Highlight 9-22, page 393: Establishing Target Distance Categories for Nearby Threat: Method 1
- Each sample location establishes an area of observed contamination. Due to site-specific conditions, it is not appropriate to connect the points into one area of observed contamination.
- Draw travel distance categories from each area of observed contamination and then aggregate travel distance categories.
- Sum the population within each travel distance category (excluding those counted in the resident population) to determine the total population within each travel distance category. From the HRS Table 5-10,determine the population within one mile factor value.
- If no individual qualifies as a resident individual, use the resident nearest an area of observed contamination to determine the nearby individual factor value.
- Do not include residences on the far side of the river, even though they are within one mile in straight-line distance, because they are not within a one-mile travel distance of the area of observed contamination.
- This method may be unweildy for sites with many areas of observed contamination.