# The Private Water Supplies (England) Regulations 2016, Paragraph 8: Calculation of the ID

Extent: E+W+S+N.I.

(1) The ID must be calculated from—
(a) the measured radionuclide concentrations and the dose coefficients referred to as “standard values and relationships” in Article 13, and recommended for the estimation of doses from internal exposure in the definition of “standard values and relationships” in Article 4(96), of Council Directive 2013/59/Euratom laying down basic safety standards for protection against the dangers arising from exposure to ionising radiation, or
(b) more recent information recognised by the Secretary of State, on the basis of the annual intake of water (730 litres for adults).
(2) Where the following formula is satisfied, it can be assumed that the ID is less than the parametric value of 0,1mSv and no further investigation is required—
∑ i = 1 n Ci(obs) Ci(der) ≤ 1Where—
“Ci(obs)” means the observed concentration of radionuclide I;
“Ci(der)” means the derived concentration of radionuclide I;
“n” means the number of radionuclides detected.
Derived concentrations for radioactivity in water intend for human consumption
1 This Table allows only for the radiological properties of uranium, not for its chemical toxicity.
Origin
Nuclide
Derived concentration
Natural
U-2381
3,0 Bq/1
U-2341
2,8 Bq/1
Ra-226
0,5 Bq/1
Ra-228
0,2 Bq/1
Pb-210
0,2 Bq/1
Po-210
0,1 Bq/1
Artificial
C-14
240 Bq/1
Sr-90
4,9 Bq/1
Pu-239/Pu-240
0,6 Bq/1
Am-241
0,7 Bq/1
Co-60
40 Bq/1
Cs-134
7,2 Bq/1
Cs-137
11 Bq/1
1-131
6,2 Bq/1

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Source: https://www.legislation.gov.uk/uksi/2016/618/schedule/3/paragraph/8 (the official version)
Page: https://openlegislation.uk/private-water-supplies-england-regulations-2016/schedule-3/paragraph-8
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.