Environmental Hazards and

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• Environmental Hazards and
• Human Health

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Case Study HIV/AIDS

• Cripples the immune system
• Die of other diseases
• TB and Kaposi's sarcoma (cancer)

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HIV Transmission

• Unsafe sex
• Sharing needles
• Mother to child
• Exposure to blood

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Statistics

• Identified in 1981
• 2005 42 million people infected (global)
• 1.1 million in U.S.
• 2/3 in sub-saharan Africa
• 4.9 million infected in 2005
• 49,500 in US
• 13,400 new cases/day
• 15-24 years old

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AIDS Statistics

• 3 million people die a year
• 16,000 in US
• Life expectancy to 40 years of age

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Loss of age group

• loss of education,
• health care,
• food production,
• economic development
• disintegration of families.
• 15 million orphans

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Risks Hazards

• Risk- possibility of suffering harm
• Risk assessment- scientific process of estimating
  harm.
• Risk management-how to reduce a particular risk.

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Types of Hazards

• Biological Hazards-pathogens( bacteria, viruses,
  parasites, protozoa, and fungi)
• Chemical Hazards-harmful chemicals in air water,
  soil and food.
• Physical Hazards- fire, earthquake, volcanic
  eruption, flood, tornado, hurricane...
• Cultural Hazards- smoking, working conditions,
  poor diet, drugs, drinking, driving, criminal
  assault, unsafe sex and poverty

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Biological Hazards Disease

• Nontransmitable disease not caused by living
  organisms and does not spread.
• Cardiovascular disease
• Diabetes
• Asthma
• Malnutrition
• emphysema

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Biological Hazards Disease

• Infectious or transmissible disease- caused by a
  pathogen.
• flu/pneumonia
• HIV
• Malaria
• Diarrheal diseases
• TB
• Hep B
• Measles

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Pathogen Transmission

• Air
• Water
• Food
• Body fluids
• Sneezes/Coughs
• Feces/Urine
• Blood
• Sexual fluids and breast milk

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Bioterrorism

• Deliberate release of disease causing pathogen.
• Centers for Disease Control and Prevention-
  developing sensors.
• Epidemic- outbreak in area or country
• Pandemic- global outbreak. (AIDS)

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Good/bad News

• GOOD Since 1900-incidences of infectious
  disease have dropped.
• BAD Disease carrying bacteria have developed a
  genetic immunity to anitibiotics.

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Case Study Antibiotics.

• 1. Productive rate of bacteria
• 16 million offspring in 24 hours.
• 2. Transfer genetic resistance
• Transformation absorbs DNA from env.
• Conjugation- swaps
• 3. Spread-global travel/trade
• 4. Overuse of Pesticides
• 5. overuse of antibiotics
• 6. Widespead use in agriculture

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Results of Antibiotic misuse

• Every disease-causing bacterium has resistant
  strains.
• 160 antibiotics available- are useless
• 2 million pick up infections in hospital
• 90,000 hospital patients die of infection

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Case Study Tuberculosis (TB)

• Strikes 9 million/year
• Kills 1.7 million/year
• 25 million by 2020
• 84 in developing countries
• People don't know they are infected
• Untreated TB infects 10-15 more people.
• Expensive to diagnose and timely

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Why recent increase in TB?

• Lack of TB screening programs
• Lack of control programs
• Most strains have developed genetic resistance to
  antibiotics.
• Population and urbanization
• Increased air travel
• AIDS weakens victims.

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Viral Diseases

• 1st What is the biggest killer?
• 2nd AIDS
• 3rd HBV Hepatitis B
• HBV-cervical cancer
• HepB-damages the liver
• Passed the same ways as HIV
• Emergent viruses
• SARS, West Nile, Avian Flu

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Case Study Malaria

• 1 in 5 is at risk in poor African countries
• Parasite spread by mosquitoes, transfusions, and
  sharing needles.
• 4 plasmodium species
• Destroys RBC causing flue like symptoms
• Kills 2-3 million/year (5,500 deaths/day)
• 90 are children
• Survivors are brain damaged/impaired learning
  abilities.

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Malaria

• Malaria cycle continues until immunity develops,
  treatment, or victim dies.
• Killed more people than all wars ever fought.
• Dropped in 1950's and 60's-draining wetlands.
• Increased since 1970's
• Mosquitoes resistant to pesticides
• Plasmodium genetically resistant to malarial
  drugs.
• ?Deforestation rates-standing water.

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New Malarial Treatments

• Developing new antimalarial drugs (fungi).
• Window screens/bed nets in poor countries.
• Spraying with low dose DDT
• Preventative treatment costs .25-2.40
• Spending 2-3 billion saves gt1 million lives

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Reducing the Incidence of Infectious Disease

• 2/3 ?in death rate of infectious disease since
  1970.
• Oral rehydration therapy
• Dehydration is a side effect. 1/4th of all
  deaths in children under 5 yrs.

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Ecological Medicine infection

• Infectious is moving between species
• Humans are invading wildlife habitats
• Bushmeat
• Clearing fragmentation of forests
• Cutting down of tropical rainforests.
• Factory farming Global trade of livestock
• New field of science Ecological or Conservation
  Medicine

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Chemical Hazards

• Toxic Chemical- temporary or permanent harm or
  death in animals/humans.
• Hazardous chemical- harm humans/animals because
  it is
• Flammable
• Explosive
• irritate/damage skin or lungs
• Interfere with oxygen uptake
• Induce allergic reactions

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Toxic agents Mutagens

• Mutagens- chemicals or forms of radiation that
  ?the frequency of mutations, ? DNA.
• Nitrous Acid (HNO2)-formed by the digestion of
  nitrite preservatives in foods.
• Linked to fast food wine
• Stomach cancer

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Toxic Agents Teratogens

• Teratogens- chemicals that harm fetus or embryo.
• Low birth weight, physical, mental, behavioral,
  developmental problems
• Ethyl alcohol, benzene, chlorine, chloroform,
  chromium, DDT, lead, mercury, PCBs, phthalates,
  thalidomide, and vinyl chloride.

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Toxic Agents Carcinogens

• Carcinogens chemicals or types of radiation that
  cause or promote cancer.
• Cancer- uncontrolled cell division.
• 10-40 years lapse before onset (since original
  exposure.)

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Effects of Chemicals Immune

• Immune system specialized cells that protect
  against disease and other substances by forming
  antibodies.
• Neurotoxins- harm the nervous system (brain,
  spinal chord, and peripheral nerves)
• Inhibit, damage or destroy nerve cells (neurons)
• PCBs, methyl mercury, arsenic, lead, certain
  pesticides.

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Effects of Chemicals Endocrine System

• Endocrine system- network of gland that release
  hormones into bloodstream.
• Hormones- chemical messengers that turn off/on
  reproduction, growth, development, learning
  ability, and behavior.
• DDT, PCBs, atrzine, aluminum, mercury

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Effects of Chemicals Endocrine System

• Hormonally active agents (HAAS or hormone Mimics-
  chemically similar impair endocrine system block
  receptor sites.
• Gender benders (estrogen mimics)- hormone
  blockers of sexual development and reproduction.

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CASE STUDY Bisphenol

• BPA is an Estrogen mimic
• Building block of certain plastics
• Water bottles, food storage containers, baby
  bottles, liners for food and beverage cans, auto
  interiors and dental fillings.
• Leach out if exposed to head or acids
• 95 of Americans have trace amounts
• Brain damage, prostate/breast cancer, ?sperm
  count, impaired immunity, hayperactivity,
  ?agressiveness, impaired learning, ?addition to
  drugs, obesity in fetuses, ?sex drive

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Effects of Chemicals Endocrine System

• Thyroid disrupters- cause growth, weight, brain
  and behavior disorders.
• Phthalates- softenersin plasticizers in products
  with PVC (polyvinyl chloride)
• Perfume, cosmetics, hair sprays, deodorants, nail
  polish, baby milk formula, processed foods, vinyl
  toys, food packaging, blood storage bags,
  hospital tubing.

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Case Study Bhopal, India

• 1984 industrial accident in pesticide plant.
• Methyl isocyanate (MIC) gas leak.
• Converted to hydrogen cyanide gas
• 30 sq miles
• 600,000 exposed
• 1996- 50-60,000 people sustained injury
  (blindness, lung damage, neurological problems.

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Toxicology Assessing Chemical Hazards

• Factors that determine harm caused by exposure.
• Amount of exposure (dose)
• Frequency of exposure
• Person who is exposed
• Body's detoxification systems
• One's genetic makeup

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Toxicology

• Toxicology- science that examines the effects of
  chemicals on humans, wildlife and ecosystems.
• Toxicity- measure of how harmful a substance is
  in causing injury, illness or death.
• Dose- amount of substance inhaled, ingested or
  absorbed.

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Multiple Chemical Sensitivity

• Sensitive to a number of toxins.

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5 Factors

• 1. Solubility- can move throughout environment.
• Water soluble toxins
• 2. Oil- or Fat Soluble toxins- organic compounds
  penetrate cell membrane (lipid bilayer)
• 3. Persistence- resistance to break down
• DDT (biomagnification)
• 4. Bioaccumulation or molecules are absorbed and
  stored in tissues and organs in higher levels.
• DDT, PCBs, radioactive isotopes (strontium)

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5 Factors

• 5. Chemical Interactions- decrease or multiply
  harmful effects.
• Antagonistic interaction- reduce harmful effects
• Vit A and E reduce cancer risks
• Synergistic interactions- multiplies effects.
• Asbestos 5x cancer risk
• Asbestos and smoking 25x cancer risk

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Response

• Response- Type and amount of damage that result
  from chemical exposure.
• Acute effect- immediate/rapid reaction
• Dizziness to death
• Chronic effect-permanent or longlasting
  consequence
• Kidney, liver damage

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Basic Concept

• Any synthetic or natural chemical can be harmful
  if ingested in large enough quantities.
• How much exposure to particular toxic chemical
  causes a harmful response?

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3 mechanisms for reducing the harmful effects of
chemicals

• Breakdown, dilute, or excrete (breath, urine and
  sweat)
• Cellular enzymes repair damage to DNA.
• Cells (GI and skin) can reproduce fast enough to
  repair damage.

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Effects of Trace Levels of toxins

• Poison or toxin- chemical that adversely affects
  health by injury, illness or death.
• Trace chemicals are in the environment, foods,
  pesticides, agricultural products.
• Debate on amounts and their affects.

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Why do we know so little?

• Under existing laws, chemicals are considered
  safe until proven guilty.
• Expense
• 10 of 85,000 registered synthetic chemicals have
  been tested.
• 2 of those have been tested to determine if
  there are a carcinogen, teratogens or mutagens.
• 99.5 of commercial chemicals are NOT regulated.

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Pollution Prevention and the Precautionary
Principle

• Pollution Prevention- EU not release into the
  environment chemicals that we know or suspect can
  cause harm.
• Look for harmless alternatives
• Recycle

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• Precautionary Principle- taking action instead of
  waiting until there is more conclusive evidence.
• New chemicals would be automatically labelled as
  harmful.
• Existing chemicals/technologies would be removed
  from market until their safety is established.

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EU nation and Global Treaty

• Phase out 12 most notorious persistent organic
  pollutants (POPs) (dirty dozen)
• DDT, PCBs, dioxans, furans and 8 other persistent
  pesticides.
• Chemicals would be added if they cause more harm
  than good.
• Went into effect 2004

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Manufacturers chemical businesses

• Too expensive
• Impossible to introduce new technology or
  chemical
• Can never have a risk free society.
• Is it and ethical responsibility?

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Risk Analysis

• Risk analysis- identifying hazards and their
  associated risks.
• Risk assessment-
• Ranking risks (comparative risk analysis)
• Risk management- identifying, reducing or
  eliminating risks.
• Risk communication- informing decision makers and
  public about risks.

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Case Study smoking

• Kills 13,700 people/day
• One every 6 seconds
• Worlds most preventable major cause of suffering
  and premature death.
• 1950-2005- 85 million people were killed
• 30 million people have been killed in battles
  since 1900.
• 5 million people die prematurely/year
• ½ from developing and ½ from developed
• Heart disease, lung cancer, bronchitis, emphysema

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smoking............

• 2030- 10 million/year will die
• 1 death every 3 seconds
• 70 of deaths will be in developing countries.
• CDC data 2002- 442,000 die
• 1,210/day
• Equivalent to 3 jumbo jets crashing daily
• 1 in 10 successfully quits smoking

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Passive smoking

• Poses health threats to children adults
• ?in allergies and athsma.
• Spouses have a 30? heart attack and lung cancer
• CDC in US
• 3,000 lung cancer deaths
• 46,000 from heart disease
• 2006 California classified second hand smoke as a
  toxic air pollutant.

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Smokers

• Smokers die 10 years earlier
• Quit by age 30 have no longevity risks
• Quit by 50, cut risks in half.
• Health
• Health expert urge 3-5 federal tax
• Help pay for 158 billion/year in health care costs

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Ways to Reduce the Smoking Death toll

• Banning all advertising
• Prohibit sales under 21
• Banning vending machines
• Banning candy flavored cigarettes
• Regulating nicotine as an addictive and dangerous
  drug
• Eliminating tax breaks for farmers/companies
• Smoking bans in workplaces, bars an

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Estimating RIsks

• Reliability or probability- expressed as
  percentage.
• System technology human
• Reliability reliability X reliability

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Perceiving Risks

• Degree of control
• Fear of the unknown
• Whether we voluntarily take the risk
• Whether the risk is catastrophic
• Unfair distribution of risks

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Becoming Better at Risk Analysis

• Recognize that everything is risky
• How risky? is the question
• Recognize that the media exaggerates
• Compare risks. How risky is it compared to other
  risks.
• Concentrate on the most serious risks that you
  have control over.

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