Pre-concentration of naturally occurring radionuclides and the determination of 212Pb from fresh waters

Short-lived variations in the background gamma-radiation dose

“…Probability plots and the Anderson-Darling goodness-of-fit statistic were used to evaluate the optimum distribution of the results (Burnett 2007). This analysis indicated that the measurements were approximated by a normal and log-normal distribution, and the respective probability density function (PDF) compared well with the observed dose measurements with correlation coefficients (r 2 ) of 0.97-0.98.…”

“…This was also reflected by the similarity in arithmetic mean (AM) and geometric mean (GM), which had a value of 80 ± 8 nGy h of symmetry in the distributions was indicated by skewness values of 0.6-0.8 and the relative peakedness of the data by a kurtosis values of 2.3-4.1. However, a consideration of the principle of maximum entropy and the arguments of Bayesian statistics (Burnett 2007) would suggest that the log-normal PDF would provide the best approximation for a wide range of conditions (figure 2). Under these assumptions, the variability in the data is best described by the geometric standard deviation (GSD) value of 1.1 ± 0.1 nGy h −1 for both sampling periods, and not that of the arithmetic standard deviation (ASD) values of 3.6 ± 0.4 nGy h −1 in the first period and 3.3 ± 0.3 nGy h −1 in the second period.…”