Treatment of measurement values below the decision threshold according to ''Berichterstattung gemaess der Richtlinie zur Emission- und Immissionsueberwachung kerntechnischer Anlagen'' by the ''working group on environmental monitoring''

The specification of measurement values below the decision threshold always causes difficulties; instructions have been proposed such as 'lower than decision threshold' ('<GE'), half of the decision threshold ('(1/2)GE'), other values between zero and the decision threshold or simply the value zero. In some fields after much discussion the decision has been made to use zero, e.g. in the Working Group on Environmental Monitoring of the German-Swiss Radiation Protection Association, which uses this value in its paper 'Berichterstattung gemaess der Richtlinie zur Emissions- und Immissionsueberwachung kerntechnischer Anlagen'. It will be shown why the value 'zero' is statistically substantiated and that the false estimation associated with this specification is within the boundaries of the - in any case - existing variances of the measurement values and its therefore suitable for radiation protection purposes. (orig.)