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How do screening tiers compare?

How do screening tiers compare?. Run RESRAD-BIOTA, ERICA Tool and EA R&D128 against 10 µGy/h screening dose rate Data from SENES-WNA report – maximum media activity concentrations = advised input for basic screening level Four freshwater and three terrestrial scenarios.

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How do screening tiers compare?

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  1. How do screening tiers compare? • Run RESRAD-BIOTA, ERICA Tool and EA R&D128 against 10 µGy/h screening dose rate • Data from SENES-WNA report – maximum media activity concentrations = advised input for basic screening level • Four freshwater and three terrestrial scenarios

  2. Initial screening tier: Tier 1 • Designed to be simple and conservative • User only needs to input media activity concentrations • Aim - to enable sites of negligible concern to be identified and removed from need for further assessment – with a high degree of confidence • Envisaged that most sites will only need this level of assessment [i.e. ‘be screened out’]

  3. Tier 1 • Media concentrations are compared to predefined concentrations (EMCLs or BCGs) = concentration giving rise to screening dose rate (to most limiting organism)

  4. Both ERICA Tool & RESRAD-BIOTA use ‘tiered assessment’ with initial assessment being very simple – minimal input/conservative output [more later] Input media concentrations compared to predefined concentrations = media concentration giving rise to screening dose rate ERICA: ‘environmental media concentration limits’ EMCLs RESRAD-BIOTA: ‘biota concentration guidelines’ BCGs ‘Concentration limits’

  5. Estimated assuming: Habitat assumption to maximise exposure Probability distributions associated with the default CR and Kd databases were used to determine 5th percentile EMCL No conservatism applied to dosimetry For aquatic ecosystems EMCL for water includes consideration of external dose from sediment and that for sediment includes external dose from water and biota-water transfer ERICA Tool - EMCLs

  6. RESRAD-BIOTA - BCGs Estimated assuming: • Infinitely large (internal) and small (external) geometries for dose calculations • Daughter T1/2’s up to 100 y included • All terrestrial organisms 100% in soil; aquatic 100% water-sediment interface • ‘Maximum’ CR values or 95th percentile CR values predicted using a kinetic-allometric approach

  7. Input data - freshwater

  8. Input data - terrestrial

  9. Freshwater

  10. Terrestrial

  11. How do screening tiers compare? ….. badly?

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