How do screening tiers How do screening tiers compare? 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
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. - PowerPoint PPT Presentation
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How do screening tiers How do screening tiers compare?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
Initial screening tier: Tier 1 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’]
Tier 1Tier 1• Media concentrations are compared to
predefined concentrations (EMCLs or BCGs) = concentration giving rise to screening dose rate (to most limiting organism)
‘‘Concentration limits’Concentration limits’• 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’
ERICA Tool - EMCLsERICA Tool - EMCLsEstimated 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