Agriculture & Food, Volume 10, 2022

Abstract: This study investigated the heavy metal concentrations and chemical compositions of the essential oils of Thymus pulegioides (Lamiaceae), growing on serpentine soils in the Eastern Rhodopes Mountains, Bulgaria. Elevated Ni content in soils does not affect the development of Thymus pulegioides and the quality and quantity of oil obtained from it. Forty-two components representing 98.38- 98.48% of the total oil were identified. The major compounds were determined β-caryophyllene (14.15-15.54%), germacrene D(16.55-17.11%), Sabinene (10.40-11.54%), caryophyllene oxide (8.41-9.65%), cis-beta- ocimene (6.62 -6.91%), trans-beta-ocimene (5.09- 5.32%), (-)- spathulenol (4.34 - 6.54%), α-cadinol (2.06-5.51%), β-selinene (3.15- 3.30%), δ-cadinene (2.07-2.17%), α-humulene (1.95-2.04%), and β- bourbonene (1.58-1.65%) in thyme oils. Thymus pulegioides can be considered as “accumulator plant”, containing high metal concentrations in the aboveground biomass. Concentrations for toxic elements (Ni and Cr) in herbs were higher than the permissible limits for consumption. The strict control of marketed herbs for toxic metal content, and people should be informed about the risk of collecting and consuming herbs from serpentine soils Thymus pulegioides found on serpentine soils are recommended to be collected only for pharmaceutical purposes.