JRC validates simple method to monitor methylmercury in fish

At the moment official control bodies measure total mercury but methylmercury is the most toxic type of mercury and is most abundant in seafood. The ablity to measure methylmercury in seafood is fundamental for protecting the well-being of pregnant women and children. According to the Scientific Opinion of the European Food Safety Agency (EFSA) published in 2012, the major source of methylmercury intake in humans is fish and seafood products.

There is currently only a recommendation from the European Commission to breastfeeding and pregnant women and children to limit their consumption of big predatory fish such as tuna and swordfish. However, no maximum limits have been set up yet.  The European Commission needed a validated method for mercury speciation analysis to eventually introduce maximum limits for methylmercury in the legislation and ensure enforcement of the regulated limits in Member States. The European Commission requested the EURL-HM to validate a method which could be used by laboratories that do not run many methylmercury analyses per year and which do not have sophisticated techniques at their disposal. This simple method would not imply the use of any fancy technology, it is easy to implement and does not require experienced technicians neither to run the analyses nor to interpret the results.

The method used is based on a double liquid-liquid extraction, first with an organic solvent and then with a cystein solution.  The validation was carried out in collaboration with the National Reference Laboratory for heavy metals from Portugal (Instituto Português do Mar e da Atmosfera) and with the Laboratori Agència Salut Pública de Barcelona.

With the method validated by the EURL-HM, maximum levels could be introduced in the legislation if desired. It is a simple method that every laboratory can use. As from the 28 February 2013, the Standard Operating Procedure for the determination of methylmercury in seafood can be downloaded for free by any laboratory in the world.

Brief summary: Standard methods for mercury speciation analysis