Appendix CRF - Part 3 - Northamptonshire County Council

Radiological Assessment 0820-2
Version 2
5.4 Leachate management and spillage
5.4.1 Leachate management
Specific doses to members of three exposed groups at a sewage treatment works
receiving leachate from the ENRMF are presented in Table 5.4. These results are
based on the Environment Agency’s Initial Assessment methodology (Environment
Agency 2006a; 2006b), which does not include the same range of radionuclides as
used in the remainder of the radiological assessment.
These results are based on the assumption that the sewage treatment works has an
overall throughput of 1,080 m 3 of effluent per day and that the average exchange rate
in the estuary is 30 m 3 / s. The specific doses for the STW worker and farming family
are sensitive to the throughput (decreasing as overall throughput increases), and the
specific doses for the fisherman are sensitive to the exchange rate (decreasing as the
exchange rate increases).
Radionuclide STW worker
Specific dose
(microSv / y per MBq / y)
Farming
family Fisherman
H-3 2.11E-09 2.83E-06 2.52E-09
C-14 7.78E-08 4.72E-03 1.30E-03
Cl-36 1.33E-06 7.78E-02 4.80E-09
Fe-55 2.00E-07 1.33E-03 1.00E-07
Co-60 4.94E-02 7.78E-01 1.87E-03
Sr-90 2.28E-05 2.17E-02 1.83E-05
Tc-99 1.17E-07 2.83E-01 2.10E-05
Ru-106 6.11E-04 3.06E-03 1.44E-04
I-129 2.44E-05 6.11E-02 6.67E-05
Cs-134 1.11E-02 1.17E-01 2.80E-04
Cs-137 4.11E-03 1.00E-01 3.50E-04
Pm-147 2.11E-07 1.67E-05 6.50E-07
Eu-152 1.39E-02 2.67E-01 3.67E-03
Eu-154 1.50E-02 2.72E-01 3.33E-03
Eu-155 3.33E-04 5.06E-03 6.17E-05
Pb-210 4.44E-04 5.33E-01 6.33E-02
Ra-226 2.22E-02 5.56E-01 1.83E-03
Th-230 3.22E-04 1.28E-02 3.67E-05
Th-232 4.89E-04 1.39E+00 2.23E-03
Galson Sciences Limited 48 14 July 2009
WS010001/ENRMF/CONSAPPCRF 598