Determination of Heavy Metals in Selected Types of Local and Imported Tea from Iraqi Markets
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Abstract
The presence of heavy metals in plants, including tea plants, is influenced by factors such as the plant's origin, geographic location, soil geochemistry, and environmental contaminants in soil, water, and air. Elevated concentrations of heavy metals pose serious health risks to humans, including the potential for various cancers and damage to vital organs such as the liver, kidneys, and brain. In this study, seven tea samples were collected from the Iraqi market to examine their safety for consumption, indicated as T1-T7. The selection of the samples is based on a questionnaire answered by 140 individuals; T1-T6 samples are black tea, and T7 is green tea. Although the primary objective of this research is to determine the heavy metal content and toxicity of all the tea samples, the secondary one is to assess whether the drying process affects the levels of heavy metals by comparing green and black tea. The analysis is conducted on the samples via the Energy-Dispersive X-ray (EDX) and atomic absorption spectroscopy (AAS). The EDX results showed the presence of S, K, Al, and P in the T1 sample, while K, Al, and Mg were identified in the T2 sample, S, K, Al, and P in T3, only K in T4, K and Fe in T5, K, P, and S in T6, and Only K in T7. The results obtained from the AAS showed that all samples have normal concentrations of Fe and Zn but not for Ni (in samples T1, T2, and T3) and manganese (in samples T1, T2, T4, T5, T6, and T7). Those detected concentrations are higher than the permissible levels, and their levels are within the toxic limits according to the standard limits set by the World Health Organization (WHO) and the Food and Agriculture Organization (FAO). However, the other heavy metals (Cd, Cu, Pb, Cr, and Co) were either not detected or were below the detection limits of AAS, indicating that these samples are free from the mentioned toxic heavy metals.
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