Biology Decision Case

1
Biology Decision Case

• Biomagnification

2
The Problem

• Peregrine Falcons
• Extirpated
• from much of U.S.

http//www.iowaccess.org/main/news/newsimages/pere
grine.jpg
3
Osprey andBald Eagles were declining,as well.
http//www.state.tn.us/twra/graphics/BLDEAGLE.jpg
http//www.state.tn.us/twra/graphics/OSPREY.jpg
4
Meanwhile, in Borneo

• Roofs began to fall
• Gecko-eating cats began to die,
• and thriving rats brought plague and typhus
• The World Health Organization began to parachute
  cats into Borneo, but what was causing these
  problems?

http//www.herpafauna.com/pics/geckos/a-felinus.jp
g
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Finding the cause

• Roof collapse traced to disappearance of
  parasitic wasp which had controlled thatch-eating
  caterpillars.

http//www.life.umd.edu/classroom/bsci124/img/pari
sitoid.jpg
6
It seemed to be a chain

• Wasps disappeared because DDT had been sprayed
  to kill mosquitos, which carried malaria -
  number one killer of humans worldwide

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The data suggested DDT

• Measurements of DDT levels seemed to multiply as
  the compound moved up the food chain
• Water to zooplankton 800x
• Zooplankton  to fish 1 31x
• Fish 1 to fish 2 1.7x
• Fish 2 to gull 4.8x
• Overall 202,368x

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More evidence against DDT

• Eggshells from Peregrines with high DDT levels
  showed significant thinning

http//www.kodak.com/US/images/en/corp/features/bi
rdcam2000/gallery/04_03/13_32__2000_04_03_fullcam2
.jpg
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How does biomagnification work?

• DDT, a synthetic molecule, cannot be broken down
  or excreted Life doesn't have enzymes that
  "know" how.
• Thus, it concentrates as animals higher on the
  food chain eat more and more food.

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Solutions

• Ban DDT
• "Hack out" captive-bred
• peregrine chicks
• Build nest platforms for Osprey

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How effective were these solutions?

• Peregrines, Osprey, and Bald Eagles recovered
• However,
• Other countries still use DDT
• and
• DDT isn't the only chemical that biomagnifies!

12
The problem magnifies

• MethylMercury concentrates just like DDT and
  damages human
• Nervous Systems
• A person who eats one meal of lake trout from
  Lake Michigan will be exposed to more PCBs in one
  meal than in a lifetime of drinking water from
  the lake!

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The Problem is ongoing

• PCBs (polychlorinated biphenyls)
• PAHs (polynuclear aromatic hydrocarbons)
• Heavy metals
• mercury
• copper
• cadmium
• chromium
• lead
• nickel
• zinc
• tin
• TBT (tributyltin)
• mercury from gold mining
• cyanide
• selenium

• The number of new molecules we introduce into our
  environment continues to increase.

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The Ultimate Solution?

• Models are being developed to predict toxicity of
  new chemicals
• Pollution control must be intensified
• Zero Tolerance in the Great Lakes?
• Education Increase awareness so
• everyone will decrease use and dispose of
  chemicals properly.

15

• "This we know The earth does not belong to man
  man belongs to the earth. Whatever befalls the
  earth befalls the sons of the earth. Man did not
  weave the web of life he is merely a strand in
  it. Whatever he does to the web he does to
  himself."
• - Chief Seattle

16
Bibliography

• "ToxFAQsTM for DDT, DDE, and DDD," ATSDRIC
  Information Center Division of Toxicology, Agency
  for Toxic Substances and Disease Registry,
  Atlanta, GA, June 11, 2001. lthttp//www.atsdr.cdc
  .gov/tfacts35.htmlgt 2/21/02
• Mader, Sylvia S. 1996. Biology - 5th Ed. WCB and
  Cox, G.W. 1997. Conservation Biology - 2nd ed.
  WCB lt http//www.marietta.edu/biol/102/2bioma95.
  htmlgt 2/21/02
• "Chapter 4 The Great Lakes Today Concerns"
  Government of Canada (Toronto, Ontario) and
  United States Environmental Protection Agency,
  Great Lakes National Program Office (Chicago,
  Illinois) The Great Lakes An Environmental
  Atlas and Resource Book, Third Edition, 1994,
  http//www.epa.gov/glnpo/atlas/glat-ch4.htmlgt
  2/20/02
• "Mercury In Your Community and the Environment."
  PUB-CE-239 98 Wisconsin Department of Natural
  Resources and the Pollution Prevention
  Partnership Last Modified November 29, 1999
  Environment Canada http//www.on.ec.gc.ca/glimr/
  classroom/millennium/mercury/mystery-e.html
• "Great Lakes Initiatie," Wisconsin Sea Grant,
  2001
• http//seagrant.wisc.edu/Communications/Publicati
  ons/One-pagers/CriticalPollutants.html 2/20/02