Urgent warning tinned tuna poses 'colossal risk to public health' due to cancer links

Nearly all tins of tuna purchased in France, Italy, Spain, Germany and Britain, and part of a study, "were contaminated with mercury," which is particularly dangerous for pregnant women and children

Tins of tuna sold in the UK could contain a toxic metal, experts have warned.

Methylmercury, which poses a particularly serious risk to pregnant women and children and has links to cancer, was found in almost all of the 150 cans purchased in France, Italy, Spain, Germany and Britain as part of a study.

Tests carried out on the tins showed "contamination" with the metal, which can impair brain development, trigger life-threatening lung damage. Researchers have claimed the probe showed the product was "a colossal risk to public health" and urged Governments to take "urgent" action.

Karine Jacquemart, CEO of consumer rights organisation Foodwatch France — one of the two groups behind the report, 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."

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. Foodwatch and Paris-based NGO Bloom, found that all 148 tins tested contained mercury — some 57 per cent of which exceeded the 0.3 mg/kg mercury limit.

One tin bought in a Paris Carrefour City store had a record level of 3.9 mg/kg, the report said — 13 times the 0.3 mg/kg limit. Bloom and Foodwatch urged the European nations to "activate a safeguard clause" to prevent the sale and promotion of products exceeding 0.3mg/kg.

They also called on governments to remove "all products" with tuna from school canteens, nurseries, maternity wards, hospitals, and care homes.

The average European consumes over 2.8 kilos of tuna per year, or roughly 25 cans. 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.

Exposure to methylmercury may damage the kidneys and nervous system, trigger issues with vision and raise the risk of cardiovascular disease. Pregnant women and children are particularly vulnerable to high levels of methylmercury, according to the World Health Organisation.

In very high doses, studies have found that some forms of mercury have triggered the development in several types of tumors in rats and mice.