SCHEDULE 3MONITORING
PART FIndicative dose
Screening for gross alpha activity and gross beta activity3
1
The enforcing authority may use screening strategies for gross alpha activity and gross beta activity (or, where appropriate, residual beta activity after subtraction of the potassium-40 activity) to monitor the water for indicative dose.
2
Subject to sub-paragraph (3), screening levels must be set at—
a
0.1 Bq/l for gross alpha activity; and
b
1.0 Bq/l for gross beta activity.
3
The enforcing authority may set alternative levels to those specified in sub-paragraph (2) if it can demonstrate that these will ensure that an indicative dose of 0.1 mSv is not exceeded.
4
If the gross alpha activity is less than 0.1 Bq/l and the gross beta activity is less than 1.0 Bq/l, the enforcing authority may assume that the indicative dose is less than 0.1 mSv.
5
Where sub-paragraph (4) applies, the enforcing authority is not required to carry out a radiological investigation unless it is aware—
a
that specific radionuclides are present in the water; and
b
that these are liable to cause an indicate dose in excess of 0.1 mSv.
6
If the gross alpha activity exceeds 0.1 Bq/l or the gross beta activity exceeds 1.0 Bq/l, the enforcing authority must carry out an analysis for specific radionuclides.
7
The enforcing authority must, in deciding which radionuclides require to be measured for the purposes of sub-paragraph (6), take into account all relevant information about likely sources of radioactivity.
8
If elevated levels of tritium are detected in a sample, the enforcing authority must also measure the gross alpha activity and gross beta activity in that sample.