Distribution risk

KH Watanabe, FY Bois. Interspecies extrapolations of physiological pharmacokinetic parameter distributions. Risk Anal 16 741-754, 1996. 

The company hazard review process was revised in June 1997 to combine reactive chemicals, loss prevention, distribution risk review, EHS review for safety and loss, project risk review, and technology center review. 

Paxton MB, Chinchilli VM, Breet SM, et al. 1994a. Leukemia risk associated with benzene exposure in the pliofilm cohort I. mortality update and exposure distribution. Risk Analysis 14(2) 147-154. 

As implied by the name, distributional risk assessments use the entire data distribution to calculate exposure and risk. As described for the EPA Tier 1 assessment [5], a distributional analysis is not necessarily a probabilistic analysis. The EPA Tier 1 acute dietary assessment produces a dietary exposure distribution using the entire food consultation distribution and point estimates of residue concentration. There is no probability sampling in the Tier 1 assessment. 

Distribution risk management Compliance review and training Carrier safety Handling and storage Emergency preparedness... 

Insurance companies began centuries ago in marketplaces, where individuals or corporations met to discuss, combine, and distribute risk. In 1688, individuals who provided shipping insurance often gathered at a coffee shop on Tower Street in London. To encourage their patronage, the ovmer of the shop provided them with reliable shipping information. The presence of the insurers attracted sailors, ship owners, and other merchants and before long the coffee shop became a commercial center for maritime trade. The name of the coffee shop ovmer was Edward Lloyd, and it was his Edward Lloyd s Coffee House that evenmaUy became Lloyd s of London. 

Scenarios, such as sites, usually imply a risk to the same (more or less) groups of individuals (he it on-site or off-site) at any time. Distributed risks, for example, pipelines across wide areas, rail journeys, tunnels, with rapidly changing identities of individuals are the scenarios for which the involuntary risk approach becomes limited. An individual may be exposed for 2 min per annum (traveling through a tunnel) whereas, at any moment, there may be KX) people at risk. The Societal Risk approach (Section 2.4) is then more appropriate. 

Table 2.1 shows how various combinations of risk factors distribute risk across different populations and turn our attention to different aspects of the problem. As Table 2.1 suggests, analysts can represent the potential threat to humans (as deaths, lost limbs, broken fingers, and torn ligaments). Or they can shift the focus of attention to calculate the probable effect upon institutions (production, profit, and investment) or environments (roof falls, explosions, and fires). By shifting the focus of attention from human to non-human factors, unscrupulous risk analysts can reduce the magnitude of risk mathematically without actually changing the number of deaths or injuries in the social world. When analysts focus on non-human elements, improved health and safety is not a necessary outcome of a mathematically reduced risk." ... 

When ethanoi is present, the risk of separation is much less than with methanol. Nevertheless, the ethanol should be relatively anhydrous (less than 3000 ppm water) moreover, if a fuel containing ethanol comes in contact with a water layer, a migration of ethanol toward the water is observed creating a fuel quality problem manifested by lower octane number and an environmental quality problem in that the water will need to be treated. Distribution of ethanol-based fuels requires extra precaution to ensure dryness in distribution systems. 

The first application of the Gaussian distribution is in medical decision making or diagnosis. We wish to determine whether a patient is at risk because of the high cholesterol content of his blood. We need several pieces of input information an expected or normal blood cholesterol, the standard deviation associated with the normal blood cholesterol count, and the blood cholesterol count of the patient. When we apply our analysis, we shall anive at a diagnosis, either yes or no, the patient is at risk or is not at risk. 

Cholesterol is biosynthesized in the liver trans ported throughout the body to be used in a va riety of ways and returned to the liver where it serves as the biosynthetic precursor to other steroids But cholesterol is a lipid and isn t soluble in water How can it move through the blood if it doesn t dis solve in if The answer is that it doesn t dissolve but IS instead carried through the blood and tissues as part of a lipoprotein (lipid + protein = lipoprotein) The proteins that carry cholesterol from the liver are called low density lipoproteins or LDLs those that return it to the liver are the high-density lipoproteins or HDLs If too much cholesterol is being transported by LDL or too little by HDL the extra cholesterol builds up on the walls of the arteries caus mg atherosclerosis A thorough physical examination nowadays measures not only total cholesterol con centration but also the distribution between LDL and HDL cholesterol An elevated level of LDL cholesterol IS a risk factor for heart disease LDL cholesterol is bad cholesterol HDLs on the other hand remove excess cholesterol and are protective HDL cholesterol IS good cholesterol... 

Since significance tests are based on probabilities, their interpretation is naturally subject to error. As we have already seen, significance tests are carried out at a significance level, a, that defines the probability of rejecting a null hypothesis that is true. For example, when a significance test is conducted at a = 0.05, there is a 5% probability that the null hypothesis will be incorrectly rejected. This is known as a type 1 error, and its risk is always equivalent to a. Type 1 errors in two-tailed and one-tailed significance tests are represented by the shaded areas under the probability distribution curves in Figure 4.10. 

In order to complete an assessment of risk, a probabiUty must be determined. The easiest method for representing failure probabiUty of a device is an exponential distribution (2). 

Conduct Hazard Analysis and Risk Assessment. Ahazardis any biological, chemical, or physical property that may cause an unacceptable consumer health risk. AH of the potential hazards in the food chain are analyzed, from growing and harvesting or slaughtering to manufacturing, distribution, retailing, and consumption of the product. 

As part of TSCA, EPA can require the testing of any chemical if there is the possibiUty of an unreasonable risk to health or environment or if there is significant human or environmental exposure. If the substance poses an unreasonable risk, EPA can prohibit the manufacture, processing, or distribution of the substance limit the amount of the substance that can be manufactured, processed, or distributed prohibit a particular use for the substance limit the concentration of the substance during manufacture, processing, or distribution regulate disposal methods for the substance and require manufacturers to maintain records of process and to conduct tests to assure compliance with EPA rules. 

The Toxic Substances Control Act (TSCA) was enacted in 1976 to identify and control toxic chemical ha2ards to human health and the environment. One of the main provisions of TSCA was to estabUsh and maintain an inventory of all chemicals in commerce in the United States for the purpose of regulating any of the chemicals that might pose an unreasonable risk to human health or the environment. An initial inventory of chemicals was estabhshed by requiring companies to report to the United States Environmental Protection Agency (USEPA) all substances that were imported, manufactured, processed, distributed, or disposed of in the United States. Over 50,000 chemical substances were reported. PoUowing this initial inventory, introduction of all new chemical substances requires a Premanufacturing Notification (PMN) process. To be included in the PMN are the identity of the new chemical, the estimated first year and maximum production volume, manufacture and process information, a description of proposed use, potential release to the environment, possible human exposure to the new substance, and any health or environmental test data available at the time of submission. In the 10 years that TSCA has been in effect, the USEPA has received over 10,000 PMNs and up to 10% of the submissions each year are for dyes (382)... 

Statistical Criteria. Sensitivity analysis does not consider the probabiUty of various levels of uncertainty or the risk involved (28). In order to treat probabiUty, statistical measures are employed to characterize the probabiUty distributions. Because most distributions in profitabiUty analysis are not accurately known, the common assumption is that normal distributions are adequate. The distribution of a quantity then can be characterized by two parameters, the expected value and the variance. These usually have to be estimated from meager data. 

A common form of societal risk measure is an F-N curve, which is normally presented as a cumulative distribution plot of frequency F... 

A measure of risk to a group of people. It is most often expressed in terms of the frequency distribution of multiple casualty events... 

The measures of dimensional variability from Conformability Analysis (CA) (as described in Chapters 2 and 3), specifically the Component Manufacturing Variability Risk, q, is useful in the allocation of tolerances and subsequent analysis of their distributions in probabilistic design. The value is determined from process capability maps for the manufacturing process and knowledge of the component s material and geometry compatibility with the process. In the specific case to the th component bilateral tolerance, it was shown in Chapter 3 that the standard deviation estimates were ... 

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