Topic 7 - Toxicology Flashcards
(40 cards)
What types of hazards and risks do we face?
- Toxicity
- Chemical hazards
- Biological hazards and diseases
Tobacco is responsible for how many deaths in Canada?
1 in every 5
100 deaths/day
How many people die from smoking per year?
37,000
What are cultural hazards?
Working conditions, smoking, poor diet, drugs, drinking, driving, criminal assault, unsafe safe, poverty
What are chemical hazards?
Harmful chemicals in the air, water, soil, and food
What are physical hazards?
Fire, tornado, hurricane, flood, volcanic eruption, earthquake
What are biological hazards?
Pathogens, pollen and other allergens, and animals such as bees and venomous snakes
What is risk assessment?
Scientific process of estimating how much harm a particularly hazard can cause to human health
What is risk management?
Risk management involves deciding whether or how to reduce a particular risk to a certain level and at what cost
What is toxicity?
Measure of the amount of harm caused by a compound
What is dose?
Quantity ingested, inhaled, absorbed
What is frequency?
Frequency of exposure to the compound
What is personal traits?
Age, organ function, genes
What factors affect the toxicity of a substance?
- Solubility
- Persistence
- Bioaccumulation
- Biomagnification
- Chemical interactions (antagonistic vs. synergistic)
What are water-soluble toxins?
Inorganic compounds that can move throughout the environment and get into water supplies and the aqueous solutions that surround the cells in our bodies
What are oil (or fat) soluble toxins?
Organic compounds that can penetrate the membranes surrounding an organism’s cells because the membranes allow similar oil-soluble chemicals to pass through them
Oil (or fat) soluble toxins can accumulate in body tissues and cells
What is persistence?
The resistance to breaking down (e.g. the pesticide DDT)
They can have long-lasting harmful effects on the health of wildlife and people
What is bioaccumulation?
An increase in the concentration of a chemical in specific organs or tissues at a level higher than would normally be expected
Some potential toxins in the environment are magnified as they pass through food chains and webs
What is biomagnification?
An increase in concentration of DDT, PCBs, and other slowly degradable, fat-soluble chemicals in organisms at successively higher trophic levels of a food chain or web
Some potential toxins in the environment are magnified as they pass through food chains and webs
What are antagonistic interactions?
They can reduce harmful effects
Example: vitamins E and A interact to reduce the body’s response to some cancer-causing chemicals
What are synergistic interactions?
They multiply effects
Example: workers exposed to tiny fibres of asbestos increase their chances of getting lung cancer 20-fold. But asbestos workers who also smoke have a 400-fold increase in lung cancer rates.
In such cases, 1 + 1 can be a lot greater than 2
What is aflatoxin?
Carcinogen produced by molds in peanut butter and corn
How do scientists use lab experiments to estimate toxicity?
Exposing a population of live lab animals (e.g. mice and rats) to known amounts of a chemical is the most widely used method for determining its toxicity
What is lethal dosage?
Aka lethal concentration
The dose it takes to kill 50% of the population
