Toxicological Threshold Risk Scoring for Non-Intentionally Added Substances in Recycled Polymers
Toxicological threshold scoring maps unidentified polymer migrates to Cramer exposure limits, mandating genotoxic screening below 0.00015 mg/kg food.
Semi-Quantitation Uncertainty Factor
Meaning
Correction multipliers account for the lack of specific calibration standards when estimating the concentration of unknown migrants in a polymer. The semi-quantitation uncertainty factor adjusts the reported value to ensure that safety margins are maintained during the analysis.
Calibration Gap
Labs often find substances for which they do not have a pure sample to use as a reference. Because the detector response might vary between different molecules, the semi-quantitation uncertainty factor provides a buffer against underestimating the amount. This adjustment is necessary to protect consumers from exposure to unidentified chemicals.
Without this correction, a lab might report a concentration that is far below the actual level present in the plastic.
Margin Adjustment
Standard practice involves multiplying the observed concentration by a fixed value, such as ten, to cover the potential error. If the result remains below the safety threshold after the semi-quantitation uncertainty factor is applied, the material is considered safe for use.
Reporting Standard
Regulatory bodies accept this conservative approach as a way to manage the risks associated with non-targeted analysis. Using a semi-quantitation uncertainty factor ensures that the final safety assessment is defensible and accounts for the limits of the measurement technology. This method reduces the chance of a false negative in the risk assessment process.