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Dose Assessments for Wildlife in England & Wales.

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Presentation on theme: "Dose Assessments for Wildlife in England & Wales."— Presentation transcript:

1 Dose Assessments for Wildlife in England & Wales

2 Contents  Legislative framework  Overview of the assessment framework  Staged approach (1, 2, 3 & 4)  Assessing doses to wildlife  Current status

3 Legislative Framework  Europe: Habitats & Birds Directives On the conservation of natural habitats and of wild flora and fauna

4 Legislative Framework  Europe: Habitats & Birds Directives On the conservation of natural habitats and of wild flora and fauna  UK: Conservation (Natural Habitats) Regulations 1994 Implements the Habitats Directive in the UK. Requires steps to maintain and restoration to favourable conservation status of habitats and species of Community level interest

5 The Environment Agency’s Role  We have a duty to comply with the EU Birds and Habitats Directives

6 The Environment Agency’s Role  We have a duty to comply with the EU Birds and Habitats Directives  The Agency’s obligations are to review:  Existing authorisations, consents, licences and permissions for chemicals  All requests for variations to existing or new applications  Ensure that no Agency-authorised activity or permission results in an adverse effect, either directly or indirectly on the integrity of identified European sites (Natura 2000 sites)

7 The Environment Agency’s Role  We have a duty to comply with the EU Birds and Habitats Directives  The Agency’s obligations are to review:  Existing authorisations, consents, licences and permissions for chemicals and radioactive substances  All requests for variations to existing or new applications  Ensure that no Agency-authorised activity or permission results in an adverse effect, either directly or indirectly on the integrity of identified European sites (Natura 2000 sites)  Pressure is from conservation not radiological protection

8 The Environment Agency’s Role Given the requirement to assess the impacts of consents and authorisations affecting Natura 2000 sites: We took the view, based on legal advice and with the support of English Nature (statutory consultee), that these assessments should include ionising radiation

9 Natura 2000 sites  About 430 Natura 2000 sites in England & Wales  Include Special Areas of Conservation (SAC) and Special Protection Areas (SPA)

10 Natura 2000 sites  About 430 Natura 2000 sites in England & Wales  Include Special Areas of Conservation (SAC) and Special Protection Areas (SPA)  Note the approach taken aims to be conservative in order to be protective

11 Timetable  Natura 2000 sites categorised by conservation agencies into:  High priority sites by 2004  Medium priority sites by 2006  Low priority sites by 2008

12 How does the assessment work?

13 In stages...

14 Stage 1  Review of likelihood that discharges from an authorised site could reach a Natura 2000 site  e.g. inland freshwater Natura 2000 site v coastal discharge  Simple rules used  authorised aerial discharges within 1km  authorised freshwater discharges within 50km

15 Stage 2

16  Dose per unit release values calculated for reference organisms (µGy h -1 per TBq) - how?

17 R&D 128  R&D 128 provided a:  Review of the latest research on the biological effects of ionising radiation  Simplified approach to determining exposure (through dose calculations) for a set of organisms which were representative of freshwater, marine and terrestrial ecosystems for a limited set of radionuclides

18 R&D 128  Radionuclides:  3 H, 14 C, 32 P, 35 S, 60 Co, 99 Tc, 90 Sr, 106 Ru, 125 I, 129 I, 131 I, 137 Cs, 210 Po, 226 Ra, 234 Th, 238 U, Pu, 241 Am, 85 Kr, 41 Ar  Uses concept of “reference” organism

19 Reference Organism Concept  Key points:  (Simplified) geometric shape for dosimetry calculations

20 Reference Organism Geometries

21 Reference Organism Concept  Key points:  Selected to represent different trophic levels (to enable transfer of radionuclides to be determined/estimated)  Selected to represent different exposure pathways - e.g. immersed in soil or water, surrounded by air etc.  Doses calculated to whole organism

22 Reference Organisms in R&D 128

23 Assessment Methodology REFERENCE ORGANISM IMPACT

24 Assessment Methodology ECOLOGICAL PARAMETERS REFERENCE ORGANISM RADIONUCLIDE SOURCE IMPACT PATHWAY OF EXPOSURE

25 Assessment Methodology ECOLOGICAL PARAMETERS REFERENCE ORGANISM RADIONUCLIDE SOURCE IMPACT TOTAL ABSORBED DOSE PATHWAY OF EXPOSURE Application of a weighting factor for RBE Compare predicted dose to known biological or ecological effects & guideline values

26 Simplifying assumptions  External doses calculated from simple infinite or semi-infinite contaminated media formulae, with modifications for self shielding by the organism  Short lived radionuclides assumed to be in secular equilibrium with longer lived parent  Equilibrium between environmental media assumed - so that concentrations in organisms can be estimated from simple concentration factors/ratios

27 Terrestrial Environment

28 R&D 128  Enter water, air, soil or biota concentrations to calculate dose rates (  Gy/h)  Provides advice on practical use of methodology, and states assumptions and constraints

29 R&D 128

30

31 Stage 2  Using R&D 128 & some simple dispersion modelling the dose per unit release values were calculated for reference organisms (µGy h -1 per TBq)  Assume discharge at permit limits and impact from combined discharges (air, sewer, river, coastal waters)  Resulting doses compared to screening level of 5 µGy h -1 as agreed with (then) English Nature

32 Stage 2 - results  Approximately 100 authorisations have been identified that exceed the screening level at 51 Natura 2000 sites & thus require Stage 3 assessment

33 Stage 2 - results  Approximately 100 authorisations have been identified that exceed the screening level at 51 Natura 2000 sites & thus require Stage 3 assessment  Note this is mainly due to choice of analogue  Initial use of other alpha and other beta/gamma categories  Expert judgement may be used to match on half-life and radiation type/energy

34 Stage 3

35  Dose per unit release values calculated for reference organisms and feature species and habitats  Threshold of 40  Gy h -1 agreed with English Nature, below which it can be concluded that there will be no adverse effect on habitat site integrity

36 Feature species & habitats  Feature Species (e.g.): Avocet, Bar-tailed Godwit, Bittern, Black-tailed Godwit, Curlew, Dunlin, Gadwall, Golden plover, Grey plover, Hen Harrier, Knot, Lapwing, Little tern, Marsh Harrier, Oystercatcher, Redshank, Ringed plover, Ruff, Sanderling, Scaup, Shelduck, Snipe, Tufted duck, Wigeon  Feature Habitats (e.g.): Birds of uplands, Birds of lowland heaths and brecks, Birds of lowland freshwaters and their margins, Birds of open sea and offshore rocks, Birds of lowland wet grasslands, Birds of farmland, Birds of coastal habitat, Birds of estuarine habitats

37 Determine authorisations affecting Natura 2000 site (from Stage 2) Obtain Natura 2000 site information Having identified a feature species, determine concentration factors and occupancy factors

38 Determine authorisations affecting Natura 2000 site (from Stage 2) Obtain Natura 2000 site information Having identified a feature species, determine concentration factors and occupancy factors Identify any predator/prey for indirect effects

39 Determine authorisations affecting Natura 2000 site (from Stage 2) Obtain Natura 2000 site information Having identified a feature species, determine concentration factors and occupancy factors Identify any predator/prey for indirect effects Determine which reference organism geometry can be used to approximate the feature species geometry

40 DPUC calculations  Uncertainty typically <10%

41

42

43 Determine authorisations affecting Natura 2000 site (from Stage 2) Obtain Natura 2000 site information Having identified a feature species, determine concentration factors and occupancy factors Identify any predator/prey for indirect effects Determine which reference organism geometry can be used to approximate the feature species geometry Run Assessment

44

45

46

47 Stage 4

48  Regulatory action required to reduce the potential impact  Not yet implemented in either chemicals or radioactive substances regulation  Currently the approach is being worked up in consultation with Natural England  Need for proportionality, transparency, fairness

49 Current Status

50 Timetable - current status  Natura 2000 sites categorised by conservation agencies into:  High priority sites by 2004 (completed and reviewed with English Nature in April 04)  Medium priority sites by 2006 (completed and reviewed with English Nature in March 06)  Low priority sites by 2008 (currently on target)

51 Current status  All habitat sites to date <40  Gy/h, except Ribble Estuary  Ribble & Alt Estuary Natura 2000 site assessment is 690  Gy h -1 due to Th-234 & short lived alpha emitters discharged from Westinghouse Springfields

52 Current status  All habitat sites <40  Gy/h, except Ribble Estuary  Ribble & Alt Estuary Natura 2000 site assessment is 690  Gy h -1 due to Th-234 & other short lived alpha emitters discharged from Westinghouse Springfields  Entering Stage 4 of the Habitats Assessment process  (Regulatory) Action to be taken by March 2008

53 Current status  All habitat sites <40  Gy/h, except Ribble Estuary  Ribble & Alt Estuary Natura 2000 site assessment is 690  Gy h -1 due to Th-234 & other short lived alpha emitters discharged from Westinghouse Springfields  Entering Stage 4 of the Habitats Assessment process  (Regulatory) Action to be taken by March 2008  What form should this take, what actions should be taken?

54 Current status  All habitat sites <40  Gy/h, except Ribble Estuary  Ribble & Alt Estuary Natura 2000 site assessment is 690  Gy h -1 due to Th-234 & other short lived alpha emitters discharged from Westinghouse Springfields  Entering Stage 4 of the Habitats Assessment process  (Regulatory) Action to be taken by March 2008  What form should this take, what actions should be taken?  However reduction in limits is already planned due to change in operations and recent review of discharges

55 So…  Discussions have been held with Springfields and the following actions undertaken:

56 So…  Discussions have been held with Springfields and the following actions undertaken:  Review of the data entered into the spreadsheets

57 So…  Discussions have been held with Springfields and the following actions undertaken:  Review of the data entered into the spreadsheets  Using Springfields environmental data water concentrations in the Ribble have been modelled (using site specific models)

58 So…  Discussions have been held with Springfields and the following actions undertaken:  Review of the data entered into the spreadsheets  Using Springfields environmental data water concentrations in the Ribble have been modelled (using site specific models)  Previous levels of discharge identified at the agreed new permit limits and the monitoring data from this period collated

59 So…  Discussions have been held with Springfields and the following actions undertaken:  Review of the data entered into the spreadsheets  Using Springfields environmental data water concentrations in the Ribble have been modelled (using site specific models)  Previous levels of discharge identified at the agreed new permit limits and the monitoring data from this period collated  Assessment re-run using ERICA tool (part of our move to update R&D128

60 So… “Risk of exceeding 40 uGy h-1 is negligible for any species likely to be present in the estuary”

61 Finally  We are currently reviewing this work  Meeting in a weeks time

62 Finally  We are currently reviewing this work  Meeting in a weeks time  Some issues identified  E.g. assessment focuses only on radionuclides discharged from Springfields, may need to consider radionuclides from other sources…

63 Finally  We are currently reviewing this work  Meeting in a weeks time  Still planning to undertake a scientific programme of research in the estuary to identify any potential biological impacts

64 Finally  We are currently reviewing this work  Meeting in a weeks time  Still planning to undertake a scientific programme of research in the estuary to identify any potential biological impacts  Regulatory action required?


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