Influence of Zeolite and Posidonia oceanica (L.) in the Reduction of Heavy Metal Uptake by Tobacco (Nicotiana tabacum) Plants of Central Greece

In two soils from Central Greece, a pot experiment was conducted with the addition of mixture at various ratios of zeolite and compost (based on Posidonia oceanica (L.) leaves) applied at a rate of 5% w/w (calculated on a soil dry weight basis). Three varieties of tobacco (Burley, Virginia, and Oriental) were cultivated, and Cu, Zn, and Cd concentrations in tobacco leaves were measured at first, second, and third primings. We found that the addition of zeolite in the soil1 led to a significant reduction of metal concentration in all three tobacco varieties compared to the control. Also, zeolite addition reduced significantly the water-soluble, as well as, DTPA-extractable metal concentrations, compared to the other treatments. Our results suggest that the most effective amendment in soil 1 was the mixture consisting of 20% compost and 80% zeolite; this mixture led to higher reduction of metal concentration in all tobacco varieties. As for soil 2, which had almost twice as high Cd concentrations as than in soil 1, Posidonia compost was more effective in reducing Cd concentrations from all three tobacco varieties. In all cases studied, both in soils 1 and 2, Cd concentration was higher in Burley tobacco leaves. The results indicate that a mixture of zeolite and compost consisting of Posidonia oceanica (L.) is a low-cost soil conditioner that is effective in reducing tobacco Cu, Zn, and Cd uptake.