Lecture 9/10 Flashcards
What are some examples of environmental impacts on human health
- air pollution
- climate change
- built environment (e.g roads, inadequate housing)
- radiation
- infectious agents
- noise
- hazardous chemicals
- water issues (e.g supply, pollution)
What are the 4 types of hazards
- physical
- cultural
- chemical
- biological
Define physical hazards
- occur naturally in our environment
- cannot prevent them, but can prepare for them
What are some examples of physical hazards
- earthquakes, volcanoes, fires, floods, droughts
Define cultural hazards
- result from the place we live, our socioeconomic status, our occupation, our behavioral choices
What are some examples of cultural hazards
smoking, drug use, diet and nutrition, crime, mode of transportation
What are the 2 types of chemical hazards
- natural
- synthetic
What are some examples of natural hazards
heavy metals, asbestos, radon gas, etc.
What are some examples of synthetic chemicals
biocides, cleansers, cosmetics, disinfectants, herbicides, pharmaceuticals, pesticides
Define biological hazards
- result from ecological interactions
- cannot avoid risk but can reduce likelihood of infection
What are some examples of biological hazards
viruses, bacteria, and other pathogens
Define zoonotic diseases
diseases passing from animals to humans
Define pollutant
Chemicals or matter that contaminate an environment (e.g. air, soil, water, plants and animals) and have potential to cause harm to human health or the environment
Define contaminant
Any physical, chemical, biological or radiological substance or matter that occurs in an environment at above normal levels and that may affect organisms either negatively (are harmful) or positively (are beneficial)
Define toxin
A toxic substance (protein) produced by organisms other than humans (e.g. venom)
Define poison
An chemical agent or substance that produces harmful biological effects (often death)
Define toxicant
A poison or poisonous agent that produces harmful biological effects
Define toxicity
- the degree of harm a toxicant can cause
- toxicity depends on combined effect of chemical and its quantity
Define toxicology
the study of nature, effects, detection and treatment of poisonous substances on humans and other organisms
Define carcinogens (toxicants)
causes cancer
Define mutagens (toxicants)
causes DNA mutations
Define teratogens (toxicants)
causes birth defects
Define allergens
over activate immune system
Define neurotoxins (toxicants)
assault nervous system
Define endocrine disruptors (toxicants)
interfere with endocrine (hormone) system
Asbestos
- insulates, muffles sounds, and resists fire
- asbestosis = scarred lungs may cease to function
- mesothelioma = chronic respiratory condition
Lead
- from lead pipes, paint, gasoline
- lead poisoning damages organs; causes learning issues, behavioural abnormalities, and death
Radon gas
- a highly toxic, radioactive gas that is colourless, undetectable
- can build up in basements
- linked to cancer
What are some examples of where you can find synthetic chemicals
industrial chemicals, household chemicals, pesticides, petroleum products, pharmaceuticals, plastics, etc.
What are the toxic 5
- asbestos - paper and floors
- dioxin - banned chemical in herbicides
- polychlorinated biphenyls - found in electrical equipment and fire retardants
- hexavalent chromium - found in paint used in boats and planes
- chlorofluoroalkanes - found in air conditioners and refrigerators
What book discussed the risks of DDT to people, wildlife, and ecosystems
Silent spring by Rachel Carson (1962)
What are some endocrine disruption problems that synthetic chemicals are linked to
- feminization of male animals
- drop in sperm counts
- testicular cancer
- rise in breast cancer rates
- neurological problems
- developmental issues
What’s an example of an endocrine disruption chemical
Bisphenol-A (BPA)
- found in plastics for infants
- can cause birth defects
- while industry protests that chemical is safe
- BPA banned in Canada
What is polybrominated diphenyl ethers (PBDE)
= has fire-retardant properties
- used in computers, televisions, plastics, and furniture
- persist and accumulate in living tissue
- act as endocrine disruptors exposure leads to accumulation in animal bodies (including humans)
- removal from environment leads to reduction of levels in the body
- PBDE – banned in Canada since 2008
What are perfluoroalkylated substances (PFAS)
= group of ~ 9000 synthetic chemicals – “forever chemicals”
What is perfluorooctane sulfonate (PFOS)
- used as a fabric protector / stain repellent in furniture and clothing
- used as a water repellent in clothing
What is perfluorooctanioc acid (PFOA)
- key ingredient in Teflon-treated cookware
- used as a fabric protector and stain repellent in furniture and clothing
What are the 10 most common toxic chemicals in products to avoid
- phthalates
- paraben
- lead
- BPA/BPS
- 1, 4- dioxine
- SLS
- PVC
- trilosan
- oxybenzone
- diazolidinyl or imidazolidinyl urea
how do toxins concentrate in water
- Runoff carries toxins from large land areas to small volumes of surface water
- Chemicals can leach into soil
- Chemicals enter organisms through drinking or absorption
- aquatic organisms are effective pollution indicators
define pesticide drift
airborne transport of pesticides
define persistent chemicals
have the greatest potential for harm
define breakdown products
toxicants degrade into simpler products that may be more harmful or less harmful than the original substance
define bioaccumulation
toxicants build up in organisms from water or soil
define biomagnification
toxicants concentrate in top predators through food web
define the innocent until proven guilty approach
- government, scientists, and public are required to prove a product is dangerous (limited testing before release)
- benefits: does not slow down technological innovation and economic advancement
- disadvantage: puts substances into wide use that may later on turn out to be dangerous
define precautionary principle approach
- product manufacturers must prove a product is safe
- assume substances are harmful until proven harmless
- identifies troublesome toxicants before release
- may impede pace of technology and economic advance
define case histories
studying sickened individual directly
- autopsies
- do not tell about future risks
define epidemiology
large scale comparisons among groups
- studies between exposed/unexposed people lasting for years
- yield accurate predictions about risk
define manipulative experiments
organisms are used as test subjects
- new techniques may replace some live-animal testing
define acute exposure
high exposure for short periods of time to a hazard
- easy to recognize
- stem from discrete events: ingestion, oil spills, nuclear accident
define chronic exposure
low exposure for long periods of time to a hazard
- hard to detect and diagnose
- affects organs gradually: lung cancer, liver damage
- cause and effect may not be easily apparent
define synergistic effects
occur when exposure to two or more chemicals at one time causes health effects that are greater than the sum of the effects of the individual chemicals
define antagonistic effects
occur when exposure to two or more chemicals at one time causes health effects that are less than the sum of the effects of the individual chemicals
define dose
amount of toxicant tests an animal receives
define response
magnitude or type of negative effects on an organism
define dose-response curve
plot of dose given against response
define LD50/ED50
amount of toxicant required to kill 50% of the subjects
define threshold
dose level where responses occur
define risk
probability that a harmful outcome results from given action
- exposure to environmental health threats does not automatically produce an effect (causes probability)
what does probability entail
- identity and strength of threat
- chance/frequency of encountering threat
- amount of exposure to the threat
- an organism’s sensitivity to the threat
define quantitative measurement and comparison of various risks
- need way to identify and outline problems
- several steps: - scientific study of toxicity
- assessing an individual or population’s likely extent of exposure to substance
