ToxicologyBy: Brian Oldakowski

Shane DeStefanoJeff Schmidt

& Dustin Schneider

15.1 Toxicology BasicsDisease occurs when there is an imbalance

resulting from a poor adjustment between an individual and the environment.

Disease depends on:1. Physical environment2. Biological environment3. 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)

TerminologyPollution- 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)

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)

Measuring PollutionHow to measure pollutants or toxins is widely

reportedDepends on the substancePesticides 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)

15.2 Infectious AgentsInfectious diseases may be spread from

interactions between food, water, air, or soulEnvironmental health concerns- can be

controlled by manipulating the environmentMost common environmentally transmitted

infectious diseases- Legionellosis, Giardiasis, Salmonella, and Malaria

Toxic heavy MetalsMajor 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)

Persistent Organic Pollutants (POPs)Properties of POPs:1. They have a carbon-based molecular

structure, often containing highly reactive chlorine

2. Synthetic chemicals3. They are not easily broken down in the

environment4. Toxic5. Fat soluble and accumulate in living tissue6. Can be transported by wind, water, and

sediments

Other PollutantsRadiationThermal Pollution- heat released into water

produces undesirable effectsParticulates- small particles of dustAsbestos- several minerals that take the form

of small, elongated particles, or fibersElectromagnetic fieldsNoise pollution

15.3 General Effects of PollutantsAlmost 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.

Dose ResponseThe effect of a certain chemical on an

individual depends on the dose.Dose dependency is demonstrated by the

dose response curve

Ecological GradientsTolerance

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.

15.4 Risk AssessmentRisk assessment is the process of

determining potential adverse environmental health affects to people exposed to pollutants and potentially toxic materials.

Steps of AssessmentIdentification 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 .

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.

Videoshttp://www.dailymotion.com/video/xggwzf_un

derstanding-toxicology-how-is-risk-assessment-measuredy_lifestyle

http://www.youtube.com/watch?v=jifoNSXvTuQ&feature=related

http://www.youtube.com/watch?v=8oTf2bGCt-Y