Similarly, the highest radon concentration in 15 tap water
samples in Table 2 was found to be 0.2070.05 Bql1 in M1 with
an average value of 0.1270.01 Bql1 and the average annual
effective dose for ingestion was found to be 0.8670.07 mSv y1.
The highest radium concentration was found to be
0.1770.08 Bql1, then the mean annual dose resulting directly