Uptake of cadmium, lead, and nickel by Origanum syriacum produced in Lebanon -

Abstract

Heavy metals are elements found naturally in the soil. However, the increase in polluting activities such as industrial, agricultural, medical, technological, and domestic has increased heavy metal contamination to an extent where human health, animal health, and the ecosystem as a whole has been put at risk. This issue has raised high concerns and caused high awareness assessments in the public health sector. This study was divided into three parts. The first part was conducted in a pot experiment at the greenhouse at AUB, Beirut, to study the effect of applying different concentrations of cadmium, lead, and nickel in soil on their absorption by Origanum syriacum plants. The second part was done to measure the concentrations of cadmium, lead, and nickel in selected soil and Origanum samples collected from several fields of different soil types in Lebanon. The third part was done to measure the concentrations of cadmium, lead, and nickel in Origanum syriacum selected from different sale outlets in Lebanon. Results for the first part showed that there was a positive relationship between the concentrations of cadmium, lead, and nickel in soil and that in Origanum syriacum tissue. In other words, the higher the concentrations of cadmium, lead, and nickel in soil, the higher the concentration was in Origanum plants. A significant difference was clearly seen between the control and the rest of the applied treatments. Results for the second part showed that none of the selected soil samples from fields in Lebanon were contaminated with cadmium, lead, and nickel because the levels did not exceed the maximum limits for any of the three elements. Results of the third part showed that the concentrations of cadmium, lead, and nickel in most of Origanum samples which were collected from different stores in Lebanon did not exceed the maximum limits set by the international organizations and governmental authorities; except one sample purchased from a major store in Beirut that was more than double the maximum limit for lead.