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The project developed a sensitive and practical test for human exposures to genotoxic agents. The test is based on observable changes in the 340 bp subsequence produced by Eco-R1 restriction of DNA obtained from peripheral leukocy...
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The project developed a sensitive and practical test for human exposures to genotoxic agents. The test is based on observable changes in the 340 bp subsequence produced by Eco-R1 restriction of DNA obtained from peripheral leukocytes. DNA is extracted from human leukocytes subsequent to in vitro genotoxic challenge by ionizing radiation or various chemical agents. The 340 bp alphoid sequence is subjected to Eco-R1 restriction, and secondary treatment to induce breakage at damaged sites. Breakage is determined by the distribution of a labeled 340 bp probe after electrophoresis and hybridization. Alternative methods of quantifying breakage are concurrently evaluated when appropriate. The development of a practical assay for genetic damage in the occupational setting would have a number of practical implications, the most immediate being a supplement to conventional personnel monitoring. While an assay for general genetic damage would most probably lack agent specificity, the agent is known in many routine occupational situations and in many cases of accidental exposure. Another application would be the assessment of genetic damage in exposure conditions so complex that conventional monitoring techniques cannot produce a meaningful interpretation of the situation.
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Problems associated with estimation of human exposures to ambient air pollution are discussed. Ideally the authors would prefer to have some indication of actual dose. For most pollutants this is not presently feasible. Specific p...
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Problems associated with estimation of human exposures to ambient air pollution are discussed. Ideally the authors would prefer to have some indication of actual dose. For most pollutants this is not presently feasible. Specific problems discussed are adequacy of outdoor monitors: the need to correct for exposures and time spent indoors: the need to have particle size distributions described and the chemistry of the particles presented. These indicate the need to develop lightweight accurate and reliable personal monitors.
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The Conceptual Framework for the U.S. EPAs National Exposure Research Laboratory (NERL) provides a foundation for addressing NERLs research mission and its scientific leadership goals. The document defines the domain of exposure s...
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The Conceptual Framework for the U.S. EPAs National Exposure Research Laboratory (NERL) provides a foundation for addressing NERLs research mission and its scientific leadership goals. The document defines the domain of exposure science; describes the uses for exposure science within the EPA; and provides the principles for developing and implementing NERL research. NERLs mission is to conduct human health and ecological exposure research that provides the pertinent databases, predictive models, and analytical tools necessary for the EPA to carry out its mission. Fulfilling the EPAs mission to protect human health and the environment carries with it the challenge of understanding exposures for tens of thousands of chemical contaminants, a wide range of biological stressors, and many physical stressors. Exposure science provides the Agency with the fundamental knowledge and tools necessary to assess potential exposures for emerging environmental threats and to mitigate exposures to known contaminants and stressors. The Conceptual Framework articulates the importance of exposure science in both assessing and managing risks. Internally, the document creates our identity as the National Exposure Research Laboratory and provides a common understanding and a common language for exposure research and its applications. The document also communicates NERLs mission; organizational goals; and processes for strategic planning, communication and organizational development. Externally, the document is intended to define and advance the field of exposure science for both the EPA and the broader scientific community.
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The document is a list of the names and addresses of researchers who work in the field of human exposure. The document also lists areas of human exposure that a particular researcher is involved with. Telephone and fax numbers are...
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The document is a list of the names and addresses of researchers who work in the field of human exposure. The document also lists areas of human exposure that a particular researcher is involved with. Telephone and fax numbers are given if available.
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In the document the likelihood that unleaded gasoline vapors are carcinogenic to humans is evaluated. From carcinogenicity data in animals, an estimate is made of the magnitude of cancer risk a person would experience, under the a...
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In the document the likelihood that unleaded gasoline vapors are carcinogenic to humans is evaluated. From carcinogenicity data in animals, an estimate is made of the magnitude of cancer risk a person would experience, under the assumption that gasoline vapors are carcinogenic. All biological factors believed to be relevant to carcinogenesis are reviewed. A quantitative analysis of cancer incidence in the two long-term animal gasoline inhalation studies is performed, an upper-bound cancer risk potency estimate is calculated, and the uncertainties in the estimate are discussed. The major conclusions are: (1) although employment in the petroleum refineries is possibly associated with cancers of the stomach, respiratory system, and lymphopoietic and hematopoietic tissues, exposure to gasoline cannot be implicated as a causative agent because of confounding exposure to other chemicals and inadequate information on gasoline exposure; (2) the occurrence of liver cancer in female mice and kidney cancer in male rats provides 'sufficient' evidence in animals that inhalation of wholly aerosolized gasoline is carcinogenic; and (3) gasoline vapors from vehicle refueling might be less carcinogenic than indicated by animal experiments using wholly aerosolized gasoline, if the less volatile components, which are apparently responsible for acute kidney toxicity, also contribute to the observed carcinogenic response.
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This report, Data Sources Available for Modeling Environmental Exposures in Older Adults, focuses on information sources and data available for modeling environmental exposures in the older U.S. population, defined here to be peop...
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This report, Data Sources Available for Modeling Environmental Exposures in Older Adults, focuses on information sources and data available for modeling environmental exposures in the older U.S. population, defined here to be people 60 years and older, with an emphasis on those aged greater than 65. The information was gathered as part of the U.S. Environmental Protection Agencys (EPAs) Aging Initiative project. In general, this report contains the same type of information found in EPAs Exposure Factors Handbook (e.g., NCEA, 1997a,b) but with older adults as the sole population subgroup of interest. We envision that this report will be used to inform exposure assessors about the data available for modeling exposures to older people. In addition, the data enable scientists to check or evaluate results obtained from the modeling assessments for older adults, such as determining whether the distribution of ventilation (breathing) rates seen in a particulate matter (PM) intake dose rate assessment, for example, is realistic or not. The same is true for their time spent in motor vehicles, outdoors, or indoors. Intra- and interindividual variability measures are discussed for all of these parameters, where available. In the situation where a time-averaged exposure model is used, the data in this report can provide aggregate information on many of the inputs needed for that type of model. This report can be a useful source book on older adult exposure modeling, similar to the Exposure Factors Handbook. The report is centered on the inputs needed for two of EPAs inhalation exposure models, the Air Pollution Exposure (APEX) model and the Stochastic Human Exposure and Dose Simulation (SHEDS) model. The report also includes a review of physical activity data available for evaluating model outputs. In addition, the report includes discussion of how general health status of older adults might affect exposure to environmental contaminants and an assessment of the interactions between exposure and possible impacts of older people on environmental loadings. The latter category focuses on pharmaceutical discharges into bodies of water. The appendix provides information on developing conditional probabilities for those individuals that have both arthritis and one or more co-morbidities often associated with it. Data shortcomings and research needs are described for each topic covered. Finally, this report presents detailed information on changes in time use, activity, and physiology as people age. It is important to understand these changes because older adults are becoming a larger proportion of the total U.S. population, and more and more societal resources will be directed toward their maintenance.
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The Environmental Methods Testing Site (EMTS) Project is being conducted by the Environmental Protection Agency with the cooperation of the state of Georgia, the state of Tennessee, Hamilton County, Tennessee, and the city of Chat...
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The Environmental Methods Testing Site (EMTS) Project is being conducted by the Environmental Protection Agency with the cooperation of the state of Georgia, the state of Tennessee, Hamilton County, Tennessee, and the city of Chattanooga. The concept is to establish one well-characterized site, designated as the Chattanooga Metropolitan Statistical Area, at which to conduct a series of studies designed to improve environmental monitoring methods and methods for assessing human exposure to toxic substances in the environment. The project, planned to span a 5- to 15-year period, is being conducted in support of the Toxic Substances Control Act of 1976. The Chattanooga area is well suited as a site to conduct human exposure methodology studies. Site users have the support of local government and of EMTS Project participants who provide a management team, information gathering services, computerized data management and analysis, and quality assurance assistance. The Chattanooga area provides a hospitable climate, a population and geographical size allowing statistically valid sampling of subpopulations, isolation from other cities, a diverse industrial base, a large existing data base, and modern technical and logistical support facilities.
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The purpose of the paper is to compare the results of two studies in which the respiratory responses of children and adults to acute ozone (O3) exposure were measured. Forty-two 18-30 year old males were exposed for 2.5 hours in a...
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The purpose of the paper is to compare the results of two studies in which the respiratory responses of children and adults to acute ozone (O3) exposure were measured. Forty-two 18-30 year old males were exposed for 2.5 hours in a controlled environmental chamber to either 0.0 or 0.12 ppm O3 while performing intermittent heavy exercise. Twenty-two 8-11 year old males were exposed in a similar manner to both air and 0.12 ppm O3. Measures of respiratory symptoms and function were made before and after exposure. Adults experienced an increase in the symptom cough and decrements in forced vital capacity and some measures of forced expiratory flow. Children experienced similar decrements in pulmonary function, but had no increase in symptoms. The authors concluded that as measured by pulmonary function children appear to be no more responsive to O3 exposure than are adults and may experience fewer symptoms.
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Estimates of an individual's ozone exposure were generated for a panel of 51 asthmatic study subjects using ambient ozone concentrations, the relationships observed between the ambient concentrations and the concentrations found i...
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Estimates of an individual's ozone exposure were generated for a panel of 51 asthmatic study subjects using ambient ozone concentrations, the relationships observed between the ambient concentrations and the concentrations found in each of two broad classes of environments and knowledge of the individual's movement through these locations. These estimates are compared to actual ozone concentrations observed during personal monitoring of 30 of the individuals. Earlier comparisons disclosed that the estimated hourly means were in much better agreement with the observed hourly means than were the ambient hourly values. The hourly maxima observed in the personal monitoring for each of three environments are compared to the exposure estimates. The ability of the exposure model to estimate average hourly exposures for individuals has been previously tested. In the present work, the ability of the exposure model to estimate peak exposures within an hour is evaluated, using measurements of ozone concentration obtained at 5 minute intervals during the personal monitoring program as a standard. One-hour exposure estimates based on fixed site measurements are evaluated as well. Sources of error within the data set are identified but appear to not seriously affect the results. The exposure model produces one-hour estimates which are 7-12 ppb below the observed personal exposures.
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Chlorozotocin (CZT; NSC 178248) is a cytostatic agent that is used in the investigational treatment of cancers of the stomach, large intestine, pancreas and lung; melanoma; and multiple myeloma. It has been given intravenously (i....
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Chlorozotocin (CZT; NSC 178248) is a cytostatic agent that is used in the investigational treatment of cancers of the stomach, large intestine, pancreas and lung; melanoma; and multiple myeloma. It has been given intravenously (i.v.) at doses of 100 to 225 mg/m2. Potential exposure of health professionals may occur during the preparation and administration of CZT. Potential occupational exposure may also occur for workers involved in the formulation and packaging ofthe pharmaceutical.
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