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Bio ppt ananya jain

Date post:21-Jun-2015
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bio magnifications
  • 1. What is bio magnification?? It is also knownas bioamplification or biological magnification,is the increase in concentration of a substance,such as the pesticide DDT, that occurs ina food chain as a consequence of: Persistence ( Can't be broken down by environmentalprocesses) Food chain energetics Low rate of internal degradation/excretion ofthe substance.

2. It also refers to the process whereby certainsubstances such as pesticides or heavymetals move up the food chain, work theirway into rivers or lakes, and are eaten byaquatic organisms such as fish, which inturn are eaten by large birds, animals orhumans. The substances becomeconcentrated in tissues or internal organsas they move up the chain. 3. Sometimes biomagnification is also usedinterchangeably with 'bioaccumulation,' animportant distinction is drawn betweenthe two, and with bioconcentration Bioaccumulation occurs within a trophiclevel, and is the increase in concentrationof a substance in certain tissues oforganisms' bodies due to absorption fromfood and the environment. 4. Bioconcentration is defined as occurringwhen uptake from the water is greaterthan excretion . Thus bioconcentration andbioaccumulation occur within an organism,and biomagnification occurs across trophic(food chain) levels. 5. Substances that biomagnify TThheerree aarree ttwwoo mmaaiinnggrroouuppss ooff ssuubbssttaanncceesstthhaatt bbiioommaaggnniiffyy.. BBootthh aarree lliippoopphhiilliiccaanndd nnoott eeaassiillyyddeeggrraaddeedd.. TThheessee aarree 'persistentorganic pollutants'' oorrPOPs aanndd MMeettaallss.. 6. Persistent organic pollutants Novel organic substances are not easilydegraded because organisms lack previousexposure and have thusnot evolved specific detoxification andexcretion mechanisms, as there has been noselection pressure from them. Thesesubstances are consequently known as'persistent organic pollutants' or POPs. 7. Chemical structure of PCBs. Thepossible positions ofchlorine atoms on the benzenerings are denoted by numbersassigned to the carbon atoms. 8. Chemical structure 9. Chemical structure 10. Metals MMeettaallss aarree nnoott ddeeggrraaddaabbllee bbeeccaauussee tthheeyy aarreeeelleemmeennttss.. OOrrggaanniissmmss,, ppaarrttiiccuullaarrllyy tthhoossee ssuubbjjeeccttttoo nnaattuurraallllyy hhiigghh lleevveellss ooff eexxppoossuurree ttoo mmeettaallss,,hhaavvee mmeecchhaanniissmmss ttoo sseeqquueesstteerr aanndd eexxccrreetteemmeettaallss.. PPrroobblleemmss aarriissee wwhheenn oorrggaanniissmmss aarreeeexxppoosseedd ttoo hhiigghheerr ccoonncceennttrraattiioonnss tthhaann uussuuaall,,wwhhiicchh tthheeyy ccaannnnoott eexxccrreettee rraappiiddllyy eennoouugghh ttoopprreevveenntt ddaammaaggee.. TThheessee mmeettaallss aarree ttrraannssffeerrrreeddiinn aann oorrggaanniicc ffoorrmm.. 11. Violet light froma helium cadmium metalvapor laser. Thehighly monochromatic colorarises from the 441.563 nmtransition line of cadmium. 12. Biomagnification has serious consequencesfor all species. It is particularly dangerousfor predator species especially if they are atthe top of long food webs. Predators are usually at or near the top oftheir food web. This puts them at riskbecause the degree of biomagnification ishigh by the time it reaches their trophiclevel. 13. Also, top predators usually consume largequantities of meat which has lots of fattytissue and contaminants. Polar bears, humans, eagles,and dolphins are examples of toppredators, and all of these organisms arevulnerable to the effects ofbiomagnification. 14. PCBs cause liver cancer in humans. 15. Predators that consume large amounts offish also have a high degree of risk becausepersistent hydrophobics are widelydispersed in aquatic food webs and arebiomagnified in fish.Biomagnifiedsubstances causespersistenthydrophobia. 16. TThhaannkk yyoouu

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