Activists are demanding an outright ban on serving tinned tuna in hospitals and schools after toxic levels of mercury were detected in the store-cupboard favourite.
The environmental campaigners also accuse food safety bodies and tuna firms of ‘cynical lobbying’ that serve ‘economic interests… to the detriment of health’.
For the past five decades, the mercury threshold has been three times higher for tuna than for other fish ‘without the slightest health justification’, they added a spokesperson from Bloom, which aims to preserve marine environments.
The calls come after Bloom and consumer-rights organisation Foodwatch published an alarming report that revealed just how pervasive the contamination is.
As revealed last week by MailOnline, tests on almost 150 tins purchased in France, Italy, Spain, Germany and Britain, found all contained mercury and 57 per cent exceeded safe limits for many fish.
Exposure to the metal can impair brain development, trigger life-threatening lung damage, cancers and can cause birth defects if consumed by pregnant women.
According to the World Health Organisation (WHO), which considers it a major public health concern, on a par with asbestos and arsenic.
The researchers claimed they has uncovered ‘a colossal risk to public health’ and urged Governments to take ‘urgent’ action.
Studies have found that in very high doses, some forms of mercury can trigger the development of several types of tumours in rats and mice
The average European consumes over 2.8 kilos of tuna per year, or roughly 25 cans.
Karine Jacquemart, CEO of consumer rights organisation Foodwatch France said: ‘What we end up with on our dinner plates is a colossal risk to public health that’s not considered seriously.
‘We won’t give up until we have a more protective European standard.’
Around four-fifths of the mercury put into the atmosphere from natural and human causes, such as burning coal, ends up in the ocean where some is converted by tiny organisms to a toxic compound known as methylmercury.
This methylmercury works its way up the food chain and accumulates in top predators in high concentrations.
As tuna — and other predators or longer-living species like sharks or swordfish — are higher up the food chain, they eat smaller fish and accumulate more mercury over time.
Under current EU and UK law, the limit for mercury in tuna is 1 mg/kg and 0.3 mg/kg for other fish such as cod.
But the canning process means that mercury concentration is doubled or tripled, according to Bloom.
Exposure to the metal can impair brain development, trigger life-threatening lung damage and has been linked to some cancers
In a statement Bloom said: ‘Since the 1970s, the public authorities and the powerful tuna lobby have knowingly chosen to favour the economic interests of industrial tuna fishing to the detriment of the health of over hundreds of million tuna consumers in Europe.
‘This cynical lobbying has resulted in the setting of an “acceptable” mercury threshold three times higher for tuna than for other fish species such as cod, without there being the slightest health justification for a different threshold.’
Bloom and Foodwatch are calling for a stricter limit of mercury in tuna, the same as for other species, of 0.3mg/kg instead of the current 1mg/kg.
And they say tuna products must be banned from hospitals — including maternity wards — schools and care homes to protect vulnerable people.
Mark Willis, head of chemical contaminants at the UK’s Food Standards Agency, told The Independent: ‘We advise those who are trying for a baby or who are pregnant to have no more than four cans of tuna a week or no more than two tuna steaks a week.
‘This is because tuna contains higher levels of mercury than other fish.’
A spokesperson for Europêche, which represents fishing fleets, denied the claims in the report, calling it ‘misleading’.
They added: ‘Canned tuna products offered to EU consumers adhere strictly to European regulations, which are based on scientific criteria for safe maximum daily intakes.
‘These thresholds are carefully set by experts from the European Food Safety Authority to ensure consumer safety.’