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
Describe diseases
- 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
What are outbreaks, epidemics, and pandemics?
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
Describe diseases in developing countries
- 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
What conditions will lead to a rapid spread of disease?
- 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
Describe the Bubonic plague
- 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
Describe cholera and early mapping of cholera
- 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
Describe HIV/AIDS
- 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
Describe influenza
- 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
Describe the Spanish flu
- 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
Describe the Asian flu and Hong Kong flu
- 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
Describe the bird flu
- 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
Describe the Swine Flu
- 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
What are rabies?
- 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
What is malaria
- 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
Describe West Nile virus
- 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
Describe COVID-19
- 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
Describe characteristics of pandemics
- 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
What was found to be the cause of the spread of the bubonic plague?
-rat flea
Natural Disasters
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