Assessing the Health Risk and the Metal Content of Thirty-Four Plant Essential Oils Using the ICP-MS Technique

Abstract

Natural ecosystems are polluted with various contaminants, and among these heavy metals raise concerns due to their side effects on both environment and human health. An investigation was conducted on essential oil samples, comparing similar products between seven producers, and the results indicated a wide variation of metal content. The recommended limits imposed by European Union regulations for medicinal plants are exceeded only in Mentha ×pipperita (Adams, 0.61 mg/kg). Except for Thymus vulgaris, the multivariate analysis showed a strong correlation between toxic and microelements (p < 0.001). We verified plant species–specific bioaccumulation patternswith non-metric multidimensional scaling analysis. The model showed that Adams, Doterra, Hypericum, and Steaua Divina essential oils originated fromplants containing highmicro andmacroelement (Cu,Mn,Mg, Na) levels. We noted that the cancer risk values for Ni were the highest (2.02 ×10-9–7.89 ×10-7). Based on the target hazard quotient, three groups of elements were associated with a possible risk to human health, including As, Hg, and Cd in the first group, Cr, Mn, Ni, and Co in the second, and Zn and Al in the third. Additionally, the challenge of coupling inter-element relationships through a network plot analysis shows a considerable probability of associating toxic metals with micronutrients, which can address cumulative risks for human consumers.