Risk assessment approach

Using formalized risk assessment techniques for industrial ventilation projects may complicate the issue more than necessary. The work environment and its exposure conditions are the focus. However, when evaluating new technology, including waste management, the risk assessment approach may be valuable. 

At present the approach to assessing the potential risks of exposure to a chemical in the diet involves the application of a standardised risk assessment approach consisting of three main elements - hazard identification and characterisation and exposure assessment. 

Bassett, J. and McClure, P. (2008). A risk assessment approach for fresh fruits. /. Appl. Microbiol. 104, 925-943. 

Application of the Preliminary Pollutant Limit Value (PPLV) Environmental Risk Assessment Approach to Selected Land Uses... 

Health IfEa (1999) Risk assessment approaches used by UK government for evaluating Human Health Effects of Chemicals. Risk Assessment, Toxicology Steering Committee (RATSC)... 

Selection of target pharmaceuticals (see Table 1) was based on the following criteria (1) the sales and practices in Spain (according to National Health system), (2) compound pharmacokinetics (the percentage of excretion as nonmetabolized substance), (3) their occurrence in the aquatic media (data taken from other similar studies), and (4) on data provided by environmental risk assessment approaches, which link the calculation of predicted environmental concentrations (PEC) with toxicity data in order to evaluate which compounds are more liable to pose an environmental risk for aquatic organisms [20-22], In the current European... 

Gerberick, G. F., et al., Understanding fragrance allergy using an exposure-based risk assessment approach, Contact Derm. 45, 333-340, 2001. 

General References Guidelines for Hazard Evaluation Procedures, Second Edition with Worked Examples, American Institute of Chemical Engineers, New York, 1992 Layer of Protection Analysis A Simplified Risk Assessment Approach, American Institute of Chemical Engineers, New York, 2001 ISA TR84.00.02, Safety Instrumented Functions (SIF)—Safety Integrity Level (SIL) Evaluation Techniques, Instrumentation, Systems, and Automation Society, N.C., 2002. 

In 1993, the Center for Chemical Process Safety (CCPS) published Guidelines for Safe Automation of Chemical Processes (referred to henceforth as Safe Automation). Safe Automation provides guidelines for the application of automation systems used to control and shut down chemical and petrochemical processes. The popularity of one of the hazard and risk analysis methods presented in Safe Automation led to the publication of the 2001 Concept Series book from CCPS, Layer of Protection Analysis A Simplified Risk Assessment Approach. This method builds upon traditional process hazards analysis techniques. It uses a semiquantitative approach to define the required performance for each identified protective system. 

Ecosystem characterization Long-term monitoring should continue in order to enable estimation of natural variability, as well as to establish a baseline against which to evaluate the effects of disturbances. Standard environmental risk assessment approaches may not be useful if the components of the ecosystem in question have not been determined. Further research on... 

There are occasional outbursts of skepticism about the value of the risk assessment approach. Some argue its full use is overly burdensome, that the only real need is to identify toxic chemicals and then eliminate them or reduce their presence. Perhaps this approach is appropriate for a few chemicals that exhibit extremely high toxicity or that are excessively persistent and bioaccumulate in an environment, and for which there are reasonably good substitutes available. But as a general approach, it ignores the elementary principle that all chemicals will... 

The environmental risk assessment approach most commonly adopted consists of estimation of the risk quotient (RQ) (as suggested by Hernando et al. [103]), which is defined as the ratio between the environmental concentration (measured or predicted, respectively MEC and PEC) and the predicted no-effect concentration (PNEC), and can be used to collocate compounds in one of three risk bands RQ < 0.1, minimal risk to aquatic organisms 0.1 < RQ < 1, median risk and RQ > 1, high risk [103—105]. In their risk assessment calculations, [106], further to [107], estimated PNEC values at 1,000 times lower than the most sensitive species assayed, so as to take into account the effect on other, potentially more sensitive, aquatic species to those used in toxicity studies. 

The protection of ground and surface water has major environmental priority because any contamination may cause a risk for its use in human and animal nutrition and may disturb aquatic biocoenosis. The OECD-indicator list (OECD 1997) subsummarises state and risk assessment approaches under this issue. We will confine our efforts to indicators that are appropriate to evaluate the impact of different farm management practices. 

Yang, R.S., H.A. El-Masri, R.S. Thomas, A.A. Constan, and J.D. Tessari. 1995. The apphcation of physiologically based pharmacokinetic/pharmacodynamic (PBPK/PD) modeling for exploring risk assessment approaches for chemical mixtures. Toxicol. Lett. 79 193-200. 

There are of course many mathematically complex ways to perform a risk assessment, but first key questions about the biological data must be resolved. The most sensitive endpoint must be defined along with relevant toxicity and dose-response data. A standard risk assessment approach that is often used is the so-called divide by 10 rule . Dividing the dose by 10 applies a safety factor to ensure that even the most sensitive individuals are protected. Animal studies are typically used to establish a dose-response curve and the most sensitive endpoint. From the dose-response curve a NOAEL dose or no observed adverse effect level is derived. This is the dose at which there appears to be no adverse effects in the animal studies at a particular endpoint, which could be cancer, liver damage, or a neuro-behavioral effect. This dose is then divided by 10 if the animal data are in any way thought to be inadequate. For example, there may be a great deal of variability, or there were adverse effects at the lowest dose, or there were only tests of short-term exposure to the chemical. An additional factor of 10 is used when extrapolating from animals to humans. Last, a factor of 10 is used to account for variability in the human population or to account for sensitive individuals such as children or the elderly. The final number is the reference dose (RfD) or acceptable daily intake (ADI). This process is summarized below. 

S. Erdal, S.N. Buchanan, A quantitative look at fluorosis, fluoride exposure, and intake in children using a health risk assessment approach. Environ. Health Perspect. 113 (2005) 111-117. 

Bhattacharya S et al (2011) Toxicity testing in the 21 century defining new risk assessment approaches based on perturbation of intracellular toxicity pathways. PLoS One 6(6) e20887... 

Essential vahdation work must therefore be identified to prove control of the critical aspects of the operations. A risk assessment approach should be used to determine the scope and extent of validation. 

The RCEP considered that the current risk assessment approach has the advantage of being evidence-based and transparent, but that a new approach, one that balances precaution with an evidence-based approach is needed (RCEP, 2003, p96). This suggests that precaution disregards evidence, which is not the case. Rather, it is more open to different types of evidence than the often narrow view taken by risk assessment. It considers the weight of evidence , the evidence from differ-... 

Chapter 10. Zenick, H., and E. D. Clegg Assessment of male reproductive toxicology a risk assessment approach. 

This describes the principles of qualification and validation which are applicable to the manufacturer of medical products. It is a GMP requirement that manufacturers identify the validation work needed to prove control of the critical aspects of their particular operations. Significant changes for the facility, the equipment and the processes which may affect the quality of the product should be validated. A risk assessment approach should be used to determine the scope and extent of validation. 

As in other risk-assessment approaches (e.g., NRC 1994), scientific uncertainties are a predictable feature of any new biomonitoring-led risk assessments. As shown above and discussed more fully in Chapter 6, identifying and communicating those uncertainties—such as the effect of interindividual variation in elimination rate and limits on extrapolating adult PK data to children—are critical in communicating the risk results. 

It can assess risks posed by multiple exposures. Large-scale biomonitoring studies illustrate the need for developing cumulative risk-assessment approaches for biomonitoring data because exposures are typically to mixtures rather than to single toxicants. An examination of the Third National Report on Human Exposure to Environmental Chemicals, for example,... 

There is no global security policy, and therefore no unique definition of threats, protection criteria and risk assessment approaches. 

FIGURE 5.1 Mixed-model mixture risk assessment approach. Note This illustrates the calculation of steps for combined effects of mixtures with similarly (e.g., Substances 1 to 3) and dissimilarly (e.g., Substances 1 to 3 versus Substances 6 to 8) acting components. 

In the different risk assessment approaches that exist (e.g., Table 10.1), there are different ways to combine the 3 axes, in prescribing the approaches that are needed to address the specific problem, collect the data, and handle the data and models. Due to their different origins and the different problems that they address, the existing tiered systems are thus very different. One method is, however, not necessarily better or worse than the other. For this guidance, we have organized the methods according to the method characteristics themselves, not to existing tiered frameworks. 

The schematic presentation (Figure 15.2) clearly shows the key characteristic of the probabilistic risk assessment approach wherein worst-case modeling a point estimate (either a maximum or a mean) is chosen as the value for the input variable, in probabilistic modeling a data distribution is used. 

The special vulnerability of children should form the basis for development of child-protective policies and risk assessment approaches. A lack of lull proof for causal associations should not prevent efforts to reduce exposures or implement intervention and prevention strategies. 

---