SWMU 48, 62 and AOC G/SWMU 49 Update

Joint Base Charleston WeaponsPartnering MeetingDecember 4, 2013

Site Status Summary• SWMU 48- Southside, Building 91, Ammunition Renovation Shop

– Recommended NFA following sandblast grit removal. – Revised report including additional information submitted July 30, 2013. – DHEC requested that additional soil data be collected from locations

adjacent to piping– Field Work anticipated January 2014

• SWMU 62- Landfill Site at 1st Ave A-B– DHEC requested delineation of contaminants in soil and groundwater.– Field work anticipated January 2014.

• AOC G/SWMU 49-Former WWTP and Outfall – RFI field activities complete, RFI Report in SC DHEC review.– DHEC requested delineation of contaminants in shallow aquifer– Field work anticipated January 2014

SWMU 48- Southside, Building 91, Ammunition Renovation Shop

• Cumulative HIs for construction workers, occupational workers and adolescent trespassers were less than 1. Cyanide was below the groundwater MCL, but contributed to an HI greater than 1 for adolescent trespassers.

• Cumulative ILCRs were less than or within EPA’s acceptable range for all scenarios.

• Recommendation was made for NFA following sand blast grit removal.

SWMU 48

Planned sampling locations January 2014

SWMU 62 RFI Field Activities

• The RFI field activities were conducted in July and August 2011

• 18 soil borings were advanced- 9 surface soil samples and 19 subsurface soil samples were collected

• 4 permanent groundwater wells were installed and sampled- 3 shallow and 1 deep

SWMU 62

• Results of the RFI included risk from exposure to groundwater as drinking water, and some exceedances of human health criteria for PAHs and aroclors in soil.

• DHEC’s recommendation was to:– Take additional soil and groundwater samples to refine and verify the

extent of contamination within the boundary of SWMU 62. – Use the results to refine the LUC boundary

• Path forward includes RFI Addendum Work Plan, field event and RFI Addendum Report.

Surface soil, subsurface soil, and groundwater samples will be collected.

The data will be presented in a SWMU 62 RFI Addendum.

Based on the results:• Refine the extent of contamination

• Evaluate application of LUCs for the appropriate area in a CMS

SWMU 62

AOC G

• RFI Field activities were conducted in July and August 2011 and the supplemental field work performed in December 2011.

• 10 surface soil samples 13 subsurface soil samples were collected from 10 soil borings.

• Five permanent monitoring wells (four shallow and one deep) were installed at four of the soil boring locations in August 2011, and an additional four were installed in December 2011. Samples were collected from all wells.

AOC GNew Deep Well Installation

AOC GSampling Locations January 2014

All wells will be sampled for metals and pesticides