Use of Low Cost Soil Amendments Reduces Uptake of Cadmium and Lead by Tobacco (Nicotiana tabacum) Grown in Medially Polluted Soils
Nyambaka, H. N.
Ngorwe, Evans Nyaenya
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The study explored the use of low cost soil amendments in reducing lead and cadmium uptake in tobacco. High levels of these metals in tobacco are of concern because of their toxicity and cumulative nature in tobacco consumers. Tobacco was planted in soils amended with cow manure and hydroxyapatite (HA), and non-amended sandy-loamy soil containing 60.57±3.74 μg/g lead and 33.95±0.49 μg/g cadmium in field and pot experiments. Tobacco leaves harvested after 75 days were dried, acid digested and their metal contents determined using atomic absorption spectroscopy (AAS). Cow manure reduced cadmium uptake by 67.20% and 71.75% in field and pot experiments while 1.5% HA reduced lead uptake by 39.69% in field experiments. Pot experiments had higher metals uptake than field experiments while fertilizer treatments recorded highest uptake. However, the levels were within WHO/FAO limits, indicating that amending medially polluted soils with cow manure and HA results in safe harvests of tobacco.