ARCTIC AND FOREST SCENARIOS Presentation for: Working Group 8 on - PowerPoint PPT Presentation

ARCTIC AND FOREST SCENARIOS Presentation for: Working Group 8 on Environmental Sensitivity 3 rd Technical Meeting Vienna, 24-28 January 2011 Bliss Tracy and Lauren Bergman Radiation Protection Bureau Health Canada

Problem Formulation: 137 Cs, 90 Sr, and 131 I; A single Source term: deposition of 1000 Bq/m 2 each under both dry conditions and heavy rainfall. Seasons: Winter, spring, summer, fall. Radionuclide concentrations: In soil, water, and plants or animals either consumed directly by humans, or as members of food chains leading to humans. Radiation doses: To adult, 10-year old, and one- year old – during the 1st year, 2nd year and 10th year after the accident.

N288.1 Model

P 14 Deposition on plant surfaces Deposition (Bq/m 2 ) x A = Plant conc (Bq/kg) Yield (kg/m 2 ) A = Foliar interception fraction = 1 for lichens, 0.3 for vascular plants Yield = 0.48 kg/m 2 for lichens = 1.0 kg/m 2 for vascular plants

P 34 Root uptake by plant Soil conc (Bq/kg) = deposition (Bq/m 2 ) density (kg/m 3 ) x depth (m) Density of soil = 1300 kg/m 3 Contaminated depth = 0.2 m Deposition of 1000 Bq/m 2  soil conc 3.85 Bq/kg Plant conc (Bq/kg) = Soil conc (Bq/kg) x conc ratio

P 45 Transfer from plant to animal Plant conc (Bq/kg) x A x feed intake (kg/d) x transfer factor (d/kg) = Meat conc (Bq/kg) A = Fraction of feed from contaminated source = 1 Feed intake = 1.96 kg dw /d for caribou = 5.22 kg dw /d for moose (dry wt)/(wet wt) = 0.19 Transfer factor = 0.15 d/kg for cesium = 0.04 d/kg for strontium = 0.032 d/kg for iodine

P 12 Deposition on water 1000 Bq/m 2 1000 Bq/m 3 = 1 Bq/L 1 m 1 m 1 m

P 26 Transfer from water to fish Fish conc (Bq/kg) = water conc (Bq/kg) x BAF BAF = Bioaccumulation factor = 3500 for cesium = 2 for strontium = 6 for iodine

P(e) 39 Groundshine dose factors (Sv/year)/(Bq/m 2 ) [Oak Ridge] Adult and Children Infants Cs-137 1.75E-08 2.28E-08 Sr-90 5.18E-11 5.18E-11 I-131 3.65E-10 4.76E-10

Human doses from ingestion of radioactivity Dose (mSv/year) = conc in food (Bq/kg) x dietary intake (kg/year) x dose coefficient (Sv/Bq) x 1000 (mSv/Sv)

Dietary intakes grams/day kg/year Caribou 66.4 24.2 Moose 15.8 5.8 Fish 21.9 8.0 Wild plants 11.0 4.0

Water consumption (L/d) [US Environmental Protection Agency ] Mean 90th %ile Infant 0.5 0.98 Child 0.72 1.4 Adult 1.4 2.3

Dose coefficients for ingestion intakes (Sv/Bq) Age group Cs-137 Sr-90 I-131 1-year old 1.20E-08 7.30E-08 1.80E-07 10-year old 1.00E-08 6.00E-08 5.20E-08 Adult 1.30E-08 2.80E-08 2.20E-08

Doses to adults (mSv/year) in 1 st year Pathway Cs-137 Sr-90 I-131 Groundshine 4.41E-03 1.31E-05 2.93E-06 Soil ingestion 2.23E-03 4.80E-03 1.20E-04 Fruit & vegetable ingestion 1.25E-02 2.69E-02 6.72E-05 Caribou ingestion 1.01E+00 5.83E-01 1.07E-03 Moose ingestion 6.43E-01 3.70E-01 6.77E-04 Fish ingestion 3.64E-01 4.48E-04 3.36E-05 Drinking water ingestion 1.09E-02 2.35E-02 5.87E-04 Total 2.05E+00 1.01E+00 2.56E-03

Cs-137 Dose by Pathway 10.000 1.000 Dose (mSv/a) 0.100 0.010 0.001 Groundshine ingestion of vegetables Caribou Moose Fish Drinking water Incidental Fruits & soil Pathway

Dose (mSv/a) 0.00 0.20 0.40 0.60 0.80 1.00 1.20 Groundshine Cs-137 Dose by Pathway Incidental ingestion of soil Fruits & vegetables Pathway Caribou Moose Fish Drinking water

Dose (mSv/a) 0.00 0.20 0.40 0.60 0.80 1.00 1.20 Groundshine Sr-90 Dose by Pathway Incidental ingestion of soil Fruits & vegetables Pathway Caribou Moose Fish Drinking water

I 131 dose by pathway 0.012 0.010 Dose (mSv/a) 0.008 0.006 0.004 0.002 0.000 Pathway

Dose by radionuclide and pathway 1.20 1.00 Dose (mSv/a) 0.80 0.60 Cs-137 0.40 Sr-90 0.20 I-131 0.00 Pathway

Dose by radionuclide and pathway 1.000000 0.100000 0.010000 mSv/a 0.001000 Cs-137 Sr-90 0.000100 I-131 0.000010 0.000001

Comparison of methods 10.00 Aggregate transfer Detailed Pathway 1.00 Dose (mSv/a) 0.10 0.01 0.00 Generic fruits Caribou Moose and vegetables

Forest ecosystem: Dietary intakes of traditional foods (kg/year) (Hatchet Lake dietary survey) 11-20 year Food item 2 -10 year old old Adults Caribou 88.97 77.56 114.7 Moose 0.29 0.11 0.9 Small mammals 0.00 0.58 1.6 Ground birds 0.04 0.91 1.0 Water birds 1.48 2.57 3.6 Traditional fruits 6.02 4.42 1.2 Fish 29.09 14.22 52.9

Table 8. Average concentrations in water and fish in year one from Lake Øvre Heimdalsvatn (from Luigi Monte’s contribution) Cs-137 Sr-90 Concentrations in water (Bq/L) 0.039 0.081 Concentrations in fish (Bq/kg) 39.16 0.68

Table 9. Summary of doses to humans during year one (mSv/a) Radionuclide one-year old 10-year old Adult Cs-137 0.01958 0.01017 0.03184 Sr-90 0.00448 0.00325 0.00305 I-131 0.00015 0.00010 0.00009 Total 0.02421 0.01352 0.03498

Doses from Cs-137 by pathway 1.E-01 1.E-02 1 year-old 10 year-old 1.E-03 Adult Doses (mSv/year) 1.E-04 1.E-05 1.E-06 1.E-07 1.E-08 h s u e l r e n s s w e e o s s n o l d t a i o o i i b r a i r F h m t i r o f i W s b r r s e M m e e a d B d g C t n a n a n u m W u i o o l l r i r l o G a G S m S

Doses from Sr-90 by pathway 1.E-02 1.E-03 1 year-old 10 year-old Adult 1.E-04 Dose (mSv/year) 1.E-05 1.E-06 1.E-07 1.E-08 1.E-09 u e h r s l e n s s w e s e o s n d o l t a i o o i b a i i r r F h t o m i r f W i s b r r s e M e a m e d B d C t g n a a n n W u m u i o o l l r i r o l G a G S m S

Doses from I-131 by pathway 1.E-03 1.E-04 1 year-old Dose (mSv/year) 10 year-old Adult 1.E-05 1.E-06 1.E-07 u e h r s l e n s s w e s e o s n d o l t a i o o i b a i i r r F h t o m i r i f W s b r r s e M e a m e d B d C t g n a a n n W u m u i o o l l r i r o l G a G S m S

Doses during first year 1.E-01 Cs-137 Sr-90 I-131 1.E-02 Dose (mSv/year) 1.E-03 1.E-04 1.E-05 one-year old 10-year old Adult

Ecological half-lives of Cs-137 and Sr-90 Ecological Sampling Observation Half-life Decay Food Item Region Period (a) Constant Cs- 137 Whole Diet Germany 1967-1985 8.1 0.0856 Sr-90 Whole Diet Germany 1967-1985 14.1 0.0492

0.045 0.040 0.035 One-year old 10-year old 0.030 Dose (mSv/a) Adult 0.025 0.020 0.015 0.010 0.005 0.000 Year 1 Year 2 Year 10