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Chapter 15

Explore the terminology, measurement, categories, and general effects of pollution and toxicology. Learn about pollutants, dose-response relationships, ecological gradients, and risk assessment.

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Chapter 15

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  1. Chapter 15 Environmental Health, Pollution and Toxicology

  2. Terminology Pollution:introduces harmful materials or produces harmful conditions to the environment - introduced through a) Point Sources: b) Area Sources: c) Mobile Sources: Contamination:making something unfit for a particular use through the introduction of desirable material Toxicology:the science that studies chemicals that should be toxic Carcinogen:a type of toxin that increases the risk of cancer Synergism:the interaction of different substances resulting in a total effect greater than the sum of the effects of the separate sources

  3. Measuring Pollutants • Measuring depends on the substance • Common Units • ppm: Parts per million • ppb: Parts per billion • Micrograms per cubicle meter (measures air)

  4. Categories of Pollutants • Infectious Agents • Toxic Heavy Metals Organic Compounds • Radiation • Thermal Pollution • Particulates • Asbestos • Electromagnetic Fields • Noise Pollution • Voluntary Exposure

  5. Toxic Heavy Metals • Travel through toxic pathways • Biomagnifications: the accumulation or increase in concentration of a substance in living tissue as it moves through a food web.

  6. Organic Compounds • Organic Compounds: composed of carbon • Synthetic Organic Compounds: used in industrial processes • Persistent Organic Pollutants: Synthetic organic compounds often containing chlorine, that do not easily break down in the environment. • Hormonally Active Agents: Chemicals in the environment able to cause reproductive and developmental abnormalities in animals

  7. General Effects of Pollutants- Changes in Abundance- Changes in Distribution- Changes in Birth Rates- Changes in Death Rates- Changes in Growth Rates

  8. Concept of Dose and Response • The effect of a certain chemical on an individual depends on the does • Individuals differ in their response to chemicals Dose-Response Curve: - LD-50 - ED-50 - TD-50 Threshold Effects: - the level below which effects are not observable and above which effects become apparent

  9. Ecological Gradients • Changes in vegetation with distance from a toxic source Tolerance: The ability to resist or withstand stress resulting from exposure to a pollutant or harmful condition - Behavior vs. Physiological Acute and Chronic Effects

  10. Risk Assessment • 4 steps 1. Identification of the hazard 2. Dose-Response assessment 3. Exposure assessment 4. Risk characterization

  11. Precautionary Principle • The idea that in spit of the fact that full scientific certainty is often not available to prove cause and effect, we should still take cost-effective precautions to solve environmental problems where there exists a threat of potentially serious and/ or irreversible environmental damage

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