1. Melissa Boggs California Department of Fish and Wildlife, Office of Spill Prevention and Response

2. GUADALUPE OIL FIELD

3. Guadalupe Oil Field

7. 5X Plume History January 1988 & February 1990 hydrocarbons observed in sand & surf. March 1990 Union Oil installed subsurface soil/bentonite slurry wall, and diluent recovery wells at 5X site. 1990 groundwater monitoring activities initiated. Determined TPH-affected soil extended from former oil production well 5X located on the Beach. 1990 – 1994 multiple environmental site assessments. 1990-1995 950,000 gallons diluent recovered with recovery wells.

8. 5X Plume History January & April 1994, hydrocarbon releases observed in surf zone at 5X site. April 1994 USCG issues OPA Administrative/Directive Order to remove pollution threat. USCG approves IAP to excavate the subsurface contamination.

9. 5X Plume History Objectives of the IAP included the following: 1. Remove & remediate diluent containing beach sand to prevent further release to the ocean. 2. Recover mobile diluent to prevent further releases. 3. Replace diluent containing sand with acceptable clean sand. 4. Restore area to its natural state. 5. Develop long-term upgradient management plan.

10. 5X Plume History September 1994 western-most portion of 5X plume excavated (approx. 900’ long X 300’ wide X 20’ deep). 250,000 gallons diluent recovered. Excavation inundated by high tides & storm surges; backfilled early.

11. 5X Plume History March 1995 USCG issues letter stating Unocal complied with Order. 1995 and early 1996 post- excavation site assessment of residual TPH-containing soils.

12. 5X Plume History 1998 RWQCB issues CAO. 1999 and 2001 two additional excavations (5X West and 5X East). Combined, 3 5X excavations removed 438,000 cy TPH affected soil. 1990 – 1995 recovery wells removed approximately 950,000 gallons of diluent from under the beach.

13. 5X Revisited March 2010 fisherman reported smelling hydrocarbons on beach. 2010 sand crabs sampled; concentrations similar to 1994; OEHHA concluded levels below health concern for a fish closure. Since 2010 sheen observed on 5 days, last in Jan. 2011.

14. 5X Revisited

15. Since 2010 5X has been further delineated and monitored: 12,000 cy contaminated sand remains 20,500 cy clean overburden West edge not delineated TPH concentrations from 10 – 4400 ppm

17. 5X Revisited

18. Based on beach profiles beach has receded to the east. SCM concludes erosional events causes releases of subsurface contaminated sand.

19. 5X Revisited

21. Surf samples 37 of 149 samples had hits.052 – 1.5 mg/L Interstitial water 81 of 149 samples had hits from.062 – 1.6 mg/L PAHs detected in 4 of 24 water samples

22. 5X Revisited October 2013 FS evaluated remedial alternatives: No action* Monitored Natural Attenuation (MNA)* Limited source removal with MNA* Source removal Enhanced biodegradation Chemical oxidation In-situ treatment (thermal treatment, soil mixing, or solidification) Beach sand replenishment.

23. 5X Revisited

24. Any questions?