Hazard characterization

While the standard combined chronic/cancer bioassay is helpful in hazard identification, it contributes in a more limited extent to hazard charactraization (i.e., the likelihood of causing adverse effects in humans). However, with some modification in the context of evolving integrated and hierarchical test strategies for groups of chemicals or individual substances, carcinogenicity bioassays have potential to contribute considerably additionally in this context. For example, as discussed 

Mechanistic data for cancer are considered in hazard characterization in the context of mode of induction of toxic effects. A postulated mode of action is a biologically plausible sequence of key events leading to an observed effect supported by robust experimental observations and mechanistic data. It describes key cytologi-cal, genetic, and biochemical events— that is, those that are both measurable and necessary to the observed effect. Mode of action is contrasted with mechanism of action, which generally involves a much greater understanding of the molecular basis for an effect. 

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Wlien utility work is located in an exclusion zone, are workers who enter the area exposed to hazardous materials Hazard characterization and exposure assessment performed by a competent person may show that the area surrounding the equipment and an access corridor leading to the equipment can be cleaned so that the utility workers can work in the... 

Critical to hazard characterization is the identification of hazards and the assessment of possible worker exposure. This can be accomplished in a variety of ways. As described before, one commonly used technique is a JHA with project teams that include the worker. The information collected is used by the SSHO and the radiation control officer to develop an appropriate hazard control and protection strategy. 

The HASP should contain the information obtained during the preparation phase concerning hazard characterization and exposure potential. If the information has gaps, ranges, or is incomplete, this should be taken into consideration so that proper protective measures are taken. If and when new information is discovered, this should be included as part of the hazard characterization as an amendment. 

Hazard controls include engineering and administrative controls and PPE. Hazard characterization is a tool that is used to develop hazard controls and safe work practices and procedures and to make sure that the appropriate PPE is selected for each job. 

Work zones are designed to control access to actual and anticipated hazards. Work zone positioning is based on hazard characterization and exposure assessment. Anticipated work activity, potential releases, and the amount of contaminant dispersion are important for delineating these zones [3]. 

FIGURE 7-1. Hazard Characterization Exposure Assessment Strategy... 

LLNL was contracted to use the results of the Seismic Hazard Characterization Project (SHCP). (NUREG/CR-5250) to calculate the seismic hazard at the SRS using methods similar to the Seismic Owners Group-Electric Power Research Institute (SOG/EPRI) and LLNL the (wo seismic hazard estimates for the SRS are different. The SHCP (Savy, 1988) seismic hazani results are typically within a factor of 5. Results of the seismic analysis are given in Table 11.3-6... 

Bernreuter, D. L. et al., Seismic Hazard Characterization of 69 Nuclear Plant Sites East of the Rocky Mountains, Methodology, Input Data, and Commparisons with Previous Results, Vol 1-8, January 1989,... 

Hazard characterization, or dose-response characterization, by using experimental animals to reveal target organs and toxic doses, and the shape of the dose-response curve... 

Hazard characterization and delineation of dose-effect or dose-response relationships. 3. Assessment of exposure 4. Risk characterization... 

Hazard characterization is a quantitative or semi-quantitative evaluation of the nature, severity, and duration of adverse health effects associated with biological, physical, or chemical agents that may be present in food. The characterization depends on the nature of the toxic effect or hazard. Eor some hazards such as genotoxic chemicals, there may be no threshold for the effect and therefore estimates are made of the possible magnitude of the risk at human exposure level (dose-response extrapolation). 

Stages in hazard characterization according to the European Commission s Scientific Steering Committee are (1) establishment of the dose-response relationship for each critical effect (2) identification of the most sensitive species and strain (3) characterization of the mode of action and mechanisms of critical effects (including the possible roles of active metabolites) (4) high to low dose (exposure) extrapolation and interspecies extrapolation and (5) evaluation of factors that can influence severity and duration of adverse health effects. 

Dose-response assessment is the process of obtaining quantitative information about the probability of human illness following exposure to a hazard it is the translation of exposure into harm. Dose-response curves have been determined for some hazards. The curves show the relationship of dose exposure and the probabihty of a response. Since vahdated dose-response relationships are scarce, various other inputs are used to underpin the hazard characterization phase of risk assessment. 

Risk characterization is the last step in the risk assessment procedure. It is the quantitative or semi-quantitative estimation, including uncertainties, of frequency and severity of known or potential adverse health effects in a given population based on the previous steps. Risk characterization is the step that integrates information on hazard and exposure to estimate the magnitude of a risk. Comparison of the numerical output of hazard characterization with the estimated intake will give an indication of whether the estimated intake is a health concern. ... 

The degree of confidence in the final estimation of risk depends on variability, uncertainty, and assumptions identified in all previous steps. The nature of the information available for risk characterization and the associated uncertainties can vary widely, and no single approach is suitable for all hazard and exposure scenarios. In cases in which risk characterization is concluded before human exposure occurs, for example, with food additives that require prior approval, both hazard identification and hazard characterization are largely dependent on animal experiments. And exposure is a theoretical estimate based on predicted uses or residue levels. In contrast, in cases of prior human exposure, hazard identification and hazard characterization may be based on studies in humans and exposure assessment can be based on real-life, actual intake measurements. The influence of estimates and assumptions can be evaluated by using sensitivity and uncertainty analyses. - Risk assessment procedures differ in a range of possible options from relatively unso-... 

Cl. Dybing, E. et al.. Hazard characterization of chemicals in food and diet dose response, mechanisms and extrapolation issues. Food Chem. Toxicol, 40, 237, 2002. 

In this chapter the risk assessment is briefly introduced. Risk assessment is divided into four steps hazard identification, hazard characterization, exposure assessment, and risk characterization. This chapter also highlights five risk and life cycle impact assessment models (EUSES, USEtox, GLOBOX, SADA, and MAFRAM) that allows for assessment of risks to human health and the environment. In addition other 12 models were appointed. Finally, in the last section of this chapter, there is a compilation of useful data sources for risk assessment. The data source selection is essential to obtain high quality data. This source selection is divided into two parts. First, six frequently used databases for physicochemical... 

Due to this, it is necessary to assess the risk to human health and the environment due to the exposure to these chemical additives. In this chapter the impacts that a substance can cause to a certain receptor (humans and the environment) and the harms to the receptor at different exposure levels are identified in hazard identification and hazard characterization steps, respectively. Exposure assessment takes into account the amount, frequency, and duration of the exposure to the substance. Finally, risk characterization evaluates the increased risk caused by such exposure to the exposed population. 

Hazard characterization (or dose-response assessment) is the qualitative and, as far as possible, quantitative description of the inherent properties of an agent or situation having the potential to cause adverse effects. This step should include a dose-response assessment that describes the severity of adverse effects (the responses) related to the amount and condition of exposure to an agent (the dose). 

Hazard characterization is the estimation of the relationship between the dose of a substance and the effects observed. To evaluate this relationship, the following studies can be performed (in order of reliability) ... 

For the two aforementioned steps, hazard identification and hazard characterization, data adequacy is of high importance. The data adequacy is defined by the reliability and the relevance of the data for human risk assessment [3],... 

Chemical Allergy Hazard Identification, Hazard Characterization, and Risk Assessment... 

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