It is known that the effect of biological magnification increases with higher trophic levels. Since, we are at the top of the food chain, how much are we affected by it? Is there any proof of humans affected by biomagnification? And should we be worried? Thank you, for your attention!

Edit: Before posting here I had searched on Google Scholar about 'effect of biological magnification on humans'. Not only I couldn't find anything specifically about humans, whatever I found were too complex for me to comprehend. (I'm not a student of Biology). Yet, some of those which I understood stated that, accumulation of substances upto hazardous levels poses health risk. What I am trying to know is that, have there been cases where we know biomagnification to have hurt humans?

Thank you again!

  • $\begingroup$ Short answer: yes. What has made you think otherwise? Your question suggests that you don't fully understand the concept of biomagnification -- the magnification takes place as you move up trophic levels . Being at or near the top would suggest we are strongly impacted by this phenomenon. $\endgroup$ – theforestecologist Apr 23 '19 at 14:37
  • $\begingroup$ For an example, see warning labels about mercury in seafood. (Seen recently on packages at the US Whole Foods grocery chain.) $\endgroup$ – jamesqf Apr 23 '19 at 15:54
  • $\begingroup$ @theforestecologist I understand the concept and I know it to be real. Neither am I thinking otherwise. Only I want to know should we be worried about it? $\endgroup$ – The Dude Apr 23 '19 at 16:21
  • $\begingroup$ @TheDude What would you differently if you were worried about it? $\endgroup$ – Bryan Krause Apr 23 '19 at 16:55
  • $\begingroup$ @BryanKrause Honestly, I was curious and just wanted to know. But after seeing your question, I guess, depending on its level of impact, I may tell my family and friends to become vegetarians (so as to stay in a lower trophic level and be less exposed to it). $\endgroup$ – The Dude Apr 23 '19 at 17:12
  1. What is biomagnification?

Biomagnification is the process by which chemical contaminants increase at a far greater rate than thermodynamics would predict. Specifically looking at organic / lipid soluble compounds. A very basic explanation is that as food is digested and the lipids are absorbed, chemical concentration (see Fugacity) within the food increases as it travels along the gastro-intestinal tract. As we consume more of the contaminated food it accumulates in our bodies, and if a threshold is passed can result in negative physical effects in our bodies.

  1. Have humans been affected?

Agent Orange - the US sprayed a significant amount of Vietnam with agent Orange, which contained dioxin. The persistent nature of the compound caused it to accumulate in the soil and vegetation, and eventually the contaminated vegetation was either consumed directly by the people, or by wildlife which in turn, could be eaten. The result was that even though the compound itself was relatively harmless to humans, as it travelled up the food web, the concentration increased via the mechanism described above. The same mechanism is what resulted in pesticides like DDT being banned in the 1970’s.

  1. Should we be worried? (Opinion)

Of course it is something that we should be aware of, and there are some guidelines with eating seafood / fish. Aquatic and marine systems typically can support a higher number of trophic levels and as such we should pay much more attention to seafood. For example, around where I live we have Fish Consumption Guidelines ) that encourage people to limit the number of fish meals per month, especially for women who are or planning to get pregnant. This allows time for our bodies to remove the accumulating compounds before reaching dangerous levels. Therefore, you do not need to eliminate higher trophic organisms from your diet, just enjoy them in moderation and not excess. Knowing where your food comes from also helps in making these decisions.

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  • $\begingroup$ Your wiki link mentions both the negative human impacts as well as biomagnification, but it doesn't explain in what way biomagnification of agent orange has impacted people. Please consider finding a source that supports your claim more directly. Thanks. $\endgroup$ – theforestecologist Apr 23 '19 at 17:58
  • $\begingroup$ @theforestecologist - there is an entire section regarding health effects on the Vietnamese people. Are you asking for a more mechanistic approach? $\endgroup$ – markmryder Apr 23 '19 at 18:03
  • $\begingroup$ Yes. Most people know (and your link provides evidence) that people are negatively impacted by agent orange. But we're also harmed by nuclear bombs and malaria. How exactly does biomagnification play a role in the harm that agent orange causes humans? I did not see anything from your article that explicitly made that link. $\endgroup$ – theforestecologist Apr 23 '19 at 19:32
  • $\begingroup$ Minamata disease is another. en.wikipedia.org/wiki/Minamata_disease?wprov=sfla1 $\endgroup$ – The Dude Apr 27 '19 at 12:46

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