masters in public health

1. Biomagnification

2. Biomagnification
• Biomagnification, also known as
bioamplification or biological magnification,
is the increase in concentration of a substance,
such as the pesticide DDT, that occurs in a food
chain as a consequence of:
• Persistence
• Food chain energetics
• Low rate of internal degradation/excretion of the
substance (often due to water-insolubility)

3. Mercury
• Minamata a disease or neurological
syndrome caused by severe
mercury poisoning.
• Symptoms include ataxia,
numbness in the hands and feet,
general muscle weakness,
narrowing of the field of vision and
damage to hearing and speech. In
extreme cases, insanity, paralysis,
coma and death follow within weeks
of the onset of symptoms

4. Mercury case study
• Humans generally uptake mercury in two ways:
• As methylmercury (CH3Hg+) from fish
consumption, OR
• By breathing vaporous mercury (Hg0) emitted
from various sources such as metallic mercury,
dental amalgams, and ambient air.
• Our bodies are much more adapted for
reducing the potential toxicity effects from
vaporous mercury, so health effects from this
source are relatively rare.

6. Biomagnification
• So what is happening because
methylmercury (CH3Hg+) is Persistent
meaning it can not be broken down
through natural process it moves up the
food chain.
• At each level in the food chain there is a
greater concentration, because it is not
broken down at the lower levels.

8. Other things which Biomagnify
• DDT’s which are a pesticide which use to be
used all the time. It was later found out it
Biomagnifies up the food chain and makes bird
eggs soft. The use stopped in most
industrialized countries after a large
environmental movement.

9. DDT’s still in use
• Some countries with large pest problems
and little money still use DDT’s
• Do you think this is right?

10. DDT’s still in use
• Some countries with large pest problems
and little money still use DDT’s
• Do you think this is right?