lecture 9 - technological hazards Flashcards
example of a technological hazards being a hybrid disaster
an earthquake that causes an oil spill from a pipeline
example of technological disaster involving the environment
the sinking of the titanic and explosion of the challenger space shuttle
vulnerability to technological hazards
death toll is low
vulnerability is greatest for those involved in specific industries or transportation systems
workers in resource industries in hinterlands are at higher risk (miners)
categories of technological hazards
widespread; long term (hazard that lead to cumulative effects)
rare events: airplane crashes, mine collapses, shipwrecks
relatively common; automobile accidents, poisons
cumulative effects of technological hazards
conditions that worsen slowly over time as exposure to a concentration
concentration reaches a threshold critical to human health
hazards that cumulative effects include exposure to radiation, toxic chemical, acid precipitation and groundwater contamination
calculating risk of infrastructure, transportation and industry
infrastructure (bridges, dams, pipelines); risk is defined as the probability of failure during the lifetime of the structure
transportation (by road, sea, rail); risk is the probability of death or injury per km travelled
industry (manufacturing, energy production); risk is probability of death or injury per person per numbers of hours exposed
what is radon?
primary source of radon GAS is from natural decay or uranium in rock and soil
becomes a hazard when released
what happens when radon gas is inhaled?
when inhaled it decays to polonium and lodges in the lungs where it damages tissues
2nd leading cause of lung cancer in North America
why is radon difficult to detect?
difficult to detect because its odourless, colourless and tasteless
how does radon move?
can move quickly through non saturated soil and seep into homes, basements are at higher risk in winter due to reduced air circulation
genetically modified organisms
have had changes made to their DNA by transfer of genes
crops are modified to increase yields
some of the crops have been genetically engineered to have greater resistance to: extreme change in temp or precipitation, herbicides, pests and acidic soil
most common genetically modified organisms
corn, soybeans, canola and wheat
examples of feats in genetic modifications
chickens that lay low cholesterol eggs
tomatoes that reduce risk of cancer
bananas & potatoes to treat viral disease in developing countries
rice that contains more vitamin A
bacteria that can clean up oil and toxic spills
citrus trees producing fruit in their first year (when take 6)
how safe are genetically modified foods?
benefits outweigh the risks
great benefits in developing countries
impacts of radiation
can be direct (effects seen within days of exposure) or delayed and chronic (cancer)
can be indirect in the form of genetic effects
example: person may not experience effects but pass them onto their children in the form of birth defects
2 potential sources of radiation
mining of uranium; produce wastes know as tailing that can be a radioactive hazard
production of electricity; uranium is used in nuclear power plants
nuclear power plants
most in North American are in the eastern half of the continent
must be near water source aka coolant
must be located near a market for electricity
considered a clean source on energy because does not emit greenhouse gases that cause climate change
nuclear accidents
nuclear meltdown is an informal term for an accident that results in damage from overheating
occurs when heat is generated by nuclear plant exceeds the heat removed by its cooling systems
in meltdown, fuel rods turn liquid and the wall of the plant could melt from extreme heat
hot liquid could melt through the bottom of the plant and seep into the soil
three mile island nuclear accident
the worst nuclear disaster in the U.S. in 1979
one of the two power plants on the island that experienced in a partial meltdown
caused by failure of a valve that controlled cool water entering the plant
no direct injuries but minor amount of radiation released and plant closed
chernobyl nuclear accident
nuclear disaster occurred in 1986
the accident was result of a flawed design, operator error and disregard of safety regulations
killed 3 workers due to radiation exposure, thousands developed thyroid cancer
nuclear energy
over 3 mile island and chernobyl slowed nuclear development for a time
concern over greenhouse gas has created high demand for cleaner sources of energy
when did he last coal plant in Ontario close?
2014
titanic shipwreck
hit an iceberg in 1912
wreckage was found by SONAR in 1985
the carpathia arrived at 4:10 and picked up survivors
oil spill impacts
most common in water but occur on land due to pipeline bursts
clean up can take months to years
oil penetrates bird feathers and mammal fur reducing the ability to insulate
birds and animals left vulnerable to changes and become less buoyant in water
exxon valdez oil spill
caused by an oil tanker ship striking a rocky reef of the coast of Alaska (1989)
region is important habitat for salmon, seals, sea otters, killer whales and seabirds
75 mil L of oil spilled; the remote location made recovery efforts difficult
deepwater horizon oil spill
caused by an oil rig that exploded in mexico (2010)
killed 11 workers caused by methane rising upward through drill pipe
approx 11 mil L oil leaked from well, well was capped with cement in 2010
caused extensive damage to wetlands and beaches
deepwater horizon oil spill; report found that the company
made a series of coast cutting choices on maintenance
did not have proper system in place to ensure safety
groundwater material are permeable because..
they have connected spaces that allow water to flow through
groundwater contamination
in 2000, water contamination killed 7 in ON
bacteria came from fertilizer manure that had leached into a well during heavy rainfall
minneapolis bridge collapse
cause was deemed to be excessive weight from vehicles and construction equipment
bridge supports were not proper thickness and an extra 2 inches of concrete that was added to roadway contributed to the collapse
tacoma narrows bridge collapse
1940, high winds caused the collapse of a suspension bridge in washington
there were no human deaths
design of bridge did not provide any open trusses for wind to pass through
2 major space shuttle explosions
2 major ones included the challenger and Columbia
the challenger shuttle explosion
associated with a rubber O ring seal
it fail 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 cold; frost and ice had developed on the rocket
cold weather reduced the elasticity of the O ring preventing it from properly sealing the joint
the Columbia shuttle explosion
disintegrated in 2003, upon re-entry into earths atmosphere after 16 days in space
during launch insulation broke off from the external tank
it struck the left wing and damaged the system that protects the wings from intense heat produced by atmospheric gases upon re-entry
pieces of the shuttle were found in texas and lousiana
how was the solar system formed
a cloud of gas and dust in space was disturbed by a supernova
4.6 million years ago
the nebular hypothesis
the supernove explosion made waves in space
caused the formation of a solar nebula (flattened cloud of gas and dust)
formation of planets
centre of the solar nebula grew hotter resulting in the formation of the sun
the outer edges cooled causing clumps of particles to stick together and form planets
2 components of outer space
galaxy; cluster of stars. our solar system makes up a tiny portion of the milky way galaxy
star; a hot glowing ball of gas that generates energy by converting hydrogen to helium
the milky way galaxy
it takes light 100,000 years to travel from one side of the galaxy to another
sun is location approx 30 quintillion km from the centre of the milky way
the sun
outermost part of the sun = photosphere
energy from sun controls the earths climate system
sun is so large that the earth only receives two billionths of the suns total energy
the solar system
composed of 8 planets, 214 moons and millions of bolides
order: mercury, venus, earth, mars, Jupiter, saturn, uranus, neptune
life cycle of stars
closest star to earth; has a life expectancy of 10 billion years
end of the life cycle of a star a massive amount of energy is released in an explosion (supernova)
what is a bolide?
a extraterrestrial body that originates in outer space
example; asteroid (rocky metallic, 10m to 1000km in diameter originating in asteroid belt btwn mars and jupiter) and metroid (similar composition but only 10m in diameter)
3 bolides
meteor: a Metroid that has entered the earths atmosphere
meteorite: a meteor that strikes the earths surface
comet: distinguished by large glowing tail of gas and dust
where do comets originate from?
area outside of the solar system called the Kuiper Belt
comets
comets create light as gases are released while the comet is heated by solar radiation
halley’s comet is most famous due to its visibility with the naked eye and passes close to earth every 75 years
airbursts
bolides travel at velocities of 12-72 km/s
as they heat upon entering earths atmosphere they produce bright light
many bolides explode at an altitude between 12km and 50km; explosion is referred to as a airburst
Tunguska airburst
1908: destroyed over 2000km of forest in sparsely populated area in Russia
determined it was an airburst due to no crater has ever been found
The meteor is responsible 25-50m in diameter
chelyabinsk airburst
2013: meteor exploded in russia creating a shockwave
largest bolide to enter earths atmosphere since Tunguska
over 1500 people where injured due to broken glass
impact craters
provide evidence of past meteorite impacts
layer of debris around a crater called an ejecta blanket (breccia) consists of rock fragments that were blown out of the crater upon impact
not as deep due to rock falling back into it
this rock is refereed to as breccia
simple vs complex impact craters
simple: less than few km is diameter and do not have an uplifted centre
complex: rim that collapses and a centre floor that slowly rises following impact (rebound) greater then 6km in diameter
Manicouagan crater
100km in diameter (one of the largest)
in central quebec formed 214 mil years ago
rim collapsed and rock eroded to form a ring shaped lake
Chesapeake crater
crater was not discovered until subsurface imaging and drilling revealed its presence off coast of virgina
crater formed 35.5 mil years ago
since then it has been overlain by sediment and seawater as seas levels have risen
why are craters much more common on the moon than in earth?
most impacts with earth are on oceans thus no crater can be produced
impacts with earths land have been eroded or buried and therefore have more subtle features than moon craters
smaller bolides often burn up and disintegerate in earths atmosphere before striking its surface
shoemaker-levy comet
comet jupiters atmosphere in 1994
massive amounts of energy were released, and gas plumes were produced as 21 fragments of the comet collided with jupiter
after this impact, one could strike the earth one day
mass extinctions
extinctions coincide with boundaries of geologic period of the geologic time scale
consistent with abrupt changes in climate from volcanism, bolides, or human impacts
5 major extinctions
K-T boundary mass extinction
occurred from abrupt cooling caused by a bolide impact
it is named for the boundary separating the cretaceous and tertiary period
caused the extinction of dinosaurs and 70% of all plant and animal species at that time
K-T boundary crater
1991: 180km in diameter underlying sediment and seawater
located in mexico and refered to as chicxulub crater
how was the extinction determined to be from a bolide impact?
found large quantities of iridium in rock that is found in bolides (first clue)
no crater had been found
linkage with other hazards
bolide impacts can trigger tsunamis, earthquakes, landslide and cause climate change
risk from bolide impacts
if bolide remains in the asteroid belt it poses no hazard to earth
orbital path of bolide could be disturbed by collision with another object
1100 bolides larger then 1km near earths orbit
managing the bolide impact hazard
can detect in decades in advance
blowing it up would cause fragments to rain down and is not advisable
pushing a bolide off course by ramming it with a spacecraft impacted the asteroid dimorphos
