Heavy metals in Egyptian spices and medicinal plants and the effect of processing on their levels.

To determine the contamination of Egyptian spices and medicinal plants with heavy metals, a total of 303 samples, which represent 20 different types of spices and medicinal plants that were collected from areas of exportation in Egypt, were analyzed for heavy metals. Some of them have different growing seasons, and each has its own agricultural practices and several shipments. The results revealed that heavy metal contents in spice and medicinal plants depend on the plant species. The maximum levels of heavy metals in the analyzed samples were 14.4, 2.44, 33.75, 2.85, 0.10, 68.80, 343.0, 11.40, and 1046.25 microg/g for Pb, Cd, Cr, Ni, Sn, Zn, Mn, Cu, and Fe, respectively. Cobalt was not detected in any of the various samples under investigation. The levels of heavy metals determined in the analyzed samples were found to exceed the maximum allowable levels of Zentrale Erfassungs und Bewertungsstelle für Umweltchemikalien. The investigated medicinal plants were also processed by two different methods to determine the behavior of their metal contents during processing. It has been found that boiling the plant in water leads to the extraction of higher amounts of the metal from the plant than immersing it in the hot water. The achieved results were tabulated.