Re: Response to NC DEHNR Comments on the Draft REmedial Investigation Report for Operable Unit 1, MCB Camp Lejeune, North Carolina

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1 J. (804) :LGB:srw CERTIFIED MAIL RETURN RECEIPT REQUESTED North Caroina Department of Environment, Heath, and Natura Resources Attn: Mr. Patrick Watters P.O. Box Oberin Road Raeigh, North Caroina Re: Response to NC DEHNR Comments on the Draft REmedia Investigation Report for Operabe Unit 1, MCB Camp Lejeune, North Caroina Dear Mr. Watters: Encosed pease find responses to NCDEHNR comments on the above referenced documents dated March 23, Responses to these comments were discussed during the meeting hed on May 3, 1994 at EPA Region IV offices. Any questions concerning these responses shoud be directed to Ms. Linda Berry at (804) Sincerey, Encosure Bind +=I823 copy (LGB) to: 2 copies w/encjs) 18s LGBDoc: minutes f:\home\berryg\ou\dfncco.doc L. A. BOUCHER, P.E. Head Instaation Restoration Section (South) Environmenta Programs Branch Environmenta Quaity Division By direction of the Commander Copy to:(w/enc) EPA Region IV (Ms. Gena Townsend) MCB Camp Lejeune (Mr. Nea Pau) Baker Environmenta (Mr. Ray Wattras, Ms. Tammi Haapin)

2 Response to Comments Submitted by NC&ZNR on Draft Remedia Investigation Report for Sites 21, 24, and 78 (Operabe Unit No. ), MCB, Camp Lejeune, North Caroina Comment Letter by Mr. Patrick Watters dated March 23, 1994 RESPONSE TO SPECIFIC COMMENTS 1 THROUGH The recommendations presented on page ES24 wi be revised to indicate that the deeper aquifer may require remediation or ongterm monitoring. The figure wi be revised to incude the ocation of the two wes. A note wi be added to indicate that wes 24GW05 and 24GW07 no onger exist, and that we 24GW07 was ater reinstaed at a different ocation. Tabe 1 and Figure 16 wi be revised to match each other. Tabe 3 wi be revised. A sentence wi be added indicating that the data from Site 22reated monitoring wes wi be considered in the RI. suppy wes wi be shown where appicabe on Figures 3 through 5. Due to the size of Site 78 (HPIA) and the number of faciities, it woud be difficut to consider the entire HPIA drainage system for this RI. Most of the drainage is infuenced by storm water drainage systems aong the reads and buidings For purposes of this RI, the groundwater investigation shoud be adequate to identify potentia source areas. The text wi be changed per the comment. Tabe 21 wi be revised to incude areas of concern indicated on Figure 3. The focus of the investigation at Site 21 was to evauate impacts from pesticide and PCB disposa. Since these contaminants are not very mobie in the environment, the instaation of deep monitoring wes is not practicabe. The deeper aquifer which underies Site 21 is the same aquifer which underies Site 78. Athough there are no deep monitoring wes at Site 21, there are severa existing deep wes at Site 78 which are ocated adjacent to the Site 21. The source of the VOC contamination in the shaow groundwater at Site 21 originated from Site 78 and is not

3 reated to disposa activities at Site Based on site history and recent groundwater samping resuts for deep suppy wes in the area (Apri 1993), the deep groundwater at Site 24 is not impacted by eevated concentrations of contaminants. Accordingy, deep monitoring wes were not instaed at the site. The scope of work for the soi investigation at Site 78 focused on the buidings identified on the tabe ony. A soi gas survey, however, was conducted throughout the site at a number of the buidings identified as potentia sources of contamination. Pease refer to Figure 2 for the ocations of the soi gas sampes. Tabe 23 wi be modified to incude an investigation of the intermediate and deep groundwater at Site 78. Figure 2 wi be modified to incude Buidings 1106, 1205, 1604, and Buiding 1480, however, was not a buiding targeted for soi gas sampes. The area identified on Figure 3 as "probabe refuse (1944) n was based on interpretations from the EPIC study. Because the area was identified as "refuse" and not "stained" or "ground scar", it was assumed that the area contained surface debris, most ikey garbage or scraps. Accordingy, the area was not investigated since the "refuse" was most ikey unreated to the pesticide disposa. Buiding 902 which is identified on Tabe 23 shoud be 903. This change wi be made on the tabe. Buiding 1608 was added to the RI during the fied program because of its cose proximity to Buiding 1601 and, therefore, was not considered as part of the origina study. Accordingy, it was not incuded on the tabe. Athough manganese was detected at concentrations above basespecific background eves in surface sois at Site 21, it is not beieved that a source of the is manganese is reated to site activities (i.e., pesticide and PCB disposa). Concentrations of this magnitude are not uncommon at the Base. This section wi be modified to incude a discussion of PCBs in the sediment. The buidings within HPIA were previousy investigated by ESE via a records search and site visits (Characterization Step Report). In addition, athough some of the individua faciities were not investigated (through a soi investigation) during this RI, the groundwater at HPIA was evauated over a arger portion of the area.

4 . F 18.. No text changes made. Agree that the decrease in contaminant eves in the shaow aquifer coud be due to the vertica migration of contaminants. The resuts from the wes samped in December 1993 appear to agree with this trend. i 19. The paragraph wi be revised. 20. The paragraph wi be revised. 21. The sentence wi be revised. 22. A copy of the EPIC photographs wi be submitted to the NC DEHNR in the next version of the report.

5 I I I :.: 1 aunr (It i: ;.,. '008C 4 Sd G SENDER:.z,,, Compete items 1 and/or 2 for additiona services. I aso wish to receive the Compete items 3. and 4a & b. foowing services (for an extra g iz L Print your name and address on the reverse of this form so that we can. fee): Q, return this card to you. e I 2 Attach this form to the front of the maipiece, or on the back if space 1.q Addressee s Address $ L does not permit. 2 Write Return Receipt Requested on the maipiece beow the artice number. 2. q Restricted Deivery E y The Return Receipt wi show to whom the artice was deivered and the date 5 deivered. Consut postmaster for fee. E 4a. Artice Number rr! o 3. Artice Addressed to: i NC DEPT OF ENVIRONMENT HEALTH g AND NATURAL RESOURCES 8 MR PATRICK WATTERS % PO BOX ; g 401 OBERLIN RD $ RALEIGH NC I z pc 5. Signature (Addressee) 3 i g 6. Signature (Agent) 3 % PS Form 3811, December 1991 *U.S. GPO: u, P b. Service Type q Registered 0 Insured B Certified 0 COD 0 ~~~~~~~ Mai1 q Return Receipt for Merchandise 7. Date of Deivery 8. Addressee s Address Onv if requested G and fee is paid) f c DOMESTIC RETURN RECEIPT b a