Term for a group of metals whose density or atomic mass exceeds a certain value. Colloquially, heavy metals are often considered "toxic substances". However, this is not correct, because iron, copper, manganese, molybdenum and zinc are among the heavy metals that are essential for life. Arsenic, lead, cadmium, chromium, nickel and mercury (amalgam) are considered dangerous above a certain amount. However, it depends on the amount, because in the human body some are required as essential trace elements, for example chromium between 10 to 20 mg for the regulation of the blood sugar level and according to the latest findings also arsenic up to 7 mg for various metabolic processes. The heavy metals are absorbed by plants from the soil and enter the food chain directly or via animals to humans and finally back into the soil. Since they are not degradable or only degradable with difficulty, they never get out of this cycle and end up in the wine via the grapes.
As already mentioned, certain heavy metals lead to the poisoning of soil, plants, animals or humans, depending on the quantity. In viticulture, they can be fixed in the soil by "passive measures" such as fertilisation with alkaline agents and thus made less harmful. During vinification, certain heavy metals such as copper or iron are removed from the young wine, if necessary, because they can cause a metallic note which, if more pronounced, is assessed as a wine defect. This is done with a special fining process. With regard to the maximum permissible quantities in wine, there are defined limits; see a list under ADI (Acceptable Daily Intake).
