ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1985.tb00167.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Experimental data from the Chemical Industry Institute of Toxicology (CIIT) are used to estimate the risk of squamous cell carcinoma of the nasal cavity in Fischer 344 (F344) rats over a range of ambient air concentrations of formaldehyde that includes current exposure guidelines for the workplace and home. These values are presented as a best estimate envelope obtained from five mathematical dose‐response formulations. The response of Sprague‐Dawley (SD) rats dosed at 15 ppm in a separate study at New York University is consistent with the predicted lifetime response for F344 rats at a slightly lower concentration (13–14 ppm). A dose‐related mortality effect beyond what is attributable to the occurrence of nasal carcinomas is found in F344 rats at all CIIT exposure levels (2, 6, and 15 ppm). There is no evidence of a mortality effect in B6C3F1 mice of the CIIT study, and data for SD rats of the NYU experiment are inconclusive. In the CIIT study, rats exposed to 15 ppm exhibited a high incidence of nasal cavity squamous cell carcinomas and polypoid adenomas. Polypoid adenomas were also observed with increased incidences at 2 ppm and 6 ppm. Statistical comparisons with matched controls, and the low historical rate of spontaneous occurrence both suggest that polypoid adenomas may be a risk to F344 rats at exposure levels below the current Occupational Safety and Health Administration (OSHA) standard of 3 ppm. Squamous cell carcinomas were observed in two mice exposed to 15 ppm. This finding may be biologically significant since this tumor is rare and has not been previously reported in 4932 untreated B6C3F1 mice from recent National Toxicology Program (NTP) feeding

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1985.tb00168.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

This article quantifies potential public health risks from tumor‐producing pollutants emitted from two synthetic‐fuel plants (direct liquefaction—Exxon Donor Solvent; and indirect liquefaction—Lurgi Fischer‐Tropsch) located at a representative site in the eastern United States. In these analyses gaseous and aqueous waste streams were characterized; exposures via inhalation, terrestrial and aquatic food chains, and drinking water supplies were modeled. Analysis suggested that emissions of “polycyclic aromatic hydrocarbons,”“aromatic amines,”“neutralN, O, Sheterocyclics,”“nitriles,” and “other trace elements” pose the largest quantifiable risks to public health. Data and analysis for these pollutant categories should be refined to more accurately match compound‐specific estimated exposure levels with tumorigenic potency estimates. Before these results are used for regulatory purposes, more detailed analysis for selected pollutant classes are needed, and more sophisticated aquatic exposure models must be developed. Also, differences in geographic scales among the environmental transport m

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1985.tb00169.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

The use of appropriately designed computer aids for policy could improve the standards of risk analysis and other quantitative policy analysis in several important ways. They could make it easier to treat uncertainties more thoroughly and systematically than is now typical. To do this, they should provide a broad variety of techniques for representing uncertain quantities as ranges of alternative values or as probability distributions, for propagating uncertainties through a model, for analyzing and comparing the impacts of different sources of uncertainty, and for displaying results in various numerical and graphic formats. A nonprocedural modeling language allowing interactive editing of input values and model structure could encourage exploration and progressive refinement of models, and comparison of alternative formulations. The integration of model documentation and explanatory text within the computer representation could encourage maintenance of consistency between different versions of the mathematical structure and their descriptions. It could also allow interactive scrutiny of the model assumptions and sensitivities by outside reviewers. We describe a particular system, Demos, designed to provide these facilities and test their usefulness. The use of Demos is illustrated by an analysis of the risks and optimal control level for a hypothetical air pollutant, with uncertainty about the population exposure, health effects, and control costs. This example demonstrates progressive refinement of a model, and various kinds of parametric and probabilistic uncertainty analysis. Demos is now being used by a growing number of risk analysts, students, and policy researchers in a wide variety of tasks.

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1985.tb00170.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Safety criteria for frequency of nuclear‐reactor accidents and for reactor‐induced risk to individuals and to society are evaluated on the basis of their comprehensiveness, clarity, recognition of uncertainty, practicability, defensibility, simplicity, and internal consistency. Many criteria were found to be comprehensive and practicable; few completely satisfied the other evaluation standards. A consensus inferred from the most favorably evaluated criteria would allow between 1.0time10‐4and 1.0time10‐3core melts per reactor year, between 1.0time10‐6and 2.0time10‐5fatalities per reactor year per individual, and a total exposure in the United States of between 1000 and 10,000 person rems per reactor year. This consensus is consistent with the criteria proposed i

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1985.tb00171.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

The basic purpose of probabilistic risk analysis is to make inferences about the probabilities of various postulated events, with an account of all relevant information such as prior knowledge and operating experience with the specific system under study, as well as experience with other similar systems. Estimation of the failure rate of a Poisson‐type system leads to an especially simple Bayesian solution in closed form if the prior probability implied by the invariance properties of the problem is properly taken into account. This basic simplicity persists if a more realistic prior, representing order of magnitude knowledge of the rate parameter, is employed instead. Moreover, the more realistic prior allows direct incorporation of experience gained from other similar systems, without need to postulate a statistical model for an underlying ensemble. The analytic formalism is applied to actual nuclear reactor dat

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1985.tb00172.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1985.tb00173.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1985.tb00174.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Recently, discrete probability distributions (DPDs) have been suggested for use in risk analysis calculations to simplify the numerical computations which must be performed to determine failure probabilities. Specifically, DPDs have been developed to investigate probabilistic functions, that is, functions whose exact form is uncertain. The analysis of defect growth in materials by probabilistic fracture mechanics (PFM) models provides an example in which probabilistic functions play an important role. This paper compares and contrasts Monte Carlo simulation and DPDs as tools for calculating material failure due to fatigue crack growth. For the problem studied, the DPD method takes approximately one third the computation time of the Monte Carlo approach for comparable accuracy. It is concluded that the DPD method has considerable promise in low‐failure‐probability calculations of importance in risk assessment. In contrast to Monte Carlo, the computation time for the DPD approach is relatively insensitive to the magnitude of the probability being estima

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1985.tb00175.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Review and analyses of three sources of data are presented indicating that 25% of hysterectomies are elective. Annual mortality associated with elective hysterectomy is estimated to be 319, or about 12,122 woman years. Cost‐benefit analyses of mortality, life expectancy, morbidity, psychological sequelae, as well as dollar expenditures, reveal high costs and relatively limited benefits. Explanations for this apparent anomaly in decision making are explored and include economic incentives, system structure, sexism, and cancer prophylaxis. Principles of risk perception are discussed in terms of potential biases associated with the cancer prophylaxis motive. It is suggested that physicians’judgements of risk may be more salient to the decision process than those of prospective patie

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1985.tb00176.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY