Assessment paradigms

Often contrasted in conceptual terms, EIA and RA have a common ultimate goal— the rational reform of policy-making (Andrews 1990). Both assessment tools are intended to provide reasoned predictions of possible consequences of planned decisions to facilitate wiser choices among the alternatives. To link risk assessment and impact assessment paradigms one can suggest a definition of environmental impact as any change in the level of risk undergone by receptors of concern that are reasonably attributable to a proposed project (Demidova, 2002). 

As described in detail in this book, the use of assessment factors is an established practice in chemical risk assessment to account for uncertainties inherent in the hazard (effects) assessment and consequently, inherent in the risk assessment. The use of assessment factors to address this uncertainty is part of the conventional approach that has developed over the years. According to the current risk assessment paradigm, the usual approach is simply to multiply these individual assessment factors in order to establish an overall composite numerical assessment factor (Section 5.10). An alternative to the traditional assessment factor approach is to combine estimates of the ranges that these factors may encompass through a probabilistic assessment this is essentially a variation of the standard paradigm. 

The committee s attention to those limitations and uncertainties is important for two reasons. First, full disclosure of limiting factors gives scientists and the public a fuller understanding of the reliability and credibility of biomonitoring results. It provides risk assessors with information needed to characterize risk conclusions fully, as called for by the National Research Council risk-assessment paradigm (NRC 1983 1994). Second, and equally important, the kinds of uncertainty define data gaps for immediate attention and related long-term research needs. 

Monitoring employee health is one part of the exposure assessment in the risk assessment paradigm. The second part is workplace monitoring, the subject of Chapter 2 of this report. 

Identifying dose-response relationships is an important component of any risk assessment. This process establishes the exposure levels that produce effects, as well as those that produce no effects. As noted in Box 2, it is important to characterize what data were used, what model was employed to develop the dose-response curve(s), and whether chemical-specific information is available to support the observed dose-response relationship. While the risk assessment paradigm shown in Figure 21 separates hazard... 

Life stage-specific risk assessments are likely to require modification of the current toxicity testing and human health assessment paradigms. 

The addition of the problem formulation step to the risk assessment paradigm will assist in focusing the purpose for determining the potential risk from specific childhood exposures and foster an increased interaction between scientists, risk assessors, public health officials, and the public. 

Felter SP, Ryan CA, Basketter DA, and Gilmour NJ (2003) Application of the risk assessment paradigm to the induction of allergic contact dermatitis. Regulatory Toxicology and Pharmacology 37 1-10. 

Exposure assessment is one of the four major steps in the risk assessment paradigm, as defined by the National Academy of Sciences in the United States. Thus, exposure assessment is a key element in any quantitative risk assessment. Exposure assessment is... 

In the original safety assessment paradigm a single safety factor (SF) of 100 was used to derive an ADI from a NOEL. The justification of the SF (also called an uncertainty factor (UF)) was based on scientific considerations as well as a judgment about how to manage the inherent uncertainty associated with the... 

Qassic risk assessment paradigm. Originally developed for human health risk assessment, this framework does not include the close interaction between effects and exposure in ecosystems. 

Arkoosh, M.R. and T.K. Collier. Ecological risk assessment paradigm for salmon analyzing immune function to evaluate risk. Hum. Ecol. Risk Assess. 8 265—276, 2002. 

Figure 22.2. New Risk Assessment Paradigm. The goal in this new paradigm is to characterize the likelihood of the occurrence for an adverse health effect. The probability of this occurring is dependent of several factors. Characterizing the target tissue dose of the toxicant is still a critical feature. The genetic background of the group or individual will determine what genes are available to be transcribed in response to the exposure.

Once the BMD is identified, the one-sided lower 95th confidence interval on the BMD called the BMDL (benchmark dose lower bound) is used as the POD. Similar to noncancer risk assessment, the POD is then divided by uncertainty factors to account for potential interspecies differences, intraindividual variability, and so on. The current risk assessment paradigm has accepted that, by accounting for uncertainty through use of the BMDL and other uncertainty factors, the resulting dose is either below a toxic threshold or so low as to constitute a virtually safe dose (Bogdanffy et al. 2001). 

The utility of the traditional risk assessment paradigm for autoimmunity associated with environmental agents is currently limited. 

Developing an objective assessment of the hazard that copper poses to humans and the environment depends on an intimate understanding of the bioavailability. Bioavailability, which is defined as the extent to which the metal is taken up by the organism upon exposure, depends on the species of the metal or metallo complex and/or how easily it can be transformed to a more or less bioavailable species. The key components of the environmental risk assessment paradigms include problem formulation, analysis (which includes both exposure and effects analysis) and risk characterization (WHO 1998). 

In determining the relative risk posed by pollutants in soils, it is not enough to simply measure the chemical concentration. It is also necessary to address the risk-assessment paradigm, the pathways by which human health and the environment can be affected, and the availability of the released chemical for transport and adverse impact (Loehr, 1996). Environmental risk is commonly defined as the adverse impact resulting from human or environmental exposure (real or potential) to contaminants under site-specific circumstances. But while decisions on the suitability of soil-remediation processes commonly focus on chemical-concentration... 

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