Cadmium content in soils and oriental tobacco leaves: A study in tobacco-growing regions of Southeast Bulgaria

Abstract

There is an extensive body of research on the content of harmful substances in tobacco raw materials and cigarette smoke. Data on the statistical relationships between the heavy metal content in soils and in tobacco plants are of interest. For this study, 38 soil samples and 38 samples from mature Oriental tobacco leaves (Nicotiana tabacum L., varietal group Basma, ecotype Krumovgrad) from the Eastern, Central, and parts of the Western Rhodope Mountains in Bulgaria were collected. Inductively coupled plasma atomic emission spectroscopy was used to measure the mobile (DTPA-extractable) forms and total content of the element Cd in soil, as well as the concentration of Cd in tobacco leaves. The basic soil characteristics: pH and texture were determined. Regression analysis was employed to study the statistical relationships between all measured variables. The total content of Cd in the soils ranged from 0.15 mg/kg to 3.30 mg/kg; and the mobile forms – from 0.02 mg/kg to 1.48 mg/kg. The Cd concentration determined in Oriental tobacco leaves varied between 0.05 mg/kg and 15.95 mg/kg. No visible symptoms of phytotoxicity were observed. Therefore, Oriental tobacco plants exhibited accumulating properties.