A range of data collection activities (soil sampling, synoptic groundwater events at ~200 wells, Membrane Interface Probe [MIP] sampling, seismic refraction surveys, etc.) performed over nearly 10 years failed to completely identify the sources or adequately delineate the nature and extent of CVOCs in soil and groundwater at Site 16 at the Former Naval Construction Battalion Center, Davisville. To address significant data gaps, a high-resolution vertical profiling study was performed employing the Color-Tec® test kit method to screen soils from DPT soil borings across the site. Beginning with an initial variably-spaced coarse grid (biased based on previous investigations), a dynamic work strategy (DWS) was used to refine the CSM based on real-time data collection. Approximately 1,300 discrete soil samples were collected from approximately 150 soil borings. Discrete soil samples were collected from continuous soil cores every 5 feet at most locations with more frequent soil samples collected based on observed lithologies and photoionization detector (PID) responses. The Color-Tec® results provided semi-quantitative results to guide immediate decisions for the subsequent placement of soil borings and the delineation of impacted/non-impacted areas. Approximately 400 soil samples spanning the full range of Color-Tec® results were sent to a fixed-base laboratory for analysis. Comparison of analytical results to the Color-Tec® results demonstrated a significant site-specific correlation allowing for identification of source areas not previously identified and significant refinement to the lateral and vertical extent of the soil and groundwater plumes. Based on the relatively low-cost ($10 per sample), a high-resolution vertical profiling study was completed in real-time; significantly more soil samples were analyzed than could be analyzed using a conventional fixed-base laboratory approach, resulting in a better defined understanding of the nature and extent of the CVOC plumes.
|Site Name||Naval Construction Battalion Center (NCBC) Davisville, Site 16|
|Location||North Kingstown, RI|
|Site Type||Naval Shipyard|
|Site Regulatory ID||EPA ID #: RI6170022036/ Site ID #: 0101430|
|Project Lead Organization||U.S. Navy, EPA Region 1, and Rhode Island Department of Environmental Management (RIDEM)|
|Project Lead Type||U.S. Navy Lead|
|Regulatory Lead Program||Superfund Remedial|
|Reuse Objective Identified||Yes|
The former Davisville Naval Construction Battalion Center (NCBC) is located 18 miles south of Providence, RI in North Kingstown and covers approximately 900 acres. Serving as a military installation since 1942, its primary mission was to provide mobilization support to Naval construction forces. Much of the NCBC-Davisville Site is contiguous with Narragansett Bay and consists of four areas: the Main Center, the West Davisville storage area, Allen Harbor area, and the Pier Support area. Site 16 is located in the eastern portion of the Allen Harbor area (“Zone 3”).
The north-central portion of Site 16 is primarily wooded with the exception of an asphalt-paved area in the center, and was formerly used by the Navy for training construction equipment operators. In the past, this area was extensively bulldozed and disrupted during training exercises, but it now has a vegetative cover of trees, shrubs, and grasses. Site 16 slopes gently from approximately 30 feet above mean sea level (MSL) to MSL along the Narragansett Bay shoreline toward the east and southeast. This area includes an old railroad spur area, other buildings and facilities to the south and east, and the former Building 41 area. The surface of the old railroad spur area previously included railroad tracks, weathered asphalt paving of former roads, and grasses and shrubs. However, this area and much of the open, previously undeveloped area to the east/southeast of the former Building 41 was paved during the summer of 2007. The Building 41 area has been the focus of most recent investigation activities. It was a preservation and packing shop and a construction equipment and automotive parts storage building. Preservation and degreasing operations occurred within the building. Based on past activities, it is likely that petroleum products and solvents were used and stored within Building 41. It was demolished and paved over in October 2002, and is currently being used for the temporary storage of new cars delivered by ship pending delivery to dealers.
The preservation tanks used within Building 41 were remediated under the Navy’s underground storage tank (UST) program. Stained asphalt floors observed during the Phase II Environmental Baseline Survey (EBS) were not considered to be of concern based on the limited extent of the staining, sorptive ability of asphalt, and lack of a direct pathway for exposure of humans or ecological receptors to associated contaminants (e.g., spill runoff from the concrete to a foundation wall or soil). No floor drains were located in Building 41. The floor staining was considered to be consistent with the previous use of the building as an equipment preservation and packing shop and for parts storage. Consequently, the Davisville BRAC Cleanup Team (BCT) recommended no further action (NFA) following a review of available Phase II EBS information and site visits conducted in conjunction with other stakeholders. No field activities were conducted and no samples were collected during the EBS or EBS follow-on activities based on the BCT recommendation for NFA.
Subsequent to the EBS, however, discussions occurred with a Seabee veteran (November 2000), who worked in Building 41 from 1951 to 1953, to improve the Navy’s understanding of the historical use of the building. Additionally, Navy representatives accompanied the Seabee veteran on a visit to the building in February 2001. According to this veteran, rust removal (using heated manganesed phosphoric acid or Phospholene), metal preservation (using Cosmolene, particularly for Quonset Huts), and degreasing operations in Building 41 (using chlorinated solvents and a solvent recovery still) were conducted during the 1950s. Since the 2001 site visit, significant further remedial activities have been performed at Site 16, including a Phase I/II RI, supplemental investigation and risk assessment studies, soil removal actions and a pilot study to assess reductive dechlorination of CVOCs. The stakeholders determined that significant data gaps concerning the nature and extent of CVOCs remained after these activities, requiring a Phase III RI.
Additional site background and CSM information is available in the presentation slides from the Triad Conference convened at the University of Amherst in June 2008 that can be linked to from this Profile (see Sources of Information section below).
Results of Investigation – the high-density Color-Tec® data set generated from the DWS field investigation revealed the following:
Results on Use of Color-Tec® – collaborative fixed-base laboratory data indicated the following:
Significant data gaps would likely still occur if Color-Tec® had not been used to perform an HRSC and the vertical distribution and comprehensive extent of the plume would not be known. The best samples for fixed-base laboratory analysis may not have been selected based on PID alone; PID and Color-Tec® helped identify the best samples.
Benefits included real-time decisions based on a DWS; cost and time savings by eliminating the need for fixed-based laboratory with rapid turn-around-time (TAT) and equipment and personnel stand-by; and higher density data due to lower cost of analysis.
Additional cost and time savings were realized from the use of Color-Tec® by reducing or avoiding other project efforts such as 1) preparation and validation of fixed-based laboratory analytical data packages, 2) preparation of Quality Assurance Project Plan (QAPP) and Work Plan Addenda for follow-on investigation activities, and 3) additional field mobilizations and fixed-base laboratory costs associated with follow-on investigations to address data gaps. Color-Tec® data cost is 10% or less of the cost of fixed-based laboratory data and can further reduce or eliminate costly future additional investigation phases.
A baseline CSM had been framed from previous investigations. The intent of the Triad-based HRSC was to address data gaps in the CSM, mostly concerning the nature and extent of contamination, using field test kits and a DWS.
Uncertainty was managed by modifying the sampling design on a real-time or near real-time basis to fill data gaps as needed. Additional field test kits were available to sample at intervals necessary for contaminant delineation – as defined by decision logic.
U.S. Navy and its contractor Tetra Tech made decisions based on screening data with limited concurrence as needed from EPA Region 1 and RIDEM. Additional work was performed while the field crew was mobilized based on the understanding of nature and extent of contamination gained from the field screening efforts (for example, a constant rate test performed to evaluate interconnectedness of various aquifer zones in overburden near an apparent source area).
The principal decision makers for the site were from the U.S. Navy, EPA Region 1, and RIDEM. Other stakeholders included Tetra Tech.
The U.S. Navy held bi-weekly conference calls for all principal decision makers to discuss and review new data results and propose modifications as necessary to the scheduled work. Tables and figures were provided to support discussions and decisions. Data was shared in as "real-time" as possible through use of EPA Region 1 web site set-up specifically for information sharing.
The DWS included the following elements:
Dynamic field investigation data were routinely shared with BCT members including EPA Region 1 and the State of Rhode Island via weekly e-mail updates, bi-weekly Triad teleconferences, and posting of field data to the EPA-host site. At these times, Color-Tec® screening results were submitted to Project Stakeholders for review and discussion to select additional locations of borings for Color-Tec® analysis and monitoring well installation.
Color-Tec® screening data were used to make real-time investigative decisions, such as the selection of soil samples from intervals within a boring for fixed-base laboratory analysis, where the next step-out boring should go, where a monitoring well should be placed, and what its screened interval should be.
Correlative analysis was performed between Color-Tec® and fixed-base laboratory results. Fixed-base laboratory results indicated that Color-Tec® gave a 98% success/match rate for total CVOC detection, and an 86% success/match rate for Color-Tec® CVOC non-detects. In this respect, the Color-Tec® kits correlated well with the comparative fixed-base laboratory results. Relative contaminant mass values reported from the kits further were highly useful in hot spot identification/ delineation and the selection of step out sampling locations and permanent well locations.
Full quantitative correlation analyses between the Color-Tec® and fixed-base laboratory methods were not performed due to differences in the nature of the methods, nor are such quantitative correlations recommended by the Color-Tec® vendor. Thus, it is important to understand the nature of the methodology and how it is best used to make "positive" and "negative" decisions concerning potential contamination with added delineation information based on the relative contaminant mass values reported by the kits.
TQRS not prepared
Quality control (QC) was attained through a rigorous sample collection and handling routine. Sample vials (40 ml volatile organic analysis [VOA] vials, pre-cleaned, no preservatives) were pre-marked to a standard fill line to ensure uniform head space volumes. A uniform amount of soils was added to each sample container from a soil syringe. Samples were distributed between the two or four Color-Tec® vials so that small zones of contamination were not missed (three syringes per sample vial were needed). Samples were collected immediately after pre-scanning with PID when the DPT sleeve was cut open, with samples taken from internal portions of the recovered DPT core where minimal disturbances occurred.
Duplicate samples were collected at a rate of approximately 1 per 20 samples. As warranted, when sample results approached the upper concentration limit of one colorimetric tube, a higher range colorimetric detector tube was exposed to make sure the result was accurate.
For groundwater, quality assurance/quality control (QA/QC) kits were used to confirm that the technique was working, but these samples were not submitted to the fixed-base laboratory.
The primary data quality assessment came from the comparison of the paired samples from Color-Tec® to the fixed-base laboratory results.
Data tools and inputs:
Logging and tracking data was conducted electronically as data were collected using a Panasonic ToughBook field computer. As discussed previously, field data were reviewed and made available to the project team and stakeholders by posting to an EPA-hosted web site.
Placed on the National Priority List (NPL) of sites in 1989.
Federal Facilities Agreement executed in 1992.
EBS Investigations: 1996 – 1998
Phase I Remedial Investigation (RI): 1999 – 2001
Phase II RI: 2002 – 2003
Phase II Screening Level Ecological Risk Assessment (SLERA): 2004
Supplemental Phase II Study and reductive dechlorination Pilot Study (Hydrogen Release Compound®): 2004
Two soil removal actions have also been conducted in the North Central area of Site 16 (PAH contamination).
Pre-Phase III Investigations included:
All field work for the Phase III RI was performed over a 4 to 6 month period in Fall 2007 and Spring 2008
|EPA Waste Cleanup and Reuse website|
|Vertical Profiling Using the Color-Tec® Method to Identify Source Releases and Delineate CVOC Soil and Groundwater Plumes at the Former Naval Construction Battalion Center Davisville in North Kingstown, Rhode Island (3,461 KB)|
To update this profile, contact Cheryl T. Johnson at Johnson.Cheryl@epa.gov or (703) 603-9045.