Risk assessment procedure

Fig. 1. Flow chart representing the complete hazard identification and risk assessment procedure.

The hazard analysis and risk assessment procedure can be appHed at any stage in the lifetime of a process or procedure including research and... 

There are a large number of standard methods suitable for each stage in the hazard analysis and risk assessment procedure. The selection of the proper method depends on several factors. Some of these are the type of process, the stage in the lifetime of the process, the experience and capabiUties of the participants, and the step in the procedure that is being examined. Information regarding the selection of the proper procedure is available in an excellent and comprehensive reference (1). 

The remaining step in the hazard identification and risk assessment procedure shown in Figure 1 is to decide on risk acceptance. For this step, few resources are available and analysts are left basically by themselves. Some companies have formal risk acceptance criteria. Most companies, however, use the results on a relative basis. That is, the results are compared to another process or processes where hazards and risks are weU-characterized. 

Usually risk assessment procedure, discussed in more detail later (see Chapter 6), is divided into four different stages or steps (see Fig. 

Ferrari B, Mons R, Vollat B, Fraysse B, Paxeus N, Lo Giudice R, Pollio A, Garric J (2004) Environmental risk assessment of six human pharmaceuticals are the current enviommental risk assessment procedures sufficient for the protection of the aquatic environment Environ Toxicol Chem 23 1344-1354... 

An exercise comprising individual statements, some describing everyday events and others more unusual, designed to increase participants awareness and understanding of the risk assessment procedure, both for themselves and others. 

Asphyxiants, See also Gases, 72, 151, 153 Assessment, See also Risk assessment procedure, 141 risk to heath, 81, 140 Asthma, See also Sensitizers, 10, 76 Atomic weights, 543 Atoms, 10, 21... 

FIGURE 7.1.3 Process of hazard identification, Source SSC, First report on the harmonisation of risk assessment procedures, Part 1, October 2000. )... 

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-... 

Franklin, C. (1985) Occupational exposure to pesticides and its role in risk assessment procedures used in Canada, in Dermal Exposure Related to Pesticide Use, Honeycutt, R., Zweig, G., and Ragsdale, N.N., Eds., ACS Symposium Series No. 273, American Chemical Society, Washington, D.C. 

The terminology used varies considerably. Hazard identification and risk assessment are sometimes combined into a general category called hazard evaluation. Risk assessment is sometimes called hazard analysis. A risk assessment procedure that determines probabilities is frequently called probabilistic risk assessment (PRA), whereas a procedure that determines probability and consequences is called quantitative risk analysis (QRA). 

Figure 10-1 Hazards identification and risk assessment procedure. Adapted from Guidelines for Hazards Evaluation Procedures (New York American Institute of Chemical Engineers, 1985), pp. 1-9.

The procedure described by Figure 10-1 is frequently abbreviated based on circumstances. If failure rate data on the applicable equipment are not available, then risk assessment procedures cannot be fully applied. Most plant sites (and even subunits within a plant) modify the procedure to fit their particular situation. 

These quantitative values of exposure to heavy metals in the relevant pathway are of importance for environment risk assessment procedures in the forest ecosystems areas. 

In accordance with this zoning the environmental risk assessment procedure should be developed, especially those related to exposure pathway and risk characterization steps. 

Figure 23-1 shows the hazards identification and risk assessment procedure. The procedure begins with a complete description of the process. This includes detailed PFD and P I diagrams, complete specifications on all equipment, maintenance records, operating procedures, and so forth. A hazard identification procedure is then selected (see Haz-ard Analysis subsection) to identify the hazards and their nature. This is followed by identification of all potential event sequences and potential incidents (scenarios) that can result in loss of control of energy or material. Next is an evaluation of both the consequences and the probability. The consequences are estimated by using source models (to describe the... 

The risk assessment procedures for the CSR will certainly be based on the current procedures, although it would be useful if the ECA software simplified them to help registrants. 

Such methodologies shall allow for the establishment of the most appropriate risk assessment procedures and remedial actions having regard to the variation of geological, hydrogeological and climatological characteristics across Europe. ... 

ECETOC (2004) has proposed a concept of generic threshold values based on hazard categories primarily intended to be used in the risk assessment procedure of industrial chemicals within REACH. The hazard categories are based on EU classihcation limits and for each substance to be risk assessed, inclusion in hazard categories depends on the substance s specific classification (or no classification) according to the Commission Directive 67/548/EC (EC 1967). Three hazard categories have been suggested ... 

A WHO/IPCS (2005) Harmonization Project Document has proposed using chemical-specific toxicological data instead of default assessment factors, when possible. The concept of Chemical-Specific Adjustment Factors (CS AFs) has been introduced to provide a method for the incorporation of quantitative data on interspecies differences or human variability in either toxicokinetics or toxicodynamics into the risk assessment procedure, by modifying the relevant default UF of 10. Incorporation of toxicokinetic or toxicodynamic data becomes possible if each factor of 10 is divided into appropriately weighted sub-factors as suggested by Renwick (1991, 1993) and adopted by WHO/IPCS (1994), see Section 5.2.1.3. 

Uncertainty may also affect the credibility of ecological risk assessment procedures. In the late 1970s, the USEPA presented a risk assessment for the use of granular carbofuran on com, including a detailed list of field studies and incidents. The Eederal Insecticide, Fungicide, and Rodenticide Act Science Advisory Panel concluded there was insufficient information to justify restricted use labeling and recommended further testing. Nearly 20 years later, the accumulation of additional field studies and incidents provided sufficient evidence such that approvals for use of carbofuran were withdrawn. 

Risk assessment is an empirically based process that estimates the risk of adverse effects from exposure of an individual or population to a chemical, physical or biological agent. The OECD test guidelines, the US EPA risk assessment guidelines and additional risk assessment procedures for new and existing chemicals have been published and put into use by many different countries in Europe, the Americas and Asia (United Kingdom Department of Health, 1991,1995 EC, 1994,1996 Health Canada, 1994 IPCS, 1994 Hertel, 1996). A list of assessments produced by various national and international agencies on specific chemicals is included in ECETOC/UNEP (1996). 

Some critical differences in risk assessment procedure lead to confusing situations on a worldwide basis. These differences are due to some very controversial areas of safety issues including the calculation of the acceptable daily intake (ADI), the assignment of the ADI to maximum residue limit (MRL)/tolerance, the validation of the analytical methods needed to regulate drug residues, and the fitness of legislation to toxicology. 

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