Levels of heavy metals in the raw and processed Ethiopian tobacco leaves

Abstract

Tobacco (Nicotiana tabacum L.) is a commercial plant. Tobacco leaves naturally accumulate and concentrate relatively high levels of heavy metals and particular cadmium in leaves. Tobacco is one of the basic agricultural products, in Ethiopia, with social and economic importance. However, there is no report in the literature on the determination of levels of heavy metals in Ethiopian tobacco leaves. Hence this research is intended to determine the levels of heavy metals in the raw and processed Ethiopian Virginia tobacco leaves. Samples of raw Virginia tobacco leaves were collected from two different regions of Ethiopia (Billate and Shewa Robit). The three processed tobacco samples were collected from National Tobacco Enterprise, Addis Ababa, Ethiopia. The samples were wet-digested using 3 mL HNO3 (69–72 %) and 3 mL HClO4 (70 %) at 350 °C for 3.5 h and concentrations of heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) in the samples were determined by flame atomic absorption spectrometer. The mean metals concentrations (in µg/g dry weight) in the raw Virginia tobacco leaves from Billate and Shewa Robit, respectively, were: Cu (4.38, 7.30), Zn (53.7, 33.2), Cd (1.20, 1.30), Cr (ND, 1.45), Ni (ND, 1.90). The mean metals concentrations (in µg/g dry weight) in the processed tobacco from Billate and Shewa Robit, respectively, were: Cu (9.80, 12.8), Ni (2.35, 2.20) Cd (1.45, 1.90), Cr (1.65, 1.75), Zn (101, 83.8). The mean metals concentrations (in µg/g dry weight) in the processed tobacco Nyala (Ethiopian cigarette leaves) were: Cu (8.95), Cd (1.55), Cr (1.62), Ni (4.70), Zn (79.3). The concentrations of Cr and Ni in tobacco leaves from Billate and Pb in all the tobacco samples were below the detection limits. This study showed that the metal contents of tobacco leaves varied with the geographical origin in which the tobacco plant grows. The metal contents of processed tobacco were higher than the corresponding raw leaves. Pb was not detected in both the raw and processed Ethiopian tobacco leaves.

Environmental Chemistry and Ecotoxicology of Hazardous Heavy Metals: Environmental Persistence, Toxicity, and Bioaccumulation

“…Bioaccumulation of toxic heavy metals in cigarette tobacco is a human health concern because tobacco leaves are used for making cigarettes. Tobacco plants naturally accumulate relatively high concentrations of heavy metals in their leaves, and the metal bioaccumulation in tobacco leaves varies with the geographical origin of the tobacco plants [94]. Tobacco crop is grown with application of commercial inorganic fertilizers especially phosphate fertilizers, which contain considerable concentrations of some toxic heavy metals.…”

Assessment of heavy metals in tobacco of cigarettes commonly sold in Ethiopia

“…Caruso et al (2014) have determined the toxic metal concentrations (As, Cd, Cr, Ni and Pb) in cigarettes obtained from U.S. smokers in 2009 under the umbrella of International Tobacco Control United States Survey Cohort. Regassa and Chandravanshi (2016) have reported the levels of heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) in the raw and processed Ethiopian tobacco leaves.…”

Mineral Contents of Selected Medicinal and Stimulating Plants in Ethiopia

“…The metal contents of processed tobacco were higher than the corresponding raw leaves. Pb was not detected in both the raw and processed Ethiopian tobacco leaves [33].…”

“…The levels of essential and non-essential metals in linseed samples collected from five different sites (Bale, East Gojam, Shoa, South Wello and Tigray) in Ethiopia were determined by flame atomic absorption spectrometry. The levels (mg kg -1 ) of metals determined were in the ranges Na (242-614), K (6,494-6,755), Mg (2,679-3,118), Ca (540-744), Cr (13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30), Mn (17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28), , Co (23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42), Ni (12-...…”