Toxicology

1. Toxicology By: Brian Oldakowski Shane DeStefano Jeff Schmidt & Dustin Schneider

2. 15.1 Toxicology Basics • Disease occurs when there is an imbalance resulting from a poor adjustment between an individual and the environment. • Disease depends on: • Physical environment • Biological environment • Lifestyle • Industrial societies eliminated diseases but now there are more acute diseases. • Environment around us can cause serious health problems and diseases. ( soil, rock, water, and air)

4. Terminology • Pollution- occurrence of unwanted change in environment caused by introduction of harmful materials of production of harmful conditions (becoming impure, dirty, unclean) • Contamination- presence of undesirable material that makes something useless • Toxic- materials that are poisonous to people and other living things • Toxicology- a science that studies chemicals that are known to be or could be toxic or study of poisons that effects living organisms ( involves clinical, industrial, economic, and legal problems)

5. Terminology cont. • Carcinogen- particular type of toxin that increases the risk of cancer. Most feared toxin in society. • Synergism- interaction of different substances resulting in a total effect greater than the effect of separate substances together • Point sources- sources of pollution that are easily found and stationary. ( Smokestacks, pipes, accidental spills) • Area sources- also called non-point sources, diffused sources of pollution such as urban runoff or automobile exhaust. Hard to stop since wide dispersion of emissions. • Mobile sources- pollutants from place to place. ( automobiles, trucks, buses, trains)

7. Measuring Pollution • How to measure pollutants or toxins is widely reported • Depends on the substance • Pesticides or small pollutants are measured by parts per million or billion (ppm, ppb) • Water pollution is measured by milligrams per liter (mg/L) or micrograms per liter (µg/L) • Air pollutants are measured by micrograms per cubic meter (µg/m^3)

8. 15.2 Infectious Agents • Infectious diseases may be spread from interactions between food, water, air, or soul • Environmental health concerns- can be controlled by manipulating the environment • Most common environmentally transmitted infectious diseases- Legionellosis, Giardiasis, Salmonella, and Malaria

9. Toxic heavy Metals • Major metals- mercury, lead, cadmium, nickel, gold, platinum, silver, bismuth, arsenic, etc. • Body burden- the content of heavy metals in the body • Biomagnification- the accumulation or increase in concentration of a substance in living tissue as it moves through a food web (Mercury)

11. Persistent Organic Pollutants (POPs) Properties of POPs: • They have a carbon-based molecular structure, often containing highly reactive chlorine • Synthetic chemicals • They are not easily broken down in the environment • Toxic • Fat soluble and accumulate in living tissue • Can be transported by wind, water, and sediments

13. Other Pollutants • Radiation • Thermal Pollution- heat released into water produces undesirable effects • Particulates- small particles of dust • Asbestos- several minerals that take the form of small, elongated particles, or fibers • Electromagnetic fields • Noise pollution

14. 15.3 General Effects of Pollutants • Almost every part of the body is affected by one pollutant of another. • Most pollutants affect multiple parts of the body. • Ex. Lead affects the brain and skin.

16. Dose Response • The effect of a certain chemical on an individual depends on the dose. • Dose dependency is demonstrated by the dose response curve

17. Ecological Gradients Tolerance • Organisms can develop tolerance to certain pollutants. • Behavioral, Physiological, and Genetic Tolerance. Acute, Chronic Effects • Ex. Someone exposed to a large dose of radiation is killed shortly thereafter. Vs. Someone exposed to the same total dose of radiation over a very long period of time lives longer.

18. 15.4 Risk Assessment • Risk assessment is the process of determining potential adverse environmental health affects to people exposed to pollutants and potentially toxic materials.

19. Steps of Assessment • Identification of the hazard- This is the first step of risk assessment. Identification consists of testing materials to see if exposure to them is likely to cause environmental health problems. This can be done by examining previously exposed populations, testing on animals, or molecular analysis of the material. • Dose-Response Assessment- This step is used to determined the relationship between the dose, or amount, of a chemical and its affect on the health of the recipient. Some studies are done by giving high doses of chemicals to animals. These results are not always accurate .

20. Steps Cont. • Exposure Assessment- This test evaluates the intensity, duration, and frequency of human exposure to a particular chemical pollutant or toxin. Hazard is directly proportional to the total population exposed. This is hard to assess because doses can be as small as part as parts per million, billion or even trillion. • Risk Characterization- This last step is used to delineate health risk in terms of the magnitude of the potential environmental health problem that might result from exposure to a specific material. To do this , the material needs to be identified, complete the dose-response step and exposure assessment. Then all of the uncertainties of these steps are considered to determine risk. Results are difficult to create and often controversial.

21. Videos • http://www.dailymotion.com/video/xggwzf_understanding-toxicology-how-is-risk-assessment-measuredy_lifestyle • http://www.youtube.com/watch?v=jifoNSXvTuQ&feature=related • http://www.youtube.com/watch?v=8oTf2bGCt-Y