Biological Amplification
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Transcript Biological Amplification
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.
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
Biomagnification
Increase in the concentration of a pollutant as it
passes from one trophic level to the next
http://www.tutorvista.com/content/biology/biology-iv/ecosystem/biological-magnification.php
Biomagnification
Small amount in environment → Large
concentration at top of food chain
http://www.tutorvista.com/content/biology/biology-iv/ecosystem/biological-magnification.php
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
http://oceanservice.noaa.gov/educat
ion/kits/estuaries/media/supp_estu
ar09a.html
Where do pollutants come from?
Coal burning power plants
Factories
Farms, lawns, and gardens.
Characteristics of pollutants:
In order for biomagnification to happen,
substance must be:
Long lived
Soluble in fat
Mobile
Biologically active
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
Ex. Biomagnification
Water
Phytoplankton
Zooplankton
Small fish
Large fish
Top Predator:
Human, osprey, eagle, otter – highest
amount of toxic chemical
http://www.dc.peachnet.edu/~ccarter/Millerlec-12/sld053.htm
Follow link to video
http://happylibrarianblogs.blogspot.com/2008/
01/biomagnification-video.html
It can happen in terrestrial systems too!
Pollutants that undergo biomagnification
Mercury
Persistent organic pollutants (POPs)
Mercury
Source: Emissions from coal-burning power
plants, metal processing, medical and other
waste
Refer to notes on deposition xx/xx
Made bioavailable by bacteria
Inorganic mercury → Organic form of
mercury that is biologically active
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
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
http://sofia.usgs.gov/sfrsf/ro
oms/mercury/food_chain/
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
http://www.usgs.gov/themes/factsheet/146-00/
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
http://img.alibaba.com/photo/11388452/Frozen_Sushi.jpg
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
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.
Concerned about the fish you eat?
Check out the Mercury calculator at
http://gotmercury.org/article.php?id=1034
For information on Sustainable Seafood
Choices check out Monterey Bay Aquarium
and print out a pocket sized card
http://www.mbayaq.org/cr/seafoodwatch.asp
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".
http://www.ci.springfield.or.us/
Museum/Mad%20Hatter%20Tea
%20Party.jpg
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
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
http://www.nature.com/nrmicro/journal/v
4/n9/images/nrmicro1498-i3.jpg
Stockholm Convention Treaty
The Dirty Dozen
1.
2.
3.
4.
5.
6.
DDT - pesticide
PCBs - Industrial
Dioxin - waste
Furans - waste
Aldrin - pesticide
Chlordane - pesticide
7.
8.
9.
10.
11.
12.
Dieldrin - pesticide
Endrin - pesticide
HCB – pest/ waste
Heptachlor - pesticide
Mirex - pesticide
Toxaphane - pesticide
Exposure
Environmental exposure – many will stay in
soil or water for decades
Slow to breakdown
Humans consume toxins via fish, meat and
dairy
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
http://commons.
wikimedia.org/wik
i/Image:DDT_W
WII_soldier.jpg
http://www.flahumforms.org/FloridaDream/images/Th
umbnails/1948-Spraying-DDT-in-war-ag.jpg
Ex. DDT
Concentration of
DDT increased 10
million times!
http://www.cfkeep.org/html/stitch.php?s=98965698293378&id=34347859802049
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
www.ctaudubon.org/action/osprey.htm
animals.nationalgeographic.com
DDT problems (cont’d)
Feminization
Acts as a hormone disrupter, mimics estrogen
Has impacted sex ratio in some birds
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
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
0
15
30
45
60
75
90
105
Amount
Remaining
100 kg
50 kg
25 kg
12.5 kg
6.25 kg
3.13 kg
1.56 kg
0.78 kg
DDT current use
Banned in US in 1972
Still used overseas to prevent malaria
Estimated it save millions of lives annually
in Africa
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
http://www.smh.com.au/ffxi
mage/2006/12/28/polar_bear
_narrowweb__300x387,0.jpg
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
Thought to ponder
Even pollutants in small quantities can build
up to toxic/lethal doses
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)
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
http://gotmercury.org/article.php?id=1034
http://www.seaturtles.org/article.php?list=type
&type=75
http://www.ec.gc.ca/Science/sandemay00/artic
le4_e.html