Potentially Toxic Elements in Virgin Vegetable Oils: Health risks, and Associations with Oil Quality and Bioactivity

Virgin vegetable oils are an essential dietary source of bioactive lipids and antioxidants, but they can also be carriers of potentially toxic elements. This study aimed to provide an integrated evaluation of the nutritional quality and toxicological safety of nine commonly consumed virgin oils in Morocco, including argan, chia, sesame, soybean, coconut, almond, peanut, sunflower and flaxseed oils. All of the oils were collected in 2023 from local producers in the Fes-Meknes region, and their nutritional and toxicological profiles were compared to those of virgin olive oil. Thirty cold-pressed samples were analyzed for arsenic, chromium, cadmium, lead, nickel, and copper by inductively coupled plasma optical emission spectrometry after microwave-assisted acid digestion. At the same time, the physicochemical parameters, fatty acid profiles, polyphenol content, and antioxidant activity were determined. All samples complied with international safety standards for potentially toxic elements. However, oils rich in polyunsaturated fatty acids and antioxidants showed greater sensitivity to metal interactions and oxidative processes. Virgin olive oil showed the highest polyphenol content (349.5 mg of gallic acid equivalents per kilogram), whereas coconut oil exhibited the lowest antioxidant capacity. A strong positive correlation was observed between the proportion of saturated fatty acids and IC₅₀ concentration values obtained from the 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) assay (r = 0.977). Hazard Index below 1, indicating no immediate non-carcinogenic risk, while carcinogenic risk estimates for nickel, lead, and arsenic suggested a moderate long-term risk. The integrated assessment showed that all virgin oils were safe for consumption, but their nutritional quality and oxidative stability depended strongly on fatty acid composition and antioxidant content, with virgin olive oil showing superior antioxidant richness and stability compared to the other oils, highlighting the need for regular monitoring to ensure both nutritional value and toxicological safety.