Biomagnification

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Biomagnification vs Bioaccumulation

• What is bioaccumulation?- collecting of substances in an organism or part of it; higher

concentration in the organism than in the surrounding environment;

• What is biomagnification?- increase of concentration of the pollutant from low to high levels

of a food chain; predator-prey relationships;

• Difference - environment vs. food chain; - biomagnification results from

bioaccumulation;

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Why do we care?

• Effects of biomagnification and bioaccumulation on the organisms:

- hard to metabolize => problems in the functions of the organism’s organs;

- passed to the next generations, causing mutations and higher death rates;

- human health; http://www.nealhendrickson.com/mcdougall/2004nl/040825Biomagnification3.gif

Accumulative substances• Types of substances that

bioaccumulate:Pesticides (HCB, DDT, aldrin, mirex), Industrial chemicals and unintended byproducts (PCB), Flame-retardant chemicals, Unintended byproducts (dioxins and furans);

• Types of substances that don’t bioaccumulate;the substances metabolized or excrete as wastes; (ex. carbohydrates, fatty acids);

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PCB• Polychlorinated Biphenyls - What is it?very stable man-made compounds consist of carbon, hydrogen and chlorine atomsthere can exist 209 different PCBs according to the

combination of the atoms1970s – bannedstill present in the environment- Where was it used?in the past in electrical equipments, surface coatings, ink,

paints, etc.

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PCB- How can it be released into the environment?when wastes that contain PCBs are kept in landfillscan burn in high temperatures and in such a way release

dangerous materials; they are not very soluble in water and hardly evaporate

- Where can it be found?in rivers or lakes – on the sedimentsif in the air – may reach the ground by rainfalls or snowmainly found within the food chain (in the fatty tissues of

the animals) => can reach to humans through their foodcan be broken down by the sunlight or certain types of

organisms that live under water

PCB- Impact on environmentexposed to the compound by eating particular food (like

fish and meat); babies by the intake of breast milk; small amounts present in the air

when entering the body the organism may turn it to another compound and become a waste product

depending on the amount of PCB in humans, it can lead to risk of cancer, decrease fertility, very dangerous for pregnant women and the baby

health risks (rashes, infections and others)- Possible solutionMany countries had either totally banned or decreased the

use of PCBs radically

Lake Baikal

• 1997 – Russian and Japanese scientists found PCB’s in the Lake Baikal;

• In the fish => seriously

toxic levels in the Baikal seal; feeds on fish;

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http://polaris.nipr.ac.jp/~penguin/penguiness/seals/phocinae/baikal.jpg

MERCURY• Hg is a highly toxic element found naturally and also as a contaminant• Toxic effectsDepend on the chemical form and how it was exposed methylmercury – most toxic – damages the immune system, the nervous system, the enzyme system. Exceptionally damaging for embryos elemental mercury – not that dangerous – causes tremors and gingivitis. Salt HgCl2 – causes kidney failure – not likely to be found in nature

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Exposure and Sources• Exposure to methylmercury –

by ingestion (especially fish and birds)

• Exposure to elemental mercury – when the thermometer breaks. Also there are high concentrations near a gold mine

• Sources of mercury: Alkali and metal procession Chemical and all kinds of waste Gold mining Atmospheric deposition –

once let in the atmosphere it can circulate for years

volcanoes

http://www.genetics.uga.edu/rbmlab/images/mercycle.gif

Threads to people and wildlife• Methylmercury accumulates

mostly in fish because of the covalent bond to protein sulfhydryl groups

Mercury biomagnification harms the aquatic systems at a greater rate

By eating contaminated seafood people can be poisoned

The FISH contamination problem is a serious thread both to people and to the wildlife

Mercury causes deformities to developing animals

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Examples of Consequences• Everglades – juvenile great

egrets behavior is affected• San Francisco Bay – diving

ducks are affected• Case from Minamata, Japan –

birds couldn’t fly, people were greatly poisoned

• Places where it is more abundant:

=> Carson River, Nevada Mississippi River Northeast and North central US Florida Everglades Gulf of Mexico Atlantic Ocean http://tdaait.files.wordpress.com/2008/08/image.jpg

Works Cited• "Bioaccumulation." USGS. N.p., 14 Dec. 2006. Web. 15 June 2010.

     <http://toxics.usgs.gov/definitions/bioaccumulation.html>. • "Bioaccumulation." EXTOXNET. Oregon State University, Sept. 1993. Web. 8 June

     2010. <http://extoxnet.orst.edu/tibs/bioaccum.htm>.• "Bioaccumulation and Biomagnification." Marietta College. N.p., 2 Apr. 2002.

     Web. 8 June 2010. <http://www.marietta.edu/~biol/102/2bioma95.html>. • "Litter and Pollution." Chintimini Wildlife Rehabilitation Center. 1999.

     Web. 15 June 2010. <http://www.chintiminiwildlife.org/Education/      LivingWithWild/Litter.htm>.

• “Mercury in the Environment”. USGS research. 19 February 2009. 15 June 2010. <http://www.usgs.gov/themes/factsheet/146-00/>.

• “Scientific Facts on Mercury”. UNEP. 5.10.2009. 15 June 2010. <http://www.greenfacts.org/en/mercury/l-3/mercury-3.htm>.

• "Scientific Facts on PCBs Polychlorinated Biphenyls." GreenFacts - Facts on Health and the Environment. 5 Oct. 2009. Web. 08 June 2010. <http://www.greenfacts.org/en/pcbs/index.htm>.