Bioaccumulation and Biomagnification
BC Science 10 – Pgs.
Today’s Objectives:
• Students will be able to assess the potential impacts of bioaccumulation including:
o Define the terms bioaccumulation, parts per million (ppm), biodegradation, and
biomagnification
o Identify a variety of contaminants that can bioaccumulate (pesticides, heavy metals,
PCB’s)
o Compare the impact of bioaccumulation (eradication of keystone species), reproductive
impacts)
o Compare the impact of bioaccumulation on consumers at different trophic levels
(pesticides in aquatic food chains, red tide in oysters and humans)
Bioaccumulation
•
_____________________ is the gradual build-up of synthetic (man-made) and organic chemicals
in living organisms
•
Bioaccumulation occurs when an organism takes in and stores _____________ faster than it can
break down and excrete (remove) them
•
Pollutants usually enter the body in food, but also through skin contact, or respiration
(breathing)
•
Some pollutants stay in the body for so long, that the concentration of the pollutants
____________over time
Biomagnification
•
___________________ is the process in which chemicals not only
accumulate, but become more concentrated at each trophic level of
the food chain
•
As higher level predators eat organisms from lower in the ______
_______, they develop higher concentrations of pollutants in their
systems.
Keystone species
•
Biomagnification can be very harmful to entire food chains because
it can kill _______________
•
A keystone species is a species that can greatly affect population numbers and the health of an
entire ecosystem
•
Example: _______________________________
Pollutants
•
What is a ____________?
o
________________________________________________________________________
________________________________________________________________________
•
What are some examples of pollutants?
o
________________________________________________________________________
•
_____________ are chemicals uses to eliminate pests, such as insecticides (kill insects) and
herbicides (kill plants)
•
__________ __________ are metallic elements with a high density that are toxic to organisms at
low concentrations
•
________ are persistent organic pollutants that contain carbon compounds that remain in soil
and water for many years. Often found in insecticide sprays
How is this measured?
o
The concentration of pollutants in a given substance is measured in ________________
o
One ppm means one particle of a given pollutant is mixed with 999 999 other particles
•
o
Example: if you put 1 mL of poison into a cup with 999 999 mL (999.9 L) of
water, the concentration of poison would be 1 ppm
Different pollutants can be dangerous at different concentrations
•
Example: The pesticide DDT can be toxic to humans at a concentration of _____
Pesticides
•
_______________ can bioaccumulate in ______________
•
First discovered in 1950’s (______ -insecticide)
•
DDT is now banned in Canada
•
It is soluble in fat not water so it gets stored in fatty tissue of consumers
•
Measured in parts per million (ppm)
•
Even after pesticides are banned, some remain in the ______ for many years
•
Some pesticides don’t bioaccumulate, instead they are immediately toxic to some organisms
and can kill them
Effects of pollutants
•
Ppm may not seem like a lot, but the effects are serious
•
Example: Eagles and Osprey unable to ________________
due to thin fragile eggshells (interferes with calcium
deposition)
Heavy Metals
• Industrial processes often produce _______ _______
chemicals that end up in the environment
•
________ _________ are a group of metal elements found
in the middle of the Periodic Table and have relatively high
densities (they are “heavy”)
•
Occur naturally in the Earth, used in ___________, and are toxic or poisonous to organisms in
low concentrations
Mercury

Burning of ________ _______ releases Mercury into atmosphere (coal)

Used to produce many different products that are useful to humans (batteries, thermometers,
lightbulbs, etc

Bioaccumulates in organisms as it moves through the food chain

Can develop _____________ _________ in Humans:

Abnormal behavior, loss of balance, paralysis
Lead
•
In the past, was often used in ______ and ____________ (1990)
•
Also used on joints in plumbing
•
Still used today in agricultural vehicles and airplanes
•
After exposure, last in living things for long periods of time
•
_______ ______________ occurs through the air, causes learning difficulties, delayed
development of brain and body, bad vision and hearing, other body systems
Persistent Organic Pollutants (POPs)

_________ containing compounds that remain in _____ and ____ for many years

__________ are a major source POP pollution


______, an insecticide used to kill disease carrying ___________ in 1941, now banned in
most countries because it biomagnifies

Very long ________
Half-life is the time it takes for the amount of a substance to decrease by half
Polychlorinated biphenyls (______)

____________ chemicals used from 1930’s-70’s in industrial products

1977, banned in North America due to environmental concerns, biomagnification,
bioaccumulation

PCBs responsible for reproduction problems in _______ (Killer Whales)
Natural Bioaccumulation
•
Bioaccumulation can occur naturally
•
Example:
o
_____ _______ caused by large numbers of toxic algae
o
Zooplankton eat these producers
o
Oysters, clams, mussels eat the Zooplankton
o
Humans buy and eat the shellfish and can die from “____________________________”