Toxicology and Human Health

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Toxicology and Human Health
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Toxicology and Human Health

• Risk and Hazards
• Risk - the possibility of suffering harm from a
  hazard that can cause injury, disease, economic
  loss, or environmental damage

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Toxicology and Human Health

• Risk and Hazards
• Probability - a mathematical statement about how
  likely it is that some event will occur
• Ranges from 0 ( absolute certainty of no risk) to
  1 (absolute certainty of risk)

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Toxicology and Human Health

• Types of Hazards
• Cultural Hazards
• Poor diet
• Unsafe sex
• Chemical Hazards
• Harmful chemicals in air, water, soil, food

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Toxicology and Human Health

• Types of Hazards
• Physical Hazards
• Ionizing radiation
• Noise
• Natural disasters
• Biological Hazards
• Pathogens
• Allergens
• Animals

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Toxicology and Human Health

• Toxicology
• Toxicology - the study of the adverse effects of
  chemicals on human health
• Toxicity - a measure of how harmful a substance is

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Toxicology and Human Health

• Toxicology
• Pathways of Exposure
• Inhalation
• Ingestion
• Absorption chemicals on human health

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Toxicology and Human Health

• Toxicology
• Dose and Response
• Dose - the amount of a potentially harmful
  substance a person has ingested, inhaled, or
  absorbed
• Response - the amount of damage to health per
  given dose

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Toxicology and Human Health

• Toxicology
• Types of Responses
• Acute Response - an immediate or rapid harmful
  reaction to an exposure
• Chronic Response - a permanent or long-lasting
  reaction to an exposure

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Toxicology and Human Health

• Toxicology
• Factors Affecting Dose and Response
• Bioaccumulation - an increase in the
  concentration of a chemical in a specific organ
  at a level higher than would normally be expected

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Toxicology and Human Health

• Toxicology
• Factors Affecting Dose and Response
• Biomagnification -an increase in the
  concentration of certain slowly-degradable
  fat-soluble compounds in organisms at
  successively higher trophic levels in a food
  chain

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Bioaccumulation and Biomagnification
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Toxicology and Human Health

• Toxicology
• Lethal Dose and Poison
• Median Lethal Dose (LD50) - the amount of a
  chemical received in one dose that will kill
  exactly 50 of all test animals within a 14 day
  test period
• Poison - a chemical with an LD50 lt/ 50
  milligrams per kilogram of body weight

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Toxicology and Human Health

• Toxicology
• Methods of Determining Toxicity
• Case Reports
• Laboratory Investigations
• Epidemiology

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Toxicology and Human Health

• Chemical Hazards
• Toxic Chemicals - substances that are fatal to gt
  50 of test animals at a given concentration

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Toxicology and Human Health

• Chemical Hazards
• Hazardous Chemicals - chemicals that cause harm
  by
• Being flammable or explosive
• Irritating or damaging skin or lungs
• Interfering/preventing oxygen uptake
• Inducing allergic reactions of the immune system

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Toxicology and Human Health

• Chemical Hazards
• Mutagens - chemicals that cause random mutations
• Radiation

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Toxicology and Human Health

• Chemical Hazards
• Teratogens - chemicals, radiation, viruses that
  cause birth defects during development of human
  embryo
• PCBs
• Thalidomide
• Steroid hormones
• Heavy metals

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Toxicology and Human Health

• Chemical Hazards
• Carcinogens - chemicals, radiation, viruses that
  cause/promote growth of malignant tumors

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Toxicology and Human Health

• Chemical Hazards
• Carcinogens
• Major Sources
• Cigarette Smoke (30-40)
• Diet (20-30)
• Occupational Exposure (5-15)
• Environmental Pollutants (1-10)

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Toxicology and Human Health

• Chemical Hazards
• Impacts on the Immune System
• Immune System - cells and tissues that protect
  the body from disease by forming antibodies to
  invading agents and rendering them harmless

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Toxicology and Human Health

• Chemical Hazards
• Impacts on the Immune System
• Synthetic chemicals
• HIV virus
• Ionizing radiation

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Toxicology and Human Health

• Chemical Hazards
• Impacts on the Immune System
• Weakening of immune system and attack by
  allergens, infectious bacteria, viruses,
  protozoans

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Toxicology and Human Health

• Chemical Hazards
• Impacts on the Nervous System
• Components of the Nervous System
• Brain
• Spinal Cord
• Nerves

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Toxicology and Human Health

• Chemical Hazards
• Impacts on the Nervous System
• Neurotoxins - chemicals that attack nerve cells
• Chlorinated hydrocarbons
• Organophosphate pesticides
• Formaldehyde
• Heavy metals
• Industrial solvents

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Toxicology and Human Health

• Chemical Hazards
• Impacts on the Endocrine System
• Endocrine System - organs and tissues whose
  actions are coordinated by chemical messengers
  called hormones

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Toxicology and Human Health

• Chemical Hazards
• Impacts on the Endocrine System
• Hormones control
• Sexual reproduction
• Growth
• Development
• Behavior

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Toxicology and Human Health

• Chemical Hazards
• Impacts on the Endocrine System
• Endocrine Disrupters
• Undersized penises
• Low testosterone levels
• Hyperactivity
• Vaginal cancer
• Malformed testicles
• Retardation
• Endometriosis

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Toxicology and Human Health

• Biological Hazards
• Types of Diseases
• Transmissible Disease - a disease caused by a
  living organism which can be spread from one
  person to another
• Pathogens - disease-causing organisms
• Bacteria - single-celled organism
• Viruses - noncellular infectious agent
• Parasites - (tapeworm)
• Protozoa - (amoeba)

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Toxicology and Human Health

• Biological Hazards
• Types of Diseases
• Transmissible Disease
• Sources of Exposure
• Air
• Water
• Food
• Body fluids
• Insects
• Non-human carriers (vectors)

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Toxicology and Human Health

• Biological Hazards
• Types of Diseases
• Seven Dealiest Transmissible Diseases
• Acute Respiratory Infections
• Bacteria, Viruses (4.7 million deaths)
• Diarheal Diseases
• Bacteria, Viruses (3.1 million deaths)
• Dysentery

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Toxicology and Human Health

• Biological Hazards
• Types of Diseases
• Seven Dealiest Transmissible Diseases
• Tuberculosis
• Bacteria (3.1 million deaths)
• Malaria
• Parasitic protozoa (Plasmodium)
• 2.1 million deaths annually

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Toxicology and Human Health

• Biological Hazards
• Types of Diseases
• Seven Dealiest Transmissible Diseases
• AIDS
• HIV (1.7 million deaths)
• Hepatitis B
• Virus (1 million deaths)
• Measels
• Virus (1 million deaths)

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Toxicology and Human Health

• Biological Hazards
• Types of Diseases
• Seven Dealiest Transmissible Diseases
• LDCs
• Infectious diseases account for 42 of all deaths
  annual
• 27,000 deaths per day due to infectious diseases

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Toxicology and Human Health

• Biological Hazards
• Types of Diseases
• Nontransmissible Diseases
• Cardiovascular disorders
• Cancer
• Diabetes
• Malnutrition
• Bronchitis
• Emphysema

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Toxicology and Human Health

• Biological Hazards
• Types of Diseases
• Tuberculosis
• Bacterial Disease
• Airborne droplets of body fluids spread by
  coughing, sneezing, talking, singing
• 95 of all new cases occur in LDCs
• Rapid reemergence

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Toxicology and Human Health

• Biological Hazards
• Types of Diseases
• Tuberculosis
• Causes of reemergence
• Poor screening and control programs
• Development of genetically resistant strains of
  bacteria to antibiotics
• Population growth and urbanization
• Spread of AIDS

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Toxicology and Human Health

• Biological Hazards
• Types of Diseases
• Influenza
• Viral Disease
• Transmitted by body fluids or airborne emissions
• Spanish Flu Epidemic - 1918-1919 killed 30
  million people
• Ebola
• Transmitted by blood or body fluids

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Toxicology and Human Health

• Biological Hazards
• Types of Diseases
• Rabies
• Viral Disease
• Transmitted by dogs, skunks, raccoons
• AIDS
• HIV - kills bodys immune cells
• Unprotected sex
• Intravenous drug use
• Blood transfusions

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Toxicology and Human Health

• Biological Hazards
• Types of Diseases
• AIDS Facts
• India has highest number of HIV-positive people
• 1996 - 36 million people were infected with HIV
• Heterosexual transmission accounts for 90 of new
  HIV infections

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Toxicology and Human Health

• Biological Hazards
• Major Diseases in MDCs
• Epidemiological Transition
• Related to Demographic Transition
• Transmissible diseases supplanted by
  non-transmissible diseases
• Cardiovascular Disease (39)
• Cancer (24)
• Infectious Diseases (5)
• Accidents (4)

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Toxicology and Human Health

• Biological Hazards
• Sexually-Transmitted Diseases
• Exposure Pathways
• Sexual activity
• Mother to infant during birth
• Intravenous drug use
• Infected blood

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Toxicology and Human Health

• Biological Hazards
• Sexually-Transmitted Diseases
• Bacterial STDs
• Chlamydia
• Gonorrhea
• Syphilis
• Viral STDs
• Genital herpes and warts
• Hepatitis B
• AIDS

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Toxicology and Human Health

• Risk Analysis
• Steps
• Risk Assessment
• Comparative Risk Analysis
• Risk Management
• Risk Communication

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Toxicology and Human Health

• Risk Analysis
• Risk Assessment - Identifying hazards, estimating
  the probability that each hazard will occur, and
  estimating how many people may suffer serious harm

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Toxicology and Human Health

• Risk Analysis
• Risk Management - determining options about
  reducing or eliminating risks
• Risk Communication - informing decision makers
  and the public about risks

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Toxicology and Human Health

• Risk Analysis
• Risk-Benefit Analysis - an estimate of the short-
  and long-term risks and benefits of using a
  particular product or technology

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Risk Analysis
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Toxicology and Human Health

• Risk Analysis
• Issues and Limitations
• Depends on toxicology assessments that have
  scientific and economic limitations
• Who does the analysis?
• Who interprets the results of the analysis?
• How are risk levels set?
• Goals of risk analysis?