210Po Log-normal distribution in human urines: survey from central Italy people.

The death in London of the former secret service agent Alexander Livtinenko on 23 November 2006 generally attracted the attention of the public to the rather unknown radionuclide (210)Po. This paper presents the results of a monitoring programme of (210)Po background levels in the urines of noncontaminated people living in Central Italy (near the Republic of S. Marino). The relationship between age, sex, years of smoking, number of cigarettes per day, and (210)Po concentration was also studied. The results indicated that the urinary (210)Po concentration follows a surprisingly perfect Log-normal distribution. Log (210)Po concentrations were positively correlated to age (p < 0.0001), number of daily smoked cigarettes (p = 0.006), and years of smoking (p = 0.021), and associated to sex (p = 0.019). Consequently, this study provides upper reference limits for each sub-group identified by significantly predictive variables.