Survey on cadmium concentration in flue-cured, burley and oriental tobacco (Nicotiana tabacum) leaves
Cadmium (Cd) is classified as a known human carcinogen (Class 1) by the International Agency for Research on Cancer. It is one of the potential carcinogenic substances in tobacco products. Cadmium accumulation in crop plants such as tobacco ( Nicotiana tabacum L.) can lead to human exposure to this metal. Using inductively coupled plasma-mass spectrometry, we measured Cd levels in 755 leaf samples of the three principal tobacco types (flue-cured, Burley and Oriental) obtained from various countries. The aim was to identify patterns of Cd accumulation in tobacco leaves from a wide range of geographic regions. This knowledge could ultimately be exploited to define strategies that may be adopted to reduce Cd concentration in the tobacco leaf. The Cd concentrations reported here are compatible with those described in the scientific literature. Significant differences between tobacco types and between countries were found, but significant type x country interactions were recorded. Variations in Cd concentrations were reported for the same country and for even more geographically restricted sampling regions. The results suggest that field characteristics account for much of the variation in the Cd concentrations. Moreover, we investigated the relationship of the Cd concentration with that of other elements. The correlations between the concentrations of various elements and that of Cd differed according to tobacco type. Finally, we could discriminate the three tobacco types based on their capability to accumulate 20 elements in defined concentrations.