Transcript toxicology_basics

CHAPTER 17: ENVIRONMENTAL HEALTH,
POLLUTION AND TOXICOLOGY
UNITS USED TO MEASURE CHEMICALS
IN THE ENVIRONMENT
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PPM – Parts per million (1 in per 1,000,000 , 10-6 )
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PPB – Parts per billion (1 part in 1,000,000,000 , 10-9 )
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PPT – Parts per trillion (1 in 1,000,000,000,000 , 10-12 )
CONSIDER A SIMPLE CUBE 1 CUBIC METER IN VOLUME
1m
1m
1m
FORMED OF 1,000,000 CUBES,
1 CUBIC CENTIMETER EACH
1 cube
would be
considered
1 PPM
ONE PART PER MILLION IS
1 inch in 16 miles
 1 minute in two years
 1 cent in $10,000
 1 ounce of salt in 31 tons of potato chips
 1 bad apple in 2,000 barrels of apples
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ONE PART PER BILLION IS
1 inch in 16,000 miles
 1 second in 32 years
 1 cent in $10,000,000
 1 pinch of salt in 10 tons of potato chips
 1 lob in 1,200,000 tennis matches
 1 bad apple in 2,000,000 barrels of apples
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ONE PART PER TRILLION IS
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1 postage stamp in the area of the city of Dallas
1 inch in 16 million miles (more than 600 times
around the earth)
1 second in 320 centuries
1 flea on 360 million elephants
1 grain of sugar in an Olympic sized pool
1 bad apple in 2 billion barrels
TERMINOLOGY
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Pollution refers to the occurrence of unwanted change
in the environment
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introduction of harmful or toxic materials into the
surroundings
Contamination
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similar to that of pollution
implies making something unfit for a particular use through
the introduction of toxic materials
THERE ARE MANY TYPES OF ENVIRONMENTAL HAZARDS
Environmental health = assesses environmental factors that influence
human health and quality of life (Natural and human-caused )
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Physical hazards = occur
naturally in our environment
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Earthquakes, volcanoes, fires,
floods, droughts
We can’t prevent them, but we
can prepare for them
We increase our vulnerability by
deforesting slopes (landslides),
channelizing rivers (flooding),
etc.
We can reduce risk by better
environmental choices
Chemical = synthetic
chemicals such as pesticides,
disinfectants, pharmaceuticals
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Harmful natural chemicals also
exist
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Biological = result from
ecological interactions
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Viruses, bacteria, and other
pathogens
Infectious (communicable, or
transmissible) disease = other
species parasitize humans,
fulfilling their ecological roles
We can’t avoid risk, but we can
reduce the likelihood of infection
Cultural = result from the place
we live, our socioeconomic
status, our occupation, our
behavioral choices
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Smoking, drug use, diet and
nutrition, crime, mode of
transportation
DISEASE IS A MAJOR FOCUS OF
ENVIRONMENTAL HEALTH
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Despite our technology,
disease kills most of us
Disease has a genetic
and environmental
basis
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Cancer, heart disease,
respiratory disorders
Poverty and poor hygiene
can foster illnesses
MANY DISEASES ARE INCREASING
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Tuberculosis, acquired
immunodeficiency
syndrome (AIDS), and the
West Nile virus
Our mobility spreads
diseases
Diseases are evolving
resistance to antibiotics
Climate change will expand
the range of diseases
To predict and prevent
diseases, experts deal with
complicated
interrelationships
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Infectious disease
 Spread by interactions between
individuals and through food, water, air or
soil.
 Can travel globally via airplanes
 New diseases emerging and previous
ones reemerging
 Some infectious diseases can be
controlled by manipulating the
environment
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If you really knew me…