Uncertainty evaluation
Uncertainty is an important element judging the relevance of data. In a tiered approach, uncertainty plays a role at content analysis, in eluate analysis, in leaching test performance, in sampling and in modelling predictions of release in specific scenario settings. Some aspects of uncertainty are easier addressed than others. Through ruggedness and subsequent intercomparison validation uncertainties related to content analysis, eluate analysis and leaching can be assessed and recorded as performance characteristics of an analysis or testing protocol.
However, not all materials and all substances can be subjected to such testing due to the shear cost involved. So, performance data give a good indication, but deviations can occur for a variety of reasons such as measurements closer to the detection limit of the method, low buffer capacity of a material leading to fluctuations in pH with associated consequences for release.
In modelling uncertainties can be due to assumptions about exposure conditions, missing thermodynamic data for relevant reactions (particularly relevant for less common elements). Comparisons between laboratory test data and field observations can help to reduce uncertainties once the underlying processes are properly understood.
