Download Pollution and Human Health

Pollution and Human Health
Environmental Effects on Health
2 ways that pollution causes illness:
• Direct poisoning – ie. lead  brain damage,
learning problems, asbestos  lung cancer
• Indirect poisoning – infectious diseases
spread through a polluted environment
– ie: cholera & river blindness caused by organisms
in polluted water
The WHO…. No, not the band…. the World
Health Organization
• Has defined poor health worldwide is
measured by the estimated # of days of
healthy life lost to death & disease
• Has determined that in general…
– People in developed countries suffer fewer health
impacts due to environmental causes than people
in developing countries do
– Main factor…the enormous role of infectious
diseases (ie- TB and cholera) that are common in
crowded areas w/ poor sanitation.
Poor Health by World Region
(Notice least developed area are affected more)
Toxicology - the study of the harmful
effects of substances on organisms
• Toxicity is determined by:
– how much of the pollutant is in the environment
– How much gets into the body
• Dose – amount of a harmful chemical to which a
person is exposed (the amount/ concentration of the
toxin that damages the body)
• Response – how the body responds to the dose of
chemical.
– depends on…
– The dose, # of times a person is exposed, person’s size, how
well the body breaks down the chemical
Pollutants . . . Their Sources and
Affects on Humans
Pollution from Natural Sources
Naturally occurring pollutants usually become hazardous
to health when they are above their normal levels
– Example --> Radon Gas
• Particulates – particles in the air that are small enough
to breathe into the lungs
– Examples --> dust and soot from dust storms, volcanic
eruption, and wildfires
• Can cause irritation in the lungs by clogging the small air sacs
which can lead to chronic bronchitis & emphysema
• Heavy Metals – includes arsenic, cadmium, lead, &
mercury which naturally occur in rocks & soil
– Most cause nerve damage when ingested beyond their
threshold dose
Pollution from Human Activities
• ~10% of commercial chemicals have been
tested for their toxicity, however ~1,000 new
chemicals are produced every year
• Recent Improvements
– US regulations have helped reduce our exposure
to pollutants
– Most vehicles & factories now have pollutioncontrol devices
– But…new health risks are being discovered
frequently
Examples of Pollution from Human
Activities:
• Burning Fuels
– in cars, homes, power plants, & factories adds
huge amounts of pollutants into the air
• including CO and many kinds of particulates
• Which contribute to premature deaths each year
– In some areas…it may be possible to predict an
area’s death rate based on the amount of
pollution
Examples of Pollution from Human
Activities:
• Pesticides - chemicals designed to kill unwanted
organisms such as insects, fungi, or weeds.
– Beneficial = allow more food to be grown
– Dangerous = to humans in large enough doses
– Organophosphates have recently replaced more
persistent pesticides (DDT)
• Benefit = breakdown in nature quickly
• Danger = very toxic to those exposed typically in application
– Persistent pesticides (like DDT) are still used in
developing countries
• Very bad for children!
Examples of Pollution from Human
Activities:
• Industrial Chemicals
– Toxic chemicals are found in new buildings b/c of
the new materials (ie- carpet, furniture, cleaners)
– In old buildings, lead-based paint, PCBs
– All of which do not breakdown in the environment
& can cause learning/development delays
Examples of Pollution from Human
Activities:
• Waste Disposal
– Wastewater from cities can carry oil & toxic chemicals
into our waterways
– Waste incinerators emit toxic products into the air
– Mines release toxic contaminants into streams &
rivers
– Improvements have been made in the last 50 years!
• But…
– Landfills leak
– Sewage treatment plants release raw sewage after heavy rains
– Waste disposal laws are not always enforced
Terms Often Associated With
Contaminated Sites
• Superfund Sites = sites with the worst
hazardous waste contamination
nationwide
– Twin Cities Army Ammunition Plant (TCAAP)
Superfund Site, in Minneapolis/St. Paul
metropolitan area (7 contaminated groundwater sites, 1
contaminated sediment site, 2 landfills, 2 firing ranges, 2
unexploded munitions/ordnance sites, 2 surface disposal areas, 1
disposal pit/dry well site, 3 chemical disposal sites, 1 small arms
range, and 4 burn areas).
• RCRA Sites = When accidents or other activities
at hazardous waste facilities lead to a release of
hazardous materials, the RCRA Corrective
Action program is one program that may be
used to accomplish the necessary cleanup
–
Motiva Terminal, Fairfax, VA
• Brownfield – property complicated by the
presence or potential presence of a hazardous
substance, pollutant, or contaminant. It is
estimated that there are more than 450,000
brownfields in the U.S.
http://www.pca.state.mn.us/index.php/waste/waste-and-cleanup/cleanup-programs-andtopics/topics/remediation-sites/twin-cities-army-ammunition-plant-tcaap-superfund-site.html?menuid=&redirect=1
Biological Hazards to Health
The Environment’s Role in Disease
The Environment’s Role in Disease
• Infectious diseases are caused by pathogens –
organisms that cause disease
– Spread person to person through the air
• ie: whooping cough & tuberculosis (TB)
– Spread by drinking water that contains the
pathogen
– Transmitted by a secondary host (ie: mosquito)
• Host – organism in which a pathogen lives all/part of its
life
Waterborne Disease
• 3/4ths of infectious diseases are transmitted
through water
• In developing countries water is used for:
– Washing
– Drinking
– Sewage disposal
• Polluted water is a good breeding ground for
pathogens
– Pathogens breed in water and transfer diseases
directly to humans through water
– Vectors – organisms that transmit diseases to
people, may also transfer diseases to humans
Waterborne Disease
• Cholera (and Dysentery)
• Deadliest waterborne diseases come from drinking
water polluted by human feces
• Cause the body to lose water by diarrhea and vomiting
– much deadlier to children because of less water in their
bodies
Waterborne Disease
– Malaria – once the world’s leading cause of death
• Caused by parasitic protists and is transmitted by a bite
from a female mosquito.
• No effective vaccine exists but preventative measure
are used to control mosquitoes.
Environmental Change and Disease
Humans altering the environment
• Humans alter the environment in ways that
make it more suitable for pathogens to live
and reproduce.
– i.e.- soil (that is polluted with chemicals &
pathogens) erodes which causes pollutants to
blow & wash away causing contamination
thousands of miles away
Environmental Change and Disease
Humans altering the environment
– Antibiotic Resistance
• Overuse of antibiotics in both humans and organisms
used for food has led to a large resistance to
antibiotics.
– ie – Salmonella, E. coli & TB – large amount of resistance
causes thousands to get sick every year
Environmental Change and Disease
Humans altering the environment
– Malaria on the March
• Global warming may increase the area where malaria
occurs.
• At one time mainly occurred in rice paddies and
marshes
– Paddies and marshes were drained & treated with pesticides
– Mosquitoes have since developed a resistance to most
pesticides
– Newer methods for control include growth regulators and
female sterilization
Environmental Change and Disease
Humans altering the environment
– Emerging Viruses – previously unknown viruses
(less than 100 years old)
• Examples:
–
–
–
–
AIDS – caused by HIV
Hanta virus – a type of hemorrhagic fever
Ebola virus – a type of hemorrhagic fever
West Nile virus – many times found in birds
• Problems with emerging viruses:
– Not many effective drugs
– Main defense is vaccination  very specific & viruses evolve
rapidly
» New strain = New vaccine
Environmental Change and Disease
Humans altering the environment
– Cross-Species Transfers
• Diseases that have crossed from one species to another
after living for a long time in one species with little
damage.
– Examples:
» HIV
» West Nile
• Some believe that the way that we are altering the
environment & destroying habitats ensure that diseases
like these will become more common in the future.
Environmental Change and Disease
Humans altering the environment
– Examples of Cross-Species Transfers
• Argentina – Hanta Virus
– Herbicides killed native grasses which allowed new plants to
move in, which brought with it rodents that carry strains of
hemorrhagic fever
• Hong Kong – Hong Kong Influenza
– Influenza spreads from animals to humans and back again
easily (particularly birds)
– Many times can be found in poultry markets in crowded areas