Analysis of methylmercury
Eurofins Food & Feed Testing Germany establishes advanced metal speciation analytics
June 2026. In February 2026, the European Food Safety Authority (EFSA) published a scientific report discussing the link between fish consumption and exposure to methylmercury. According to the report, unborn children are particularly at risk. Pregnant women, children and adolescents, as well as individuals with a generally high fish intake, may also be especially exposed – depending on the types of fish consumed.
Already in 2024, the German Federal Institute for Risk Assessment (BfR) commented on potential risks posed by methylmercury in fish and seafood, based on findings from the BfR MEAL Study.
From June 2026 onwards, the Eurofins network of Food & Feed Testing laboratories in Germany offers a new sensitive and selective IC‑ICP‑MS method for the quantification of methylmercury. Together with the established methodology for total mercury analysis, this enables a comprehensive assessment of mercury contamination in food and feed.
Formation and entry into food
Mercury is a nat urally occurring heavy metal that enters the environment through geogenic sources (e.g. volcanic eruptions or fires) and anthropogenic activities (e.g. mining, cement production). In aquatic environments and sediments, inorganic mercury is converted into methylmercury by microorganisms. Methylmercury accumulates in plankton and thus enters the aquatic food chain. The higher an organism is in the aquatic food chain, the higher its level of methylmercury. According to a 2024 statement by the German Federal Institute of Risk Assessment (BfR), species such as tuna and redfish exhibit particularly high concentrations of methylmercury.
Effects on human health
Elemental and inorganic mercury are absorbed only to a small extent in the gastrointestinal tract, whereas methylmercury is almost completely bioavailable. Following absorption, it is distributed throughout the entire body and can also be detected in umbilical cord blood, the placenta and breast milk in pregnant or breastfeeding women. Methylmercury accumulates primarily in the liver, kidneys and brain, a process facilitated by its long elimination half-life of 80 days. Methylmercury is highly neurotoxic, triggering symptoms such as tremors, perceptual disturbances and psychological changes. Already in 2012, EFSA established a tolerable weekly intake (TWI) of 4 µg/kg body weight for inorganic mercury and 1.3 µg/kg body weight for methylmercury in a Scientific Opinion.
According to EFSA (2012) (unborn) children are particularly vulnerable, as exposure can lead to developmental disorders. Pregnant women – who often consume more fish due to its perceived health benefits – as well as individuals with a generally high fish intake are also affected. The German Federal Institute for Risk Assessment (BfR) found in its BfR-MEAL-Study that adolescents and young adults aged 14-25 may exceed the TWI of methylmercury if they consume large amounts of fish or species with particularly high contamination level.
Legal situation
The European Contaminant Regulation (EU) No. 2023/915 sets maximum levels for mercury in fishery products, shellfish, food supplements and salt. The maximum levels for mercury in crustaceans, shellfish and fish muscle meat range from 0.3 mg/kg to 1 mg/kg. However, stricter limits apply to commonly consumed fish, such as salmon, trout or herring, than to fish that typically have high mercury levels (mainly predatory fish).
In addition, Directive 2002/32/EC sets maximum levels for mercury in various feed materials.
Analysis of methylmercury
A robust, accurate and sensitive methodology is essential for determining the (methyl)mercury content in food. Until now, our Production Centre for Metals and Elements has offered analysis of total mercury content using cold vapour atomic absorption spectrometry (CV-AAS) or (tandem) mass spectrometry with inductively coupled plasma (ICP-MS, ICP MS/MS). From June 2026 onwards, methylmercury will also be determined using ICP-MS following ion chromatography (IC-ICP-MS). This new method is also offered as part of a package with total mercury quantification using ICP-MS. This allows for a better assessment of the toxicological risk of a foodstuff, as the proportion actually absorbed by the body can be estimated.