## 3 Results and Discussion
### PAHs in Dried Medicinal Plants and Infusions
[PERSON] and [PERSON] (1995) mentioned that PAH absorption from soil is very reduced, and the respective compounds accumulate in plants mainly through the air-plant path rather than through the soil-root path [24]. At the same time, [PERSON] et al. (2009) showed that in the case of HMW compounds, the root systems of plants prove to be major pathways involved in their absorption [25]. Taking into account the aspects mentioned above, we can conclude that in this study, the concentrations of PAHs are especially influenced by the species and the characteristics of the environment in which the plant developed. Also, taking into account the quality criteria regarding medicinal plants, we could exclude the age of the leaves because young plants are collected for therapeutic purposes. On the other hand, in our study, we can exclude the aspects reported by some authors, who analysed green, black and yerba mate tea that was processed in various ways (steaming, smoking, exposure to the sun, fermentation or heating in ovens) [26; 27; 28; 29]. In the case of medicinal plants, according to the protocol, drying is carried out in dry spaces protected from light, possibly with ventilation, which would not bring additional amounts of PAHs. So, in the case of the dried medicinal plants, the possible origin of PAHs would be contamination from the environment of the crops. The results in Table 3 show the PAH levels in plants influence their concentrations in infusions, showing different values for the individual compounds. The presence of both LMW-PAHs (Flu and Ph) and HMW-PAHs (BaP and BabF) compounds is also observed, especially in _Achillea millefolium_. The infusions analysed revealed the presence of 16 PAHs in the following order: _Achillea millefolium > Tilia_ sp. > _Calendula officinalis > Taraxacum officinal > Hypericum perforatum > Crataegus monogyna > Matricaria chamomilla > Artemisia absinthtium_. The data presented show that the dominant compound in both dried plants and infusions is BaP, which has been considered for many years as a marker of PAH contamination in food. Its concentration varies from 22.18 \(\pm\) 2.81 ng/L (_Matricaria chamomilla_) to 436.21 \(\pm\) 12.56 ng/L (_Crataegus monogyna_). Similarly, fluorene and phenanthrene were also present in the infusions at high concentrations in _Hypericum perforatum_ (510.0 \(\pm\) 32.14 ng/L) and _Calendula officinalis_ (512.95 \(\pm\) 38.21 ng/L), respectively. Some authors have mentioned that PAH absorption and transformation processes by the plant can determine differences in PAH levels in infusions [30]. This was also shown in our study, in the cases of _Taraxacum officinal_ and _Artemisia absinthium_, where the dry products were heavily contaminated, while the infusions had a relatively lower content of PAHs. This discrepancy confirms that there is no obvious relationship between the levels of contamination of the dried plant and its infusion. The level itself depends on parameters such as the type and composition of the plant from which the infusion was prepared. The average total PAH content (\(\sum\)16 PAHs) in the infusions varied between 612.55 \(\pm\) 46.12 and 2292.2 \(\pm\) 140.24 ng/L. These values are higher than the data reported by [PERSON] et al. (2019), reference [12], for herbal infusions (153-253 ng/L) but lower than those reported by [PERSON] et al. (2017), of 3471-3120 ng/L [31].