Environmental Health, Pollution, and Toxicology Chapter 8

8.1 Some Basics Environmental health: disease that is determined by or related to environmental factors such as toxic chemicals, toxic biological agents, or radiation Disease: an impairment of an individual’s health.

8.1 Some Basics Pollution: an unwanted change in the environment caused by the introduction of harmful materials or the production of harmful conditions Contamination: making something unfit for a particular use through the introduction of undesirable materials

8.1 Some Basics Toxin: substances that are poisonous to living things Toxicology: science that studies toxins or suspected toxins Carcinogen: toxin that causes cancer

8.1 Some basics Synergism: interaction of different substances. May amplify or make worse the effect of just one of those substances.

8.1 Some Basics Point sources: you can pinpoint exactly where the pollution is coming from Ex: smoke stacks, pipes discharging into waterways Nonpoint sources: more diffused and hard to figure out where it’s coming from Ex: all the cars on the freeway, urban runoff

8.1 Some Basics Biomagnification: the chemical accumulates or increases concentration of a substance as it moves through the food web AKA bioaccumulation EX: Mercury in fish

8.2 Categories of pollutants and toxins Infectious agents – caused by bacteria, viruses, or fungus. Think of some examples? Toxic Heavy Metals (metals with a large atomic weight) Mercury, lead, cadmium, nickel, etc. Case Study: Minimata in Japan

8.2 Categories of pollutants and toxins Organic compounds: compounds that have carbon in them EX: pesticides, pharmaceuticals, food additives Many manufactured by people Polluting and toxic They do not easily break down in the environment They are soluble in fat and can accumulate in living tissue

8.2 Categories of pollutants and toxins EX: PCBs – shipped from GE in Massachusetts, used in household appliances They leaked into the soil or damaged PCBs went into the algae, the insects ate the algae, then they were eaten by shrimp and fish, eventually eaten by people

8.2 Categories of pollutants and toxins Dioxin: one of the most toxic human-made chemicals Not usually made intentionally; it is a waste product of some chemical reactions Led to cancer in humans (as well as other animals) Labeled Carcinogen by EPA STILL hasn’t been banned or regulated by government.

8.2 Categories of pollutants and toxins Hormonally active agents (HAAs) Messed with the hormones of an animal (including humans!!) Many found in pesticides and herbicides DDT – used as a pesticide, thinned out shells out bald eagle

8.2 Categories of pollutants and toxins Nuclear Radiation Can lead to serious problems, including cancer Thermal pollution (heat pollution) heat is released into water or air Can come from volcanic eruptions, agricultural burning Power plants use water to cool the equipment down. Can affect wildlife near by it

8.2. Categories of pollutants and toxins Particulates: small particles of dust in the air that can come into our lungs Asbestos: minerals that are in the form of small, elongated particles Used in houses for insulation

8.2 Categories of pollutants and toxins Noise pollution: unwanted sound

8.4 Old and New Environmental Health Problems Pandemic – disease that spreads rapidly across wide regions of the planet affecting a high proportion of the population EX: Bubonic Plague EX: HIV/AIDS Pigs and other animals such as chickens in commercial farms can increase the possibility of new diseases evolving and spreading to humans

8.4 Hospitals with large numbers of sick people can become a breeding ground for disease In 2006, E. coli spreading

8.5 General Effects of Pollutants Almost every part of the human body is affected by one pollutant or another. Dose response: effect of a certain chemical on an individual depends on the dose EX: Fluorine: a little bit keeps tooth decay at bay, but too much can lead to osteoporosis, a disease characterized by loss of bone mass. LD-50: crude approximation of a chemical’s toxicity Dose at which 50% of the population dies, or the Lethal Dose 50.

8.5 ED-50 (effective dose 50) dose that causes an effect in 50% of the observed subjects TD-50 (toxic dose 50) is the dose that is toxic to 50% of the observed subjects. Threshold – a level below which no effect occurs and above which effects begin to occur Tolerance: ability to resist or withstand stress from exposure to a pollutant or harmful condition