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  1. Activator: What’s the deal about mercury poisoning?clip

  2. Biological Magnification What is it? • Toxic pollutants enter the ecosystem that are absorbed or ingested by organisms. Some substances accumulate in organism’s tissue over time.

  3. Bioaccumulation • An increase in the concentration of a pollutant in a biological organism compared to its concentration in the environment • It is how pollutants enter a food chain

  4. Ex. Biomagnification • Water • Phytoplankton • Zooplankton • Small fish • Large fish • Top Predator: • Human, osprey, eagle, otter – highest amount of toxic chemical

  5. Biomagnification • Increase in the concentration of a pollutant as it passes from one trophic level to the next

  6. Biomagnification • Small amount in environment → Large concentration at top of food chain

  7. Biomagnification Substances such as pollutants become concentrated as you move up the food chain Energy passes through the food chain Energy is lost as you move up the Food Pyramid Levels of toxins and harmful substances can increase as you move up the Food Pyramid

  8. Bioaccumulation vs Biomagnification • Both describe the increase of the amount of a substance in an organism (1,3) • Bioaccumulation occur within a single organism (1) • Biomagnification occurs across trophic levels (3)

  9. Why should we care? • Because the two processes together mean that when we release even small amounts of pollutants into the environment, eventually they build-up in organisms to toxic dosages

  10. Where do pollutants come from? • Coal burning power plants • Factories • Farms, lawns, and gardens.

  11. Characteristics of pollutants: • In order for biomagnification to happen, substance must be: • Long lived • Soluble in fat • Mobile • Biologically active

  12. Characteristics of pollutants: Putting it into perspective: • Only some substances biomagnify • Most substances are water soluble and are excreted into the water • Many breakdown quickly • Many are not biologically active

  13. Follow link to video • Example of DDT

  14. Pollutants that undergo biomagnification • Mercury • Persistent organic pollutants (POPs)

  15. 24 units 12 units 6 units 2 units 1 unit

  16. Mercury in Fish • Fish absorb mercury efficiently • Larger fish eat many small fish and build up higher levels of mercury • Some have been banned forconsumption for they present a toxic risk

  17. ”Madd as a hatter”

  18. Origins of the term “Mad as a Hatter” • Hg(NO3)2 Mercury is a compound that was used to soften fur in the making of felt hats. • The phrase “Mad as a Hatter”, and the Mad Hatter of Alice in Wonderland -- both refer to thetoxic effect of mercury on the central nervous system of the hat makers, producing mental effects and "hatter's shakes".

  19. Mercury • Elementary Mercury (Hg) • Methylmercury (CH3Hg) – most toxic form • Form ingested by consuming fish • Concentrated in muscle tissue • More in older fish than younger fish • Note – changed from Hg to this form by bacteria

  20. Mercury • Source: Emissions from coal-burning power plants, metal processing, medical and other waste • Made bioavailable by bacteria • Inorganic mercury → Organic form of mercury that is biologically active

  21. Where in the US is it a problem? • Low pH (acidic) lakes in Northeast and and Northcentral US • Everglades (FL) • Certain Wetlands • Coastal wetlands along San Francisco Bay, Gulf of Mexico and Atlantic Coast

  22. Impacts of Wildlife • Loons – diet of fish • Decrease in chicks in areas of high mercury • Large concentration of mercury in eggs • Great Egrets – study in Everglades indicates behavior of juveniles is effected • Deformities in developing animals

  23. Risk to People • Exposed by eating contaminated fish • Pregnant women and children most at risk • 60,000 children born annually suffering from neurodevelopmental problems due to in utero exposure to mercury

  24. Fish Advisories • 13 states have state wide advisories for fish from rivers and lakes • 40 states have advisories on selected bodies of water • Parts of Eastern Coast and Gulf of Mexico have advisories

  25. Concerned about the fish you eat? Recommendations per the FDA • Avoid shark, swordfish, king mackerel and tilefish = all are high in Mercury • 12 oz can be consumed a week of a variety of fish and shellfish that are lower in mercury. • Fish that are low in mercury are shrimp, canned light tuna, salmon, pollock, and catfish. • Note, albacore tuna has more mercury than canned light tuna. You may eat up to 6 oz of it in a week.

  26. Concerned about the fish you eat? • Check out the Mercury calculator at • For information on Sustainable Seafood Choices check out Monterey Bay Aquarium and print out a pocket sized card

  27. Persistent Organic Pollutants (POPs) • Also called organochlorines • Synthetic organic chemicals that persist in the environment and biomagnify through the food web • Poses a risk to human health and the environment Sources: • Pesticides, some plastics, paints, industrial chemicals, bleaching, burning garbage • Examples: DDT, PCBs, dioxin

  28. Ban on POPs • 1995 UN estimated 20,000+ substances with properties of POPs • Stockholm Convention 2004, banned 12 worst • “The Dirty Dozen” • U.S. signatory in 2001 • Congress has not ratified • Signed by

  29. DDT - pesticide PCBs - Industrial Dioxin - waste Furans - waste Aldrin - pesticide Chlordane - pesticide Dieldrin - pesticide Endrin - pesticide HCB – pest/ waste Heptachlor - pesticide Mirex - pesticide Toxaphane - pesticide Stockholm Convention Treaty The Dirty Dozen

  30. Exposure • Environmental exposure – many will stay in soil or water for decades • Slow to breakdown • Humans consume toxins via fish, meat and dairy

  31. DDT (dichloro-diphenyl-trichloroethane) • Insecticide used to control malaria and typhus by killing mosquitoes and lice. • Commonly used after WWII • Inventor received Noble Prize • Overused on crops as a pesticide

  32. Ex. DDT • Concentration of DDT increased 10 million times!

  33. DDT problems Eggshell thinning • DDT interferes with metabolism of calcium • Result - thin shells in predator birds such as osprey, bald eagles, brown pelicans • Birds unable to brood (aka sit on) their eggs without breaking them

  34. DDT problems (cont’d) Feminization • Acts as a hormone disrupter, mimics estrogen • Has impacted sex ratio in some birds

  35. DDT - it’s a long term problem • It has a half life of 15 year; it takes 15yrs for its quantity to be ½ its original

  36. DDT - it’s a long term problem • It has a half life of 15 year; it takes 15yrs for its quantity to be ½ its original • Ex. If we start with 100 kg, we will still have ~ 1 kg after 100 yrs

  37. DDT current use • Banned in US in 1972 • Still used overseas to prevent malaria • Estimated it save millions of lives annually in Africa

  38. POPs are everywhere! • Even Polar Bears have POPs in their system • Top predator • All toxins in prey is transferred to them, stored in fat • Concentration increases 5 – 10x each trophic level,0.jpg

  39. Health Impact of POPs • Some cause cancer, damage nervous system • Some act like hormones (estrogens) leads to: • Developmental changes, birth defects • Reproductive and Behavioral problems • Toxins can be passed to young

  40. Thought to ponder • Even pollutants in small quantities can build up to toxic/lethal doses

  41. Solutions to Toxic Pollution • Worst ones are banned or no longer used in U.S. • Still need to eliminate/reduce the processes that create toxins (i.e. burning coal)

  42. Why We Should Care • Ironically, biomagnification 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 biomagnification. • Some cancers are also linked through ingesting these toxins. • It can also lead to organ failure in both animals and humans. • Since some animals have weaker immune systems then humans, they will die faster which can lead to extinction if it continues.

  43. Question of the Day Which group of pollutants is suspected to act like hormones (estrogens)? • Heavy metals • Persistent organic pollutants (POPs) • Inorganic plant nutrients • Organic oxygen-demanding wastes

  44. • •