Biological Amplification- What is it?
 Toxic pollutants enter the ecosystem that are absorbed or ingested by organisms. Some substances accumulate
in organism’s tissue over time.
Biological Accumulation
 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
Biological Magnification
 Increase in the concentration of a pollutant as it passes from one trophic level to the next
 Small amount in environment → Large concentration at top of food chain
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
Where do they come from?
1. Coal burning power plants
3. Farms, lawns, and gardens.
2. Factories
Characteristics
 In order for biomagnification to happen, substance must be:
1. Long lived
3. Mobile
2. Soluble in fat
4. Biologically active
Putting it into perspective:
1. Only some substances biomagnify
3. Many breakdown quickly
2. Most substances are water soluble and are
excreted into the water
4. Many are not biologically active
a. Ex. Biomagnification
Pollutants that undergo biomagnification
1. Mercury
2. Persistent organic pollutants (POPs)
Mercury
1. Source: Emissions from coal-burning power plants, metal processing, medical and other waste
2. Made bioavailable by bacteria
a. Inorganic mercury → Organic form of mercury that is biologically active
3. Elementary Mercury (Hg)
4. Methylmercury (CH3Hg) – most toxic form
a. Form ingested by consuming fish
c. More in older fish than younger fish
b. Concentrated in muscle tissue
d. Note – changed from Hg to this form by
bacteria
Where in the US is it a problem?
1. Low pH (acidic) lakes in Northeast and
Northcentral US
2. Everglades (FL)
3. Certain Wetlands
4. Coastal wetlands along San Francisco Bay, Gulf
of Mexico and Atlantic Coast
Impacts on Wildlife
1. Loons – diet of fish
a. Decrease in chicks in areas of high mercury
b. Large concentration of mercury in eggs
2. Great Egrets – study in Everglades indicates behavior of juveniles is effected
3. Deformities in developing animals
Risk to People
1. Exposed by eating contaminated fish
2. Pregnant women and children most at risk
a. 60,000 children born annually suffering from neurodevelopmental problems due to in utero exposure to
mercury
Fish Advisories
 13 states have state wide advisories for fish from rivers and lakes
 40 states have advisories on selected bodies of water
Concerned about the fish you eat?
Recommendations per the FDA
1. Avoid shark, swordfish, king mackerel and tilefish = all are high in Mercury
2. 12 oz can be consumed a week of a variety of fish and shellfish that are lower in mercury.
3. Fish that are low in mercury are shrimp, canned light tuna, salmon, pollock, and catfish.
a. Note, albacore tuna has more mercury than canned light tuna. You may eat up to 6 oz of it in a week.
Persistent Organic Pollutants (POPs)
1. Also called organochlorines
2. Synthetic organic chemicals that persist in the environment and biomagnify through the food web
3. Poses a risk to human health and the environment
Sources:
1. Pesticides, some plastics, paints, industrial chemicals, bleaching, burning garbage
2. Examples: DDT, PCBs, dioxin
Ban on POPs
1. 1995 UN estimated 20,000+ substances with properties of POPs
2. Stockholm Convention 2004, banned 12 worst
a. “The Dirty Dozen”
c. Congress has not ratified
b. U.S. signatory in 2001
3. Stockholm Convention Treaty
 The Dirty Dozen
1. DDT - pesticide
5. Aldrin - pesticide
9. HCB – pest/ waste
2. PCBs - Industrial
6. Chlordane – pesticide
10. Heptachlor - pesticide
3. Dioxin - waste
7. Dieldrin - pesticide
11. Mirex - pesticide
4. Furans - waste
8. Endrin - pesticide
12. Toxaphane - pesticide
Exposure
1. Environmental exposure – many will stay in soil
or water for decades
2. Slow to breakdown
3. Humans consume toxins via fish, meat and dairy
DDT (dichloro-diphenyl-trichloroethane)
1. Insecticide used to control malaria and typhus
by killing mosquitoes and lice.
3. Inventor received Noble Prize
4. Overused on crops as a pesticide
2. Commonly used after WWII
DDT problems
1. Eggshell thinning
a. DDT interferes with metabolism of calcium
b. 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
2. Feminization
a. Acts as a hormone disrupter, mimics estrogen
b. Has impacted sex ratio in some birds
c. DDT - it’s a long term problem
d. It has a half- life of 15 year; it takes 15yrs for its quantity to be ½ its original
DDT current use
a. Banned in US in 1972
b. Still used overseas to prevent malaria
c. Estimated it save millions of lives
annually in Africa
POPs are everywhere!
1. Even Polar Bears have POPs in their system
a. Top predator(All toxins in prey is transferred to them, stored in fat)
2. Concentration increases 5 – 10x each trophic level
Health Impact of POPs
1. Some cause cancer, damage nervous
system
2. Some act like hormones (estrogens)
leads to:
3. Developmental changes, birth defects
4. Reproductive and Behavioral problems
5. Toxins can be passed to young
Thought to ponder

Even pollutants in small quantities can build up to toxic/lethal doses
Solutions to Toxic Pollution
1. Worst ones are banned or no longer used in U.S.
2. Still need to eliminate/reduce the processes that create toxins (i.e. burning coal)