Determination of Lead, Cadmium and, Mercury in Some Medicinal Plants and their User’s Urine Samples

Abstract

Herbal medicines constitute an important part of healthcare throughout the
world. Although many benefits can be derived from the use of herbs, potential areas of
concern include possible product contamination and/or adulterations and potential
toxicity. This study evaluates the prevalence of toxic heavy metals, (Pb, Cd, and Hg), in
medicinal herbs and their level in urine samples of users of these herbs. 5 different types of
medicinal plants were collected from the herb market in Riyadh. A total of 60 urine
samples, consisting of 30 users and 30 control, was collected and processed for the
determination of toxic metals. The herbs were digested using (HNO3+HF+H2O2), while
urine samples were digested with (HNO3+H2O2). The heavy metals content in herbs and
urine samples were determined by AAS. The results showed that Cd and Pb concentration
in medicinal herbs did not exceed the maximum permissible levels of WHO, while Hg
exceeded the maximum permissible levels. On the other hand, the average concentration of
Cd and Pb in urine samples was less than the maximum permissible levels of WHO, while
the concentration of the Hg exceeded the maximum permissible levels of WHO indicating
associated toxicity and risk of using these herbs as therapeutic agents. This study have
proved that exposure to these metals through consumption of medicinal plants unsafe.