| (ii) the attenuation action level for the nearest monitoring point when the use of a plume management zone is authorized under §350.33(f)(4) of this title; and/or (iii) the maximum concentration of COCs in the groundwater source area at the time of RAP submittal when a plume management zone is authorized for class 2 groundwater in response to §350.33(f)(4) of this title. (B) The person shall establish this PCL using the applicable equations as shown in the figure in subsection (b)(1) of this section for Tier 1. (C) The person may not be required to establish a soil leachate-to-groundwater PCL in accordance with subparagraphs (A) and (B) of this paragraph when a demonstration can be made with appropriate soil and groundwater monitoring data that the soils will attain the soil response objectives for groundwater protection set forth in Subchapter B of this chapter (relating to Remedy Standards). The determination that the soils are adequately protective shall be based on soil sample data, the concentration trends of groundwater monitoring data over time when groundwater is impacted, probable time since release occurred, adequate identification of the soil source areas, appropriate leachate test results, or other hydrogeologic or property-specific information. The executive director may also require that the change in soil concentrations over time be documented to support this evaluation in a property-specific situation. The executive director may require the person to install a sufficient number of groundwater monitoring wells to demonstrate that groundwater is not affected when soil COC concentration data are inadequate to sufficiently substantiate that groundwater is not affected. (8) PCLs for inhalation of volatile emissions in outdoor air from COCs in subsurface soils (Air Soil Inh-V ). The person shall establish this PCL using the applicable equations as shown in the figure in subsection (b)(1) of this section for Tier 1. (9) Theoretical soil saturation limit (C sat ). The person may establish a property-specific theoretical soil saturation limit for the volatilization exposure pathways required in paragraphs (6) and (8) of this subsection under Tiers 2 or 3. The C sat shall be based on the same property-specific parameters as those used to calculate Air Soil Inh-V . If the property-specific Air SoilInh-VP or Air SoilInh-V is greater than the property-specific Csat , then that exposure pathway shall not be considered a relevant exposure pathway for that COC. (10) Residual soil saturation limit (Soil Res ). The person shall establish the residual saturation level for each organic COC present in surface and subsurface soils which is a liquid at standard temperature and pressure using the applicable equation as shown in the figure in subsection (b)(1) of this section to estimate the mobile NAPL concentration and to determine if NAPL may be present. (11) PCLs for other complete or reasonably anticipated to be completed surface and subsurface soil exposure pathways. The person shall establish PCLs for surface and subsurface soil exposure pathways other than those listed in paragraphs (6) - (8) of this subsection when, in the executive director's determination, those other exposure pathways are complete or reasonably anticipated to be completed. (12) Air inhalation exposure pathways ( Air AirInh ). For air inhalation exposure pathways, the person may be required by the executive director to establish Air AirInh solely for the purposes of determining the protective concentration that must be met in air at the POE. The person shall use the applicable equation as shown in the figure in subsection (b)(1) of this section to establish Air AirInh . (13) Surface water exposure pathways ( SW SW). The person may be required by the executive director to establish SW SW when COCs are present in surface water or when COCs will enter into surface water due to a release, and a surface water response action is necessary to protect human or ecological receptors. The person shall use the applicable equation as shown in the figure in subsection (b)(1) of this section to establish SW SW. (14) Other air and surface water exposure pathways. The person shall establish PCLs for air and surface water exposure pathways other than those listed in paragraphs (12) and (13) of this subsection when, in the executive director's determination, those other exposure pathways are complete or reasonably anticipated to be completed. (15) The person shall establish PCLs for complete or reasonably anticipated to be completed sediment exposure pathways when, in the executive director's determination, those exposure pathways are complete or reasonably anticipated to be completed. (j) The person is not required to combine exposure pathways for a single environmental medium when determining PCLs with the exception of the combined exposure pathway required in subsection (i)(6) of this section, unless otherwise directed by the executive director. |
