RESPONSE TO DEQE'S COMMENTS REGARDING WELL GD-1154 BENT'S CREEK AREA QUINCY SHIPYARD QUINCY, MASSACHUSETTS Prepared for: General Dynamics Corporation Quincy, Massachusetts Prepared by: Goldberg-Zoino & Associates, Inc. Newton Upper Falls, Massachusetts June 1989 File No. F-7400.5 Copyright* 1989 Goldberg-Zoino & Associates, Inc. GENERAL DYNAMICS Quincy Shipbuilding Division 116 East Howard Street, Quincy, Massachusetts 02169 June 2, 1989 Mr. Richard J. Chalpin, P.E. Deputy Regional Engineer Department of Environmental Quality Engineering 5 Commonwealth Avenue Woburn, MA 01801 Re: General Dynamics Corporation DEQE Case No. 3-0536 Response to DEQE's Comments Regarding Well GD-1154, Bent's Creek Area, Quincy Shipyard, Quincy, MA Dear Mr. Chalpin: On behalf of General Dynamics Corporation I am pleased to submit for your review and approval a report entitled Response to DEQE's Comments Regarding Well GD-1154, Bent's Creek Area, Quincy Shipyard, Quincy, Massachusetts, prepared by our environmental/ geotechnicai consultant Goldberg-Zoino & Associates, Inc. (GZA), in conjunction with our environmental/remediation consultant, Groundwater Technology, Inc. (GTI). The report contains extensive additional studies conducted in this area of the Shipyard by several groups of technical consultants under the direction of General Dynamics, GZA and GTl, including a facilities' historical review, test pits, a soil gas study, petroleum and groundwater analytical chemistry (fingerprinting) and well installation. The objective of this work was to address DEQE's concern as to whether previously unidentified sources of petroleum contamination were present in the Bent's Creek fill area. As discussed more fully in the report, GZA, in conjunction with GTI, after careful review of the data, has concluded that the source of intermittent separate phase oil detected in well GD-1154 and some of the other monitoring wells in the Bent's Creek area is probably product from the main plume that reached the fill area when not under the influence of the recovery system. GZA recommended that General Dynamics continue to closely monitor the area for separate phase oil. If and when detected, it will be manually removed by bailing. According to GZA, no separate phase oil was observed in the monitoring wells of the former Bent's Creek area adjacent to the Weymouth Fore River and downgradient of well GD-1154 and the test pits. General Dynamics is also reevaluating the performance and distribution Mr. Richard J. Chalpin, P.E. Page two June 2, 1989 of its recovery system, and will modify the system as necessary to enhance recovery and assure stabilization of the remaining product while recovery continues. As always, field adjustments or modifications to the recovery system will be communicated to DEQE. General Dynamics would greatly appreciate your prompt review and comment on this and the other reports on the Quincy Shipyard - by DEQE. Should you have any questions, please do not hesitate to call me. Sincerely yours, Robert F. White Manager of Operations xc: C. Barnett - MWRA L. Burt, Esq. - FH&E L. Feldman - GZA R. Lohmann - GTI Elliot Werk - GTI R. Hill - GD/CO D. McCallum, Esq. - GD/CO C. R. Stoker - GD/CO E. J. Willwerth - GD Env. Mgmt. Consultant June 2, 1989 File No. F-7400.5-C F-7400-C Mr. Robert F. White General Dynamics Corporation 116 East Howard Street Quincy, Massachusetts 02166 Re: Response to DEQE's Comments Regarding GD-1154 Bent's Creek Area Quincy Shipyard Quincy, Massachusetts Dear Mr. White: At your request, GZA has completed additional studies in the Bent's Creek area of the Quincy Shipyard. These studies were an extension of our previous work in this area, and were conducted in order to address DEQE's concern as to whether a previously unidentified source of petroleum contamination was present in the Bent's Creek fill area. As discussed in the report, GZA's studies did not indicate the presence of such a source. The Bent's Creek study area of the Quincy Shipyard is located adjacent (northeast) to the central yard separate phase oil area, where Groundwater Technology, Inc. (GTI) has been performing passive oil recovery since August 1986 and active oil recovery, including groundwater pumping and treatment since October 1986. GTI's work has been conducted with the approval of the DEQE. GTI routinely monitors (on a weekly basis) certain monitoring wells in the Bent's Creek area for the presence of separate phase oil as part of the ongoing central yard oil recovery system monitoring program. The former Bent's Creek was once used as a wet basin which emptied into the Weymouth Fore River until the early 1940s when the creek was completely filled and diverted via a storm drain to the River. GZA's additional studies in this area included a field exploration program which incorporated the excavation of test pits by GTI, a soil gas survey by NERI/Petrex, sampling and analysis of existing wells, review of the existing central yard oil recovery system, installation of additional borings with wells, measurement of groundwater levels and separate phase thicknesses, and sampling and analysis of soils and groundwater. General Dynamics Corporation - June 2, 1989 File No. F-7400.5 - Page 2 The separate phase oil that has been observed by GTI in the previously installed monitoring wells and tests pits in the former Bent's Creek area indicated minor and intermittent amounts of separate phase oil. The separate phase and dissolved petroleum hydrocarbons (PHCs) that were detected during the present study and previous studies consisted of a mixture of slightly weathered and moderately weathered No. 2 fuel oil, with some occurrences of No. 4 and No. 6 fuel oils. The No. 2 oil fingerprint was similar to that of the central yard area, which suggests that separate phase oil from the central yard area migrated into the Bent's Creek Area, probably prior to the installation of GTI's oil recovery system. The review of GTI's 27 monthly monitoring reports indicates that the northern edge of the central yard oil plume (in the vicinity of Bent's Creek) has generally been under control with the seven GTI recovery wells operating, although small amounts of separate phase oil could potentially have migrated into the Bent's Creek area. Another potential source of No. 2 fuel oil detected in the Bent's Creek area could be from a fuel oil line which ran from Building 53 (aboveground storage tanks) north across Bent's Creek to Building 8. This line was decommissioned in 1964 by GD, and removed in August, 1986, from the aboveground storage tanks to Building 95 by Clean Harbors, Inc. However, GD personnel did not observe any obvious leakage when this section of pipe was removed. Two possible sources of the No. 4 and No. 6 oil have been identified. The first is the use of contaminated material in the filling of Bent's Creek. The second possible source is the former powerhouse located in the western portion of the current machine shop (Building 11) which was fueled by No. 6 fuel oil and stored in the aboveground storage tanks at Building 53. The former powerhouse was demolished in 1940, and was possibly incorporated into the fill material for Bent's Creek. During this study, no separate phase oil was observed in the monitoring wells of the former Bent's Creek area adjacent to the Weymouth Fore River and downgradient of well GD-1154 and the test pits. In summary, GZA's additional work has indicated that the occurrence of separate phase oil is minor and intermittent within the Bent's Creek area. The separate phase oil detected in the Bent's Creek area may have come from the central yard area, contaminated fill, and/or past tanks or lines at the shipyard. However, the data does not indicate the presence of any new sources for this contamination. General Dynamics Corporation - June 2, 1989 File No. F-7400.5 - Page 3 GZA recommends that previously selected and newly installed wells in the Bent's Creek area continue to be monitored for separate phase oil; if separate phase oil is detected it should be manually removed by bailing the monitoring well. It is GZA's understanding that GD is planning to re-evaluate the central yard oil recovery system as part of its continuing efforts to fine- tune the system, if necessary, to optimize the rate of oil recovery. Any recommended system modifications and/or additions to the oil recovery system will be presented to DEQE. The study was conducted by the undersigned as well as William Morse and Sara Faldetta. GZA has appreciated the opportunity to work with you on this project. Please contact the undersigned for any questions or discussion. Very truly yours, GOLDBERG-ZOINO & ASSOCIATES, INC. Paul F. Reiter Christopher W. McDermott Project Reviewer Project Manager Lawrence Feldman Senior Associate CWM/LF:bsr Attachment: Report TABLE OF CONTENTS Page 1.00 INTRODUCTION 2.00 BACKGROUND 2.10 STUDY AREA DESCRIPTION 2.20 MONITORING WELL GD-1154 OBSERVATIONS 3.00 REVIEW OF EXISTING SEPARATE PHASE OIL RECOVERY SYSTEM 4.00 FIELD EXPLORATION AND LABORATORY TESTING PROGRAM 4.10 TEST PITS 4.20 NERI PETREX SOIL GAS SURVEY 4.30 GROUNDWATER SAMPLING AND OBSERVATIONS OF EXISTING MONITORING WELLS 4.40 TEST BORINGS/MONITORING WELLS 4.41 Measurement of Groundwater Elevations and Separate Phase Oil Thickness 4.42 Soil Screening and Laboratory Analyses 4.43 Groundwater Sampling and Laboratory Analyses 5.00 HYDROGEOLOGIC SITE CHARACTERIZATION 5.10 SUBSURFACE CONDITIONS 5.20 GROUNDWATER FLOW DIRECTIONS 5.30 SEPARATE PHASE OIL ASSESSMENT 6.00 CHEMICAL SCREENING AND ANALYTICAL RESULTS 6.10 TEST PITS 6.11 Soil 18 6.12 Separate Phase Oil 18 TABLE OF CONTENTS (CONT'D) Page 6.20 NERI/PETREX SOIL GAS SURVEY 18 6.30 EXISTING MONITORING WELLS 19 6.40 NEWLY INSTALLED SOIL BORINGS AND MONITORING WELLS 19 6.41 Soils 19 6.42 Groundwater 20 7.00 SUMMARY AND CONCLUSIONS 20 TABLES TABLE NO.