"The proposed European Union regulation for labelling foodstuff, currently being considered in the European Parliament, should include advice for vulnerable groups about the mercury content of fish and seafood," the NGOs assert in a report released on 10 February.
The European Environmental Bureau (EEB) gave its backing to the call, insisting that the labelling of certain fish products "should be instituted without delay".
"All governments should agree on launching an International Negotiating Committee (INC) to start work immediately on a global mercury treaty next week [at the United Nations convention in Nairobi]," says Elena Lymberidi, coordinator of the EEB's Zero Mercury campaign.
To protect consumers against the risks of mercury ingestion, the Commission stated that "member states should be provided with all the relevant information to be able to issue consumer advice" and "consumers are entitled to receive concrete information where possible".
In particular, the EU executive stressed that "pregnant women or women who are breastfeeding should not eat more than one portion per week of large predatory fish, such as swordfish, shark, marlin and pike". Moreover, parents should be aware that young children "should not eat tuna more than twice per week".
Given the high levels of mercury pollution to which fish are exposed in the sea, the NGOs' report claims that eating fish can be "hazardous".
Indeed, it has been shown in a report by the United States Environmental Protection Agency (USEA) that the consumption of fish is by far the most significant source of ingestion-related mercury exposure in humans.
"Mercury contamination of fish and mammals is a global public health concern," said Michael Bender, co-author of the report.
Following tests of fish in different locations around the world, the study shows that "internationally accepted exposure levels of methylmercury are exceeded, often by wide margins, in each country and area".
Furthermore, the report emphasises that the risk is "greatest for populations whose per capita fish consumption is high".
"In cultures where fish-eating marine mammals are part of the traditional diet, mercury in these animals can add substantially to total dietary exposure," it adds.
Ivan Bartolo, spokesperson for the Sea Fish Industry Authority (SFIA), said the "EU-wide legal limits in place for mercury have been set following rigorous scientific assessments".
As for the risk of mercury ingestion, Bartolo said "it is true that specific groups, such as pregnant women, need to be aware of advice from their national food authority". "But in all other cases, we would encourage everyone to eat at least two portions of seafood a week, because of the overwhelming health benefits of eating fish," he added.
The report comes after the EU adopted a regulation banning all exports of mercury from the bloc in 2011, as part of a wider strategy to limit emissions of the toxic heavy metal into the environment (EurActiv 25/09/08).