended.

ISSN:0738-6168    

DOI:10.1089/hzw.1984.1.93

年代:1984

数据来源: MAL

摘要:

ABSTRACTIn October 1983, residents of Cape Cod, Massachusetts participated in the region's first program for the collection of household hazardous wastes. This program was organized by the Cape Cod Planning and Economic Development Commission (CCPEDC) in an attempt to provide a continual method for preventive maintenance of the area's ground water aquifer, the sole source of drinking water to the fifteen towns comprising Barnstable County (Cape Cod). The widespread use and improper disposal of small quantities of hazardous chemicals used in the home is a suspected source of contamination of the aquifer by synthetic organic chemicals such as trichloroethane and dichlorobenzene. An analysis of this waste disposal problem on Cape Cod, a discussion of appropriate solutions, and results of a successful region-wide collection program are presented.

ISSN:0738-6168    

DOI:10.1089/hzw.1984.1.111

年代:1984

数据来源: MAL

摘要:

ABSTRACTHyde Park Landfill was used from 1953 to 1975 as a disposal site for chemi cal wastes, including chlorinated hydrocarbons. A compacted clay cover was installed in 1978 and a tile leachate collection system, in 1979. The present treatment of Hyde Park leachate by conventional activated carbon technology, although producing a suitable quality effluent, is unacceptable for economic and technical reasons. The cost forecast for purchase of carbon alone is 21 million dollars over the next ten years. In addition, carbon adsorption of compounds of interest is not efficient because of competition for adsorptive sites by less hazardous compounds. As a result, technologies were investigated which would remove these competing compounds. Biological waste treatment in a Sequencing Batch Reactor (SBR) was selected as the most cost effective alternative. Biological degradation of the lechate in the SBR was tested both with and without the addition of Occidental organism HCV. Between 85 and 95% of the total organic carbon (TOC) was removed by the SBR operating strategies investigated. Any increased TOC removal obtained from organism addition was small and will require additional research before the full potential can be evaluated. Nevertheless, use of biological waste treatment in the SBR is expected to result in substantial cost savings because of the extended life of the activated carbon beds.

ISSN:0738-6168    

DOI:10.1089/hzw.1984.1.123

年代:1984

数据来源: MAL