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Uma oya
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CATCHMENT AREA OF UMA OYA
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SUB WATERSHEDS
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AGRO-ECOLOGICAL REGION OF THE
WATERSHED
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SAMPLING SITES
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Sampling design 25m X 25m
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Sample preparation Core samples 0 10 cm , 10
20 cm, 20-30 cm Air dry Grind Sieve and obtain lt
2 mm fraction Sub sample (coning and
quartering) Oven dry 105 o C Send for detection
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Quality Control By analyzing the reference
material IAEA soil 375 in different counting
geometries (138 g cup) - checked performance of
analytical procedure. The result of 4347 ?
285 Bq/kg Cs- 137 Concentration was obtained for
31.07.03. The reference value (from certificate)
equals to 4642 Bq/kg and the confidence interval
quoted is 4546 4721 Bq/kg.   Analyzing the
sample from reference site (Ret 2) in similar
counting Geometry - checked performance of
analytical procedure.
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(Source SOP for Uncertainty Budget for Gamma
Spectrometry - AEA/NAT/Sop 08 )
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The main Cs137 peak is located at an energy of
661.5 keV. Interference from an overlapping
Bi214 peak at 665.5 keV. Count rate of Cs137 peak
was corrected for Bi214 interference using
interactive peak fitting option in Genie 2000 .
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Profile Cs137 activity distribution in a
reference site
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Cs137 levels of reference sites
Range 308 - 339 Bq m-2 Mean
318 Bq m-2 Variability 10
Detection Uncertainty 47 - 56 Bq m-2
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Cs137 levels Land use Tea (High MI)
Range 182 - 233 Bq m-2 Mean
212 Bq m-2 Variability 15
Detection Uncertainty 28 -34 Bq m-2
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Cs137 levels Land use Tea (Low MI)
Range 22 - 69 Bq m-2 Mean
53 Bq m-2 Variability 15
Detection Uncertainty 6 - 12 Bq m-2
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Cs137 levels Land use Secondary forest
Range 92 - 182 Bq m-2 Mean
127 Bq m-2 Variability 19
Detection Uncertainty 16 - 28 Bq m-2
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Cs137 levels Land use Vegetable and
Homestead
Range 43 - 111 Bq m-2 Mean
87 Bq m-2 Variability 22
Detection Uncertainty 10 - 20 Bq m-2
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TERRAIN OF THE AREA
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CURRENT LAND USE OF THE AREA
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EROSION LEVELS
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Soil loss calculations (Proportional model) Tea
(High MI) 17 t ha 1 yr 1 Tea (Low
MI) 43 t ha 1 yr 1 Secondary
forest 31 t ha - 1 yr 1 Vegetable and
home garden 37 t ha - 1 yr 1
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