Effect of Salinity Stress, Phosphate Fertilizer, and Cadmium Contamination on Cadmium Fractions in Tobacco Cultivated Soil

Absorbed cadmium (Cd) in the body is the source of many known cancers. The absorption of Cd through tobacco smoke inhalation is much greater than drinking and eating Cd contaminated food. This research was carried out to investigate the effect of irrigation salinity, TSP, and Cd contamination on the concentration of Cd in the ash, tobacco smoke, and the fate of Cd in the different soil fractions. The experiment was done with three factors of irrigation salinity (0, 20, and 40 mM NaCl), TSP (0 and 1.5 g. kg-1 soil), and contamination of Cd added to the soil (0 and 12 mg.kg-1 soil) by factorial arrangement in a completely randomized design with four replications. The results showed that the highest concentration of Cd in the Cd contaminated soil was observed in carbonate fraction with a total average of 6.84 mg.kg-1, and the lowest Cd concentration was observed in the iron oxide fraction with a total average of 0.4 mg.kg-1. Application of TSP in the Cd contaminated soil in salinity of 0, 20, and 40 mM increased the concentration of Cd in tobacco ash by 1.47%, 15.98%, and 29.87 percent, and the concentration of Cd in smoke increased by 23.20%, 23.30%, and 18%, respectively, compared to the control treatment. By increasing the salinity levels in Cd contaminated soils, Cd concentration of solution+exchangeable fraction in 20 and 40 Mm salinity, was increased with an average of 22.15% and 42 percent, respectively. This increase was significant at 5% level. Application of TSP in Cd contaminated soils and at levels of 20 and 40 mM salinity resulted in a decrease of 14.65% and 12% in solution + exchange Cd concentration compared to the control. The interaction of irrigation salinity with phosphate fertilizer had a synergistic effect on the concentration of Cd in ash and tobacco smoke.