Test: Chemicals in canned tuna

4. okt 2016

Canned tuna contains heavy metals but in varying amounts. This is the result of a test of 14 canned tuna products. The cans are free from bisphenol A which is a potential endocrine disruptor, but five of the cans contain a substance which bisphenol A forms part of.

tun-test-daaser-2.gif

Tuna chemicals
Photo: The Danish Consumer Council THINK Chemicals

Many cans without bisphenol A

Cans with bisphenol A have attracted much attention for many years because bisphenol A, among other things, is a potential endocrine disruptor.

The Danish Consumer Council THINK Chemicals found no bisphenol A in the 14 tested canned tuna products. In five products however we found a substance, BADGE, that bisphenol A forms part of. Those products have been given a yellow score. Read more about BADGE in "Behind the test" below.

See the test results for each product (In Danish).

Tuna with heavy metal

We found small amounts of heavy metal in all the fish.

Four products stood out however as they contained higher levels of heavy metal than the other ones.

Heavy metals come from pollution in the sea, accumulate in fish and may for instance affect the brain development.

Children and pregnant women should limit the intake of tuna because of the mercury content.

Sustainable tuna

The Danish Consumer Council THINK Chemicals has also evaluated the sustainability of the 14 canned tuna products.

Behind the test

How we tested 

The Danish Consumer Council THINK Chemicals submitted 13 cans of tuna in oil or water and one glass jar of tuna in oil for a chemical test in a laboratory.

We searched for the following substances:

  • Bisphenol A
  • Bisphenol F
  • Bisphenol S
  • BADGE - bisphenol A diglycidyl ether

Analyses for bisphenols and BADGE were made on the coating on the inside of the cans or on the inside of the lid. In some cases we also searched for substances in the fish.

We also examined the content of heavy metals in the fish.

  • cadmium
  • lead
  • mercury

The content of phthalates and other plasticisers was also measured on the inside of the lid of the tuna in glass jar.

Read about how we conduct our tests in The Danish Consumer Council THINK Chemicals.

What we found 

Bisphenols

None of the 14 examined tuna cans contained bisphenol A, F or S in measurable quantities.

In five products we measured a content of BADGE, bisphenol A diglycidyl ether, which bisphenol A forms part of. BADGE was found in the cans and in some cases also in the tuna.

The content of BADGE was below the current threshold limit value in all five products.

We know however far less about BADGE than about bisphenol A.

In Denmark both substances are banned for use in packaging for food intended for children under three years of age. We have therefore given products containing BADGE a yellow score.

BADGE is also on the Danish EPA List of Undesirable Substances. The Danish EPA is in the process of indentifying, on behalf  of the EU and others, whether the substance can be an endocrine disrupter like bisphenol A.

Read more about the Danish EPA’s work on BADGE (external link)

Phthalates and plasticisers

The lid of the one tuna in glass jar that was tested contained traces of the phthalate DEHP and larger amounts of another plasticiser, ATBC.

The content of ATBC in the tuna was just around the current threshold limit value for the release of ATBC to foodstuff (60 mg/kg).

Heavy metals

All of the 14 tuna products contained detectable levels of cadmium and mercury, but in all cases the content was below current threshold limit values.

In four cases however the content was somewhat higher than in the other 10 tuna products.

Three of these get a yellow score, while ‘Havets fristelser Tun i vand’ that had the highest content of mercury (0.784 milligrams per kilo fish) gets a red score.