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Ecotoxicology & Environmental Toxicology. Tee L. Guidotti GWUMC. Comparison: infectious disease, chemical exposure. Ecotoxicology. Fate and disposition Release into medium Pathways of migration, accumulation Biomodification Removal, degradation or precipitation Ecosystem health

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Ecotoxicology environmental toxicology

Ecotoxicology & Environmental Toxicology

Tee L. Guidotti


Comparison infectious disease chemical exposure
Comparison: infectious disease, chemical exposure


  • Fate and disposition

    • Release into medium

    • Pathways of migration, accumulation

    • Biomodification

    • Removal, degradation or precipitation

  • Ecosystem health

    • change in population structure

    • health of individual species

    • damage to ecosystem

Substances move around and change in the ecosystem
Substances move around and change in the ecosystem

  • Once released into media: partition

  • Pathways of movement, exposure

  • Metabolism and biomodification

  • Exposureof “receptors”

  • Effects on individuals

  • Effects on populations

  • Recycling and uptake

How do we judge the risk of this incident
How do we judge the risk of this incident?

  • Exposure assessment

    • pathway

    • magnitude

    • duration

  • Characterize the population exposed

  • Risk assessment

    • formal/informal risk assessment

    • identify subpopulations at risk

Concerns in environmental toxicology




occupational airborne






uptake and migration


Consumer products





hazardous substances

waste disposal

Environmental security

Concerns in Environmental Toxicology

Human toxicology
Human Toxicology

  • Toxicokinetics

    • Absorption

    • Distribution

    • Metabolism

    • Excretion

  • Toxicodynamics

    • mechanisms

    • exposure-response

    • susceptibility

There are also differences


Host defense mechanisms

Individual susceptibility states

Single effects

Cumulative exposure



Bioconcentration (in water)


Never single effects

Movement between media (air, water)

There are also differences.

Broad generalizations in toxicology
Broad generalizations in toxicology!

  • The dose makes the poison

  • The most susceptible are the very young, the very old and the infirm

  • Interaction and multiple effects may occur

  • Occupational and environmental exposures never go away - they reappear in other settings.

The risk to the next generation
The risk to the next generation.

  • First period of risk: embryo

    • peak period of risk is first trimester, first ten weeks, during organogenesis

    • severe damage is likely to result in spontaneous abortion

  • Second period of risk: fetal development

    • some late developing organs

    • neurological development and behaviour

    • cancer risk

The risk to the next generation1
The risk to the next generation.

  • After birth:

    • lactation and exposure through breast milk

    • environmental exposure

  • Toddlers and young children

    • accidental exposures

    • inquisitive behaviour

    • compulsive ingestion

Children and toxic exposures
Children and Toxic Exposures

  • Children are different

  • Higher minute ventilation

  • More active, behaviourally and metabolically

  • Growing

  • Incomplete defenses and physiological barriers

Physiological aspects of exercise
Physiological Aspects of Exercise

  • Increased minute ventilation increases exposure to airborne hazards

  • Bypass of host defense mechanisms

  • Reduces athletic performance

  • Increased metabolic rate

  • Airways reactivity

  • Increased cardiovascular risk with some exposures

How do we manage the risk of this incident
How do we manage the risk of this incident?

  • Risk characterization - what is the risk?

  • Risk assessment - how big is it?

  • Risk perception - how do people see the problem?

  • Risk communication - talking about risk

  • Risk management - doing something about it

Exercise and environmental health
Exercise and Environmental Health

  • Exercise and ecosystem preservation

    • wilderness, climbing

    • hiking, orientiering, cross-country skiing

    • parks and open space

    • water sports, sailing

  • Extreme environments

    • heat stress

    • cold stress

Exercise and environmental health 2
Exercise and Environmental Health - 2

  • Environmental health and risk

    • water quality

      • water supply

      • microbial contamination

      • chemical contamination

      • bathing facilities

    • air quality

      • air pollution, health risk and performance

      • asthma

Exercise and occupational health
Exercise and Occupational Health

  • Ergonomics

  • Occupational health risk

  • Fitness to work

    • Preplacement screening

    • Return to work

  • Rehabilitation, impairment

    • musculoskeletal

    • cardiovascular and endurance

Exercise and air pollution
Exercise and Air Pollution

  • Heavily studied area of environmental physiology

  • Increased delivery of oxidant air pollutants (e.g. ozone) to lower respiratory tract)

  • Ozone has a direct effect on J-receptors in lung, inhibits deep inspiration

  • Older people show less effect

  • Tolerance developed, lost quickly

Example air pollution
Example: Air Pollution

  • A complex set of issues

  • Recognition that PM, ozone associated with increased mortality

  • Concern that this reflects cardiovascular risk, esp. elderly

  • Exhaustion of susceptibles = “harvesting”

    • not proven

  • Triggering effect for asthma

Air pollution
Air pollution

The major issues:

  • reducing

  • photochemical

  • air toxics

  • stratospheric ozone layer depletion,

  • enhanced greenhouse effect

  • occupational

  • indoor air quality

Ambient air pollution


Industrial activity

Mostly sulfur

High coarse and fine particulate levels

Characteristic of developing countries

Bronchitis, most lethal AQ incidents


Vehicular traffic

Mostly oxidants

Fine particulates

Developing and developed countries

Population health effects

Ambient Air Pollution

Health issues associated with modern ambient air pollution
Health Issues Associated with Modern Ambient Air Pollution

  • Mortality, associated with PM, ozone

  • Morbidity

    • aggravating lung disease, cardiovascular disease

    • eye irritation

    • increased risk of URI

    • increased frequency of asthma attacks

  • Not cancer!

Secondary issues in air pollution management
Secondary Issues in Air Pollution Management

  • Secondary ambient air quality standards may be set for:

    • plant life

    • materials

    • visibility

  • Loss of amenity is a major issue

    • loss of natural beauty

    • loss of enjoyment