# Comparative Study of the Presence of Heavy Metals in Edible Vegetable Oils
###### Abstract  
Currently, the processes of obtaining and producing food as well as consumption habits give rise to new challenges for food safety. The presence of heavy metals in edible vegetable oils has harmful effects for humans. In this study, the scientific literature which reports the presence of heavy metals in different types of vegetable oils was analysed. More than 25 heavy metals are evaluated in 35 different oils from 24 countries. The widely studied metals are Cd, Pb, Cu, and Fe in olive oil, sunflower oil, rapeseed oil, and corn oils, mainly in Brazil, Turkey, China, Iran, and India. Likewise, the presence of Antimony (Sb) as a product of migration from PET containers to edible vegetable oils is a topic of great interest in recent years. Additionally, the different analytical techniques used for this purpose and the standards are analysed. This study highlights the main findings and challenges in this research field. heavy metals; olive oil; sunflower oil; rapeseed oil; corn oil; cadmium; lead; copper; iron; antimony; analytical techniques +
Footnote †: journal: Medical  
the abnormal presence of any extrinsic agent in food that may compromise the safety and health of humans. This presence can occur throughout the entire food chain or as a result of environmental contamination, but always under the premise that it has never been intentionally added to food [4]. At this point, the concept of food intoxication, or food disease, arises. This occurs when there is an incidental, accidental, or intentional ingestion of water and poorly prepared, or prepared food improperly preserved, due to physical, biological, and/or chemical contamination, i.e., toxins generated by bacteria or chemical products that can be found in food naturally. One type of chemical contamination is the contamination by the presence of heavy metals. These are a group of chemical elements that are not biodegradable and are highly toxic to humans, especially when the exposure is prolonged over time. Some of the most harmful are: cadmium, present in the environment due to erosion or industrial and mining activity; mercury, as a consequence of natural volcanic activity, mining activity, or paper industries; lead, a natural contaminant used in fuels, paints, varnishes, or pipes for water; or arsenic, used in pesticides, medicines, or ceramic objects [5]. Traces of heavy metals, such as arsenic, mercury, lead, zinc, nickel, or cadmium, were found in vegetables, meat, fish, or milk, due to mobility and bioaccumulation in water points. Similarly, heavy metals, such as cadmium, were found in molluscs, crustaceans, and shellfish. Depending on the type of heavy metal or the chemical and biochemical reactions in which it is involved, the health conditions are different, ranging from vital organ damage to different types of cancer [5]. In addition, continued exposure to low doses of heavy metals cause accumulation in the skeleton, nervous system, digestive system, cardiovascular system, or kidneys, forming stable metal complexes with proteins, vitamins, nucleic acids, and hormones, leading to pathological changes and a high health risk [6]. In a complementary way, human beings are also exposed to chemical contamination through migration from food packaging. In general, the migration term describes the diffusion process which is influenced by the interaction of the package material and the components of the food [7]. The selected packaging material can affect the nutritional quality and the safety of the food itself. This is why the packaging has to comply with legislation to guarantee safety and avoid possible contamination by transfer or migration of different compounds to food. An example can be the additives and non-polymerized monomers in plastic containers that can migrate to food products [8].