137Cs and 40K in some traditional herbal teas collected in the mountain regions of Serbia.

Herbal teas are an important part of traditional medicine in Serbia. The objective of the present study was to determine the activity concentrations of (40)K and (137)Cs in herbal tea, using the gamma spectroscopy method. The samples were collected during the period 2011-2012 in three mountain regions in Western and Central Serbia. The activity concentrations of (40)K and (137)Cs were found to be in the range of 130-1160 and 0.7-124 Bq kg(-1), respectively. The average annual effective dose equivalents from ingestion of (40)K and (137)Cs for an adult person consuming one cup of herbal tea daily were found to be 588.4-5250.2 nSv for (40)K and 4.0-706.1 nSv for (137)Cs. Our investigation showed that the herbal teas originating from Maljen, Zlatibor and Tara mountains are radiologically safe for human consumption.