Leaching tests to assess the release of 210Po from discarded cigarette butts

In this study, the concentration of 210Po was determined by alpha spectrometry after its spontaneous deposition on a silver disk from butts of the most popular cigarette brands in Italy. When assessing the effects of this radionuclide on human health, its leachability in the environment by aqueous solution must be taken into account. Hence, the presence and mobility of 210Po in cigarette butts were assessed. The results obtained using two different procedures (batch extraction and column percolation) were compared in terms of radionuclide release. Five solutions at different pH were used for leaching tests to simulate a closed system environment: Leachant A: 0.4 M MgCl2, pH = 6.5; leachant B: CH3COOH + CH3COONa pH 5; leachant C: CH3COOH, pH 2.5; leachant D: 0.02 M HNO3 and 30% H2O2 and (ratio 3:5), pH <1; leachant E: NaOH pH 8. Overall, leachants B and C showed a greater ability to dissolve the elements than the other leachants that were tested. On the other hand, low acid or alkaline environments did not promote the leachability of elements. The ratio between the total % extraction using the bath test and the total % extraction using the column percolation test was >1 (mean ± SD: 1.66 ± 0.40). Hence, it appears that the column percolation test, which provides a better approximation of the leaching process under natural conditions, may leach out a larger amount of the radionuclide than the batch extraction test.