Implementation of In Situ Activated Carbon
Remedies at Contaminated Sediment Sites



MONITORING

SEDIMENT CORE PROFILING

Collecting and analyzing sediment core profiles are the single-most important tool for evaluating
amendment placement efficiency, and long-term efficacy of the amendment for HOC sequestration.
Sediment cores collected from a treatment area can be used for

  • Visual confirmation of the depth and aerial coverage of AC placement
  • Analytical measures of total and black carbon pre-placement, post-placement and LTM
  • Total bulk sediment hydrophobic organic compounds
  • Ex situ porewater measures (passive samplers)
  • Ex situ bioaccumulation testing
  • Measures for changes to benthic infaunal populations
  • Vertical measures in narrow increments (generally 2 cm) provide a means to assess mixing



The table below provides examples of the use of sediment core profiles at AC demonstration sites



Site Contaminant Year Con-structed Core Profile Project Web Link
AC Vertical and Horizontal Distribution Total and Black Carbon  Bulk Sediment HOCs Ex Situ Porewater Ex Situ Bio-accumulation Benthic Infauna
Activated Carbon Pilot Study,
Lower Duwamish Waterway, Seattle, WA		 PCBs 2017 ✔ ✔ ✔   ✔ ✔ LDWG Web Site
USN Sierra 1B Pier
Pearl Harbor, HI		 PCBs & mercury 2015 ✔ ✔ ✔   ✔   USN Sierra 1 B Case Study
Mirror Lake Restoration
Dover DE		 PCBs 2014 ✔ ✔ ✔       Mirror Lake Case Study
Puget Sound Naval Shipyard
Bremerton, WA		 PCBs & mercury 2012 ✔ ✔ ✔ ✔ ✔ ✔ PSNS Case Study
Berry’s Creek, NJ Mercury & PCBs 2012 ✔ ✔ ✔   ✔   EPA, 2013
ESTCP ER-200835
Lower Duwamish Slip 4
Seattle, WA		 PCBs 2011 ✔ ✔ ✔       Slip 4 Lower Duwamish Case Study
Canal Creek, MD PCBs & mercury 2010 ✔ ✔ ✔ ✔ ✔ ✔ Canal Creek Case Study
ESTCP ER-200835
Naval Air Station, Cottonwood Bay, Dallas TX PCBs, PAHs, chromium, lead 2009 ✔ ✔ ✔       SERDP ER-1493
NAVFAC TR-2366-ENV Technical Report
Bailey Creek, Fort Eustice, VA PCBs 2009 ✔ ✔ ✔   ✔   Bailey Creek Case Study
Grasse River, Massena, NY PCBs 2006 ✔ ✔ ✔       Grass River Pilot Project Web Site
Hunters Point 2005 Pilot Project
San Francisco Bay, CA		 PCBs & PAHs 2005 ✔ ✔ ✔   ✔ ✔ SERDP-1207
ESTCP ER-200150
Hunters Point 2005 Case Study
Abbreviations
PAH - poycyclic aromatic hydrocarbons
PCBs - polychlorinated biphenyles



Collecting Sediment Cores

There are any number of ways to collect sediment cores (see EPA's Sampling for Contaminants in Sediments and Sediment Porewater web site), but generally monitoring programs will use 2 – 4 inch diameter core tubes driven to a depth of 0 – 30 cm. These may be hand-driven, collected by divers, use of a vibra-core device, or even using a box core. The critical element is to gain a relatively undisturbed sediment sample, that can be subsectioned and/or screened to run the necessary tests.



Sediment core profiles are the only effective method for tracking the permanence and stability of the applied AC over time. At Canal Creek on the U.S. Army Aberdeen Proving Grounds, AC placed as either a slurry spray, or as AquaBlok or SediMite, the overall carbon concentration increased as a result of treatment application. The post-placement survey showed the expected increase in percent carbon, and the placement resulted in similar concentrations among treatments. Ten months after application, there was a significant decrease in the surface percent carbon concentration for all treatments.

Cores can also be fractioned into intervals and measured for black carbon and total organic carbon to evaluate the extent of vertical mixing of the carbon over time. At the Puget Sound Naval Shipyard demonstration project, three interval depths (5 cm increments) were measured for TOC and black carbon over a 33 month period. During that time, the TOC content decreased in the surface interval, while increasing in the deeper intervals.

Additional Resources

  • Sampling for Contaminants in Sediments and Sediment Porewater U.S. Environmental Protection Agency,
    Technology Innovation Program
  • Demonstration of In Situ Treatment with Reactive Amendments for Contaminated Sediments in Active DoD
    Harbors     ESTCP Project ER-201131
  • In situ Wetland Restoration Demonstration ESTCP Project ER-200825
  • Evaluating the Efficacy of a Low-Impact Delivery System for In Situ Treatment of Sediments Contaminated
    with Methylmercury and Other Hydrophobic Chemicals     ESTCP Project ER-200835
  • NAVFAC Technology Transfer Review: Sediment Reactive Capping. Naval Facilities Engineering Command.