Natural gamma radioactivity, ingestion dose, and excess lifetime cancer risk in medicinal plants from northern Morocco.

This study quantified naturally occurring gamma-emitting radionuclides (226Ra, 232Th, 40K) in eight medicinal plants collected from the Senhaja Srair region of northern Morocco using HPGe gamma spectrometry. 40K activities ranged from 214.66 to 1060.34 Bq kg-1 (highest in the Lamiaceae family), whereas 226Ra (0.23-2.10 Bq kg-1) and 232Th (1.07-4.03 Bq kg-1) activities remained low. The estimated annual committed effective dose by ingestion ranged from 8.04 × 10-6 to 1.36 × 10-5 Sv y-1 for adults and from 1.23 × 10-5 to 6.29 × 10-5 Sv y-1 for children. The corresponding excess lifetime cancer risk (ELCR) reached a maximum value of 2.20 × 10-4. These results indicate that the investigated gamma-emitting radionuclides contribute only a limited fraction of the estimated ingestion dose and provide baseline data on natural gamma radioactivity in medicinal plants from northern Morocco.