Home > Food & Water > Fish and Heavy Metal Contamination

Fish and Heavy Metal Contamination

By: Helena Stratford - Updated: 6 Oct 2016 | comments*Discuss
Fish Metal Mercury Contamination Health

The heavy metal contamination of fish does not mean that the oceans are buzzing with the sound of salmon and tuna, head banging to AC/DC – although that would be a rather nice image!

Rather, it is the more serious issue of our marine life being poisoned by toxic levels of metals, which are then passed up the food chain.

What Are Heavy Metals?

Heavy metals such as zinc, iron, and copper are naturally occurring substances in the Earth’s crust. Some are needed by humans in trace amounts to maintain optimum body function, whilst others such as mercury, arsenic, and cadmium can be harmful. All metals can be toxic if levels are too high.

Why do Heavy Metals Contaminate Fish?

Marine animals such as fish are able to readily absorb metals and their bodies regulate to accommodate their presence. They are easily stored in fatty tissue and will bio-accumulate if the fish is exposed to further contamination.

Copper And Zinc

It has been found that the presence of copper in water affects the populations of fish even in very low doses. Metals such as copper and zinc can leach into water from the mining industry, via storm drains and from agricultural run-off from fields.

Although levels of these metals are monitored in water, at such low levels as 2 parts per billion they are considered almost too insignificant to worry about. However recent research has discovered that even at extremely low levels copper will disrupt the sense of smell of fish preventing them from detecting predators or recognising their eggs.

High levels of copper in humans can cause diarrhoea, stomach cramps, and vomiting.


There is currently triple the amount of mercury falling from the sky than at the time of the Industrial Revolution. It is also contaminating many areas as a result of unregulated gold mining.

The metal is absorbed by fish and other aquatic animals, and passed up the food chain to any other fish-eating species.

Scientists today are concerned that people who eat fish contaminated with mercury will be put at risk – particularly pregnant mothers and children as mercury poisoning has been shown to adversely affect brain development. However it is also being linked to a higher risk of heart disease and stoke in men as well as memory loss, and central nervous system damage.


Cadmium is a heavy metal which has been found in quite high quantities in larger fish like tuna and swordfish. This is because the metal accumulates over time and also because these fish are higher up in the food chain and so will be eating already contaminated prey.

Cadmium is very toxic to humans and has been linked to kidney disease, lung problems, and prostate cancer.

Should You Eat Fish?

Whilst it would be wise to watch the amount of fish you consume – especially if pregnant, there is also evidence from British scientists to support the theory that the health benefits of the beneficial nutrients from fish such as Omega 3 outweigh the negative effects of heavy metal contamination.

You might also like...
Share Your Story, Join the Discussion or Seek Advice..
When ordering fish for a restaurant, is there any area that would be questionable?
???? - 27-May-14 @ 7:10 PM
what are the limits of heavy metals in fishery products like arsenic, berllylium, nickel, chromium, cynides.
trevor - 16-Jun-11 @ 12:32 PM
Share Your Story, Join the Discussion or Seek Advice...
(never shown)
(never shown)
(never shown)
(never shown)
Enter word:
Latest Comments
    Re: Complaining About Smell Pollution
    I ordered the laminate flooring from UK Flooring Direct Limited online and fitted in March 2018.After that i noticed very…
    29 November 2018
  • Lenard
    Re: Complaining About Smell Pollution
    The person that resides in the apartment above my apartment about 2 weeks ago seems to be making something that has caused…
    24 November 2018
  • J M
    Re: Negative Effects of Sky Glow
    Honestly, this is extremely helpful to know especially because so many people in the world don’t pay attention to these things…
    26 October 2018
  • SeaSiderSeth
    Re: Complaining About Smell Pollution
    Hello. I'm the premises manager of a tv company in Clapham and recently Thames Water built 4 or 5 large storm drains all…
    15 October 2018
  • tolu
    Re: Complaining About Smell Pollution
    Hello i have a neighbor who lives behind my daughter and me he have Hogs there and this mail is excruciating it makes you…
    19 September 2018
  • Ben
    Re: Complaining About Smell Pollution
    Hello, we are in a new build semi detached house. We moved in at the same time as our neighbours last November. However over…
    8 September 2018
  • PollutionIssues
    Re: Complaining About Smell Pollution
    Lou - Your Question:What can I do about local farmer spreading putrid slurry/ fertiliser over fields near me? On a warm…
    14 August 2018
  • puppy
    Re: Complaining About Smell Pollution
    There’s a house being built across the field to our house. There is a constant smell of diesel which is making me and my…
    6 August 2018
  • Lou
    Re: Complaining About Smell Pollution
    What can I do about local farmer spreading putrid slurry/ fertiliser over fields near me? On a warm summer’s evening the…
    1 August 2018
  • savita sharma
    Re: Complaining About Smell Pollution
    Hi twice or thrice a week my neighbour do water intake in thire silver that produce horrible smell from his house its…
    27 July 2018