Biological Magnification and Bioaccumulation

Contributed by:
Sharp Tutor
In this presentation, we will be discussing biomagnification and bioaccumulation and their differences. Biomagnification, also known as bioamplification or biological magnification, is any concentration of a toxin, such as pesticides, in the tissues of tolerant organisms at successively higher levels in a food chain.
1.  What’s the deal about mercury poisoning?clip
2. Biological Magnification
What is it?
 Toxic pollutants enter the
ecosystem that are absorbed or
ingested by organisms. Some
substances accumulate in
organism’s tissue over time.
3.  An increase in the concentration of a pollutant
in a biological organism compared to its
concentration in the environment
 It is how pollutants enter a food chain
4. Ex. Biomagnification
 Water
 Phytoplankton
 Zooplankton
 Small fish
 Large fish
 Top Predator:
 Human, osprey, eagle, otter – highest
amount of toxic chemical
5.  Increase in the concentration of a pollutant as it
passes from one trophic level to the next
6.  Small amount in environment → Large
concentration at top of food chain
7. Substances such as pollutants become
concentrated as you move up the food chain
Energy passes through the food chain
Energy is lost as you move
up the Food Pyramid
Levels of toxins and harmful
substances can increase as you move
up the Food Pyramid
8. Bioaccumulation vs Biomagnification
 Both describe the
increase of the
amount of a
substance in an
organism (1,3)
 Bioaccumulation
occur within a single
organism (1)
 Biomagnification
occurs across trophic
levels (3)
9. Why should we care?
 Because the two processes
together mean that when we
release even small amounts
of pollutants into the
environment, eventually
they build-up in organisms
to toxic dosages
10. Where do pollutants come from?
 Coal burning power plants
 Factories
 Farms, lawns, and gardens.
11. Characteristics of pollutants:
 In order for biomagnification to happen,
substance must be:
 Long lived
 Soluble in fat
 Mobile
 Biologically active
12. Characteristics of pollutants:
Putting it into perspective:
 Only some substances biomagnify
 Most substances are water soluble and are
excreted into the water
 Many breakdown quickly
 Many are not biologically active
13. Follow link to video
 Example of DDT
14. Pollutants that undergo biomagnification
 Mercury
 Persistent organic pollutants (POPs)
15. 24 units
12 units
6 units
2 units
1 unit
16. Mercury in Fish
 Fish absorb mercury
 Larger fish eat many
small fish and build up
higher levels of mercury
 Some have been banned
for consumption for they
present a toxic risk
17. ”Madd as a hatter”
18. Origins of the term “Mad as a Hatter”
 Hg(NO3)2 Mercury is a compound that was
used to soften fur in the making of felt hats.
 The phrase “Mad as a Hatter”, and the Mad
Hatter of Alice in Wonderland -- both refer to
the toxic effect of mercury on the central
nervous system of the hat makers, producing
mental effects and "hatter's shakes".
19.  Elementary Mercury (Hg)
 Methylmercury (CH3Hg) – most toxic form
 Form ingested by consuming fish
 Concentrated in muscle tissue
 More in older fish than younger fish
 Note – changed from Hg to this form by
20.  Source: Emissions from coal-burning power
plants, metal processing, medical and other
 Made bioavailable by bacteria
 Inorganic mercury → Organic form of
mercury that is biologically active
21. Where in the US is it a problem?
 Low pH (acidic) lakes in Northeast and and
Northcentral US
 Everglades (FL)
 Certain Wetlands
 Coastal wetlands along San Francisco Bay,
Gulf of Mexico and Atlantic Coast
22. Impacts of Wildlife
 Loons – diet of fish
 Decrease in chicks in areas of high mercury
 Large concentration of mercury in eggs
 Great Egrets – study in Everglades indicates
behavior of juveniles is effected
 Deformities in developing animals
23. Risk to People
 Exposed by eating contaminated fish
 Pregnant women and children most at risk
 60,000 children born annually suffering
from neurodevelopmental problems due to
in utero exposure to mercury
24. Fish Advisories
 13 states have state wide advisories for fish
from rivers and lakes
 40 states have advisories on selected bodies of
 Parts of Eastern Coast and Gulf of Mexico
have advisories
25. Concerned about the fish you eat?
Recommendations per the FDA
 Avoid shark, swordfish, king mackerel and tilefish
= all are high in Mercury
 12 oz can be consumed a week of a variety of fish
and shellfish that are lower in mercury.
 Fish that are low in mercury are shrimp, canned light
tuna, salmon, pollock, and catfish.
 Note, albacore tuna has more mercury than canned
light tuna. You may eat up to 6 oz of it in a week.
26. Concerned about the fish you eat?
 Check out the Mercury calculator at
 For information on Sustainable Seafood
Choices check out Monterey Bay Aquarium
and print out a pocket sized card
27. Persistent Organic Pollutants (POPs)
 Also called organochlorines
 Synthetic organic chemicals that persist in the
environment and biomagnify through the food web
 Poses a risk to human health and the environment
 Pesticides, some plastics, paints, industrial chemicals,
bleaching, burning garbage
 Examples: DDT, PCBs, dioxin
28. Ban on POPs
 1995 UN estimated 20,000+ substances with
properties of POPs
 Stockholm Convention 2004, banned 12 worst
 “The Dirty Dozen”
 U.S. signatory in 2001
 Congress has not ratified
 Signed by
29. Stockholm Convention Treaty
The Dirty Dozen
1. DDT - pesticide 7. Dieldrin - pesticide
2. PCBs - Industrial 8. Endrin - pesticide
3. Dioxin - waste 9. HCB – pest/ waste
4. Furans - waste 10. Heptachlor - pesticide
5. Aldrin - pesticide 11. Mirex - pesticide
6. Chlordane - pesticide 12. Toxaphane - pesticide
30.  Environmental exposure – many will stay in
soil or water for decades
 Slow to breakdown
 Humans consume toxins via fish, meat and
32. DDT (dichloro-diphenyl-trichloroethane)
 Insecticide used to control malaria and typhus
by killing mosquitoes and lice.
 Commonly used after WWII
 Inventor received Noble Prize
 Overused on crops as a pesticide
33. Ex. DDT
 Concentration of
DDT increased 10
million times!
34. DDT problems
Eggshell thinning
 DDT interferes with metabolism of calcium
 Result - thin shells in predator birds such as
osprey, bald eagles, brown pelicans
 Birds unable to brood (aka sit on) their eggs
without breaking them
35. DDT problems (cont’d)
 Acts as a hormone disrupter, mimics estrogen
 Has impacted sex ratio in some birds
36. DDT - it’s a long term problem
 It has a half life of 15
year; it takes 15yrs for
its quantity to be ½ its
37. DDT - it’s a long term problem
 It has a half life of 15 Amount
year; it takes 15yrs for Remaining
its quantity to be ½ its 0 100 kg
original 15 50 kg
 Ex. If we start with 30 25 kg
100 kg, we will still 45 12.5 kg
have ~ 1 kg after 100 60 6.25 kg
yrs 75 3.13 kg
90 1.56 kg
105 0.78 kg
38. DDT current use
 Banned in US in 1972
 Still used overseas to prevent malaria
 Estimated it save millions of lives annually
in Africa
39. POPs are everywhere!
 Even Polar Bears have POPs
in their system
 Top predator
 All toxins in prey is
transferred to them, stored
in fat http://
 Concentration increases 5 – ffximage/2006/12/28/
10x each trophic level _300x387,0.jpg
40. Health Impact of POPs
 Some cause cancer, damage nervous system
 Some act like hormones (estrogens) leads to:
 Developmental changes, birth defects
 Reproductive and Behavioral problems
 Toxins can be passed to young
41. Thought to ponder
 Even pollutants in small quantities can build
up to toxic/lethal doses
42. Solutions to Toxic Pollution
 Worst ones are banned or no longer used in
 Still need to eliminate/reduce the processes
that create toxins (i.e. burning coal)
43. Why We Should Care
• Ironically, biomagnification and bioaccumulation are caused by humans but
also have a profound impact on us.
• It can lead to neurological effects such as mental retardation in infants who
contract it through their mothers.
• A weakened immune system is also the result of biomagnification.
• Some cancers are also linked through ingesting these toxins.
• It can also lead to organ failure in both animals and humans.
• Since some animals have weaker immune systems then humans, they will
die faster which can lead to extinction if it continues.
44. Question of the Day
Which group of pollutants is suspected to act
like hormones (estrogens)?
 Heavy metals
 Persistent organic pollutants (POPs)
 Inorganic plant nutrients
 Organic oxygen-demanding wastes
45. 