Determination of some toxic heavy metal accumulation in medicinal plants commonly used in Gondar area district, Northwestern Ethiopia

Abstract

In Ethiopia, up to 80% of the population uses traditional medicines. The common sources of these medicines are plants.
However, medicinal plants are contaminated with environmental pollutants especially heavy metals, which pose a great
health risks upon long term exposures. Hence, this work was done to determine the level of three most common and toxic
metals (Arsenic, Cadmium and Lead) in ten medicinal plants commonly used in Gondar area district. The concentrations
of selected heavy metals were determined in medicinal plant samples using Flame Atomic Absorption Spectrometer and
Graphite Furnace Atomic Absorption Spectroscopy (for Cd and Pb) and Hydride Generation Atomic Absorption
Spectrometer (for As) after they were digested following the already developed method. The accuracy of the analytical
procedures was evaluated by performing spike recovery tests. The percentage recoveries were from 85 - 105%.The result
showed that the concentrations of the metals detected in the samples range from 0.03 – 2.06, 0.001 – 6.75, and 0.002 –
35.97 mg of metal per kg of sample for As, Cd, and Pb, respectively. Over all, out of each ten samples analyzed two for
Arsenic (20%), seven for cadmium (70%) and three for Lead (30%) were found to contain concentrations above maximum
WHO permissible limit (1, 0.3 and 10 mg/kg, respectively) which showed possible risk of toxic effects of the studied
metals in the medicinal plants used.