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Toxicology and Human Health

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Title: Toxicology and Human Health


1
Toxicology and Human Health
2
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

3
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)

4
Toxicology and Human Health
  • Types of Hazards
  • Cultural Hazards
  • Poor diet
  • Unsafe sex
  • Chemical Hazards
  • Harmful chemicals in air, water, soil, food

5
Toxicology and Human Health
  • Types of Hazards
  • Physical Hazards
  • Ionizing radiation
  • Noise
  • Natural disasters
  • Biological Hazards
  • Pathogens
  • Allergens
  • Animals

6
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

7
Toxicology and Human Health
  • Toxicology
  • Pathways of Exposure
  • Inhalation
  • Ingestion
  • Absorption chemicals on human health

8
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

9
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

10
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

11
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

12
Bioaccumulation and Biomagnification
13
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

14
Toxicology and Human Health
  • Toxicology
  • Methods of Determining Toxicity
  • Case Reports
  • Laboratory Investigations
  • Epidemiology

15
Toxicology and Human Health
  • Chemical Hazards
  • Toxic Chemicals - substances that are fatal to gt
    50 of test animals at a given concentration

16
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

17
Toxicology and Human Health
  • Chemical Hazards
  • Mutagens - chemicals that cause random mutations
  • Radiation

18
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

19
Toxicology and Human Health
  • Chemical Hazards
  • Carcinogens - chemicals, radiation, viruses that
    cause/promote growth of malignant tumors

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

21
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

22
Toxicology and Human Health
  • Chemical Hazards
  • Impacts on the Immune System
  • Synthetic chemicals
  • HIV virus
  • Ionizing radiation

23
Toxicology and Human Health
  • Chemical Hazards
  • Impacts on the Immune System
  • Weakening of immune system and attack by
    allergens, infectious bacteria, viruses,
    protozoans

24
Toxicology and Human Health
  • Chemical Hazards
  • Impacts on the Nervous System
  • Components of the Nervous System
  • Brain
  • Spinal Cord
  • Nerves

25
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

26
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

27
Toxicology and Human Health
  • Chemical Hazards
  • Impacts on the Endocrine System
  • Hormones control
  • Sexual reproduction
  • Growth
  • Development
  • Behavior

28
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

29
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)

30
Toxicology and Human Health
  • Biological Hazards
  • Types of Diseases
  • Transmissible Disease
  • Sources of Exposure
  • Air
  • Water
  • Food
  • Body fluids
  • Insects
  • Non-human carriers (vectors)

31
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

32
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

33
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)

34
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

35
Toxicology and Human Health
  • Biological Hazards
  • Types of Diseases
  • Nontransmissible Diseases
  • Cardiovascular disorders
  • Cancer
  • Diabetes
  • Malnutrition
  • Bronchitis
  • Emphysema

36
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

37
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

38
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

39
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

40
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

41
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)

42
Toxicology and Human Health
  • Biological Hazards
  • Sexually-Transmitted Diseases
  • Exposure Pathways
  • Sexual activity
  • Mother to infant during birth
  • Intravenous drug use
  • Infected blood

43
Toxicology and Human Health
  • Biological Hazards
  • Sexually-Transmitted Diseases
  • Bacterial STDs
  • Chlamydia
  • Gonorrhea
  • Syphilis
  • Viral STDs
  • Genital herpes and warts
  • Hepatitis B
  • AIDS

44
Toxicology and Human Health
  • Risk Analysis
  • Steps
  • Risk Assessment
  • Comparative Risk Analysis
  • Risk Management
  • Risk Communication

45
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

46
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

47
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

48
Risk Analysis
49
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?
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