Tiered approach, regulatory risk assessments

Interest has been expressed in the possibility of using biomarker assays as a part of risk assessment for regulatory purposes, and some workers have suggested tiered testing procedures that follow this approach (see, for example, Handy et al. 2003). It is to be hoped that regulatory schemes, such as that of REACH (see European Union 2003), will be sufficiently flexible to incorporate new assays and testing strategies as the science advances. 

Typically, exposure and risk assessments conducted during regulatory evaluations are performed in a tiered or phased approach. A tiered approach refers to a process in which the exposure or risk assessment progresses systematically from relatively simple to more complex. An important feature of a tiered analysis is that the exposure or risk assessment and the accompanying uncertainty analysis may be refined in successive iterations. 

Technical Guidance Document and Water Framework Directive approaches EU member state, North American, and other international approaches) and the way in which they are implemented (e.g., mandatory pass or fail probabilistic, e.g., 95th percentiles or tiered risk assessment frameworks). Soil and water standards were considered, as were values for the protection of human health and the natural environment. The focus was on European regulatory frameworks, although expert input was sought from other jurisdictions internationally. Chemical standards for aquatic (water and sediment) and terrestrial (soil and groundwater) systems were the main focus for the meeting. This workshop built on, and included some participants from, a 1998 SETAC workshop Re-evaluation of the State of the Science for Water-Quality Criteria Development (Reiley et al. 2003). 

ASSESSMENT OF RISKS TO HUMANS EXPOSED TO PESTICIDES 2 The Four Steps in Risk Assessment 2 Hazard Identification 2 Dose-Response Assessment 3 Margin of Safety Approach 3 Quantitative Risk Assessment 3 Exposure Assessment 4 Risk Characterization 4 RISK MANAGEMENT 5 ADVANCES IN DATA INTERPRETATION 5 Probabilistic Approaches 5 Recognition of the Tier Approach 5 Aggregate Exposure 6 Cumulative Exposure 6 Impact of New Scientific Advances 7 Post-Registration Monitoring 7 HARMONIZATION OF REGULATORY APPROACHES SUMMARY 9... 

In principle, this freedom to choose a scientific approach when planning and performing a higher-tier risk assessment provides an excellent basis for any scientific innovation in the regulatory context — including the development and implementation of ecological modeling. 

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