Biological magnification, also known as biomagnification, is the increasing concentration of substances, such as pesticides and mercury, in organisms up the food chain. These toxins are absorbed by plants and animals lower in the food chain and become more concentrated in organisms higher up due to multiple exposures through predation. A classic example is the use of the pesticide DDT in the 1960s-70s, which became concentrated in bald eagles through their diet and nearly drove the species to extinction by interfering with reproduction. While natural in small amounts, human activities have increased mercury and other toxins in the environment that biomagnify up food chains and can have harmful neurological and health impacts on both wildlife and humans. Efforts are

1. Biological
Magnification
Cycle

2. What is Biological Magnification?
 Biological Magnification, also known as
Biomagnification, is the increase of substances that
occurs in food chains.
 These substances are usually found in contaminated
environments. Substances, such as pesticides and
mercury, are absorbed by organisms due to their
environment or the food they consume. The substance
then accumulates inside the cells.
 When an organism higher in the food chain eats
multiple organisms below, each of them containing
some of the toxins, the toxins becomes more
concentrated in the higher food chain. Since this
continues throughout the food chain, organisms higher
in the food chain are the ones who will obtain the most

3. Bioaccumulation
 Biological Magnification is often related with
Bioaccumulation, which is the increase of the toxic
substance in an organism’s body.
 These two terms are different:
o Accumulation pertains to harmful substances in a
living organism's body and its effects.
o Magnification deals with the substance being passed
along the food chain.
 Bioaccumulation will cause a number of problems within
the body that contains it.

4. How Biomagnification affects animals
 A common example of Bio magnification and Bioaccumulation is
the use of DDT in the 1960's and 1970’s. DDT, or
dichlorodiphenyltrichloroethane, was overly used by humans as a
pesticide. It soon found its way into the environment.
 DDT and other toxins eventually climbed up the food chain, and
affected the bald eagles, nearly driving them to extinction. The
DDT was absorbed by organisms which the bald eagles hunted,
such as fish and carrion. Each bald eagle would eat multiple
numbers of these fish and carrion.
 The DDT would accumulate inside each of the eagles' bodies.
The DDT would sterilize the birds or cause them to make fragile
eggs that would break easily. This caused the birds population to
dwindle rapidly.

5. Bald Eagle Population
http://www.fws.gov/midwest/eagle/population/chtofprs.html
Figure 1

6. How DDT rises in a food chain

7. Mercury
 Mercury is a natural substance, that is found in very
small quantities in the ocean. Human interference with
the environment, causes higher levels of mercury in the
ocean.
 Algae, a producer, consistently absorbs the mercury
which is found in its environment. However, it excretes
it slowly. Often, zoo plankton will consume the algae
and the mercury along with it.
 The plankton is then consumed by small fish, which is
in turn consumed by larger fishes. Eventually, the fishes
end up on human dinner tables. Humans, who consume
fishes high in mercury, will easily become ill from
mercury poisoning.

8. Biological Magnification of Mercury

9. The Biological Magnification of DDT in a marine
ecosystem.

10. Toxins that Bio magnify
DDT and Mercury are not the only toxin that biomagnifies. Other
examples include, but are not limited to:
 PCB'S (polychlorinated biphenyls): used in insulators, as a
plasticizer, and fire retardant. It biomagnifies, impairs
reproduction and is widespread in aquatic systems.
 Cyanide is used in leaching gold and in fishing. It is a dangerous
toxin and is known to have effects on coral reefs.
 Selenium is concentrated by farming desert soils. It is toxic and
causes reproductive failures in organisms.
 Heavy metals such as mercury, copper, nickel, zinc, and lead
affect the nervous system and they may affect reproduction.

12. More Biological Magnification
http://jan.ucc.nau.edu/~doetqp-
p/courses/env470/Lectures/lec39/Lec39.htm
Figure 5

13. Why We Should Care
 Ironically, bio magnification 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 bio
magnification.
 Some cancers are also linked through ingesting these
toxins.
 It can also lead to organ failure in both animals and
humans.

14. Prevention of Bio magnification
 In an attempt to eradicate bio magnification, the U.S. and
several countries worldwide have placed a ban on the use of
DDT.
 People are trying to prevent harmful substances such as oil
and human waste from being dumped in water.
 Landfills are also trying to get rid of these substances
because they can seep into ground water.

15. Special Thanks / Citations
Information
 http://en.wikipedia.org/wiki/Biomagnification
 http://toxics.usgs.gov/definitions/biomagnification.html
 http://www.marietta.edu/~biol/102/2bioma95.html
 http://www.epa.gov/med/grosseile_site/indicators/erie_fish.html
 http://jan.ucc.nau.edu/~doetqp-p/courses/env470/Lectures/lec39/Lec39.htm

16. Special Thanks / Citations Continued
Pictures
 http://www.calgoldrush.com/graphics/images/contamination.gif
 http://image.wistatutor.com/content/ecosystem/biological-
magnification.jpeg
 http://www.corg/html/stitch.php?s=98965698293378&id=34347859802049f
keep.
 http://www.fws.gov/midwest/eagle/population/chtofprs.html

17. PREPARED BY:
ANGELIKA OLBOC
BIOLOGICAL SCIENCE
MAJOR