Overview of Environmental Medicine

Definition of Environmental Medicine

"Environmental medicine deals with diseases that other physicians encounter in their practice, whether cancer, lung disease, contact dermatitis or other chronic and acute diseases. The physician practicing environmental medicine focuses on the nexus between the patient or a group of people and the environment and utilizes disciplines from the environmental sciences that analyze the four major environmental media: air, water, soil and food. As a discipline, environmental medicine shares concerns, protocols and knowledge base with preventive, community, and occupational medicine. Historically, environmental medicine involved studying and controlling infectious disease, but the focus has moved to chemical and physical hazards in the environment. For other medical specialties, such as a primary care, environmental medicine principles and practices may help the clinician isolate the cause of the patient's problems and take the appropriate steps for a physician to help the patient and community prevent ill-health effects from environmental exposures."

— Michael Gochfield, in Environmental Medicine, pp. 3- 8.


Exposure Assessment

Exposure assessment examines potential and actual exposures to hazardous agents through the media of food, water, air and soil or a combination of any of these four media. Upon determining the exposure source, exposure media, and the hazardous agent, the investigator needs to characterize the exposure in terms of amount, duration of exposure and frequency of exposure. This exposure assessment is then as part of a risk assessment.

Three environments

  1. Home
  2. Workplace
  3. Community

Environmental media

  1. Food
  2. Water
  3. Air
  4. Soil

Types and examples of environmental hazards

  1. Chemical agents (heavy metals, pesticides)
  2. Physical agents (ionizing radiation)
  3. Biologic agents (bacteria, viruses)
  4. Psychosocial (personal, family)
  5. Trauma (acute, repetitive)

Means and examples by which hazards may enter the environment

  1. Consumer products (pesticides, cigarette smoke)
  2. Direct discharges into environment (smokestack emissions, waste discharge into water)
  3. Environmental catastrophic events (unplanned releases such as Bhopal, India release of methyl isocyanate)
  4. Ecological catastrophic events (flooding, famine)

 

Exposure assessment characteristics

Route of exposure

  1. Inhalation
  2. Ingestion
  3. Dermal

Dose: a function of the amount of toxin absorbed over a period of time

  1. Exposure magnitude
  2. Duration (in minutes, hours, days, or lifetime)
  3. Exposure frequency (daily, weekly, monthly, seasonally)

Dose characterizations

  1. Acute: single large exposure over a period of minutes or hours
  2. Intermittent: brief but regularly or sporadically repeated exposures over a period of months or years
  3. Chronic: continuous exposure
  4. Combinations of the above

— Stuart Brooks, Lynette Benson, and Michael Gochfield, in Environmental Medicine, eds. Stuart M. Brooks, Michael Gochfield, Jessica Herzstein, Richard J. Jackson, and Marc B. Schenker, Mosby, 1995, pp. 9 - 14.