## 3 Results and Discussion
### Heavy Metal Analysis  
In a previous study, heavy metals and the most studied edible vegetable oils internationally were identified [28]. Based on this foundation, the most studied metals were selected, which in this case, were cadmium (Cd), lead (Pb), iron (Fe), and copper (Cu). Table 11 presents the obtained results in Experiments A and B for the two types of olive oil (OO) analyzed, O04 and O1. In A, it was observed that cadmium (Cd) concentrations were below permissible levels in both T0a and T6. Copper (Cu) levels recorded in both oils, O1 and O04, were below the maximum recommended by Codex Alimentarius, which was set at 0.1 mg/kg. Both oils were under this threshold in both control sample (T0a) and treated sample (T6). Cu emerged as a predominant heavy metal, showing elevated levels among the analyzed metals, following antimony (Sb) and iron (Fe). Some studies suggest that recycled plastics, incorporated in small percentages into packaging, may contain trace amounts of Cu due to the use of copper catalysts in PET recycling processes [72]. Therefore, the presence of Cu could account for the elevated carbonyl index values in the O04 and O1 packaging, as this metal acts as a catalyst, accelerating PET degradation during treatments. Lead (Pb) levels were similar across both control sample (T0a) and treated sample (T6) for both oils. Fe was higher after treatments in oil O1 and remained constant in O04. Finally, Sb showed higher values only in O1 after treatments. The results obtained were below the limits specified by regulations for all heavy metals and oils studied. Previous studies have shown that thermal treatments on olive oils of various varieties increase antimony content as temperature and exposure time rise [25]. Although the trend was similar across the three varieties, Arbequina exhibited the highest Sb concentrations, exceeding the WHO limit of 20 ppb after three weeks at 60 \({}^{\circ}\)C. Temperature appears to be the most influential factor in migration, especially in the initial stages. Specifically, _P  
Figure 3: DSC curves in PET from mild (O04) and intense (O1) olive oil, where Tg is the glass transition temperature, and Tc is the crystallization temperature. highest increases in Sb, followed by _Arbequina_ and, finally, _Hoijblanca_. However, the study concluded that the specific characteristics of each oil variety (such as composition, physical properties, and surface tension) likely contributed to these results. The levels of all heavy metals were below the specific limits indicated in the regulations. In B, Cd showed a higher concentration in the most severe treatment (T12) than in the control sample (Tbb), both in O04 and O1. For Pb, Cu, and Fe, the results were lower in the most severe treatment (T12) compared to the control sample (T0b) in both oils, except for O04 and O1 in Sb, in which T12 was higher than T0b. It is important to note that the Sb levels obtained in the oils in this study are much lower than those in previous studies, which could be due to a substantial modification in the type of plastic being used or the type of catalyst, which is very satisfactory from a food safety perspective. The obtained results showed lower levels for all heavy metals and oils studied in relation to the regulations indicated above. These findings coincide with the obtained results by the authors mentioned in the initial referenced study [28]. The obtained results for Cd are lower than those determined in olive oils from Iran and Cyprus, with values between 0.094 and 0.097 mg/kg [73] and 0.09 mg/kg [74], respectively. In the case of Cu, other works determine values close to 0.10 mg/kg and others that exceed it significantly for olive oils. For proximity, there is olive oil from Iran, with values between 0.091 and 0.098 mg/kg [73], while among the results that exceed this limit are the oils from Ukraine and Cyprus, with values of 0.355 mg/kg and between 1.02 and 3.81 mg/kg, respectively [74; 75].