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Turbidity

Turbidity. A measure of water’s cloudiness Caused by suspended sediments in the water Measured with a Secchi disk. Water “Hardness”. Hard water: water that has a high mineral content Calcium, limestone, chalk, and magnesium Not harmful to human health. Agenda . Warm Up

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Turbidity

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  1. Turbidity • A measure of water’s cloudiness • Caused by suspended sediments in the water • Measured with a Secchi disk

  2. Water “Hardness” • Hard water: water that has a high mineral content • Calcium, limestone, chalk, and magnesium • Not harmful to human health.

  3. Agenda • Warm Up • Collect and organize portfolios • Toxicology Lecture • Blackworm Toxicity Pre-lab • Closing

  4. Number of deaths per year in the world from various causes. Parentheses show deaths in terms of the number of fully loaded 400-passenger jumbo jets crashing every day of the year with no survivors. Figure 18-13

  5. Number of deaths each year in USA

  6. Toxic Vocab • Toxin • Substance that is inhales, ingested, or absorbed at sufficient dosages that it damages a living organism • Toxicity • The degree to which the toxin is biologically harmful • **Almost any substance is considered a toxin if it’s present in large enough quantities.

  7. “The Dose makes the poison”

  8. Even Water Can Kill You (if you drink enough of it)

  9. Toxicity Consideration • In order for a substance to be harmful, the following must be considered: • Dosage amount over time • Number of times of exposures • Size and/or age of the organism exposed • Ability of the body to detoxify the substance • Synergistic effect • More than one substance combines to cause a toxic effect that’s greater than any one component.

  10. Risks • The probability of suffering harm from a hazard that can cause injury, disease, death, economic loss, or damage • Probability: an estimate of the likelihood of such an event • Possibility: this event could happen

  11. Risk Assessment and Management • Risk Assessment: Process of using statistical methods to estimate how much harm a particular hazard can cause to human health or the environment. • Risk management: whether or how to reduce a particular risk

  12. Types of Hazards • Biological • organism that can cause disease in another (bacteria, viruses, parasites, and fungi) • Two types: non-transmissible and transmissible • Chemical • harmful chemicals in the air, water, soil, food and human-made products • Natural • Fire, earthquakes, volcanic eruptions, floods and storms • Cultural • unsafe working conditions, unsafe highways, criminal assault, poverty • Lifestyle • smoking, making poor food choices, drinking too much alcohol

  13. Biological Hazards: Non-Transmissible (AKA non-Communicable) • Non-transmissible disease: caused by something other than a living organism and does not spread • Examples • Heart disease, cancer, asthma, stroke, cataracts, Alzheimer’s, obesity, high blood pressure

  14. Biological Hazards: Transmissible • Infectious disease: pathogen invades the body and multiplies in its cells and tissues • Transmissible (contagious or communicable) • In 1990 infectious disease was the leading cause of death in the world and the U.S. • Still a threat • Epidemic • Pandemic • Genetic Resistance

  15. Effects of Chemicals on the Immune, Nervous, and Endocrine Systems* • Long-term exposure to some chemicals at low doses may disrupt the body’s: • Immune system: specialized cells and tissues that protect the body against disease and harmful substances. • Nervous system: brain, spinal cord, and peripheral nerves. • Endocrine system: complex network of glands that release minute amounts of hormones into the bloodstream.

  16. What types of chemicals do toxicologists study? • Carcinogen • Teratogens • Mutagens • Neurotoxins • Endocrine disruptors

  17. Carcinogens • Chemicals, types of radiation, or viruses that cause/promote cancer • Examples: Arsenic, benzene

  18. Teratogens • Chemicals that cause harm or birth defects to fetus or embryo • Examples: Alcohol, Accutane, Mercury

  19. Accutane (Isotetrinoin)

  20. Mutagen • Chemicals or forms of radiation that cause or increase the frequency of mutations. • Ex: Radiation (UV, X-rays, gamma), LSD

  21. Neurotoxins • Can harm the human nervous system (brain, spinal cord, peripheral nervous system) • EX: lead, ethanol, nitric oxide Botox Mercury

  22. Endocrine disruptors • Mess up hormones and the endocrine system

  23. Bisphenol-A • The most infamous endocrine disruptor • Found in almost all plastics (makes them flexible) • http://www.usatoday.com/news/health/2007-10-30-plastics-cover_N.htm

  24. What types of chemicals are we exposed to??? • http://www.epa.gov/kidshometour/tour.htm

  25. Dose Response Curve • Organisms are exposed to a toxin at different concentrations.

  26. LD50 • “Median Lethal Dose” • The dosage of toxin it takes to kill 50% of the test animals.

  27. ED50 • Median Effective Dose • The point at which 50 percent of the test organism show an effect (+/-) from the toxin. • Paralysis, headache, inflammation, pain relief

  28. LD50 and Poison • A poison is any substance that has an LD50 of 50 mg or less per kg of body weight.

  29. Threshold Dose • The dosage at which a negative effect occurs

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