Modeling exposure assessment Sample Clauses

Modeling exposure assessment. Deterministic exposure assessments are straightforward spreadsheet calculations that do not take into account the demographic diversity, variability or uncertainty of an exposure assessment. These calculations are typically performed using simple tools such as Microsoft Excel. The result is intended to be a conservative point value estimate which is thought to be well above any realistic range of exposure, but does not provide any estimate of how likely the exposure would be to occur. Simplistic probabilistic exposure assessments can be performed by products like @Risk or Crystal Ball where probability distributions are used to quantify uncertainty and variability in the inputs and outputs of exposure assessment. Specific food safety exposure assessment models have been developed which allow more detailed probabilistic models to be used, these models include the CREMe 2.0 model (xxx.xxxxxxxxxxxxx.xxx), the MCRA model (RIKILT) and the CSL model. These tools have allowed uncertainty and variability to be quantified in more detailed exposure assessments. Issues with the current state of the art include the following. Although current deterministic methods are thought to be conservative – or perhaps over-conservative – their true relation to actual intakes has not been established. Therefore it is not known whether they provide an appropriate level of protection for consumers. The existing probabilistic models require data from detailed food consumption surveys. They are thus restricted to the minority of EU member states where which such data exist, and their benefits cannot be realised for EU-level assessments. The existing probabilistic models quantify only a few of the uncertainties affecting dietary intakes, typically only sampling uncertainty for consumption and concentrations. Consequently, confidence intervals produced by these models represent only part of the overall uncertainty. In practice, many current exposure assessments follow standard screening procedures that are intended to produce conservative estimates of exposure. These screening assessments do not involve an analysis of uncertainty, provided that they include conservative assumptions. The requirement for increased transparency in risk assessment in food has been articulated in recent publications by the European Commission. Furthermore, it is necessary to characterise scientific uncertainty so that risk managers can determine when to take appropriate measures and where best to target the...