NOTE: Steps 1 – 4 may be completed in any order.

  1. Enter project identification information plus any comments.(optional)
  2. Select and click on the desired "exposed party", i.e., site resident, site worker, construction worker. Selection of more than one exposed party, or removal of a selected exposed party, may be made by holding the "Control" key while clicking on the desired item. (Click on the question mark next to "Exposed Parties" for descriptions of each exposed party.)

    NOTES: Cumulative risk can be calculated simultaneously for the site-resident exposed party and site-worker exposed party, if the same exposure point concentrations apply to both. The construction-worker scenario must be run separately since it will involve different exposure point concentrations (i.e., deeper soil). A warning will appear if an attempt is made to evaluate the construction-worker scenario with another party.
  3. Select and click on the "medium of concern", i.e. groundwater, soil, and/or air. Selection of more than one medium, or removal of a selected medium, may be made by holding the "Control" key while clicking on the desired item.

    • Each medium of concern should be selected in which exposure to the same exposed party is possible.
    • Groundwater exposure should be included for a site resident or site worker only if their drinking water is obtained from, or may be obtained from, an on-site well.
    • In situations where on-site use of impacted groundwater is precluded, groundwater should not be included in cumulative risk calculations.
    • The construction worker scenario does not include exposure to groundwater.
  4. Select contaminants of concern from the list labeled "Available Chemicals" by individually clicking on a contaminant followed by clicking on the box below the table with the arrow pointing to the right. (Chemicals can be removed from the list of selected chemicals in like fashion using the box with the arrow pointing to the left.) Include each chemical for which you have an analytical result above the detection level, even if it wasn't found in all the selected media. Click on the question mark adjacent to "Available Chemicals" if you need help in finding a chemical from the list of available chemicals.
  5. Click on the box labeled "Next" when steps 1-4 are completed and a new screen will appear for input of site-specific contaminant concentrations for each selected medium.
  6. Enter the exposure point concentration and site-specific background concentration, if any, for each selected contaminant for each medium in the appropriate space. Click on the question mark next to "Exposure Point Concentration" for each medium for help in determining appropriate values. Leave blank spaces for concentrations less than the detection limit and contaminants not analyzed in a medium. Also leave blank spaces for background concentrations when site-specific background concentrations have not been determined. Blank spaces will be treated as zeros. Do not include backgroundconcentrations of lead in soil.
    • Groundwater: mg/l or PPM
    • Soil: mg/kg or PPM
    • Air: mg/m3 (not equivalent to PPM, chemical-specific adjustment necessary)
    Click on the question mark next to each unit (e.g., mg/l) for help on converting from other units.
  7. Upon completing input of contaminant concentrations, click on the "Calculate Risk" box and the results will be displayed. Interpretation of the results is described briefly at the bottom of the page. A more in-depth discussion of what results mean can be accessed by clicking on the question mark adjacent to "Interpretation of Results".