8.21.
The results of source monitoring and environmental monitoring in relation to a practice should be used to confirm that the actual doses which result from normal conduct of the practice comply with the criteria for public exposure.
8.22.
Whereas discharge limits are established by means of dose modelling for a critical group, the compliance of source monitoring data with the discharge limits ensures the compliance of doses estimated on the basis of source monitoring data with the exposure criteria if the same or a similar model is used. In particular, as the doses assessed on the basis of source monitoring results are clearly attributable to the source, the results from source monitoring should be used specifically to verify compliance with the dose constraints.
8.23.
When comprehensive environmental monitoring data relating to the major human exposure pathways are available, they should be directly used to assess the doses to critical groups and to ensure that discharges and radiation levels in normal conduct of the practice actually comply with the public exposure criteria. In the case of a single source of environmental discharges, the assessed dose should be compared with the appropriate dose constraint, and in the case of multiple sources of discharges of radionuclides the doses should comply with the 1 mSv per year limit.
8.24.
The dose received by individuals in the population should be derived from the results of environmental monitoring, with the natural background taken into account. The background levels should be subtracted from the results of the measurements so as to assess the doses due to practices only. Both statistically significant measurement data (above the detection limit) and measurements under the detection limits can be used for dose assessment purposes with the associated uncertainties taken into account.
8.25.
The source related doses can also be derived from the results of environmental monitoring by removing the base line, including natural background radiation and other sources. Such source related doses should nevertheless be interpreted cautiously since the fractions of radiation or radionuclide concentrations that are attributable to other sources may be subject to large uncertainties.
8.26.
Uncertainties in monitoring results should be fully taken into account in the assessment of doses and their comparison with public exposure criteria. Uncertainties should be taken into account in a conservative way; in other words, the assessed doses should encompass the actual doses received by the individuals of the critical group:
Both uncertainties in measurements above the detection limit and uncertainties in modelling should be taken into account to assess doses and their uncertainties;
Measurements under the detection limit should be assumed in the dose assessment to be the value of the detection limit, unless there are convincing reasons to assume that undetected radionuclide concentrations and undetected radiation levels are actually negligible.