Module 6: Enviromental Toxicology and Cancer

• what is an envionment toxicant?

  a chemical that is realsed into the enviroment and that can produce adverse health effects on living organisms
• What are some common enviromental toxicants?

  air pollution, tobacco smoke, pesticides
• what are some specific chemicals that are toxic?

  lead, mercury, bisphenol A (BPA)
• What is acute toxicity?

  refers to a single exposure to a chemical (usally a large dose)
• Example of acute toxicity?

  chemical spill
• what is chronic toxicity?

  is asscociated with reapeted small dose exposure to a chemical over a long period of time
• What is an example that is associated with chronic toxicity?

  eating contaminated food
• What is aflatoxin B1?

  contaminates food in southeast Asia and central Africa
• Acute toxicity of aflatoxin B1 can lead to what?

  can lead to liver necrosis, liver faliure, and death
• Chronic toxicity of aflatoxoin B1 can lead to what?

  liver cancer
• Can acute and chronic toxicity cause different effects or just exaggerated effects?

  The exaggeration of the effects of chemical depends on the dose, where as acute and chronic toxicity can cause different effects all together.
• What are the two main catagories of air pollution?

  particulate matter and gaseaous air pollutants
• what is particulate matter?

  is the mixture of tiny paticules composed of non-gaseous pollutants.
• What state can particulate matter pollutant be?

  solid or liquide, can't be gas
• What are gaseous air pollutants?

  are pollutants in gaseous form
• Examples of gaseous air pollutants?

  carbon monoxide, carbon dioxide, nitrogen oxides, sulfur oxides, hydrogen sulfide, and ozone
• Can air pollutants come from what kind of sources?


  natural and anthropogenic air pollutants
• Natural air pollutants examples?

  volcanoes, forest, praire fires, and dust storms
• Three main sources of anthropogenic air pollutants?

  heating and power

  autombiles

  Indutrial processes
• Why is heating and power an air pollutant?

  bc combustion of fossil fuels realses carbon dioxide, carbon monoxide, sulfur oxides, nitrogen oxides
• How do automoblies contribute to air pollution?

  exhaust realses smoke, lead particles, carbon monoxide, and nitrogen oxides
• Examples of industrial prosesses air pollutants?

  acids, solvents, chlorine, ammonia gas, metals
• how of the popluation is more effected by air polluation?

  very young childeren, older adults, people with cardiorespitory diease (eg asthma)
• What is the main heath concern of air pollutants?

  chemical irration of the respiratory tract
• Is there a single air pollutant that is responsible for the health concerns?

  No, most are due to the combined action of particulates and sulfur oxides
• What is enviromental tobacco smoke/secondhand smoke?

  is the combination of mainstream smoke (exhaled smoke) and sidestream smoke (from the burning end of a cigarette)
• can secondhand/enviromental smoke cause lung cancer?

  yes
• Is smoking or inhaling secondhand/enviromental smoke more harmful?

  environmetal smoking carries the same health risk as directly smoking
• Why are pesticidies unique among enviromental pollutants?

  they are used intentionally to kill organisms
• Two main classes of pesticides that act a anviromental toxicants?

  insecticides and herbicides
• what are two types of insecticides?

  organochlorine insecticide and organophosphorus insecticide
• how do organochlorine insectides kill insects?

  increasing the sensitvity of neurons which causes more CNS stimulation that results in tremors, convulsions, and death.
• why have organochlorides been phased out?

  organochlorine insectides residue can cause long-term problems that aren't complety understood in humans, animials, and environment
• Example of an organochlorine insecticide?

  dichlorodiphyentrichlorethan / DDT
• what is organophorus insectides?

  an pesticdes first made during WWII (nevre gas) and is now a selective pesticde that needs metabolic activation to work.
• Why are organophosphorus insecticides considered to have small impact on the enviroment overall?

  they are realitvey unstable and breakdown in the enviroment
• Mechanism of action of organophospus?

  they irreveribly inhibit acetycholinestrease. acetycholinestrease is responsible for the breakdown of acetycholine in the synaptic clef. Now that acetycholine is not breaking down there is an increase of it in the nervous tissue. The increase of acetycholine in the nerveous tissue causes increase acetycholine-mediated neuronal firing throughout the body.
• what does acetycholine-mediated neuronal firing throughout the body cause?

  decreased heart rate, severse diffucluty breathing, fecal and urinary incontience, and blurred vision. Death can occur due to repirtory faliure.
• is organophorphorus very toxic?

  yes.
• How are organophorphorus insectices absorbed?

  through the skin