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Toxicology

Toxicology. The study of poisons and their effects, on living systems. Love Canal Cleanup Finished, Mutants Return to Homes.

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Toxicology

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  1. Toxicology The study of poisons and their effects, on living systems

  2. Love Canal Cleanup Finished, Mutants Return to Homes We knew there were too many miscarriages, too many birth defects, too many central nervous system problems, too many urinary tract disorders, and too much asthma and other respiratory problems among us."

  3. Health: A state of complete physical, mental, and social well-being • Disease: A deleterious change in the body’s condition in response to an environmental factor that could be nutritional, chemical, biological, or psychological • Morbidity: Illness

  4. Types of Environmental Health Hazards • Infectious Diseases • Toxic Chemicals • Natural or Synthetic Toxins • Physical Agents, Trauma and Stress • Diet

  5. Pathogens are infectious organisms • Bacterial • Protozoans (guardia) • Fungal • Invertebrate Animals • Viruses are non living

  6. Bacterial Infections: Trachoma is an inflammation of eye Sexual Transmitted Diseases (gonorrhea and syphilis) Respiratory Diseases: Pneumonia, tuberculosis, influenza, and pertussis

  7. Bacteria have developed resistance to antibiotics Improved drugs and sanitation can eliminate some diseases

  8. Trachoma,the most commonly contracted STD, caused by Chlamydia trachomatis

  9. Emergent diseases • Those not previously known or that have been absent for more than 20 year *many are viruses

  10. Viral Infection • SARS and Bird flu • HANTA, Ebola • West Nile virus causes encephalitis • HIV and AIDS

  11. Fungal • Sudden oak death • Fungal spores *black mold

  12. Protozoans • Malaria: Infection of red blood cells by the protozoan Plasmodium spread by the Anopheles mosquito • Giardia: dysentery • Amoeba:dysentery

  13. Invertebrate Animals (Parasitic) • Flatworms (flukes) and tapeworms • Nematodes (roundworms) • such as hookworms, guinea worms • Filariasis worms block lymphatic vessels • causeselephantiasis

  14. Caused by Nematodes (Roundworms) Elephantiasis Filariasis Guinea worms

  15. prions • Proteins resistant to temperature. They cause Chronic Wasting in Wild Animals and Mad Cow Disease also known as Creutzfelt-Jacop disease

  16. Toxic Chemicals • Hazardous: Dangerous • Toxic: Poisonous • Irritants: Corrosives (acid), caustics (base), and other substances that damage biological tissues • Respiratory Fibrotic Agents: Irritants that damage the lungs

  17. Asphyxiants: Chemicals that exclude oxygen or actively interfere with oxygen uptake and distribution (i.e. MIC)

  18. Allergens: Substances that activate the immune system. Some act as Antigens which are recognized as foreign by white blood cells. Antigens cause the immune system to produce Antibodies.

  19. Mutagen: with change the base sequence in DNA, may be harmless or harmful. • Cancer: Invasive, out-of-control cell growth that results in malignant tumors • Carcinogens: Substances that cause cancer • Promoter: Bases sequences in DNA that regulate expression of that gene • Terratogens: discussed further

  20. Mutagens: Agents that damage or alter DNA • Teratogens: Factors that cause abnormalities during embryonic growth and development (example: thalidomide) • Fetal Alcohol Syndrome: Symptoms including craniofacial abnormalities, developmental delays, behavioral problems, and mental defects. • Thalidamine: used to prevent morning sickness and in treatment of leprosy.

  21. Thalidomide for morning sickness

  22. Carcinogens aflatoxin acrylamide

  23. Francis Oldem Kelsey Prevent FDA from approving Prevented 1000 birth defects in USA Awarded President’s Award for Distinguished Federal Civilian Service

  24. Endocrine Disrupters • Neurotoxins: Attack nerve cells • Heavy metals (mercury, lead) • Chloronated hydrocarbons (DDT, dioxin) disrupt nerve cell membranes • Organophosphates (pesticides

  25. mercury organophosphates

  26. How Do Environmental Toxins Enter Our Bodies? • introduced into our lives everyday • depend on where we live • They are in the air you breath, the food you eat, water, buildings, pesticides, and consumer products. • They are the byproducts of industry

  27. Basic Concepts • Def: science that studies poisons or toxics • Pathways from environment -> us • oral ingestion • inhalation • percutaneous absorption (skin)

  28. 17.8% of California’s lakes are under fish consumption advisories due to mercury, dioxins and other Persistent Bioaccumulative Toxins!!!

  29. The average household uses and stores more than 60 hazardous materials, including household cleaners, automotive products, paints, solvents and pesticides

  30. Household sources of Toxic Chemicals • Off the shelf pesticides, herbicides, fungicides and insecticides • Paints and paint cleaning supplies • Household cleaning solutions, laundry detergents with phosphates • Bleached paper products

  31. Over 150 chemicals found in the average home have been linked to allergies, birth defects, cancer and psychological abnormalities Consumer Product Safety Commission www.earthwellness.com

  32. Some of the biggies • Dioxin is an unintentional bi-product of industrial processes using chlorine. It includes more than 200 chemicals. • PVC, Polyvinyl Chloride, is the most widely used plastic

  33. Physical Agents, Trauma, and Stress • Trauma: Injury caused by accidents or violence • Stress: Physical, chemical, or emotional factors that place a strain on an organism for which there is inadequate adaptation

  34. Movement, Distribution and Fate of the Toxin • Solubility water vs fat soluble • Bioaccumulation and Biomagnification • Persistence • Chemical Interaction

  35. Bioaccumulation and Biomagnification • Bioaccumulation: The ability of cells to absorb and store of a select molecules When is this beneficial vs detrimental? • Biomagnification: the toxin level accumulates in those organisms higher up in the food chain. i.e. DDT

  36. Chemical Interactions • Antagonistic: One chemical counteracts the effects of another • Vitamins A, C, and E reduce response of some carcinogens • Additive and Synergistic: : two chemical that occur together exacerbates the effects of another

  37. How Do We Measure Toxicity • Animal testing • Toxicity ratings • Acute verses chronic doses and effects • Detection limits

  38. Animal Testing • LD50: The dose of a toxic chemical to which 50% of the test population is sensitive 9.11, 9.12

  39. Acute vs Chronic Doses and Effects • Acute Effects: Effects causes by a single exposure to the toxin resulting in an immediate health crisis • Chronic Effects: Long lasting or permanent effects • Exposures: If long lasting can be chronic 9.13

  40. Fig 8.17

  41. Risk • Risk: The probability of harm times the probability of exposure Assessment & Management High Risk: Habitat destruction, loss of biodiversity Medium Risk: Toxins Low Risk Oil Spills, Radionuclides

  42. What happened in Bhopal, India?

  43. Methylisocyanate • An irritant, causes burning and swelling of soft tissue • The lack of oxygen lead to death • Blindness to the survivors

  44. What happened in Chernobyle

  45. How Can We Reduce Our Risk of Exposure to Environmental Toxins?

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