Integrating Research and Education > Environmental Health Risk Assessment > Tutorial

Environmental health risk inventory of your neighborhood.

By Laurie Cantwell
The following tutorial is an example activity designed for students and teachers interested in completing an environmental health risk inventory of a specific locale. The tutorial provides step-by-step instructions for completing an environmental health risk inventory using Bozeman, Montana as an example. Also included are helpful links to publications and web pages with valuable information about environmental health and risk assessments.

What is an environmental health risk assessment and why do we do them?


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." -World Health Organization

The terms 'hazard' and 'risk' are frequently used interchangeably in environmental health assessments and literature. However, the terms have different definitions and carry significantly different connotations. Hazards hold the potential to cause harm and are formally defined as "a property or situation that in particular circumstances could lead to harm" (EEA, 1999). Risk typically means potential for disaster. However when used in the process of risk assessment it has a specific definition. Risk is formally defined as "the combination of the probability, or frequency, of occurrence of a defined hazard and the magnitude of the consequences of the occurrence" (EEA, 1999). Risk assessments, then, are a systematic approach for characterizing the nature and magnitude of an occurrence of a hazard(enHealth, 2002).

Health risk assessments are designed to provide complete information to risk managers, policymakers and regulators, so that they can make the best possible decisions about policy and safety. Completing an environmental health risk assessment of a their town or city can help inform citizens about their surroundings, the potential hazards and risks associated with their neighborhood and the environment in which they are living and working. Using tools and databases available on the World Wide Web, you can inform yourself about the environmental health hazards in your neighborhood and the risk involved with living there.

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Environmental Health Risk Inventory of Bozeman, Montana


Risk Assessment Flow Chart.
Health Risk Assessment Flow Chart. Details

A formal risk assessment involves a multi-step process (seen in the flow chart on the right) including issue identification, hazard identification, dose-response assessment, exposure assessment and so on. Official environmental risk assessments are highly detailed, analytical studies with much data and statistics involved. The goal of this activity is to gather information about Bozeman, Montana and become informed about any environmental health risks in the area. Therefore, we are going to complete an environmental health risk inventory, a simplified version of a full environmental health risk assessment. We will complete the inventory in three steps: hazard identification, risks/effect on human health and summary/assessment of the locale.

Step 1: Hazard Identification


  1. I am interested in identifying facilities that produce potential environmental hazards in the area (such as harmful air emission, toxic releases, Superfund sites, etc.). I choose to use EPA's Enviromapper Tool: Envirofacts. After locating a map of Bozeman, here is what I discover:
  2. Envirofacts map of Bozeman MT
    • There are 50+ hazardous waste handlers in and around Bozeman - meaning that the facility handles some type of hazardous waste).
    • There are five sources of air emissions - meaning that the facility releases some kind of potential air pollutant.
    • There are five facilities with Water Discharge Permits - meaning that a facility holds a permit to release waste water into rivers and tributaries.
    • There are four multiple-activity facilities - meaning that the facilities hold more than one permit and/or release more than one kind of potentially hazardous material.
  3. Next, I am interested in finding out some details about the facilities in Bozeman. I go to GATHER, which will provide me with some specifics about hazardous waste releases and the facilities associated with those releases. Here is what I discover:
  4. GATHER map of Bozeman Montan
    • Bozeman has two identified hazardous waste sites: Bozeman Solvent Site and Idaho Pole Company.
  5. Now I would like to find more information about the chemicals released by those sites using TOXMAP. Here is what I discover:
  6. TOXMAP of Bozeman
    • I find some details about releases by the Idaho Pole Company. The company reported 740 lbs of Pentacholorophenol released between 1987 and 2002.
  7. I am curious to find out if there have been any recent toxic releases reported in or around Bozeman. I am going to use the EPA's Toxic Release Inventory Explorer to identify recent toxic releases. Here is what I find:
  8. TRI Report for Bozeman
  9. What about water quality? I would like to find out a little about the water quality in my neighborhood using Surf Your Watershed. Bozeman is located in three watersheds; Gallatin, Madison and Upper Yellowstone. I surf all three reports and gather information. I am most interested in finding out if streams, rivers or lakes in my neighborhood are impaired. Impairment is listed by watershed and here is what I discover:
    • Gallatin and Madison watersheds have 15 impairments reported.
    • Upper Yellowstone watershed has 14 impairments reported.
    • Impairments range from habitat alterations to chemical impairments.

Step 2: Effect on Human Health


So far, I have identified potentially hazardous facilities, toxic releases, and air and water quality information. I am also interested in how this relates to human health. I address the question, "Are there any unusual health problems prevalent in my neighborhood?"
  1. I am going to use BRFSS Maps to answer some of my questions. I wonder how air quality might contribute to the number of people with asthma and the overall health status of Montanans, so I investigate. Here is what I find:
    • 14.5% of Montanans have been told they have asthma.
    • Only 3.4% of Montanans report poor health.
  2. I am also curious about the incidence of cancer in Montana. I am going to use the Atlas of Cancer Mortality Maps to find information. I locate a map for all cancer types and find information about Caucasian men and women. Here is what I discover:
  3. Cancer Maps for Montana
    • Montana has an average to less than average cancer mortality rate (as compared to the rest of the nation).
    • Gallatin County had a 128.3 cancer mortality rate in women and 191.4 cancer mortality rate in men from 1970-1994. Mortality rate is number of deaths per 100,000 people. These numbers are average and slightly lower than average respectively.

Step 3: Putting It All Together


To finalize my assessment, I will compile the information I found and address a few questions. This is my chance to interpret and summarize the data I have found. I am interested in seeing how environmental health in Bozeman compares to other cities nationwide. To determine how my neighborhood ranks, I will use Scorecard. Here is what I find:
Scorecard graph for Bozeman
Second, I will address some questions: Third, I would like to find out more about some of the chemicals I identified.

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