- The target vector includes resident individual, population (Level I or Level II), workers, resources, and sensitive environments.
Question: Guess how many target points result from a household of 4 people subject to Level I concentrations. ANSWER
- Resident Individual: Read the definition of resident individual carefully:
Resident individual - a person living or attending school or day care on a property with an area of observed contamination and whose residence, school or day care center, respectively, is on or within 200 feet of the area of observed contamination. (HRS Rule, Section 5.1.3, page 51647)
The HRS Guidance Manual gives further clarification in Highlight 9-9, page 361 (included below).
- Remember the 50 points for Level I and 45 points for Level II? How many points for potential?
- Population: All persons considered as population must meet the definition of resident individual.
- Note that workers are a separate category in this pathway and are not included in the population count.
- The HRS Guidance Manual, page 369, contains valuable tips and reminders on how to count population. (see graphic below)
- The Guidance Manual also gives examples on how to assess population in a typical residential neighborhood (see Highlight 9-10) and for multiple residences on a single property such as trailer parks (see Highlight 9-11)
Workers: Workers are evaluated using HRS Table 5-4, page 51647. (included below)
Workers are treated as a separate category because of the wide range of possible ingestion scenarios. See Section N of the HRS Preamble, page 51563.
- Document that the workers' activities, including parking and lunch breaks, take them within 200 feet of an area of observed contamination and count only those workers for whom such documentation can be presented.
- Workers are treated as a separate category because of the wide range of possible ingestion scenarios. See Section N of the HRS Preamble, page 51563.
- Resources: Certain commercial agricultural resources are counted if they lie on an area of observed contamination.
Determining Resources Factor value
Terrestrial sensitive environments: Terrestrial sensitive environments are counted if they lie on an area of observed contamination. Note: "on an area", not simply within 200 feet.
See Table 5-5, page 51648 below for the list of terrestrial sensitive environments.
- For guidance on how to identify these sensitive environments, review Section 14-4 of this training, Targets: Sensitive Environments in HRS Table 4-23.
Question: What about wetlands and species associated with wetlands? ANSWER
- See Table 5-5, page 51648 below for the list of terrestrial sensitive environments.
The maximum contribution that sensitive environments targets may make to the pathway score is 60 points.
- To determine whether this limit is exceeded, enter the target value for sensitive environments into the pathway formula. If the result exceeds 60.00, you will have to back-calculate the maximum target value for sensitive environments.
- Enter the value for Likelihood of Exposure and Waste Characteristics in the pathway formula, set the formula equal to 60.00, and solve for targets. The HRS gives the formula for doing this on page 51648.
Try looking at a brief Exercise presented in the HRS Guidance Manual before you finish this section.
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