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Table 4 Main elements of our proposal for a harmonized assessment of persistence across regulatory frameworks

From: Proposal for a harmonised PBT identification across different regulatory frameworks

 

Persistence

Definitive assessment

Screening assessment

Criteria

Half-life

Ready biodegradability

 Water:

Enhanced ready biodegradability

  > 60 days in marine (>60 days)

  > 40 days in fresh- or estuarine (>60 days)

 Sediment:

  > 180 days in marine (>180 days)

  > 120 days in fresh- or estuarine (>180 days)

 Soil:

  > 120 days (>180 days)

Proposal

Considering DegT50 and not DissT50

Other information to consider

 Normalising DegT50 to 12°C

 Abiotic degradation

 Inclusion of field studies if DegT50 can be derived

 Monitoring data

 Selecting DegT50 from multiple studies:

 QSAR

  For ≤4 values: worst case

 Read-across from structurally related substances

  For ≥5 values: geometric mean, or WoE

  Water and sediment systems: comparing DegT50 to trigger

  Values of water and sediment; need clear criteria

Other information to consider

 Formation of NER or mineralisation rate

  1. The P and vP criteria are included for definitive and screening assessments.