1. Toxicology
Chapter 16
APES
Catherine de Medici Mother of Toxicology

2. Categories of pollution
Infectious Agents
Transmissible disease: spread from person to person
Pathogen: infectious agent spread by air, water, food, body fluids or insects (insects are called vectors when they carry disease)
Pathogens can be bacteria or viruses

3. Worlds 8 most deadly diseases
Acute respiratory infections (pneumonia, influenza, whooping cough)

4. Diarrheal diseases (dysentery, cholera, etc.)

5. Tuberculosis

6. Malaria

7. AIDS

8. Measles

9. Hepatitis B

10. Tetanus

11. Lesson 9.1 An Overview of Environmental Health
Epidemiology
The study of disease in human populations—how and where they occur and how they can be controlled
Often involves studying large groups over long periods
Can determine statistical associations between health hazards and effects, but can’t prove the hazards actually caused the effects

12. Lesson 9.2 Biological and Social Hazards
Emerging Diseases
Diseases appearing in the human population for the first time or suddenly beginning to spread rapidly
Humans have little or no resistance, and no vaccines have been developed.
Facilitated by increasing human mobility, growing antibiotic resistance, and environmental changes

13. Emergent Diseases
New Diseases like Ebola, since 1973 there have been 28

14. Responding to Emerging Diseases
Lesson 9.2 Biological and Social Hazards
Responding to Emerging Diseases
World Health Organization (WHO): Monitors health events worldwide and coordinates international responses to emerging diseases
Centers for Disease Control and Prevention (CDC): Responds to emerging diseases in the United States; the CDC developed pandemic plans to deal with the spread of the H1N1 flu virus.
H1N1 Virus

15. Factors that affect the spread of diseases
Travel, migration, deforestation, climate change, loss of biodiversity, agriculture, urbanization, & nature disasters
It sure is nice to get away from the colon for awhile

16. Types of Environmental Health Hazards
Lesson 9.1 An Overview of Environmental Health
Types of Environmental Health Hazards
Biological: Viruses, bacteria, and other organisms that cause disease
Social: Lifestyle choices that endanger health
Chemical: Harmful artificial and natural chemicals in the environment
Physical: Natural disasters and ongoing natural phenomena, such as UV radiation, that can cause health problems

17. Social Hazards Some social hazards are easier to avoid than others.
Lesson 9.2 Biological and Social Hazards
Social Hazards
Some social hazards are easier to avoid than others.
Examples of social hazards include smoking, being exposed to secondhand smoke, living near an old toxic waste site, working with harmful chemicals, and eating fatty foods.

18. Toxicology
Study of poisons: which are substances that cause harmful effects to living things
Toxin: poison produced by living things
Toxicant: poison manufactured by us
Toxicity: ability of a substance to cause harm

19. Lesson 9.1 An Overview of Environmental Health
Toxicology
The study of how poisonous substances affect an organism’s health
Toxicity is a measure of how harmful a substance is.
Toxicologists look at toxicity by determining dose-response relationships.

20. Dose response curve
Threshold Level- the lowest concentration that could cause a lethal effect
Variability among people who are exposed to a toxin can influence response so we use LD50
LD50=lethal dose 50- the dose that kills 50% of the organisms tested- only for dermal and oral ingestion
LC50-lethal concentration 50-for inhalation
Only for acute effects

21. Threshold dose
The dosage at which the negative effect occurs

22. Poison
Any substance that has an LD50 of 50mg or less per kg of body weight

23. Exposure
Dose: actual amount of a chemical that enters and reacts with our body systems over time
Exposure: amount of toxic chemical our body comes in contact with
Absorption: ability of a chemical to find its way into our bloodstream

24. Routes of Exposure Inhalation: thru lungs Dermal absorption: thru skin
Oral: thru digestive system
Injection: enters directly into veins

25. Acute Short term exposure Effects occur immediately after exposure
Often reversible
Can be minor or severe
Relationship between exposure and effect is usually obvious
Knowledge is based on human exposure

26. Chronic Occurs over time Low exposure over long period
Many effects not reversible
Chronic effects still unknown for many chemicals
Difficult to establish a link between cause and effect
Knowledge based on animal studies

27. Types of Effects Local effect: causes damage only where it touches
Systemic: gets into bloodstream and effects many organs
Bioaccumulation: toxin builds up in body systems over time
Antagonism: one substance interferes with the action of another
Synergism: the interaction of two or more chemical is greater than the sum of their parts

28. Lesson 9.3 Toxic Substances in the Environment
Chemicals are all around us, and all of them can be harmful to our health in large enough amounts. In other words, “The dose makes the poison.”

29. Chemical Hazards Any chemical can be harmful in large enough amounts.
Lesson 9.3 Toxic Substances in the Environment
Chemical Hazards
Any chemical can be harmful in large enough amounts.
A pollutant is something released into the environment that has some harmful impact on people and other organisms.
Chemical hazards are not necessarily pollutants, and pollutants are not necessarily chemical hazards.
Oil Pollution

30. Sick Building Syndrome
When the majority of a building’s occupants experience certain symptoms for which no other cause can be identified
Irritation of eyes, nose, throat,
Headaches, dizziness
Skin irritation, nausea, vomiting

31. Toxic Heavy Metals:
mercury, lead, cadmium, nickel, gold, arsenic, chromium, platinum, selenium, vanadium
Heavy metals bioaccumulate (biomagnifications), which means they are stored in animals’ tissues as they accumulate more through the food chain. The top carnivores end up with the most in their blood stream.

32. Bioaccumulation and Biomagnification
Lesson 9.3 Toxic Substances in the Environment
Bioaccumulation and Biomagnification
Bioaccumulation: The buildup of toxic substances in the bodies of organisms
Biomagnification: The increased concentration of toxic substances with each step in a food chain
Persistent organic pollutants are biomagnified and stay in the environment for long periods of time and over long distances.

33. Organic Compounds
(a.) 4 million different ones (b.) Pesticides, industrial processes, & other consumer products
(c. ) Dioxin (from burning plastic), PCB’s – electrical industry, oils.

34. Indoor Chemical Hazards
Lesson 9.3 Toxic Substances in the Environment
Indoor Chemical Hazards

35. Indoor Air Pollutants
Asbestos-increased risk of lung cancer, mesothelioma
Benzene
Chloroform
Radon-radioactive gas, lung cancer
Formaldehyde-found in carpets, furniture
Lead
Mercury
Nickel
Perchloroehtylene (dry-cleaning chemical)
**all can damage immune system and cause neurological, reproductive, developmental, and respiratory problems

36. Sick Building Syndrome
When the majority of a building’s occupants experience certain symptoms for which no other cause can be identified
Irritation of eyes, nose, throat,
Headaches, dizziness
Skin irritation, nausea, vomiting

37. Types of Chemical Hazards
Lesson 9.3 Toxic Substances in the Environment
Types of Chemical Hazards
Carcinogens: Cancer-causing chemicals
Chemical mutagens: Chemicals that cause genetic mutations
Teratogens: Chemicals that harm embryos and fetuses
Neurotoxins: Chemicals that affect the nervous system
Endocrine disruptors: Chemicals that interfere with the endocrine system
Allergens: Chemicals that over-activate the immune system
Dust mite protein is a common allergen.

38. Carcinogenicity- the tendency to cause cancer
Cancer: uncontrolled growth and spread of abnormal cells
Malignant: tumor invades surrounding tissue
Benign: well defined tumor
that does not spread

39. Teratogen
Causes birth defects

40. Carcinogen
Agent that
causes cancer

41. Mutagen
Causes changes in the genetic make-up of cells that can be passed to future generations

42. Risk Assessment Risk: The probability that a hazard will cause harm
Lesson 9.1 An Overview of Environmental Health
Risk Assessment
Risk: The probability that a hazard will cause harm
Risk assessment: The process of measuring risk
Takes into account:
The type of hazard
How frequently humans will be exposed to it
How sensitive people are to it

43. Risk Analysis A. Estimating Risks
Risk Assessment: identifying hazards and evaluating their risks, this includes determining what types of hazards are involved, estimating the probability it will happen and estimating how many people it will effect.
comparative risk analysis: ranking risks
risk management: making decisions about reducing risks
risk communication: informing the public

44. Risk Benefit Analysis: do the risks outweigh the benefits
. Risk Benefit Analysis: do the risks outweigh the benefits. The problem with this is that people who decide usually have economic ties to the decision.

45. Greatest Risks People face
1. poverty
2. being born male
3. smoking
4. being 35% overweight