Lecture 9 Flashcards
1
Q
What are environmental hazards?
A
- these have a wide and varied interpretation
- they can vary from a single toxic chemical accident to an entire industry (eg. nuclear energy)
- other examples may include exposure to pollutants or hazardous waste
- hybrid disasters may fit into this category (ex: an earthquake that causes an oil or chemical spill from a pipeline)
- technological disasters involving the environment are included in this category as well (ex: sinking of the Titanic, explosions of the Challenger and Columbia space shuttles)
2
Q
Who is most vulnerable to environmental hazards?
A
- typically the death tolls from environmental hazards are relatively low
- vulnerability is greatest for those involved in industry or transportation systems
- workers in resource industries in hinterlands are at higher risk (eg. miners)
3
Q
What are categories of environmental hazards?
A
Widespread: long term (nuclear accidents), hazards leading to cumulative effects
Rare Events: airplane crashes, mine collapses, shipwrekcs
Common: automobile accidents, poisons
4
Q
What are cumulative effects?
A
- conditions that worsen slowly over time as exposure to a concentration increases
- eventually, the concentration reaches a threshold critical to human health
- situations related to this include exposure to toxic chemicals, acid precipitation, groundwater contamination, and ozone depletion
5
Q
How is risk calculated for large-scale structures, transportation, and industry
A
Large-scale structures (buildings, bridges, dams): risk is defined as the probability of failure during the lifetime of the structure
Transportation (road, sea, rail): risk is the probability of death or injury per km travelled
Industry (manufacturing, power production): risk is the probability of death or injury per person per number of hours exposed
6
Q
What is radon?
A
- the primary source of radon gas is from the natural decay of uranium in rock and soil
- when radon is inhaled it then decays to polonium and lodges in the lungs where it damages tissues
- it is the 2nd leading cause of lung cancer in NA
- radon becomes a hazard when it is released into our living space
- it is difficult to detect because the gas is odourless, colourless, and tasteless
- potentially high radon levels are present in 5-10% of homes in NA
- radon detectors are commerically available in areas where it is of greater concern
- the gas can move quickly through non-saturated soil and can seep into homes
- basements are at higher risk especially in winter due to reduced air circulation
7
Q
What are genetically modified organisms?
A
- these are organisms that have had changes made to their DNA by the transfer of genes
- example feats in genetic engineering: chickens that lay low-cholesterol eggs, tomatoes that can prevent some cancers, bananas and potatoes to treat viral diseases in developing countries, rice that can produce more vitamin A
- bacteria that can quickly clean up oil and toxic spills
8
Q
What are genetically modified foods?
A
- the most common crops that are genetically modified are corn, soybean, and canola
- crops are modified to increase yields
- some crops have been genetically engineered to have greater resistance to changes in temperature and precipitation, herbicides, pests, and acidic soil
- bioengineers have been able to alter citrus trees (that would normally take 6 years to produce fruit) to yield fruit in only one year
- how safe are genetically modified foods? scientists believe that the benefits outweigh the potential risks but most support more reserach studies
- the UN food and agriculture organization believes that genetically modified crops have great benefits for developing countries
9
Q
Describe radiation
A
- the pathways of radiation include inhalation and ingestion (food,water)
- the impact can be direct (effects are evident within days of exposure) or delayed and chronic (leukemia, cancer)
- the impact could also be indirect in the form of genetic effects
- a person may not experience effects but may pass them on to their children in the form of chromosomal changes or birth defects
10
Q
What are sources of radiation?
A
- mining of uranium: in Canada, uranium is mined in northern Saskatchewan and northern Ontario, mines produce wastes known as tailings that can be a radioactive hazard
- production of electricity: uranium is used in nuclear power plants
11
Q
Where are nuclear power plants located?
A
- most nuclear plants in North America are located in the eastern half of the continent
- they must be near sources of coolant (rivers or lakes)
- they must be located near a market for electricity (eastern NA is much more populated)
- nuclear is considered a clean source of energy because it does not emit the greenhouse gases that cause climate change
12
Q
What is a nuclear meltdown?
A
- informal term for an accident that results in damage from overheating
- it occurs when the heat generated by a nuclear plant exceeds heat removed by cooling systems
- in a meltdown, fuel rods turn to liquid and the walls of the plant core could melt from extreme heat
- the hot liquid could melt through the bottom of the power plant and seep into the soil
13
Q
Describe the Three Mile Island nuclear accident
A
- this is the worst nuclear disaster in US history; it occurred on March 28 1979
- one of the two power plants on three mile island in central pennsylvania experienced a partial meltdown
- it was caused by a failure of a valve that controlled cool water entering the plant core
- there were no direct injuries; minor amounts of radiation were released around the site
14
Q
Describe the Chernobyl nuclear accident
A
- worst nuclear disaster in world history; it occurred on April 26 1986
- the accident was a result of a flawed design, operator error, and disregard of safety regulations
- an explosion at the plant caused the immediate deaths of 3 workers
- within one year 28 more workers died from extreme radiation exposure
- an estimated 6000 people in the area developed thyroid cancer as a result of radiation poisoning
15
Q
How did the concern over nuclear meltdown impact nuclear energy?
A
- halted nuclear development for a time
- however, concern over greenhouse gas emissions has created a greater demand for cleaner sources of energy
- for example, Ontario has recently closed all of its coal power plants
- to meet this objective the province is investing in refurbishing existing nuclear power platns and is planning to build new nuclear plants as well
16
Q
Describe the Titanic Shipwreck
A
- The Titanic was a passenger ocean liner that struck an iceberg and sank on its maiden voyage (April 15 1912)
- the ship left Southampton, England on April 10th and was bound for New York City with 2224 passengers
- ship was designed using advanced technology and was believed to be unsinkable
- the death toll was 1517; the high number was due to the lack of lifeboats for all passengers
- the wreckage was found by SONAR in 1985 at a depth of 3.8km
- a lookout on the ship spotted an iceberg in the ship’s path at 11:40pm and alerted the captain
- the ship struck the iceberg 37 seconds later; 18 lifeboats were launched and Titanic sank at 2:20am
- the Carpathia arrived at 4:10am and picked up survivors from the lifeboats
17
Q
What are oil spills?
A
- oil spills most commonly occur in marine areas but can also occur on land due to pipeline bursts
- the environmental impact can be devastating and clean-up can take months to years
- oil penetrates bird feathers and mammal fur reducing their ability to insulate
- animals and birds are left vulnerable to temperature changes and become less buoyant in water
18
Q
Describe the Exxon Valdez oil spill
A
- the spill was caused by an oil tanker striking a rocky reef off the south coast of Alaska on March 24 1989
- the region is an important habitat for salmon, seals, sea otters, killer whales, and seabirds
- there were 75 million litres of oil spilled; the remote location made recovery efforts difficult
- it remained the worst oil spill in NA history until the Deepwater Horizon oil spill
19
Q
Describe the Deepwater horizon oil spill
A
- the spill was caused by an oil rig that exploded in the Gulf of Mexico on April 20 2010
- the explosion killed 11 workers
- it was caused by methane gas rising up a drill pipe
- approximately 11 million litres of oil escaped from the well every day for months
- after several failed attempts the well was finally capped with cement on Sep 19 2010
- the spill caused extensive damage to wetlands and beaches along the US Gulf Coast
- the tourism industry faced severe economic loss during the summer of 2010
- the US federal investigative report ultimately blamed the BP oil company for the disaster
- the report found that the company: made a series of cost-cutting choices on maintenance, did not have a proper system in place to ensure safety
20
Q
What is groundwater?
A
- groundwater is water that is found underground within the cracks and spaces in soil, sand, and rock
- these materials are permeable because they have connected spaces that allow water to flow through
- many cities and towns obtain drinking water from groundwater
- this presents a risk if the water supply becomes contaminated
- in 2000, water contaminated with E coli bacteria killed 7 people in Walkerton ON
- the bacteria came from fertilizer manure that had leached into a well during a heavy rainfall
21
Q
What is a well known infrastructure failure?
A
- the most well-known example of infrastructure failure in NA occurred in Minneapolis in 2007
- a highway bridge over the Mississippi River suddenly collapsed during evening rush hour killing 13 people
- the cause was deemed to be excessive weight from vehicles and construction equipment
- the bridge supports were not of proper thickness and an extra 2 inches of concrete that was added to the roadway also contributed to the collapse
22
Q
Describe the Tacoma Narrows Bridge Collapse
A
- in 1940 high winds caused the collapse of a suspension bridge in Tacoma, Washington
- there were no human casualties from the collapse
- the design of the bridge did not provide any open trusses for wind to pass through
- the incident has served as a good case study for engineering and architecture students
23
Q
Describe the Challenger shuttle
A
- Challenger: exploded 73 seconds into its flight on Jan 28, 1986, all 7 crew members were killed as the space shuttle disintegrated; its remains were scattered over the Atlantic Ocean
- the cause was found to be a faulty O-ring seal
- it failed to seal a joint leading to the release of hot gas that led to failure of the rocket booster
- the night before the launch was particularly cold; frost and ice had developed on the rocket
- it is believed the cold weather lowered the resiliency of the rubber O-ring
24
Q
Describe the Columbia shuttle
A
- the Columbia disintegrated on Feb 1 2003 upon re-entry into Earth’s atmosphere after 16 days in space
- during launch, a piece of insulation broke off from the external tank
- it struck the left wing and damaged the system that protects the wing from intense heat produced by atmospheric gases upon re-entry
- pieces of the shuttle were found in Texas and Louisiana
25
Q
Describe diseases
A
- of all hazards, large scale diseases affect human populations most directly
- these hazards are different than others studied since they only impact people rather than property
- communicable diseases are the leading cause of mortality in less developed countries
26
Q
What are outbreaks, epidemics, and pandemics?
A
Outbreak: a simultaneous, related occurrence of several cases
Epidemic: an uncontrolled outbreak of communicable (contagious) disease
Pandemic: international or wide-travelling simultaneous epidemics of the same condition
27
Q
Describe diseases in developing countries
A
- they are the direct result of poor hygiene and are indirectly related to socio-economic conditions
- the spread of disease is enhanced by limited preventative programs
- the water system is a common source for disease agents
- over 60% of people in developing countries have limited access to clean water
28
Q
What conditions will lead to a rapid spread of disease?
A
- a population lacks immunity
- a population includes carriers
- an increase in susceptibility due to some external factor (eg. malnutrition)
- contamination of water supply
- lack of programs for disease control
- overcrowdig and close human contact
- poor sanitation
29
Q
Describe the Bubonic plague
A
- this is also known as Black Death and is spread by rodents
- swelling of lymph nodes, infection, pneumonia, high fever, delirium, vomiting
- it has not reached the level of pandemic for over a century
-over the last 2000 years, plague has become widespread three times:
1st pandemic: from 542 to 546AD, plague in Asia, Africa, and Europe claimed nearly 100 million victims
2nd pandemic: from 1347 to 1350AD, plague claimed 50 million people, half were in Asia and Africa while the other half were in Europe, in Europe 1/4 of the population succumbed to this pandemic
3rd pandemic: this event begain in Hong Kong in 1894 and rapidly spread around the world, it was carried by rats aboard steamships, within 10 years it entered 77 ports on 5 continents and caused over 13 million deaths, it was discovered at this time that rats spread plague and a rat flea was the common vector
30
Q
Describe cholera and early mapping of cholera
A
- it is a water-borne disease that originates in sewage and contaminated streams within an urgan or rural water supply
- it is caused by infection of the intestine by a bacterium
- this disease is extremely rare in developed countries
- it is still common today in parts of rural India and sub-Saharan Africa
- when cholera emerged in London, England in 1854 the source was unknown
- at this time it was not known that cholera was spread by drinking contaminated water
- each reported case of cholera was mapped and the source was then traced to a specific water source
- this is the first example of using mapping to identify the source and spread of a disease
31
Q
Describe HIV/AIDS
A
- the Human Immunodeficiency virus (HIV) leads to AIDS (acquired immune deficiency syndrome)
- it first surfaced in 1980 and became a major pandemic of the 20th century
- it is transferred through exchange of bodily fluids
- it was originally believed the disease was limited to homosexual activity and intravenous drug use
- when the disease first surfaced it was somewhat ignored because it was not affecting the mainstream population
- it has claimed over 30 million lives
- estimated that 40 million people are currently infected
- most current cases (95%) are found in developing countries
- there is no cure, but antiretroviral drugs are extending life thus turning it into a chronic disease
32
Q
Describe influenza
A
- since they were first documented in the 1500s, flu pandemics have occurred once every few decades
- occurrences typically spread globally within a year and are highly contagious
- the global population appears to be universally susceptible
33
Q
Describe the Spanish flu
A
- in 1918 and 1919, the Spanish flu killed 20 million people (this was over twice the amount of World War 1 fatalities)
- it was spread to NA by soliders coming from Europe after the war ended
- it caused the deaths of approx 50 000 people in Canada
34
Q
Describe the Asian flu and Hong Kong flu
A
- these were less severe epidemics occurring in 1957 (asian) and 1968 (hong kong)
- by this time, there were better coping mechanisms such as vaccinations
- education and communication was coordinated by the WHO
- vulnerability was greater in the elderly and infants
35
Q
Describe the bird flu
A
- it is also referred to as avian flu
- it first became evident in 1997 in Hong Kong where there was a large death of poultry with 100% mortality
- it was combatted by the killing of all poultry but another outbreak occurred in 2003
- the focus is on the virus strain H5N1 because it is able to transfer from birds to humans, there is high mortality in humans, it has the potential to produce a severe pandemic
- the disease is caused by a virus that occurs naturally among birds
- spread of H5N1 virus from person to person is rare and presently the spread has not continued beyond one person
- humans infected have been those who work daily in close contact with poultry
- of people who become infected, 70% die from the virus
36
Q
Describe the Swine Flu
A
- in 2009, there was a pandemic involving the H1N1 virus that spread around the world
- this was a new strain of a virus that resulted from a mix of bird, swine, and human flu viruses that combined with a Eurasian pig flu virus
- this led to the term ‘swine flu’ to describe the pandemic
- spread from person to person by transmission through respiratory droplets
- it could not be spread through consumption of pork
- treatment was through antiviral drugs (Tamiflu)
- the end of the pandemic was announced by the WHO 16 months after it began
- the virus claimed the lives of over 18 000 people worldwide
37
Q
What are rabies?
A
- rabies is a viral disease most often transmitted through the bite of an animal by infected saliva
- the central nervous system becomes infected ultimately causing disease in the brain and death
- small animals (squirrels, mice, rats, hamsters, rabbits) are almost never found to have rabies and have not been known to cause rabies in humans
- of all human cases, 99% are caused by dog bites
- over 50 000 people die from rabies each year, mostly in less developed countries
- the most common carriers are bats, foxes, raccoons, and skunks
38
Q
What is malaria
A
- malaria is an infectious disease transferred by mosquitoes
- it results from the multiplication of parasites within red blood cells
- malaria kills nearly 800 000 people every year
- today 90% of malaria-related deaths occur in sub-Saharan Africa
- malaria is best controlled by eliminating mosquitoes through the draining of wetlands and insecticides
- DDT was a powerful insecticide that was formerly used to control mosquitoes but was banned in the 1970s due to its potentially harmful effects on humans and the environment
- as climate changes, there is great concern that malaria will spread as more regions on Earth experience hotter, wetter conditions
39
Q
Describe West Nile virus
A
- this virus mainly affects birds but it can affect many different animals as well as humans
- it infects humans through the bite of a mosquito
- most people exposed experience symptoms of fever and weakness that are resolved after two weeks
- the human daeth rate from the disease is 4%
- over the past decade 50 people in Canada have died from West Nile Virus
40
Q
Describe COVID-19
A
- this novel coronavirus was first identified in late 2019 in Wuhan, China
- it is believed to have originated from an animal in a market that sells live animals and was then transmitted to a person
- it spreads between people through respiratory droplets in coughs and sneezes
- the human death rate is highest among elderly people and those with pre-existing health concerns
41
Q
Describe characteristics of pandemics
A
- research on diseases has led to several conclusions on the characteristics of pandemics:
- the disease is unpredictable in its severity, mortality, and pattern of spread
- there is a rapid surge with a quick exponential increase that may overcome a population’s capacity to cope
- while quarantine and restricted travel has some effect, reduced crowding and public gatherings can better limit the spread
- delaying spread is a very desirable strategy since it helps to reduce stress on the health care system (flattening the curve)
42
Q
What was found to be the cause of the spread of the bubonic plague?
A
-rat flea
