An introduction to Environmental health, toxicology

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An introduction to Environmental health,
toxicology risk assessment

• Lecture 1

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• Contact me at
• Office 1st Floor Block 5 SHCV
• Tel [phone]
• Email gracebao_at_uic.edu.hk

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Lecture Objectives

• Define fundamental terms
• Explain the basic relationship between the
  environment and health
• Explain impact of environmental factors on health
• Explain risk assessment
• Consider the risk management model and process.

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Content

• Environmental health
• Toxicology
• Risk assessment

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Health

• Health is a state of complete physical, mental
  and social well-being and not merely the absence
  of disease or infirmity' (WHO, 1948)
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Human Health is affected by

• An individual genetic factors(????)
• determine an individual how to be affected by
  environmental hazard.
• Exposed Environment (????)
• that which is external to the individual human
  host.
• Physical, chemical, biological, social and
  cultural environment

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Health

• Health is only possible where resources are
  available to meet human needs and where the
  living and working environment is protected from
  life-threatening and health threatening
  pollutants, pathogens and physical hazards.'
  (WHO, 1992)

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Environmental health

• Environmental health comprises those aspects of
  human health, including quality of life, that are
  determined by physical, chemical, biological,
  social and psychosocial factors in the
  environment.
• It also refers to the theory and practice of
  assessing, correcting, controlling and preventing
  those factors in the environment that can
  potentially affect adversely the health of
  present and future generations.
• (WHO, 1993)

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Environmental health

• Assesses environmental factors that influence
  human health and quality of life.
• Seeks to prevent adverse effects on human health
  and ecological systems.
• Contains environmental toxicology within its
  scope.

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Basic Healthy Environment

• Clean Air
• Safe and sufficient water
• Adequate and safe food
• Safe and Peaceful Settlements (????)
• Stable Global Environment (???????)

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Health and environment

• Genetics loads the gun
• but the environment pulls the trigger.
• Dr. Judith Stern (2009)
• Professor of Nutrition Internal Medicine
• Univ. of California, Davis

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Environment and the Economy

• Environment is frequently sacrificed for the sake
  of the economy in our society. This policy is
  shortsighted because destruction of the
  environment undermines future economic resources.

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Which one is a developing country?
China (nowadays) London
(1952)
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Before and after
1952 nowadays
Nelson's Column, London
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Flooding, New Orleans (2005)
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Flooding, New Orleans (2012)
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Drought, China (2011)
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Ice melting, Arctic Circle (2007)
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Deforestation, Borneo (1950-2010)
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• Drought, deforestation, flooding, hurricanes,
  ice melting, heat waves
• are these incidents above isolated?

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Everything is linked
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Toxicology

• Toxicology toxico logy poisons study
• Toxicology is traditionally defined as the study
  of the harmful effects of drugs, chemicals and
  chemical mixtures on living organisms.

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Toxicology

• Toxicologists assess and compare toxic agents, or
  toxicants, for their toxicity, the degree of harm
  a substance can inflict.
• Environmental toxicology focuses on effects of
  chemical poisons released into the environment.

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Environmental toxicology

• Studies toxicants that come from or are
  discharged into the environment, and
• Health effects on humans
• Effects on animals
• Effects on ecosystems

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Environmental toxicology

• Animals are studied
• For their own welfare
• As canaries in a coal mine to warn of effects
  on humans

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Silent Spring and Rachel Carson

• Carsons 1962 book alerted the public that DDT
  and other pesticides could be toxic to animals
  and people.
• Further research led the EPA to ban DDT in 1973.
• These developments were central to the modern
  environmental movement.

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• Download and listen to the eAudiobook of Silent
  Spring in the Reference section

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Early Risk Assessment

• What is food to one man may be fierce poison to
  others.
• Lucretius (c. 99 B.C.c. 55 B.C.)

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Which one is Risky?

• Genetic Modified Foods
• Nuclear Power
• Mercury
• Dioxins
• Pesticides in Agriculture
• X-Rays
• Landfill of Domestic Waste

Ranking!
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Hazard

• An event, or property, associated with an
  activity, product, process or site which has the
  potential to cause harm

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Environmental health hazards

• Physical or climatic hazards (floods, heat wave,
  acid rain, UV exposure)
• Biological hazards (viruses, bacterial
  pathogens)
• Chemical hazards (Synthetic and natural
  toxicants)
• Cultural or lifestyle hazards (drinking,
  smoking, bad diet)

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Risk

• A combination of the probability, frequency, of
  occurrence of a defined hazard, and the magnitude
  (severity) of the consequence of the occurrence

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Key Risk Questions

• What are undesirable outcomes and who decides,
  what undesirable means?

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Key Risk Questions

• How can we specify, qualify and quantify the
  possibilities of undesirable outcomes?

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Key Risk Questions

• How do we aggregate different types of
  undesirable outcomes into a common concept which
  allows comparisons and priority setting?

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Harm

• Harm to the health of living organisms or other
  interference with ecological systems of which
  they form a part and, in the case of man,
  includes offence caused to any of his senses or
  harm to his property

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Tolerable Risk

• 'Tolerability' does not mean 'acceptability'.
• No risk is acceptable, only tolerable to the
  extent that there is some benefit arising from
  the activity and all possible controls are in
  place.

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Tolerability of Risk
(HSE, 2010)
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Risk assessment

• Analyses risks quantitatively
• Measures and compares risks involved in different
  activities or substances
• Helps identify and prioritise serious risks
• Helps determine threats posed to humans,
  wildlife, ecosystems

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Risk assessment

• Involves
• Dose-response analysis or other tests of toxicity
• Assessing likely exposure to the hazard
  (concentration, time, frequency)
• Risk rating

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Risk rating
Actual risk outcome
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Risk rating

• RISK LIKELIHOOD TABLE - Guidance

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Five steps
http//www.hse.gov.uk/
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RA Example

• Scenario 1- Bitten by snakes when working outdoors

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Risk management

• Consider risk assessments in light of social,
  economic, and political needs and values.
• Weigh costs and benefits, given both scientific
  and nonscientific concerns.
• Decide whether or not to reduce or eliminate risk.

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The process of risk management
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Four Simple Stages

• What is the possible problem?
• How big a problem might it be?
• What will be the effect?
• Does it matter?

Hazard Identification
Hazard Assessment
Risk Evaluation
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Source-Pathway- Receptor

• Without a source or pathway or target there
  cannot be a risk. Therefore, determining the
• Source-pathway-Receptor
• relationship is the key to risk assessment and
  management

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Toxicants take many routes through the environment
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Hazard Identification(What is the possible
problem?)

• Identify the chemicals, events, releases, the
  pathways and targets taking into account the
  environmental setting and proposed activity

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Hazard Assessment(How big a problem might it be?)

• Understand potential exposure and adverse effects
  based on fate and behaviour of chemicals in the
  environment
• Screen to determine whether an identical
  frequency or dose might be significant

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Risk Evaluation

• Requires consideration of
• The qualitative or quantitative statements about
  risk derived from the risk estimation process
• Other site-specific factors which may affect the
  risk
• The uncertainties in the estimates
• The costs and benefits of taking action to
  control or reduce unacceptable risks
• The social pressures for action

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Uncertainty/Complexity

• Sources natural variability people - poor data
  collection models which do not reflect the real
  world data manipulation availability
• Methods to manage worst-case scenario safety
  factors collect more data

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Case study

• Scenario 2
• Your mom calls you to say that your little cousin
  broke a thermometer and ate the silvery-grey
  material inside.
• You know the silvery-grey material is mercury.
• The FDA advises that pregnant women, women who
  may become pregnant, nursing mothers, and young
  children should avoid eating shark, swordfish,
  king mackerel and tilefish due to high levels of
  mercury in these fish.

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Lets consider a few questions

• Q1. Does this mean that eating the material from
  the thermometer is a serious problem?

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• Q2. With the mercury from the thermometer, what
  risks other than swallowing might be a problem?

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• Q3. Do you think there could be a difference in
  health effects depending on the route of exposure?

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• Q4. How else might the mercury be absorbed?

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• Q5. Do you think that the health risks from
  mercury in a thermometer might be different from
  the risks related to mercury in fish? What could
  be different?

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• Q6. Do you think there could be a difference in
  the effects of mercury on children, as opposed to
  adults?

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