Hazardous Substance Migration Path
- The overland segment from surface water sources to the probable point of entry (PPE) is replaced by a ground water segment through the uppermost aquifer from ground water sources to a PPE. The in-water segment extends from this PPE to its target distance limit (TDL) and is evaluated for the drinking water threat, the human food chain threat, and the environmental threat.
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Three criteria must be met or this component cannot be evaluated:
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Press here to review the exact wording of the HRS:
Evaluation Criteria
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Press here to review the exact wording of the HRS:
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The PPE for this component, which is based on straight-line distance, may be different from the PPE for the overland/flood migration component.
Hazardous Substance Migration Path
- The in-water segments may be quite different for the two components. If this component picks up significant surface water targets that the overland flow/flood migration component misses, rough out a score for both components to determine whether this component is worth evaluation. This is one of the few conditions where this component might yield the higher score.
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