Heavy metals such as lead, cadmium and mercury are among the environmental contaminants in foodstuffs which can pose health risks for consumers depending on their concentrations. Heavy metals can occur in the environment and therefore also in foodstuffs without human intervention, for example they occur naturally. However, they can also occur in the environment due to human activities, for example they can be anthropogenic. Heavy metals can also be introduced into foodstuffs through contaminated additives. It is not possible to clearly define the pathways of heavy metals into foodstuffs.
The naturally occurring mercury content of fish in the world's oceans, a source of food for humans, is so low that it does not pose a health risk. This does not apply, however, to species on top of the food chain such as swordfish, the Atlantic halibut or the shark which are exposed to high concentrations, mature slowly and have a long life. These fish may show a rather high mercury content under "natural" conditions. Therefore, in Germany maximum levels of one milligram per kilogram were laid down for mercury concentrations in fisheries products as early as 1975 to protect consumers' health. Another price increase was implemented in 1993. Corresponding provisions at EU level were stipulated in 1993.
Since April 2002, maximum levels for lead and cadmium in various foodstuffs such as cereals, vegetables, fruits, additives, foods for infants and young children, meat and fisheries products have been applied EU-wide to protect human health. These maximum levels are also stipulated in Regulation (EC) 1881/2006. When lead, cadmium and mercury levels were determined in the course of the annual food monitoring, only a small share of food samples exceeded the maximum levels for the heavy metals listed above.
Dioxins and polychlorinated biphenyls (PCBs) are environmental contaminants. Dioxins are unwanted and unavoidable by-products which must be minimised. They are mainly released through certain industrial thermal or combustion processes, in particular from sintering installations, metal production and residential fireplaces or woodstoves. Dioxins were not and are not produced intentionally. In contrast, PCBs were manufactured for a specific purpose, mainly as non-burning, non-conductive viscous liquids in transformers and hydraulics. Pollution legacies are the main source of dioxin and PCB emissions. Some compounds of these unwanted substances are chemically very stable, particularly toxic and persistent. Both groups of substances accumulate in human and animal fatty tissue. People generally absorb these harmful substances by eating food containing animal fat. In order to protect consumers, mandatory maximum levels (limit values) for non dioxin-like PCBs in various foodstuffs produced from animals were adopted as far back as 1988. These national limit values were supplemented in 2002 by Europe-wide mandatory maximum levels (limit values) and voluntary action values for dioxins and, since 2006, for dioxin-like PCBs in various foodstuffs. In early 2012 most national maximum levels for non dioxin-like PCBs were replaced by more stringent EU-wide maximum levels. These maximum levels are also stipulated in Regulation (EC) 1881/2006.
The analysis of the dioxin and PCB levels measured in air, water and soil reveals that the environmental protection measures taken so far have been successful. Overall environmental pollution with these substances, also referred to as background level, has been declining for years and is now very low. This also leads to relatively uniform nationwide low contamination levels in most foodstuffs with regard to both dioxins and PCBs. The background level today therefore as a rule does not lead to the admissible levels for these harmful substances being exceeded in food such as milk, meat or eggs.