The heavy metals content (HMs) was investigated in 14 different medicinal plants collected from the three regions in Central Serbia, Zlatar, Sokobanja, and Kopaonik. The concentrations of Cd, Cr, Ni, Hg and Pb were determined: Cd (<0.03–2.72 mg/kg); Cr (<0.08–12.1 mg/kg); Ni (<0.08–12.2 mg/kg); Pb (0.6–49.0 mg/kg); the Hg concentration was below the detection limit of 0.06 mg/kg in all samples. The daily intake of HMs due to ingestion of 200 mL of herbal infusion was in all cases below the recommended limit prescribed by the World Health Organization. The estimated daily intake values were below the values for the oral reference dose regulated by the U.S. Environmental Protection Agency (USA EPA). The target hazard quotient and hazard index for Cd, Cr Ni, and Pb were below 1. Nevertheless, due to the tendency of heavy metals to accumulate in the organism, attention should be paid to the daily intake of herbal infusion during long-term usage. Specifically, it is recommended to consume not more than one cup (200 mL) of infusion per day made from thyme (Mt. Zlatar) and blueberry (Mt. Kopaonik), and not more than two cups per day for other herbs.

In this study, the specific activity of ¹³⁷Cs was determined by gamma-ray spectrometry in 72 surface soil samples and 11 soil profiles collected from the territory of Belgrade 25 years after the Chernobyl accident. Based on the data obtained the external effective gamma dose rates due to ¹³⁷Cs were assessed and geographically mapped. The influence of pedogenic factors (pH, specific electrical conductivity, cation exchange capacity, organic matter content, soil particle size and carbonate content) on the spatial and vertical distribution of ¹³⁷Cs in soil was estimated through Pearson correlations. The specific activity of ¹³⁷Cs in surface soil samples ranged from 1.00 to 180 Bq kg⁻¹, with a mean value of 29.9 Bq kg⁻¹, while in soil profiles they ranged from 0.90 to 58.0 Bq kg⁻¹, with a mean value of 15.3 Bq kg⁻¹. The mean external effective gamma dose at 1 m above the ground due to ¹³⁷Cs in the soil was calculated to be 1.96 nSv h⁻¹. Geographic mapping of the external effective gamma dose rates originating from ¹³⁷Cs revealed much higher dose rates in southern parts of Belgrade city and around the confluence of the Sava and Danube. Negative Pearson correlation coefficients were found between pH, cation exchange capacity and ¹³⁷Cs specific activity in surface soil. There were positive correlations between organic matter and ¹³⁷Cs specific activity in surface soil; and between specific electrical conductivity, organic matter, silt content and ¹³⁷Cs specific activity in soil profiles.