Module 11

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Module 11

• Hazard and Risk

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Learning Objectives

• Hazardous and Toxic materials
• Toxic waste
• What is Hazard?
• Natural and Anthropogenic
• Hazardous places
• Spatial and Time aspects

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Learning Objectives

• What is Risk?
• Assessment, Estimation, Evaluation and
  Management
• Magnitude and Frequency analysis
• Geography of Risk

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Hazardous Materials

• Materials having one or more of the following
  characteristics
• Ignitability (fire hazard), Corrosiveness,
  Reactivity (unstable), Toxicity
• Each year, roughly 1,000 new chemicals are
  produced and distributed.
• Chemical products and by-products of industry are
  often handled and disposed of improperly.

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Hazardous versus Toxic

• Toxic - refers to substances that cause acute
  human injury or death.
• Hazardous - a broader term, referring to all
  dangerous materials that pose a human health or
  environmental problem.
• Effects depend on level of exposure and tolerance
  thresholds
• Thus we have quality standards/objectives

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Toxic Wastes ...

• Cause or significantly contribute to an increase
  in mortality or an increase in serious
  irreversible, or incapacitating illness and
• Pose a substantial present or potential hazard to
  human health or the environment when improperly
  treated, stored, transported, disposed of, or
  otherwise managed.

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Setting Regulations

• Identification of Hazardous Toxic Materials
• List often limited to current known offenders
• New materials appearing all the time
• Setting Exposure Limits
• Nearly all substances are toxic in sufficient
  quantities
• There are species-specific thresholds
• Science of detection (limits of detection)

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Hazardous Waste Dumps The Legacy

• Prior to mid 1970s, hazardous waste was
  essentially unregulated.
• Most common disposal solution was to bury or dump
  the wastes without explicit concern for
  environmental or health risks.
• When sites became full or unnecessary, they were
  simply abandoned.
• In North America, there are over 25,000 sites
  containing hazardous wastes.
• Where are they?

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What is Hazard?

• An event or condition with the potential for
  causing harm, injury or damage

Severe flooding in the Red River Valley,
Manitoba, 1997
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Nature of Hazards

• Anthropogenic - created by humans, such as
• toxic chemicals, oils spills, air pollution, etc.
• Natural - extreme events such as
• tornadoes, hurricanes, floods, droughts,
  volcanoes, landslides, avalanches, etc.

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Consequences of Hazards

• Health and safety (public and individual)
• acute and chronic
• Environmental impact
• damage to ecosystems
• bioaccumulation
• keystone species
• Economic losses
• property damage
• loss of livelihood

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What is Risk?

• Definition the probability of occurrence of a
  hazardous event.
• A measure of the likelihood of an adverse effect
  to health, property or the environment.
• In other words, exposure to the chance of
  loss/harm, within the context of some expected
  net benefit.
• Risk Hazard x Exposure

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Risk Assessment

• What can go wrong?
• Hazard identification
• How likely is it?
• Risk estimation
• What are the consequences?
• Risk evaluation - who or what suffers harm or
  injury

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Hazard Identification

• Those hazards which generate risk of harm or
  injury in a particular place or situation
• Based on experience and historical records
• Based on medical evidence
• Event Tree Analysis
• Environmental Assessment

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Risk Estimation

• The use of available information to estimate the
  probability of occurrence of a harmful event or
  condition
• the harm to human health or the environment that
  may result from exposure to pollutants, toxins,
  or extreme natural events.
• E.g. How likely are
• Toxic spills, oil spills, chemical releases,
  earthquakes, tornadoes, flooding, etc

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Risk Estimation Involves ...

• Determining likelihood of occurrence e.g.
• as based on frequency analysis of historical data

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Flood Level Data
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Return Interval Analysis
Large events are less frequent
Large events are increasing in frequency - a
result of climate change?
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Practical Application

• Estimates of the magnitude and frequency of
  floods are used by engineers in the design of
  bridges, culverts, dams, and embankments, and by
  land-use managers to assess the hazards related
  to the use and development of flood plains.
• This is known as the design event
• But there will always be an event thats bigger
  than the design event ? Consequences?

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Return interval the spatial aspects of risk
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Risk Evaluation

• A process that identifies the consequences
  associated with a hazard.
• Provides a basis for decisions concerning
  acceptable risk, by comparing the results of risk
  analysis with harm criteria.
• E.g. air quality objectives

Frozen Orange Juice!
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Risk Evaluation

• Do the consequences matter?
• What is an acceptable level of harm?
• What is judicious risk-taking?
• What is the proper allocation of responsibility
  for risky activity?
• Who suffers harm from what?
• Socio-economic factors
• Geographical factors

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Perception of risk

• Everyone engages in some form of risky behaviour
• Examples?
• But the perception of risk is heightened by the
  fear of falling victim unfairly to uncompensated
  loss. (A random act or occurrence)

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Risk Management

• Can we avoid risk?
• No.
• Can we expose ourselves to greater risk?
• Yes. By using or modifying the environment
  without thought, by settling on marginal lands.
• How can we reduce risk?
• Zoning, planning, regulation, building codes,
  safety standards, clean up of hazardous materials

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Risk Distribution

• Spatially - earthquake zones, flood plains, toxic
  waste dumps, etc.
• Through time - extreme event probability
• Socio-economically- who suffers damage, harm and
  death?
• Who lives near dumps and industrial plants?
• Who can protect themselves from risk?

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Hazardous Places

• Are all places equally vulnerable? No.
• Hazards are spatially distributed (they are
  geographical)
• What makes a place hazardous?
• What kinds of hazards are there?
• Including secondary hazards (e.g. landslides
  triggered by earthquakes or heavy rains)
• What hazards do we have here in our region?

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So, where you live matters

• There are different types of hazards
• Different levels of occurrence
• Do you have choices?
• Socio-economic factors
• Environmental justice
• Perception of risk
• The fear of falling victim unfairly to
  uncompensated loss.

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Hazard of Place
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Hazard of Space
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We can make matters worse ...

• Events that are typically classed as natural may
  be caused or worsened by human actions. For
  example
• The severity (and frequency) of flooding may be
  exacerbated by channelisation, floodplain
  reclamation (infilling wetlands), deforestation
  and other land use changes.
• The Saguenay floods.
• Other examples?

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Natural disasters represent the intersection of
two sets nature and population. As the
population continues to grow, so does the area of
intersection, leading to costlier and perhaps
deadlier disasters.
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Summary

• Risk assessment uses facts and assumptions to
  estimate probability of harm from hazardous
  events and conditions
• Hazards are natural and human-made
• Risk management depends on socio-economic and
  political factors as well as the adequacy of
  scientific evidence
• Hazard and Risk have geographical (spatial)
  aspects.

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Geography of Risk Scale Factor
May 1999 Tornado, Oklahoma City