Method Three
SPAR Programs
The Petroleum Cleanup Level Calculator is designed to assist consultants, potential responsible parties, and regulators in calculating site-specific gasoline, diesel, and residual range organics contamination in soil under 18 AAC 75.340(e)
What is Method Three?
Method three was developed to provide flexibility in determining alternative cleanup levels for soil. This method allows for the use of site-specific soil data, aquifer data or both, and it also allows for the use of commercial/industrial exposure values without performing a full risk assessment under method four.
Method three provides methods of determining site-specific alternative cleanup levels for three soil exposure pathways: inhalation, ingestion, and migration to groundwater. In this web calculator, the following site-specific soil and aquifer parameters may be modified:
- Dry bulk density
- Total soil porosity
- Air-filled soil porosity
- Water-filled soil porosity
- Average soil moisture content
- Organic carbon content of soil
- Aquifer hydraulic conductivity
- Hydraulic gradient
- Infiltration Rate
- Aquifer Thickness
- Source length parallel to groundwater flow
In addition, the user has the choice between selecting the residential and commercial/industrial land use scenarios.
The soil and aquifer parameter values used to develop the Department's default cleanup levels may not be reflective of soil or aquifer conditions at a particular site. Therefore, method three allows for the use of site specific data for selected parameters. The Department requires submittal of the parameters proposed for modification, the site specific values for those parameters proposed for use and a description of the basis for each site specific value prior to calculating site-specific cleanup levels.