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Bi o m a g n i f i cati on. Bioaccumulation vs Biomagnification. Bioaccumulation: increase in concentration of a pollutant from the environment to the first organism in a food chain Biomagnification : increase in concentration of a pollutant from one link in a food chain to another.
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Bioaccumulation vsBiomagnification • Bioaccumulation: increase in concentration of a pollutant from the environment to the first organism in a food chain • Biomagnification: increase in concentration of a pollutant from one link in a food chain to another
Why use DDT? • Not particularly harmful to humans- therefore could be handled with few negative side effects • Very effective at killing insects- used extensively during World War I to kill lice and mosquitos- limited malaria and louse-born diseases among refugees
The Problem: Peregrine Falcons Extirpated locally extinct) from much of U.S. http://www.iowaccess.org/main/news/newsimages/peregrine.jpg
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
Meanwhile, in Borneo: • Why were roofs falling on people’s heads? • Gecko-eating cats had begun 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.jpg
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/parisitoid.jpg
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
Cat Parachuted into Borneo http://www.freewebs.com/an4rkia/DDT.jpg
The data suggested DDT: • Measurements of DDT levels seemed to multiply as the compound moved up the food chain: Case study in Long Island Estuary: • 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
More evidence against DDT: Sub-Lethal Effects: Eggshells from Peregrines with high DDT levels showed significant thinning http://www.kodak.com/US/images/en/corp/features/birdcam2000/gallery/04_03/13_32__2000_04_03_fullcam2.jpg
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.
Solutions: • Ban DDT • "Hack out" captive-bred peregrine chicks • Build nest platforms for Osprey
How effective were these solutions? • Peregrines, Osprey, and Bald Eagles recovered However, • Other countries still use DDT • DDT isn't the only chemical that biomagnifies!
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!
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. The Problem is ongoing:
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.
Laws and Regulations • Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) • 1972 requires registration of pesticides for specific uses • London Dumping Convention • 1972 ratified by 64 countries • bans deliberate discharge of various toxic or other wastes • International Convention for the Prevention of Pollution from Ships (MARPOL) • 1988 prohibits dumping of plastics at sea • ratified by 40 countries
"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
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. <http://www.atsdr.cdc.gov/tfacts35.html> 2/21/02 • Mader, Sylvia S. 1996. Biology - 5th Ed. WCB and Cox, G.W. 1997. Conservation Biology - 2nd ed. WCB < http://www.marietta.edu/~biol/102/2bioma95.html> 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.html> 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/Publications/One-pagers/CriticalPollutants.html 2/20/02 • Mader, Sylvia S. 1996. Biology - 5th Ed. WCB and Cox, G.W. 1997. Conservation Biology - 2nd ed. WCB retrieved from 1/29/13 http://www.marietta.edu/~biol/102/2bioma95.html