Since t is time after 20 days from TOA, the second expression contains a systematic error: the cumulative exposure for the interval is underestimated by a factor of exp(20λ). If this is truly a calculation error, rather than simply a documentation error, it could be large. However, this appears not to be a problem for 137Cs, in that λ is small. The impact of the error would depend on how many of the short-lived radionuclides considered had substantial gamma emissions. External gamma-ray exposure-calculation methods used should be checked for the possibility of the indicated systematic error. If it is determined that such an error exists, its impact should be evaluated for each gamma-emitting radionuclide of interest.
The committee suggests that the glossary include radioactive elements referred to in the text with only chemical symbols and include explanations of various models (such as linear no-threshold and linear-quadratic). The models are important in interpreting data in Chapters 3 and 4.