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EHS 507
Setting the PEL
Old PEL Sig Risk* New PEL L.F. Risk* Data
Arsenic 500 g/m3
148-767 10 g/ m3
2.2-2.9 Epidemiology
Ethylene Oxide
• 50 ppm• 63-109• 1 ppm• 1.2-2.3• Toxicology
*Excess deaths/1000 exposed for 45 yr.
THE MORAL/ETHICAL DIMENSION
•When it comes to setting standards and exposure limits:-–who decides what?–on behalf of whom?–on what basis?
INTERDISCIPLINARY FACTORS IN ENVIRONMENTAL HEALTH ISSUES
• Natural scientists• Life sciences• Physical sciences• Social scientists• Behavioral sciences• Management sciences• Political
A STANDARD AS THE BASIS FOR CONTROLLING EXPOSURE
1 Elimination of the risk factor.2 Technical reduction of
exposure.3 Administrative procedures to
reduce exposure.4 Personal responsibility.
. . . . THE STANDARD AS A ‘YARDSTICK’ AGAINST WHICH TO MEASURE THE EFFECTIVENESS OF
CONTROL.
HIERARCHYOF CONTROLS
REGULATION OF THE ENVIRONMENT IN THE U.S.• Environmental Protection Environmental Protection
Agency (EPA)Agency (EPA) founded in 1970• President Nixon’s charge to
the first EPA Administrator “to “to treat air pollution, water treat air pollution, water pollution and solid wastes as pollution and solid wastes as different forms of a single different forms of a single problem . .”problem . .”
EPA MISSION• Clean air• Clean and safe water• Safe food• Preventing pollution and reducing risk
in communities, homes, etc. and ecosystems
• Better waste management• Reduction of global environmental risks• Expansion of right to know• Sound science• Effective management
SOME KEY ENVIRONMENTAL REGULATORY MILESTONES
Environmental Protection Agency (EPA)Environmental Protection Agency (EPA)• Clean Air Act (1970, amended 1990)• Clean Water Act (1977)• Lead Contamination Control Act (1988)• Food Quality Protection Act (1996)Occupational Safety and Health Occupational Safety and Health
Administration (OSHA)Administration (OSHA)• Occupational Safety and Health Act
(1970)
CONTROL OPTIONS FOR AIR POLLUTION FROM INDUSTRY
• Change process or equipment.
• Reduction in production• Substitution of materials.• Air cleaning technology.• Improve dilution and
dispersal.• Shut down operation!
CONTROL OPTIONS FOR MOBILE EMISSIONS
•Less cars and trucks.
•Cleaner vehicles.•Better fuel
economy•Cleaner fuels.
CONTROL OPTIONS FOR SAFE DRINKING WATER
• Protect groundwater at source:-– reduce agricultural runoff.– careful placement of landfill.– control industrial discharges.
• Water treatment:-– filtration (sand, adsorbers).– softening.– distillation.
ENGINEERING TREATMENT OF MUNICIPAL LIQUID WASTE
(i.e., sewage)• Primary :-
– holding tank to remove suspended solids by settling; floating oils, etc. are skimmed off and passed to anaerobic digester.
• Secondary (biological):-– transformation under aerobic and
anaerobic conditions. • Tertiary:-
– filtration and disinfection.
STANDARDS FOR SOLID WASTE• In the USA, the primary agency
for promulgating and enforcing regulations about solid waste is EPA.
• Solid Waste Disposal Act in 1974; Comprehensive Environmental Response, Compensation and Liability Act (Superfund) in 1980; later amendments.
SOLID WASTE MANAGEMENT• EPA now requires minimization
of production of solid waste by polluters:-– segregation at source.– elimination/substitution of raw
materials.– changing manufacturing
processes.
SOLID WASTE TREATMENT
•A wide range of physical, chemical or biological processes aimed at:-–neutralizing the material (making it safe).
–recovering useful energy or materials.incineration a useful approach,
but need to be careful when burning plastics
FOOD SAFETY• In the USA, several agencies are
responsible for food safety:-– FDA (labeling, food additives, food
processing, etc.)– DoA (inspection and labeling of meat
and eggs, imports, human nutrition aspects of food, etc.)
as well as EPA (use of pesticides, etc.)• Microbiological hazards a major part,
both in processing and in domestic use.
KEY INTERVENTIONS (Food Code, US
Department of HHS, FDA, 1999) • Demonstration of knowledge
• Employee health controls• Controlling hands as a vehicle of
contamination• Time/temperature controls• Consumer advisory• Address risk factors documented
by CDC
CONTROL MEASURES FOR INDOOR AIR POLLUTANTS
Pollutant Control
Radon progeny, tobacco smoke, aerosols, etc.
Ventilation
Organic materials, lead, asbestos, tobacco, etc.
Eliminate source
Aerosols, vapors Air cleaners
Organic substances, tobacco, etc.
Behavioral adjustment
STANDARDS FOR OCCUPATIONAL HAZARDS
• In the USA, the primary agency for promulgating and enforcing workplace standards is the Occupational Health and Safety Administration (OSHA).
• Occupational Safety and Health Act in 1970, amended in 1974, 1978, 1982 and 1984.
• Also influential: the American Conference of Governmental Industrial Hygienists (ACGIH).
TECHNICAL CONTROL OPTIONS FOR THE WORKPLACE
• Change process or equipment.• Reduction in production.• Substitution of materials.• General exhaust ventilation.• Local exhaust ventilation.• Personal protective equipment
– respirators– hearing protectors– eye protectors, etc.}the last
resort!!
RADIATION SAFETY• The players:-
– International Commission on Radiological Protection (ICRP)
– NCRP– Federal Radiation
Council (FRC)
NCRP RECOMMENDATIONS (1987) FOR TOTAL RADIATION DOSE
TYPES OF EXPOSURE LIMIT VALUE
Occupational 50 mSv (annual)
Public 1 mSv (annual)
Embryo-Fetus 5 mSv
a heavy smoker may be getting
close to this
a uranium miner may be getting
close to this
FACTORS INFLUENCING RADIATION
PROTECTION•Distance•Time•Shielding•Sanitation
stay as far away as possible
keep exposure time as short as possible
do all that is necessary to keep radioactive materials
out of the body
interpose dense material (e.g., lead,
concrete, water, etc.) between
source and subject
STORAGE OF WASTE RADIOACTIVE MATERIALS
(e.g., SPENT NUCLEAR FUEL)
•For long-lived radioactive material (e.g., Pu239):-–Treatment and concentration.
–Encapsulation.– Interment at sea or underground.