2. Definitions
• Bioaccumulation is the process by which
substances not readily broken down or
excreted can build up and be stored in
living tissue (usually in fatty tissue.)
• Biomagnification, also known as
bioamplification, is the process by which
substances become more concentrated
in the bodies of consumers as one moves
up the food chain (trophic levels).
3. FACTORS AFFECTING
BIOACCUMULATION
1. Some chemicals bind to specific sites
in the body, particularly in fat tissue,
prolonging their stay
http://extoxnet.orst.edu/tibs/bioaccum.htm
5. FACTORS AFFECTING
BIOACCUMULATION
3. Duration of exposure is also a factor in
bioaccumulation. Most exposures to
chemicals in the environment vary
continually in concentration and
duration, sometimes including periods
of no exposure.
http://extoxnet.orst.edu/tibs/bioaccum.htm
6. FACTORS AFFECTING
BIOACCUMULATION
4. Bioaccumulation varies between individual
organisms as well as between species.
Large, fat, long-lived individuals or species
with low rates of metabolism or excretion
of a chemical will bioaccumulate more than
small, thin, short-lived organisms.
– Thus, an old lake trout may bioaccumulate
much more than a young bluegill in the
same lake.
http://extoxnet.orst.edu/tibs/bioaccum.htm
7. Case Study:
DDT
• DDT is a pesticide that
was widely used until
being banned in the U.S.
in 1972
• DDT accumulates in
living tissue, particularly
in fat tissue
• High concentrations in
some bird species caused
failure of eggs by
thinning the shells
8. What makes methylmercury so dangerous?
Methylmercury is rapidly taken up but only slowly
eliminated from the body by fish and other aquatic
organisms, so each step up in the food chain
(bio)magnifies the concentration from the step below.
Bioaccumulation factors (BAF's) of up to 10 million in
largemouth bass have been reported for the
Everglades.
Fish-eating birds, otters, alligators, raccoons and
panthers can have even higher bioaccumulation factors.
U.S. Department of the Interior, U.S. Geological Survey, Center for Coastal Geology
This page is: http://sofia.usgs.gov/sfrsf/rooms/mercury/achilles_heel/cause.html
Case Study:
Methyl Mercury
10. Case Study:
PCBs
• PCBs, or polychlorinated
biphenyls, are a group of man-
made chemicals.
• Introduced in 1929 and widely
used in electrical transformers,
cosmetics, varnishes, inks,
carbonless copy paper, pesticides
and for general weatherproofing
and fire-resistant coatings to
wood and plastic.
• The federal government banned
the production of PCBs in 1976
• PCBs can effect the immune
system, fertility, child
development and possibly
increase the risk of certain
cancers
