Index > 3 Characterisation of radioactively contaminated sites >

3.9 Site characterisation: Analysis of samples

The selection of appropriate analytical methods based on detection limits is important to survey planning. The detection limit of the method directly affects the usability of the data because results near the detection limit have a greater possibility of false negatives and false positives. Results near the detection limit have increased measurement uncertainty. When the measurement uncertainty becomes large compared to the variability in the radio-nuclide concentration, it becomes more difficult to demonstrate compliance using the guidance provided in EURSSEM.

The detection limits (i.e., minimum detectable concentrations; MDCs) have to be compared with radionuclide-specific results to determine their effectiveness in relation to the DCGL. Assessment of preliminary data reports provides an opportunity to review the detection limits early and resolve any detection sensitivity problems. When a radionuclide is reported as not detected, the result can only be used with confidence if the MDCs reported are lower than the DCGL.