Unit 8 – Public Health Environmental Issues in Public Health: Part I Chapter 19 – A Clean...
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Transcript of Unit 8 – Public Health Environmental Issues in Public Health: Part I Chapter 19 – A Clean...
Unit 8 – Public HealthEnvironmental Issues in Public
Health: Part I
Chapter 19 – A Clean Environment: The Basis of Public Health
Role of Government in Environmental HealthEnvironment is beyond the control of
individualsLocal governments provide clean water
and disposal of wastesAs population grew, environmental
problems transcended local government1960s and 1970s – state and federal
governments took more responsibilityNow, world population growth has led to
global environmental problems
Environmental HazardsRadiationMercuryLeadAsbestosPesticides and industrial chemicalsFederal government does research, sets
standards for exposure limitsEnvironmental Protection Agency (EPA)
RadiationUltraviolet light from the sun – skin
cancer and melanomaRadon gas – natural radioactivity – lung
cancer?Early scandals with patent medicines and
radium led to regulationX rays used in medicine and dentistry Lessons on health effects of radiation
learned from atomic bombings in Japan
MercuryNeurological damage in workersMinamata, JapanEmissions from coal-burning power plants in
US leads to air pollution, water pollution, contamination of fish
Concern about fever thermometers, school laboratory equipment
LeadHarmful to brain and nervous system,
especially of childrenContamination of drinking water by lead
pipes and lead solder for copper pipesAir pollutant from use in gasoline until
banned in the 1980sWas used in paint until 1977 – still a
threat in old housing – peeling paint or contaminated dust
Young children should be screened for blood lead levelsPermissible levels have been steadily lowered
AsbestosWas widely used because of fire resistanceUsed in insulation; still used in roofing, gaskets,
brake liningsWas required in schools between 1940 and 1973
Still a danger from deteriorating walls and ceilingsFibrous dust causes scarring of lungs
(asbestosis) and mesothelioma (cancer)Affected asbestos workersManville Corporation bankrupt – 1982Libby, Montana – whole area affected from
minesWorld Trade Center – clean-up and rescue
workers
Pesticides and Industrial ChemicalsRachel Carson’s Silent Spring – 1962 –
beginning of environmental movementDDT and other pesticides– now bannedPCBs – industrial uses
Hudson River – contaminates fishYusho accident (Japan) – contamination of cooking
oil – other similar accidentsProduction halted in US by 1977
Endocrine disrupters, affect reproduction, nervous system, immune system, maybe cancer
Soluble in fat, persist in environment, very stable
Occupational ExposuresWorkers are often the first to suffer effects of an
exposure – serve as guinea pigsCarcinogens recognized through occupational
cancersScrotal cancer in chimney sweepsBladder cancer in dye factory workersLung, lymphatic cancer from arsenic (copper smelters)Angiosarcoma from vinyl chloride (plastics)
Neurotoxins also recognized through occupational illnessHexane (shoemakers), trichloroethylene (dry
cleaners), pesticide applicators.
Factory FarmsAnimals crowded together and tended by
automated systemsProduce huge volumes of wastes – lagoonsAir pollution (ammonia, hydrogen sulfide,
methane) and water pollution after rainPolitical power protects them from
environmental regulation
Setting StandardsMost chemicals have not been tested for
health effectsOccupational Safety and Health ActToxic Substances Control ActFederal Insecticide, Fungicide, and
Rodenticide ActClean Air ActProcess of standard setting is slow and
always controversial
Risk-Benefit AnalysisAbsolute safety is impossibleOver-regulation can cause under-regulationMust balance risk against other societal
goals, including economic well-beingCurrent administration and Congress favor
economic and business interests over environment and public health
Unit 8 – Public HealthEnvironmental Issues in Public
Health: Part I
Chapter 20 – Clean Air: Is It Safe to Breathe?
Air Pollution EventsWeather inversion in London, 1952 – more
than 4,000 deathsDonora, Pennsylvania in 1948 – similar
weather inversion Smog in Los Angeles in 1950s and 1960sClean Air Act of 1970
Criteria Air PollutantsParticulate matterSulfur dioxideCarbon monoxideNitrogen oxidesOzoneLead
Particulate MatterProducts of combustionFirst regulated total particulatesSix Cities Study – death rates higher in
most polluted citiesSmaller particles penetrate deeper into
lungs1987 set standards for PM10
1997 set standards for PM2.5
Lung cancer, other lung diseases, heart disease proportional to PM2.5
Sulfur DioxideCombustion of sulfur-containing fuels,
especially coalIrritates respiratory tractAcid rain
Nitrogen oxidesMotor vehiclesResponsible for yellowish-brown smogIrritates respiratory tractAcid rainContribute to ozone formation
OzoneProduced by sunlight acting on other air
pollutantsIrritating to eyes and respiratory systemIncreases mortality from cardiovascular and
respiratory diseases
LeadDamages nervous system, blood, and kidneysWas used in leaded gasoline, banned in
1980sHas decreased dramatically as an air
pollutant
Other Air PollutantsClean Air Act directed EPA to set standards
for 188 othersAs of 1993, only acted on asbestos, mercury,
beryllium, benzene, vinyl chloride, arsenic, radionuclides, coke oven emissions
Controversy over each standard
Strategies for Motor VehiclesTailpipe emissions limits
Catalytic convertersReformulated fuel
Vapor recovery systems on gasoline pumps
Inspection and maintenance requirementsRequirements that auto makers develop
zero emission vehiclesPublic transportationEncourage carpooling
Strategies for Industrial SourcesScrubbers on smokestacksLess polluting fuels (limit high-sulfur coal)Pollution allowances bought and soldNew Source Review
Industry has flouted the rulesLawsuits by statesBush Administration replaced this provision
with weaker “Clear Skies Initiative” Emergency Planning and Community
Right-to-Know Act
Good News54% decrease in air pollution since 1970California, with the worst pollution, has
instituted many special regulations and incentives, with some success
Indoor Air QualityMost people spend more time indoors than
outSources of indoor air pollution:
Tobacco smokeWood-burning stoves and fireplacesGas ranges and furnaces
Radon Danger is unclearSeeps up from soil and rockCan be sealed out
Formaldehyde from insulation, particleboard, plywood, some floor coverings and textiles
Indoor Air Quality, ctd.Formaldehyde from insulation, particleboard,
plywood, some floor coverings and textilesRegulated by Dept. of Housing and Urban
DevelopmentConsumer products such as pesticides, dry-
cleaning solvents, paints and paint thinners, hair spray, air freshenersShould be used with caution
Microbes such as legionella, hantavirusAllergens such as mold, house mites, animal
dander
Global Effects of Air PollutionAcid rain damages forests and crops, turns
lakes and rivers acidic, kills fish and plantsDepletion of the ozone layer
Montreal Protocol -- 1987Production of CFCs phased outOzone layer has stabilized
Carbon dioxide produced by burning fossil fuels causes greenhouse effect, global warming
Unit 8 – Public HealthEnvironmental Issues in Public
Health: Part I
Chapter 21 – Clean Water: A Limited Resource
Water Pollution IncidentsLake Michigan, Chicago – cholera -- 1885Minamata Bay, Japan – mercury – 1950sHudson River, New York – PCBs – 1970sLake Superior, Duluth – asbestos -- 1970s James River, Virginia – Kepone – 1960sCuyahoga River, Ohio – caught fire (oil) –
1969Lake Michigan, Milwaukee –
cryptosporidiosis -- 1993
Federal LegislationClean Water Act – 1972, 1977, 1987
Lakes and rivers should be fishable and swimmable
All pollution discharges should be eliminatedSafe Drinking Water Act – 1974, 1996
EPA should set standards for local systemsStates should enforce the standards
Clean Water ActPoint source pollution
Requirements for treating wastewaterSewage treatment plants or septic systemsTreat with chlorine or other disinfectantSludge -- Congress prohibited ocean dumpingPretreatment of industrial wastes
Non point source pollutionAgricultural runoffUrban runoffAir pollutants deposited by rain
Safe Drinking WaterSurface water
Clean water act helpsGround water
Generally cleanerCommunity water treatment to produce
potable waterCoagulation and flocculationSettlingFiltrationDisinfection
Safe Drinking Water, ctd.EPA has set standards for 87 identified
contaminantsSecondary standards for 15 contaminants
that may affect taste, odor, color, or cause discoloration of teeth
Annual reports required for customers – “right-to-know” about contaminants and health effects
CDC collects data on water-borne disease outbreaks
Regulated ContaminantsDisinfectants -- chlorineDisinfection byproducts -- chloriteInorganic chemicals – metals, asbestos, cyanideOrganic chemicals – herbicides, pesticides,
PCBsMicroorganisms – bacteria, viruses,
cryptosporidiumRadionuclidesTurbidity
Dilemmas in ComplianceNew York City fighting EPA order to filter
its water – cost is too highTrying to protect watershed for reservoirs in
Catskill MountainsCost is a problem in many communitiesDisinfectants may produce harmful
byproductsNew concern – trace amounts of
hormones, pharmaceuticals and household chemicals in many waterways
Shortages of Potable WaterMost water on earth’s surface is salt water or
iceLess than 1 percent is fresh waterWater shortages in many parts of the worldWater shortages in U.S. south and westPolitical disputes