LDEQ’s RECAP

1. LDEQ’s RECAP Soil Protective of Groundwater - SoilGW Soil Saturation - Soilsat

2. SOILGW & SOILSAT • SoilGW values are soil concentrations for constituents of concern that are protective of a groundwater use • Soilsat values are the maximum soil concentrations allowed for constituents of concern. Above Soilsat free product is assumed to exist.

3. MO-1: Determination of SoilGW for Organic COC • 1. Identify the appropriate GW classification • ex. Shallow groundwater - GW3NDW • Determine the GW value for the COC • ex. COC is Benzene, GW3NDW = 0.013 mg/l < Watersol • 2. Use GW value to calculate Csoil • ex.Csoil = 0.00668 =

4. MO-1: SoilGW Organic COC cont. • 3. Multiply Csoil by vertical DF of 20 • ex. SoilGW = 0.00668 * 20 = 0.13 • 4. Multiply SoilGW by DF from Table in Appendix I • ex. From Table x = 300 & Sd = 10 then DF = 15 • SoilGW3 = 0.13 * 15 = 1.95

5. MO-1: SoilGW Organic COC cont. • 5. If the SoilGW3 value from Step 4 is lower than the next more protective groundwater classification SoilGW value then use the more protective groundwater classification SoilGW value • ex. SoilGW3 = 1.95 SoilGW2 = 0.051 • SoilGW3 > SoilGW2 • Therefore, use SoilGW3 as the SoilGW value

6. MO-1: Determination of Soilsat • Soilsat = 900 = • Soilsat is not applicable to constituents that are in the solid phase at ambient temperatures (i.e., constituents having melting points less than or equal to 20o C)

7. MO-1: Determination of SoilGW for Inorganic COC • If TCLP level available: SoilGW = TCLP level * 20 • If TCLP level not available: SoilGW = GW1 * 100 * 20

8. MO-2: Determination of SoilGW Method 1-Organic COC: • 1. Identify the appropriate GW classification ex. Shallow groundwater - GW3NDW • Determine the GW value for the COC • ex. COC is Benzene, GW3NDW = 0.013 mg/l < Watersol • 2. Use GW value to calculate Csoil • ex.Csoil = 0.00668 =

9. MO-2: SoilGW Method 1-Organic COC cont. • 3. Multiply Csoil by site-specific DF • SoilGW3 = 0.00668*DAFSummers*DAFDomenico • 4. If the SoilGW3 value from Step 3 is lower than the next more protective groundwater classification SoilGW value then use the more protective groundwater classification SoilGW value • SoilGW3 = 0.00668*DAFSummers*DAFDomenico > or < SoilGW2 • If SoilGW3 > SoilGW2 use SoilGW3 • If SoilGW3 < SoilGW2 use SoilGW2

10. MO-2: Determination of SoilGW Method 1-Inorganic COC • If TCLP level available: SoilGW = TCLP level * 20 • If TCLP level not available: SoilGW = GW1 * 100 * 20

11. MO-2 Determination of SoilGW Method 2-Organic and Inorganic COC • This method may be used when the following conditions are met: • Groundwater and soil data are available, • Groundwater concentrations are less than soil concentrations, and • Groundwater data indicate the RS GW value has been exceeded

12. MO-2: SoilGW Method 2-Organic and Inorganic COC cont. • 1. Calculate site specific water/soil partition coefficient to determine SoilGW • SoilGW = (SoilSS / GWSS) * GW1,2 or 3 • GWSS & SoilSS - site-specific values (see footnotes on sample requirements p. I-49) • GW1,2 or 3 - refer to Table • 2. Multiply SoilGW by appropriate site-specific DF

13. MO-2: Determination of SoilGWMethod 3-Organic and Inorganic COC Synthetic Precipitate Leaching Procedure (SPLP) - Used to evaluate Soil Protective of GW - SW-846 Method 1312 - SPLPConcentration < (GW RS)(20)(DAF) then SoilGW is not an issue

14. MO-2: Determination of SoilGW Method 3-Organic and Inorganic COC How is the SPLP data used to evaluate the soil to gw pathway? • SoilGW1: Compare SPLP to GW1 x DFSummers • SoilGW2: Compare SPLP to GW2 x DFSummers x DF2 • SoilGW3: Compare SPLP to GW3 x DFSummers x DF3

15. MO-2: Determination of SoilGW Method 3-Organic and Inorganic COC cont’d. • If SPLP <, then screen out soil to gw pathway • If SPLP >, then delineate area of concern • SPLP vs TCLP • SPLP vs LRS