What PNEC represents
Predicted no-effect concentration (PNEC) is derived from environmental effects information using the applicable assessment methodology, including the relevant endpoint and assessment factor considerations.
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ERA risk characterisation
PEC and PNEC in Pharmaceutical Environmental Risk Assessment
PEC and PNEC are central concepts in environmental risk characterisation. PEC describes predicted environmental exposure, while PNEC represents the concentration below which adverse effects are not expected under the defined assessment framework.
Key considerations
What PEC represents
Predicted environmental concentration (PEC) is an exposure estimate. Depending on the assessment stage and environmental compartment, the calculation and refinement approach can differ.
How PEC and PNEC are used together
Risk characterisation compares exposure with the environmental effect threshold under the applicable framework. A ratio above or below the relevant comparison point must be interpreted in the context of the guideline, refinement approach and underlying evidence.
Why substance-specific evidence matters
Environmental fate, degradation behaviour, sorption, bioaccumulation potential and ecotoxicological endpoints can materially affect the risk characterisation. The assessment should therefore use evidence that is appropriate to the substance and regulatory question.
Documenting the conclusion
A strong ERA records the assumptions, calculations, source data and scientific rationale so the conclusion can be reviewed and reproduced within the submission context.
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