1. (a) Except as specified in § 250.405 (relating to when to perform a risk assessment), a person shall perform a risk assessment when using a site-specific standard under Subchapter D (relating to site-specific standards) to determine if there are unacceptable exposures to humans or unacceptable exposures to ecological receptors, or both.
2. (b) A person who proposes to perform a risk assessment under the site-specific standard shall use the methodologies used to develop the Statewide health standards contained in Subchapter C (relating to Statewide health standards) to conduct the risk assessment. If methodologies are not specified in Subchapter C or this subchapter, the risk assessment shall be conducted in accordance with the methodology specified in EPA or ASTM guidelines approved by the Department.

3. (c) A risk assessment for human exposure shall include the following components:

   1. (1) Data collection, including source characterization and development of a conceptual site model, and evaluation to identify contaminants of concern.
   2. (2) Exposure assessment that considers ingestion, inhalation and volatilization pathways and exposure assumptions based on land use.
   3. (3) Toxicity assessment that includes the use of toxicity information from sources identified in § 250.605 (relating to sources of toxicity information).
   4. (4) Risk characterization that evaluates if the risks meet the human health protection goals and ecological receptor protection specified in § 250.402 (relating to human health and environmental protection goals).
4. (d) An exposure assessment that is based on sampling shall use a data handling methodology that is consistent with the statistical method used to demonstrate attainment.
5. (e) When performing an exposure assessment, a person shall use the appropriate exposure factors identified in § 250.603 (relating to exposure factors for site-specific standards) and meet the requirements of § 250.604 (relating to fate and transport modeling requirements for exposure assessments).
6. (f) The risk assessment report shall discuss the degree of uncertainty associated with the risk assessment.

Cross References

This section cited in 25 Pa. Code § 250.606 (relating to development of site-specific standards).