Meaning
Toxicological limit defines the maximum exposure level at which a chemical substance is unlikely to cause damage to genetic material. Establishing a genotoxicity threshold is a critical part of the safety assessment for non-intentionally added substances that migrate from polymer packaging. Substances that fall below this level are considered to pose a negligible risk of causing mutations or cancer.
Safety Assessment
Evaluation involves reviewing the chemical structure for known alerts that suggest dna reactivity. If a migrant from a plastic part is identified, the genotoxicity threshold helps determine if further expensive animal testing or cell-based assays are required. For many unknown compounds found in recycled resins, a conservative threshold of 0.15 micrograms per person per day is often applied.
Risk Management
Exceeding the limit requires the manufacturer to either identify the source of the contaminant or change the processing conditions to reduce its migration. Because the genotoxicity threshold is so low, even trace amounts of a catalyst residue or a thermal breakdown product can trigger a compliance failure. Moulders must work closely with resin suppliers to ensure that the virgin materials are free from hazardous precursors.
Exposure Calculation
Total risk is calculated by multiplying the concentration of the migrant by the amount of food a person is likely to consume.
