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 for consumption 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 the toxic 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
Previous class on acid deposition – focused on Coal fired electric plants. Plants in MidWest – mercury released in atmosphere travels and comes down with the acid deposition from nitrates and sulfates. 12 states have law suit about mercury deposition against midwest states. Remind them of map we looked at in previous class.

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
Congress needs to change 2 laws on books before it can ratify. Does not appear to be any pressure to make changes for this to happen.

29. Stockholm Convention Treaty
The Dirty Dozen
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

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

32. 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
Typhus killed 3 million people in WWII. Originally DDT was heralded as a wonder pesticide. Low toxicity to humans. Saved many lives. Tell stories of sprayer truck and children playing in its wake. Mention Carson’s Silent Spring and the finger pointed at DDT as a threat, beginning of environmental awareness.

33. Ex. DDT Concentration of DDT increased 10 million times!

34. 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
animals.nationalgeographic.com

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

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

37. 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
Year
Amount Remaining
100 kg 15
50 kg 30
25 kg 45
12.5 kg 60
6.25 kg 75
3.13 kg 90
1.56 kg
105
0.78 kg

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

39. Even Polar Bears have POPs in their system Top predator
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

40. 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

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

42. 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)

43. 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.

44. 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