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Home My WebLink AboutNCD991278953_19980716_National Starch & Chemical Corp._FRBCERCLA RA_Response to US-EPA NRML and NC-DENR Comments on Phase I Natural Degredation Treatability Study Report OU-4-OCRI I I t2l ENVIROGEN New Solutions to Hazardous Waste Problems Prim:cton Research Center 4100 Qua kcrbridg.c Road La\vn:1Kcvilk. New Jersey OS(,4S Td: WlJ/9.Hi-9300 Fax: 60lJj(J36-922 l I .lulyl6,1998 I I I I I I I I I I I I I I I Mr. Jon Bomholm Remedial Project Manager United States Environmental Protection Agency Waste Management Division Atlanta Federal Center 100 Alabama Street, S.W. Atlanta, Georgia 30303-3104 RECEIVED JUL 2 7 1998 SUPEAFUND SECTION Subject: Response to USEPA Region IV, USEPA NRMRL, and NCDENR Comments Phase I Natural Degradation Treatability Study Report for Operable Unit 4 National Starch and Chemical Company Cedar Springs Road Plant Site Salisbury, North Carolina Dear Mr. Bornholm: On behalf of National Starch and Chemical Company (NSCC), ENVIROGEN, Inc. is transmitting herewith (7) bound and one (1) unbound copy of responses to Agency comments on the Draft Phase I Natural Degradation Treatability Study (NOTS) report. Specifically, this document responds to the May 26, 1998 comments and suggestions of the USEP A Region IV and NRMRL, and the NCDENR. In addition, this document addresses issues discussed during the conference call of July 9, 1998. As agreed upon during the conference call, results of the Phase II laboratory study (Blue Planet Technologies Phase 11 BIOreport™ #1060 dated November 19, 1996 and revised March 5, 1998) have been omitted from the Phase I NDTS report. Accordingly, comments concerning this report have not been addressed. The Phase I NOTS report incorporating these responses will be included as an appendix to the Phase II NOTS report. The literature review discussed during the July 9, 1998 conference call will be provided under separate cover by July 31, I 998. Upon review of the enclosed document, NSCC would like to schedule a meeting in August 1998 to discuss the scope of work for Phase I! of the NOTS. Please feel free to call me ifthere are any questions. l·.N\'IJ{()(;J-.'N is o /1'.rhnology /)(lsfri 1:1111inmn11:11tal J)'Sl1:m a11d .w:rvin:,, r:11111/HUI_)' derficataf lo solving industrial 1/jl1wnt and l11r: .. llrri"11s 1N1Sl1: ro11t:11i(lfion J1mb/1:111s. I I I I I I I I I I I I I • I I I I I Mr. Jon Bornholm July I 6, 1998 Page 2 of2 Sincerely, ENVIROGEN, INC. ~& ~~~ Stewart Abrams, P.E. Mid-Atlantic Operations Manager cc: Richard Franklin, NSCC Michael Ford, NSCC Alex Samson, NSCC 78504\corr\RspcvrO.doc f)ENVIROGEN I I I I I I I I I I I I I I I I I I I RESPONSE TO COMMENTS BY USEPA REGION IV USEPANRMRL NCDENR ON DRAFT PHASE I NATURAL DEGRADATION TREATABILITY STUDY FOR OPERABLE UNIT 4 CEDAR SPRINGS ROAD PLANT SITE SALISBURY, NORTH CAROLINA ENVIROGEN, INC. 4100 Quakerbridge Road Lawrenceville, New Jersey 08648 (609) 936-9300 July 16, 1998 I I I I I I I I I I I I I I I R I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 USEPA REGION IV -COMMENTS PHASE I NATURAL DEGRADATION TREATABILITY STUDY REPORT .................................................................................................................................................................... 12 GENERAL COMMENT .............................................................................................................................................. 12 Con1111ent No. I:..................................................... . ........ 12 Response No. I:. . ........................................................... 12 EXECUTIVE SUMMARY ........................................................................................................................................... 12 Conunent No. 2: .......................................... . ............... 12 Response No. 2:......................................... .. ............... 12 Conunent No. 3: .......................................... . ............... 12 Response No. 3:................. .. ...................................................... 13 Comment No. 4: ... 13 Response No. 4 .... 13 RESPONSE TO REGULATORY COMMENTS ................................................................................................................ 14 Comment No. 5: .. 14 Response No. 5: 14 Comment No. 6: J 4 Response No. 6 ....................... 14 Comment No. 7: ....................... / 4 Response No. 7:. . ... /4 Comment No. 8: ................................ / 4 Response No. 8: .................. 15 Comment No. 9: ................. 15 Response No. 9: .. 15 PHASE 1 NATURAL DEGRADATION TREAT ABILITY STUDY REPORT FOR OU #4 ..................................................... 15 Comment No. JO: ........ 15 Response No. IO ... 15 Comment No. 11: 15 Response No. 1 I ............. 15 Comment No. 12:. 15 Response No. 12 ......... 1 5 Comment No. 13: Response No. 13: ..... Comment No. 14: Re.\ponse No. 14: Comment No. 15: Response No. 15 Comment No. 16: Response No. 16 Comment No. 17: Response No. 17: ....... . Comment No. 18: ............ . Response No. 18: ................................ . Comment No. 19: ......................... .. Response No. 19: ...... . Comment No. 20: .......................... . Response No. 20 Comment No. 21: Response No. 21 Comment No. 22: Response No. 22: Comment No. 23: Response No. 23: Commellt No. 24: Response to Comments -Phase I NOTS (final) ........ 16 .. 16 .... 16 .... 16 ... 16 16 .... 17 ................ 17 ........................................................................ 17 . ............... 17 . .................................................... 17 . ........................................................................... 17 .. ............ 17 .. ....... 17 . ........................... 17 ......... 17 .. 18 ......... 18 ..... 18 ....... 18 ........ 18 ............. 18 .... /8 July 16. 1998 I I I I I I I I I I I I I I. I I I I I NSCC Response to Comments on Phase I NOTS ENVIROGEN Project No. 78504 Response No. 24: ................ . Comment No. 25: Response No. 25 Comment No. 26: Response No. 26:. Comment No. 2 7: Response No. 27: ........ . Comment No. 28: ... . Response No. 28:. Comment No. 29: Response No. 29: .......... . Comment No. 30: . Response No. 30: ... Comment No. 31: Response No. 3/:. Comment No. 32: Response No. 32: Comment No. 33: Response No. 33 Comment No. 34: .. Response No. 34 Comment No. 35: Response No. 35 Comment No. 36: Response No. 36: Comment No. 37: Response No. 3 7 Comment No. 38: Response No. 38 Comment No. 39: Response No. 39 Comment No. 40: Response No. 40: Comment No. 41: Response No. 41: .... Comment No. 42: Response No. 42 Comment No. 43: Response No. 43 Comment No. 44: .... Response No. 44 Comment No. 45: Response No. 45 Comment No. 46: Response No. 46 Comment No. 4 7: Re.,ponse No. 47: Comment No. 48: Response No. 48:. Comment No. 49: Response No. 49 Comment No. 50: Response No. 50 Comment No. 51: Response to Comments -Phase I NDTS (final) 2 . ........................ /8 . . ... 18 ................ 18 ·············· 19 ··············· /9 .... 19 ·················•········· /9 ································· 19 ························•························ /9 ···············•·· /9 ······················································ 20 ········•································ 20 ··························· 20 ·················· 20 ··················· 20 ···························· 20 ································· 20 ············· ························ 20 ·············· 20 . ............. 20 .... ········ 21 ········ 21 ...... 21 21 ... 21 2/ .. ··················· 21 .................. 21 ............... 2 I ................ 22 ············· 22 ······································· 22 .. ························ 22 ............. 22 . ............... 22 ······················ 22 ············· 22 ····················· 22 ·········································· 22 ········································· 22 ........... ··································· 23 ································· 23 ···················· 23 ·································· 23 ················· 23 ························ 24 ··················· 24 ···················· 24 ········· 24 .... 24 .... 24 .......... 24 ···················· 24 ·········· ...... ............ 24 July I 6, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 Response No. 51: ................... . Comment No. 52: Response No. 52: ........................ .. Comment No. 53:. Response No. 53: ... Comment No. 54: ···························•······· 24 ·············· ... 24 . ............................. 25 .. .......................... 25 . .................................. 25 ............................................................. 25 Response No. 54:.... . ............................................ 25 Comment No. 55: ...................... 25 Response No. 55:.......................... .. 26 Comment No. 56: ........................ 26 Response No. 56 ................. 26 Comment No. 5 7: ...................... 26 ReJJHJnse No. 57 .. 26 Comment No. 58: ...................... 26 Response No. 58:.................................................... . ........... 26 TABLES .................................................................................................................................................................. 26 Comment No. 59: .. 26 Response No. 59 Comment No. 60: .. Response No. 60:. Comment No. 6/: Response No. 6/: Comment No. 62: .............. 27 .. ................ 27 . ......... 27 ..................... 27 ···················································27 .... 27 Response No. 62 ........... 27 Comment No. 63: ........... 27 Response No. 63 ..... 27 APPENDIX A -BLUE PLANET TECHNOLOGIES PHASE l B!OREPORT™ 111060, DATED SEPTEMBER I 7, 1996 ......... 28 Comment No. 64: ... . ..................................... 28 Response No. 64 .... 28 APPENDIX A -BLUE PLANET TECHNOLOGIES PHASE II BlOREPORT™ #I 060,DATED NOVEMBER 19, !996 (AND REVISED ON MARCI I 5, 1997) ................................................. .. ..................................... 28 Comment No. 65: 28 Response No. 65: ........ 28 Comment No. 66: ...... 28 Response No. 66:..... . 28 Comment No. 67: ... 28 Response No. 67 ............... 29 Comment No. 68: ... 29 Response No. 68:....... . .... 29 Comment No. 69: ......... 29 Response No. 69: .. 29 COMMENTS FROM NATIONAL RISK MANAGEMENT RESEARCH LABO RA TORY ........................... 30 GENERAL COMMENTS ......................................... 1 ................................................................................................... 30 Co1111nent No. I: . . ...................................................... 30 Response No. /:.... . ......................................... 30 Comment No. 2: ....... . ... 30 Response No. 2: ......................................... 30 Comment No. 3: ............................. 30 Response No. 3:.. ... 31 SECTION 2 -LABORATORY BIOTREATABILITY STUDY (LBS) ............................................................................... 3 ! Comment No. 1: ..... 31 Response No. l ........................... 3/ Comment No. 2: ················· 31 Response to Comments -Phase I NOTS (final) 3 July I 6, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NOTS ENVIROGEN Project No. 78504 Response No. 2: ............ . .. 31 Comment No. 3: .............. .. 3 I Response No. 3: ..... 32 SECTION 3 -SOIL PLOTS AND SOIL GAS MONITORING WELLS .............................................................................. 32 Comment No. I:. . .... 32 Response No. /: ........... . Comment No. 2: ............. . Response No. 2: Comment No. 3:. Response No. 3: .. Comment No. 4: .. Response No. 4:. Comment No. 5: Response No. 5: Comment No. 6: .. ........... 32 . ............ 32 32 ......... 32 ········ 32 . ........ 32 . .......... 32 ······ 32 ... 33 . ····················· 33 Response No. 6:. . .... 33 SECTION 4 -TREATMENT AND MONITORING ACTIVITIES ..........•........................................................................... 33 Comment No. 1: . .. 33 Response No. /: ............... 33 Comment No. 2: ... . .......... 33 Response No. 2:.. . ............. 33 Comment No. 3: .... . ........ 34 Response No. 3: .. Comment No. 4: Response No. 4 Comment No. 5: Response No. 5: ..... Comment No. 6: Response No. 6:. Comment No. 7:. Response No. 7:. SECTION 5 -RESULTS ....................................... . Comment No. I: Response No. /: .... Comment No. 2: Response No. 2: Comment No. 3: ..... . Response No. 3 Comment No. 4: . Response No. 4: ... . Comment No. 5: ...... . Response No. 5: .. Comment No. 6: . Response No. 6: .. Comment No. 7:. Response No. 7: ...... . Comment No. 8: ...... . Response No. 8: ..... . Comment No. 9: .. . Response No. 9 Comment No. 10. Response No. JO: Comment No. JJ: Response No. JJ: ... I i .. T ·······.!. .. ' Response to Comments -Phase I NDTS (final) 4 34 .... 34 ...... 34 .................. 34 . ... 34 . 34 ........ 34 ······ 34 ... 35 ···················································••································· 35 ········ 35 . .. 35 .................. 35 .... 35 ... 35 .... 35 ······ 36 . .... 36 .. . ............ 36 . ............................ 36 ···············•····· 36 ···································•································· 36 . ................... 36 . ....... 36 . .. 36 . .. 36 ······· ... 37 ... 37 ····· ··············· 37 ·········· .... 37 ··················· 37 . ............. 38 July I 6, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 Comment No. 12: ...... . Response No. I 2:. Comment No. 13: Response No. 13: Comment No. 14: ....... . ........ 38 . ............ 38 . ............. 38 ........ 38 . ... 39 Response No. 14:... . .. 39 Comment No. I 5: .. . .... 39 Response No. 15:.. . ................................................... 39 SECTION 6 -DISCUSSION ..................................................................•................................••.................................. 39 Comment No. I: . 39 Re!.ponse No. I: Comment No. 2: Re!.ponse No. 2 Comment No. 3: Response No. 3 Comment No. 4: Response No. 4: Comment No. 5: Response No. 5:. SECTION 7 -SUMMARY AND CONCLUSIONS ........................................................ . ... 39 39 ···················· 40 ················ 40 ················•···· 40 .............. 40 ··············· 40 ...... 40 . ....... ···················· 40 ··················· 41 Comment No. 1: ......................... 41 Response No. I ................ 41 SECTION 8 -RECOMMENDATIONS ...............................................•.......................................................................... 41 Comment No. I: ......... 41 Response No./:. . .... 41 Comment No. 2: Reponse No. 2: Comment No. 3: Response No. 3:. Comment No. 4: Reponse No. 4. Comment No. 5: Response No. 5: .. Comment No. 6: Response No. 6 Comment No. 7: ....... 41 ...... 41 .. 41 . .. 42 ........... 42 ······················ 42 ........ 42 ··············· 42 ............................. 43 ··················· 43 ............... 43 Response No. 7:.. . ............. 43 Comment No. 8: ................................ 43 Response No. 8 .............. 43 APPENDIX A -LABORATORY BIOTREATAilILITY STUDY (LBS) -PHASE I BIOREPORT #] 060 ............................. 43 Comment No. !: ***. .. 43 Comment No. 2: *** ........................ 44 Comment No. 3: *** ............... 44 Comment No. 4: ***. . .............. 44 Comment No. 5: *** .................................... 44 APPENDIX A -LABORATORY BIOTREATABILJTY STUDY (LBS)-PHASE II BIOREPORT #] 060 ...........••............... 44 Comment No. 1: . ..... .. 44 Re;ponse No. I:........ . .... 44 Comment No. 2: *** .... 44 Comment No. 3. '** . ...... 45 Comment No. 4: '** .. 45 Comment No. 5.· ''* ......... 45 Comment No. 6: '*' ........ 45 Comment No. 7: ....... ·············· 45 Response to Comments -Phase I NDTS (final) 5 July I 6, I 998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NOTS ENVIROGEN Project No. 78504 Response No. 7: .... Comment No. 8: * * * ········· 45 45 Comment No. 9: *** .......................... 45 APPENDIX A -LABORATORY BIOTREATABILITY STUDY (LBS)-PHASE II Bl0REPORT#l060: AEROBICiABIOTIC RESULTS ................................................................................................................................................................. 46 Comment No. 1: *** .............................. . ······················································· 46 Comment No. 2: *** .............. . .. 46 APPENDIX A -LABORATORY BIOTREATABILITY STUDY (LBS)-PHASE II Bl0REPORT#l060: AEROUIC/BIOTIC RESULTS ................................................................................................................................................................. 46 Comment No. I: ...................................... . ....... 46 Response No. /:...................... . ... 46 APPENDIX A -LABORATORY BIOTREATABILITY STUDY (LBS)-PHASE II Bl0REPORT#l060: ANAEROBIC/A1310TIC RESULTS ............................................................................................................................... 46 Comment No. I:*** ... 46 Comment No. 2: *** ...................... .. 46 Comment No. 3: *** ........................ ... 47 Comment No. 4: ............................ . .. ········· 47 Response No. 4: ..... . 47 Comment No. 5: *** ... . ...... 47 Comment No. 6: ***. . ...... 47 Comment No. 7: .............. . ......... 4 7 Re.,ponse No. 7: .................... 47 APPENDIX A -LABORATORY BIOTREATABILITY STUDY (LBS) -PHASE 11 BIO REPORT #I 060: BT-I (4-6) AEROBIC ABIOTIC .................................................................................................................................................. 47 Comment No. I: *** ... . ..... 47 APPENDIX A -LABORATORY BIOTREATABILITY STUDY (LBS) -PHASE II BIOREPORT #I 060: BT-I (4-6) AEROBIC BIOTIC ..................................................................................................................................................... 48 Comment No. I: *** ...... 48 Comment No. 2: *** ....................... 48 APPENDIX A -LABORATORY BIOTREATABILITY STUDY (LBS)-PHASE 11 BIOREPORT #1060: BT-I (4-6) ANAEROBIC ABIOTIC .............................................................................................................................................. 48 Comment No. I:*** .... ····· 48 Comment No. 2: *** ................ . Comment No. 3: *** APPENDIX A -LABORATORY BIOTREATABILITY STUDY (LBS)-PHASE 11 BIOREPORT #1060: BT-I (4-6) . .... 48 ........ 48 ANAEROBIC BIOTIC........................................ . ................. 48 Comment No. I: * * * . 48 Comment No. 2: *** ........................ . .. 49 APPENDIX A -LABORATORY BIOTREATABILITY STUDY (LBS)-PHASE II BIOREPORT #1060: BT-2 (4-6) ANAEROBIC BIOTIC ................................................................................................................................................ 49 Comment No. I: * ** ..... 49 Comment No. 2: *** .......................... .. ..... 49 Comment No. 3: *** ...................... .. .. 49 APPENDIX A-LABORATORY BIOTREATABILITY STUDY (LBS)-PHASE II Bl0REPORT#l060: BT-2 (4-6) ANAEROBIC AB!OTIC .............................................................................................................................................. 49 Con11nent No. /: *** ..................................... '................... . .......................... 49 APPENDIX A -LABORATORY BIOTREATABILITY STUDY (LBS) -PHASE II BIOREPORT #I 060: BT-2 (4-6) ' AEROBIC ABIOTIC .................................................................................................................................................. 49 Comment No. I:***........................ . ............ 49 Comment No. 2: *** APPENDIX A -LABORATORY BIOTREATABILITY STUDY (LBS)-PHASE II BIOREPORT #1060: BT-2 (4-6) AEROBIC BIOTIC .......................... . Commellt No. I:*** ...... . Response to Comments -Phase I NOTS (final) 6 July I 6, I 998 ......... 49 . .. 50 . ..... 50 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NOTS ENVIROGEN Project No. 78504 APPENDIX A -LABORATORY BIOTREATABILITY STUDY (LBS)-PHASE II BIOREPORT #I 060: SUMMARY (PAGE 43) ········································································································································••································ 50 Comment No. 1: *** ................... 50 Comment No. 2: *** ....... . .............. 50 NCDENR COMMENTS ON PHASE I NATURAL DEGRADATION TREAT ABILITY STUDY PROGRESS REPORT FOR OPERABLE UNIT 4 ...................................................................................................................... 51 LIST OF TABLES .................... . Comment No. I: ............ . Response No. /: .............. . Comment No. 2: ........ . Response No. 2: ........ . Comment No. 3: ........... . Response No. 3: .... . Comment No. 4: .......... . Response No. 4: ..... . .................................................................................................................... 51 .. 51 ·········· 51 . 51 . 51 . ................... 51 ....... 51 51 51 Comment No. 5: ...... 52 Response No. 5: ... 52 NSCC RESPONSES To US EPA AND NCDENR COMMENTS -USEPA GENERAL COMMENTS ............................... 52 Comment No. 6:. . ..... 52 R~=&~ ll Comment No. 7: Response No. 7: Comment No. 8:. Response No. 8: .. Comment No. 9: ......... . Response No. 9: ........... . Comment No. IO: .......... . ReJponse No. 10: .......... . Comment No. I/: ······----- Response No. //: ........... . Comment No_ 12: _______ _ Response No. 12: .. LBS RESULTS .............................. . Comment No. 13: ······· 52 52 .. 52 .. 52 . ..... 52 ....... 52 . .. 53 ········ 53 . 53 . ...... 53 ········· 53 . ... ·················· 53 53 .... 53 Response No. 13: ....... 53 SOIL PLOTS AND SOIL GAS MONITORING WELLS ................................................................................................... 53 Comment No. 14: .... ·-·----·--···---· ............... 53 Response No. 14:........... . .... 54 TREATMENT AND MONITORING ACTIVITIES ........................................................................................................... 54 Comment No. 15: .... . .. ..I. .................. !........ . .......... 54 ' . Response No. 15: ............... , ..... !. .... ·-··-··-------------···-··----------·------54 PRECIPITATION AND GROUNDWATER ELEVATION MONITORING ............................................................................ 54 Comment No. 16: ......................................... ' .................................................................................................... 54 Response No. 16:............................... . ....................................................... 54 SOIL GAS MONITORING .......................................................................................................................................... 54 Conunent No_ 17: -······· .. ··---·----··· .. ·········---------------·········-----------54 Response No. 17 ..... 54 GROUNDWATER QUALITY DATA ............................................................................................................................ 55 Comment No. 18: .. --······-· .. -----55 Response No. 18:......... . .. 55 Comment No. 19: ........... . ...... 55 Response No. 19: ............ 55 BACTERIAL ENUMERATION AND IDENTIFICATION DATA..... 55 Response to Commcnls -Phase I NDTS (final) 7 Jnly I 6, I 998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 Comment No. 20: .. ..... 55 Response No. 20:... . ........................... 55 VOLATILE ORGANIC COMPOUNDS-MASS ESTIMATES OF l,2-DICHLORETHANE (l ,2-DCA) IN SOIL.. ..........•....... 55 Comment No. 21: ..... . .... 55 Response No. 2 I:.... . .............................. 56 Comment No. 22: ......... . ............................... 56 Response No. 22:..... . ............................... 56 INORGANIC COMPOUNDS.................................................... . .......................................................•• 56 Con11ne11t No. 23: .......................... . ............................................. 56 Response No. 23:. . ............................................ 56 MASS ESTIMATES OF l ,2-DCA IN SOIL ..............................................................................................................••. 56 Comment No. 24: ............. 56 Response No. 24:............ . ................................ 56 SUMMARY AND CONCLUSIONS ............................................................................................................................... 56 Comment No. 25: .................................. 56 Response No. 25:.......................... . ................................. 57 RECOMMENDATIONS ............................................................................................................................................. 57 Comment No. 26:. .. 57 Response No. 26: ................. 57 SUMMARY OF SOIL SAMPLING LOCATIONS AND SAMPLE l.D ................................................................................. 57 Comment No. 27: .......... 57 Response No. 27:..... . ...................................... 57 Comment No. 28: ..... . Rejponse No. 28: ... . Comment No. 29: Response No. 29: SUMMARY OF SOIL AERODIC BACTERIA COUNTS ........ . Comment No. 30: Response No. 30 Comment No. 31: Response No. 31 SUMMARY OF SOIL ANAEROBIC BACTERIA COUNTS .... Comment No. 32: Response No. 32: ... .................. 57 .......... 58 .................. 58 ..... 58 ······································································· 58 ........ 58 ..... 58 ........ 58 ····• 58 ················································· 58 ... 58 . ........... 58 Comment No. 33: ...... 58 Response No. 33 .... 58 PLOT I: SOIL CONCENTRATION OF VOLATILE ORGANIC COMPOUNDS .................................................................. 59 Comment No. 34: ···························· 59 Response No. 34: ........... . . ... 59 Comment No. 35: ·········· 59 Response No. 35:.................... . .... 59 PLOT 2: SOIL CONCENTRATION OF VOLATILE ORGANIC COMPOUNDS ................................................................... 59 Comment No. 36: ...... . ... 59 Response No. 36:.......... .. 59 PLOT 3: SOIL CONCENTRATION OF VOLATILE ORGANIC COMPOUNDS ......................•...............•............................ 59 Comment No. 37: .............................. 59 Response No. 3 7: ....................................................................... 59 SUMMARY OF SOIL l ,2-DICHLOROETHANE CONCENTRATIONS ..................................................•........................... 59 Comment No. 38: ..... . ........ 59 Response No. 38:.................... . ............. 60 PLOT l: SOIL CONCENTRATIONS OF NUTRIENTS, METALS, AND OTHER PARAMETERS .......................................... 60 Comment No. 39: ...... 60 Response No. 39:. ················ 60 PLOT 2: SOIL CONCENTRATIONS OF NUTRIENTS, METALS, AND OTIIER PARAMETERS .......... . 60 Response to Comments -Phase I NOTS (final) 8 July 16, l 998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS •:NVJROGEN Project No. 78504 Comment No. 40: ................... . Response No. 40: .. Comment No. 41: ... ·············· 60 . ..................... 60 ················································ 60 Response No. 41 :..... . ...................................................... 60 PLOT 3: SOIL CONCENTRATIONS OF NUTRIENTS, METALS, AND OTHER PARAMETERS .......................................... 60 Comment No. 42: ................... . .... 60 Response No. 42:..... . ........................ 60 SUMMARY OF SOIL K.!ELDAHL NITROGEN CONCENTRATIONS ................................................................................ 60 Comment No. 43: .. .. 60 Response No. 43:................................... . .. 61 Comment No. 44: ................... . Response No. 44: .... . .. 61 .. 61 Conunent No. 45: .......... . ............................................... 61 Response No .. 45:.......... . ........................................ 61 SUMMARY OF SOIL AMMONIA NITROGEN CONCENTRATIONS ................................................................................ 61 Comment No. 46: ..... 61 Response No. 46:..... .. 61 Comment No. 47: .... 6/ Response No. 47:.............................. . 61 SUMMARY OF SOIL NITRATE NITROGEN CONCENTRATIONS .................................................................................. 62 Comment No. 48: ....... . ...... 62 Response No. 48:. . .............. 62 Comment No. 49: ......... . ............. 62 Response No. 49: ............... 62 Comment No. 50: ................ 62 Response No. 50: ............... 62 SUMMARY OF Son, TOTAL PHOSPHOROUS CONCENTRATIONS········································ ... · ................................... 62 Comment No. 51: ............ . ......... 62 Response No. 51: .......... . 62 Comment No. 52: ......... . .. 62 Response No. 52: .......... 63 Comment No. 53: .... 63 Response No. 53:.. . ...... 63 Comment No. 54: .. .. 63 Response No. 54: ......... 63 Comment No. 55: ........ . .... 63 Response No. 55:...................... .. 63 SUMMARY OF SOIL TOTAL ALKALINITY CONCENTRATIONS •.................................................................................. 63 Comment No. 56: ............................. . ............... 63 Response No. 56:... . ............................................ 63 Comment No. 5 7: . . ........................................ 64 Response No. 57:. . ....... 64 Comment No. 58: ..... . ............................................................... 64 Re.,ponse No. 58:......... .. 64 SUMMARY OF Son, CHLORIDE CONCENTRATIONS .................. : ............................................................................... 64 Comment No. 59: .................................... . .. 64 Response No. 59: ........... . Comment No. 60: ......... . Response No. 60: ............... . Comment No. 61: ......... . Response No. 61 : .... . Comment No. 62: .......... . Response No. 62:. Comment No. 63: Response to Comments -Phase I NDTS (final) 9 . ........ 64 ····· ......... 64 . ... 64 .... . ........ 64 . ....... 64 ········ 65 July I 6, I 998 . ..... 65 .. 65 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 Response No. 63: ... Comment No. 64: Response No. 64 Comment No. 65: Response No. 65 Comment No. 66: Response No. 66: Comment No. 67: Response No. 67 Comment No. 68: .. ..... 65 ...... 65 ··············· 65 ················ 65 .......... 65 ··············· 65 ················· 65 ···························· 65 ·············· 66 .............. 66 Re.,ponse No. 68:....... . .... 66 MONTHLY SUMMA CANISTER SAMPLING RESULTS, SOIL GAS MONITORING WELLS I, 2, 3 AND 4 ....................... 66 Comment No. 69: ................. 66 Re.,ponse No. 69:. . .......................... 66 Comment No. 70: .................................. 66 Re.1ponse No. 70:. . ... 66 Comment No. 71: ............ 66 Response No. 71 ................. 66 MONTIILY SUMMA CANISTER SAMPLING RESULTS, SOIL GAS MONITORING WELLS 5, 6, 7 AND 8 ... : ... : ............... 67 Comment No. 72: . . ........ 67 Response No. 72:. . ........... 67 GROUNDWATER ELEVATIONS: WELLS NS-14, NS-35, NS-36, NS-39, NS-40, NS-42 ...............................•..... 67 Comment No. 73: .... 67 Response No. 73 Commenl No. 74: ....... 67 .... 67 Response No. 74 .. 67 SHALLOW (2-4') S011_ GAS CONCENTRATIONS (SGMW-4), FIELD MEASURED w/GA-90 .................................... 67 Comment No. 75: ····························· 67 Response No. 75:...... .. 67 APPENDIX A -BLUE PLANET TECHNOLOGIES, PHASE I 1310REPORT #I 060, SEPTEMBER 17, 1996 .................... 68 Comment No. 76: .............. 68 Re.,ponse No. 76 68 Comment No. 77: ............................................ 68 Response No. 77 68 Comment No. 78: .... 68 Response No. 78 ... 68 BLUE PLANET TECHNOLOGIES, PIIASE II 1310REPORT #1060, NOVEMBER 19,1996 .............................................. 68 Comment No. 79: ...... !. ...... 68 ~~-~~ ...... M Comment No. 80: . 69 Response No. 80 ..... 69 Comment No. 8 I: ... 69 Response No. 81 ... 69 APPENDIX C -FIELD ACTIVITY DAILY LOGS (FADL'S) ................................................................................ 69 Comment No. 82: .................. 69 Response No. 82 Comment No. 83: Response No. 83: .. APPENDIX D -BLUE PLANET ANALYTICAL REPORTS ....... . Comment No. 84:. Response No. 84 SEPTEMBER 29, 1997 BLUE PLANET TECHNOLOGIES REPORT .. Comment No. 85: Response No. 85:. Response to Comments -Phase I NOTS (final) 10 ..... 69 ... 69 ···················· ........ 69 ···························•······························· 70 .. 70 ········ 70 ················· 70 ···················· 70 July I 6, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 APPENDIX E-DATA VALIDATION, PACE ANALYTICAL, INC. REPORT#72221 ................................................... 70 Comment No. 86: ........ 70 Response No. 86: ..... 70 Comment No. 87: 70 Response No. 87: .. 70 Comment No. 88: ............. .. 71 Response No. 88:............ 7 I Comment No. 89: .......... 7 I Response No. 89: .... .. ................................... 7 I Comment No. 90: .. ............... . ....... 71 Response No. 90:...................... . ...... 7 I CommentNo.91: ............. 71 Response No. 9 I: ... 7 I Comment No. -92: .. 71 Response No. 92 .......................... 7 I DATA VALIDATION, PACE ANALYTICAL, INC. REl'ORT#3089 ................................................................................ 72 Comment No. 93: ... . ...... 72 Response No. 93:............ . .... 72 Comment No. 94: ...... . ..... 72 R-=¼~ ........................ 72 Comment No. 95: Response No. 95: DATA VALIDATION, PACE ANALYTICAL, INC. REPORT#SPl65 ........ Comment No. 96: Response No. 96:. Comment No. 97: ...... 72 .............. 72 ··································· ......... 72 ...... 72 .. ... 72 . 72 Response No. 97 ........... 72 DATA VALIDATION, PACE ANALYTICAL, INC. REl'ORT#3333 ............................................................................... 73 Comment No. 98: 73 Response No. 98:. Comment No. 99: Response No. 99 Comment No. 100: Re.,ponse No. JOO:. Comment No. JOI: 73 ...... 73 73 73 . ....... 73 ....... 73 Response No. IOI:.. . ..... 73 DATA VALIDATION, PACE ANALYTICAL, INC. REPORT #105089 .......................................................................... 73 Comment No. 102: ... . .... 73 Response No. 102:. .. .................... 73 Response to Comments -Phase I NOTS (final) 11 July 16, 1998 I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ~:NVIROGEN Project No. 78504 USEPA REGION IV COMMENTS -PHASE I NATURAL DEGRADATION TREATABILITY STUDY REPORT General Comment /comment No. 1: There is quite a lot of confusion in the document as to what sample depth represents the "shallow" soil interval and what is referred to as "deep". In numerous cases the shallow interval referred to samples taken from 4-6', while at other times data taken in this interval was included with an evaluation of the deep interval (generally from 6-8'). In addition, numerous samples were obtained from 0-4; and included in the shallow interval. It is recommended that all data tables and interpretations discussions in this document be revised to provide a standard of0-6' for the shallow interval and 6-8' as representing the deep. Several of the following specific comments present effects of this noted inconsistency. Response No. 1: Agreed. All data tables and interpretation discussions have been revised to provide a standard of 0-6' for the shallow interval and 6-8' as representing the deep interval. It should be noted that there were only a few isolated instances when a sample collected from 4-6' was used in an evaluation of the deep interval (generally from 6-8'). This occurred when there was no soil sample collected from an interval deeper than 4-6', e.g., in the instance when soil samples were collected from 2-4' and 4-6'. Therefore, the overall conclusions of the report will not change as a result of adopting the standard of 0-6' for the shallow interval and 6-8' as representing the deep interval for purpose of data interpretation. Executive Summary ./Comment No. 2: Page ES-I, Executive Summary, Results, Item #2: The laboratory results do not support the conclusion that anaerobic conditions favor the degradation of 1,2-dichlorethane (1,2-DCA). In fact, the laboratory report, Phase II concludes quite the opposite (See Summary, page 43 of Lab report). Response No. 2: As agreed upon during the conference call of July 9, 1998, the Phase II laboratory study will be disregarded and removed from the Phase I report. Therefore, this comment has not been addressed. /comment No. 3: Page ES-2, Executive Summary, first bullet (field biotreatability study conclusions), Item #2: Although anaerobic degradation daughter products of 1,2-DCA were detected in soil gas samples, these products (most notably vinyl chloride) were not detected (or not sampled for) in Response to Comments -Phase I NOTS (final) 12 July 16, 1998 I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 the soils. In addition, this conclusion should be resolved with the conclusions of the laboratory testing (see comment #2 above). Response No. 3: Actually, vinyl chloride (VC) was sampled for and detected in the soil matrix under the CLP protocol. Vinyl chloride is a very volatile compound (vapor pressure~ 2660 mm Hg) and is normally a gas at ambient soil temperature. Therefore, one would expect to observe VC in soil gas rather than the soil matrices. In addition, VC was detected in soils of Plot I, Plot 2 & Plot 3, refer to Table 5-6 (pages 2, 4, and 5 of 5), Table 5-7 (page 4 of 5), and Table 5-8 (pages 2 and 4 of 5). With respect to the laboratory study, vinyl chloride was not analyzed in the soil gas phase during the 28-day test. ./Comment No. 4: Page ES-2, Executive Summary, first bullet (field biotreatability study conclusions), Item #3: What evidence is there to support the conclusion that alternating aerobic and anaerobic environments is well suited for promoting the complete mineralization of 1,2-DCA, especially since the degradation pathways are so different? This statement either needs to be supported with conclusive evidence collected from the Site or it should be deleted. Response No. 4: Non-site speci fie evidence to support the conclusion that alternating aerobic and anaerobic environments is well suited for promoting the complete mineralization of 1,2-DCA will be provided under separate cover along with an updated literature review of aerobic and anaerobic degradation pathways and 1,2-DCA natural attenuation case studies. Figure 6-1 shows the aerobic degradation pathways for 1,2-dichloroethane. Evidence of aerobic degradation of 1,2-DCA based on the formation of intermediate by-products does not exist for the site because the Phase I program did not analyze for these parameters. However, indirect evidence based on soil gas readings and the formation of carbon dioxide, the final degradation product, does exist for the site. A qualifying statement to this end will be added to the text. For instance, NRMRL noted that (Section 8 -Recommendations, Comment #3) soil gas data collected at the site " ... demonstrates that there is aerobic degradation in the vadose zone." " .... because the oxygen depletion in the contaminated plots (Plots I, 2 or 3) is greater than in the uncontaminated plot (Plot 4), it appears that at least part of the oxygen depletion is due to soil contaminant degradation." Response to Comments -Phase I NOTS (final) 13 July 16, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 Response to Regulatory Comments /comment No. 5: Page R-8, Response to Comment #15, first paragraph, last sentence: this sentence states, there does not appear to be any inhibition of microbial activity ... " However, a large number of the soil samples collected from the Site did not contain viable bacterial colonies. Is there an explanation? Response No. 5: A possible explanation may lie in the sampling method and type of bacteria present in the soil. Soil samples were collected in amber jars exposing the sample to atmospheric air. This sampling method would limit subsequent bacterial enumeration to aerobic and facultative bacteria. Since Area 2 is paved it is possible that anaerobic conditions may have existed in the subsurface at the time of sample collection in which case anaerobic bacteria may have been predominant. These strict anaerobes probably would have died during the sampling event from exposure to oxygen thus explaining the sampling results for Area 2. In the Lagoon Area, heterotrophic bacteria were detected in all four samples collected at concentrations ranging from 1.1x106 to l .6x 108 organisms/g soil. /comment No. 6: Page R-9, Response to Comment #17: Why weren't the procedures specified in the approved work plan followed? No explanation was offered. Response No. 6: This comment pertains to Phase II of the Laboratory Study. As discussed and agreed upon during the conference call on July 9, 1998, the Phase II Lab Study has been disregarded and removed from the Phase I NDTS Report. /comment No. 7: Page R-9, Response to Comment #19: Why weren't the procedures specified in the approved work plan followed? No explanation was offered. Response No. 7: This comment pertains to Phase II of the Laboratory Study. As discussed and agreed upon during the conference call on July 9,1998, the Phase II Lab Study has been disregarded and removed from the Phase I NDTS Report. /comment No. 8: Page R-9, Response to Comment #20: In review of the response to comments and of the laboratory study reports, the response to EPA's comment #20 is unacceptable. The purpose of the first phase of testing conducted on the soil samples was to establish a baseline for the second phase of testing. During the second phase, 500 ppb of 1,2-DCA was spiked into soil sample Bt-1 4-6' and the assumption was made that this represented the total in the sample. What happened to the 7400 ppb detected in the sample when it was analyzed in Phase I? The second phase relies Response to Comments -Phase I NOTS (final) 14 July 16, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 on Phase I testing for the baseline of other parameters, why not for the 1,2-DCA? Numerous comments made on the first submittal depend on the resolution of this issue. Response No. 8: This comment pertains to Phase II of the Laboratory Study. As discussed and agreed upon during the conference call on July 9, 1998, the Phase II Lab Study has been disregarded and removed from the Phase I NOTS Report. /comment No. 9: Page R-11, Response to comment #28, last sentence: A short explanation needs to be inserted into this sentence starting why "IO ppb" was used as the final concentration. Response No. 9: This comment pertains to Phase II of the Laboratory Study. As discussed and agreed upon during the conference call on July 9, 1998, the Phase II Lab Study has been disregarded and removed from the Phase I NOTS Report. Phase I Natural Degradation Treatability Study Report for OU #4 I comment No.10: Page 2-1, Section 2.2. The depths of samples BT-I, BT-la and Bt-2A should be specified. Response No. 10: Agreed. The depth of samples have been added to the text. /comment No.11: Page 2-2, Section 2.5, Item #2: Refer to comment #2 above. Response No. 11: As agreed upon during the conference call of July 9, 1998 all results of the Phase II laboratory study will be disregarded and removed from the Phase I report. Therefore this comment has not been addressed. /comment No. 12: Page 3-1, Section 3.0, fourth paragraph: It is the Agency's recollection that NSCC ascertained why the boxes were retaining water and rectified the situation. If so, this information needs to be added to this paragraph. How long did this situation persist? Response No. 12: Response #7 provided in January 1998 Progress Report explained why the boxes were retaining water and the corrective actions implemented by NSCC. The water infiltration problem persisted for approximately six months. The explanation why the boxes were retaining water has been added to the text of the report. Response to Comments -Phase I NOTS (final) 15 July 16, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NOTS ENVIROGEN Project No. 78504 /comment No. 13: Page 3-1, Section 3.0, fourth paragraph: The problems with precipitation entering the soil plots is discussed in this paragraph and then dropped. In reviewing the moisture analysis results it appears that enough precipitation entered Plot I to make the level of moisture approximately equal to Plot 2 where moisture was being added. This effectively neutralized the difference in the testing conditions, which were to be established and evaluated for Plot I and Plot 2. Refer to comment# 12 above. Response No. 13: Infiltration to the soil plots nomially occurred during rainfall events of greater than approximately½" of rain throughout the Phase I Field study. Rainfall data collected at the site showed 32 rain events (less than 3 per month) in excess of½" of rain occurred during the Phase I Study. The water entering the plots was removed immediately by hand bailing using a large beaker. However, since infiltration was removed immediately it is most likely that the unexpected infiltration had a minimal impact on the study. /Comment No. 14: Page 3-1, Section 3.0, fourth paragraph, last sentence: Typo the referenced section here should be 5.1 not4.l. Response No. 14: The typo has been corrected. / Comment No. 15: Page 4-1, Section 4.0, third paragraph, last sentence: This sentence states that for the last three months the quantity of water and amendments was increased, No explanation was given for why the quantity of water and amendments was increased, The July 1996 Natural Degradation Treatability Study Work Plan, Section 2.4.2 states that the quantity of water would be increased, if necessary, to keep the soil moisture level at 50 percent. ls this why the quantity of water was increased from 3.6 liters to 4.5 liters? Refer to comn\ent #60 below. I Response No. 15: The quantity of water was increased in an attempt raise the soil moisture content in Soil Plot 3 to 50% of saturation as specified in the Work Plan. In tum, the amount of water added to Soil Plot 2 had to be increased. It should be noted that the Work Plan specifies that soil moisture content be maintained at 50% of saturation, which equates to a soil moisture content of approximately 20 to 25% for clays. The quantity of nutrients was raised from 27 to 54 grams of ammonium phosphate because the actual concentration of 1,2-dichloroethane in soil was significantly higher than the estimated concentration of 2 ppm. The increase occurred after receiving and reviewing soil data for the six month sampling event. Response to Comments• Phase I NOTS (final) 16 July I 6, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 /comment No. 16: Page 4-2, Section 4.2: A figure needs to be referenced in this "Section" that gives the reader a perspective of the location of the soil plots and where the groundwater samples were collected. Response No. 16: A figure has been added. Comment No. 17: Page 4-2, Section 4.3: Methylene Chloride was the indicator chemical analyzed for during the laboratory testing of the degradation of 1,2-DCA. Why was this compound excluded from the parameter list for the field-testing? -► Response No. 17: The laboratory study used USEPA Method 624 to analyze for volatile organic compounds during the laboratory study. Methylene chloride was not a targeted compound but was detected at low concentrations during the study. This may be an artifact from the laboratory. Actually, methylene chloride was analyzed for in the soil and soil gas during the field study. However, methylene chloride is not an intermediate compound of 1,2-DCA degradation and therefore was not listed as a target compound on Table 4-2. /Comment No. 18: Page 4-2, Section 4.3, second paragraphs, third sentence: Typo, this sentence should read" ... PI- S, 2-4 4 6 refers to Soil Plot I ... " Response No. 18: The typo has been corrected. / Comment No. 19: Page 4-4, Section 4.5: The title of this section "Microbial Activity Monitoring" is misleading. This section does not include any discussion with respect to work performed to determine the "Activity" of the microbes. The section focuses on the identification/classification of the microbe. The title of this section should be changed to read "Microbial Identification/Enumeration''. Response No. 19: Agreed. The heading has been changed as suggested. /Comment No. 20: Page 4-4, Section 4.5: this section should refer the reader to appendix D. Response No. 20: Agreed. A reference to Appendix D has been added. Response to Comments -Phase I NDTS (final) 17 July 16, 1998 I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 -Comment No. 21: Page 5-1, Section 5.2,first paragraph: This paragraph relates that a number of groundwater sampling efforts has occurred at the Site. This paragraph needs to be expanded to state what analyses were run on the samples collected during each monitoring effort (i.e., volatile organic compounds, semi-volatile organic compounds, metals, cyanide). Response No. 21: Groundwater analytical data was provided at the request of the NRMRL and as specified in the approved NOTS work plan. However, evaluation of the impact to groundwater from contamination in vadose zone soils was not an objective of Phase I of the NOTS nor is it possible to discern since the monitoring wells are not located near the Soil Plots or Soil Gas Monitoring Wells. Therefore, groundwater quality data will be removed from the report. /comment No. 22: Page 5-1, Section 5.2, first paragraph, last sentence: This sentence need to clarify which wells are in the saprolite and which ones are in the bedrock zone. A figure should be referred to so that the reader can determine the locations of these wells. Response No. 22: A figure has been added. /comment No. 23: Page 5-2, Section 5.3.1, first paragraph, second sentence. The conclusion declared here is not supported by the data. I Response No. 23: I I I I I The disputed statement has been deleted. ✓Comment No. 24: Page 5-2, Section 5.3.1, -second paragraphs, and (carry over to page 5-3): Time periods for all referenced measurements should be provided. Response No. 24: Acknowledged. Time periods for all referenced measurements have been provided. / Comment No. 25: Page 5-3, Section 5.3.2, Bacterial Enumeration Data, first paragraph, second and third sentences: The information provided in these two sentences appear to contradict each other. As presented, these two sentences do not make sense. Response No. 25: I Sentences in question contained a typo. The values quoted I 06 to IO' should be I 03 to IO'. I I Response to Comments -Phase I NOTS ( final) 18 July 16, I 998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 /Comment No. 26: Page 5-3, Section 5.3.2, Bacterial Enumeration Data first paragraph, and last sentence: There is no Site specific data to support the conclusion that bacterial counts in soils vary with environmental conditions. If this is a documented trend, then either Site specific supporting information or a reference needs to be furnished. Response No. 26: Variations in bacterial population density with environmental conditions is well documented in the literature, and the following references are provided: Alexander, M. 1977. Introduction to Soil Microbiology. 2"' Ed. John Wiley & Sons. pp:21-24. Atlas, R.M, and R. Bartha. 1981. Microbial Ecology: Fundamentals and Applications. Addison- Wesley Publishing Company. pp:133-169. / Comment No. 27: Page 5-3, Section 5.3.2, Bacterial enumeration Data. third paragraph, and first sentence: this sentence refers to two variables, "media used" and !'incubation conditions". Were these two variables kept constant throughout the study? Response No. 27: A consistent media (R2A agar) and "incubation conditions" were used in cultivating both aerobic and anaerobic bacteria. J Comment No. 28: Page 5-4, Section 5.3.3, Bacterial Identification: A reference should be included for the infonnation provided in this section, specifically, for which bacteria are most commonly found in soils. Response No. 28: Alexander, M. 1977. Introduction to Soil Microbiology. 2"' Ed. John Wiley & Sons. pp:26-31. Atlas, R.M, and R. Bartha. 1981. Microbial Ecology: Fundamentals and Applications. Addison- Wesley Publishing Company. pp:171-219. / Comment No. 29: Page 5-4, Section 5.3.3. This section refers to Tables 5.6-5.9 and 5.10. The shallow and deep intervals described in this section do not match those presented in the tables. The intervals should be presented as 0-6" for the shallow interval and 6-8' for the deep. This would fix many of the problems in Table 5-10. Many samples from 0-4' were included in the shallow interval (supposedly 4-6'). In Soil Plot 3, duplicate samples for location S (4-6) were used first as part of the shallow interval calculation and then as part of the deep. In addition, is the location code for the 3/26 sample date "A I" "AD" or "AF" (Table 5-6, 5-7, 5-8 and 5-10 should be resolved). Response to Comments -Phase I NOTS (final) 19 July I 6, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NOTS ENVIROGEN Project No. 78504 Response No. 29: Reference intervals have been changed as suggested to 0-6' for the shallow interval and 6-8' for the deep interval. The discrepancy in use of Soil Plot 3 duplicate samples has been resolved by including these samples in the shallow interval calculation only. The location code for the 3/26 sample data is AF and has been corrected in Table 5-6, 5-7, 5-8 and 5-10. ,/ Comment No. 30: Page 5-5, Section 5.3.3 Mass Estimates of 1,2-DCA in Soil, fourth paragraph: The time intervals for comparison should be kept the same. As presented, it is hard to draw any conclusions about the effectiveness of the full twelve-month Treatability study. Response No. 30: Agreed. Discussion has been edited using one time interval ( one year) for comparison. / Comment No. 31: Page 5-5, Section 5.3.3, Mass Estimates of 1,2-DCA in Soil, fourth paragraph, first two sentences: Typo, these two sentences are duplicates of each other. Response No. 31: The typo has been corrected. JComment No. 32: Page 5-5, Section 5.3.3, Mass Estimates of 1,2-DCA in Soil, fourth paragraph: This paragraph refers to Table 5.11 (Mass Estimates of 1,2-DCA in Soil). Is there any correlation between the data presented in Table 5.11 and Table 5.4 (Summary of Soil Aerobic Bacteria Counts)? Response No. 32: Due to a limited number of data points a correlation between mass estimates of 1,2-DCA and aerobic bacteria counts in soil could not be made. /comment No. 33: Page 5-5, Section 5.3.3, Mass Estimates of 1,2-DCA in Soil, fourth paragraph, and last sentence: Typo, the mass "2,329 g" should read "2,339 g". Response No. 33: The typo has been corrected. / Comment No. 34: Page 5-5, Section 5.3.3, Mass Estimates of 1,2DCA in Soil, fourth paragraph, last sentence: This sentence refers to the first six months of data for Soil Plot 2 and to the first nine months of data for Soil Plot 3. If the twelve month data was used to calculate the decline in 1,2-DCA mass for both of these plots, then the percentage ofremoval of 1,2-DCA for Soil Plot 2 would be 17% (2,339 g to 1,942 g) and the percentage of removal of 1,2-DCA for Soil Plot 3 would be 0% (5,325 g to 5,639 g). Response to Comments -Phase I NOTS (final) 20 July 16, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NOTS ENVIROGEN Project No. 78504 Response No. 34: Agreed. The estimates of the percentage of removal of 1,2-DCA for all Soil Plots has been revised (as suggested) for all soil plots, and is now based on one time interval (one year). The revised estimates of percentage removal of mass ofl,2-DCA in soil Plots 1, 2, and 3 are 80%, 17%, and 0%, respectively. These rates are only to comp_are the treatment methods used during Phase I and a valid degradation rate will be established in Phase IL / Comment No. 35: Page 5-5, Section 5.3.3, Mass Estimates of 1,2-DCA in Soil, fifth paragraph: This paragraph attempts to rationalize why the last three and the last six months of data for Soil Plots 2 and 3, respectively, should not be included. Although Section 5.3.3 only presents facts, the Agency does not accept the rationalization presented in this section for disregarding the last several months of data for each soil plot. It can just as easily be argues that the June 1997 data was not representative as a few slightly contaminated soil samples were collected. Response No. 35: Agreed. The said data have been included in the estimates of percentage removal of mass of 1,2- DCA in soil Plots I, 2, and 3 (refer to response to USEPA Comment 34). /comment No. 36: Page 5-5, Section 5.3.4: What is meant by shallow and deep intervals in this discussion? Refer to comment# 1 above. Response No. 36: Reference intervals have been changed as previously suggested to 0-6' for the shallow interval and 6-8' for the deep interval. ./ Comment No. 37: Page 5-8, Section 5.4.1: When the laboratory data for methane is used, the results for all soil gas locations is very near background conditions found at SGMW-4. Response No. 37: NSCC respectfully disagrees. Using the laboratory data, the average methane concentration (by volume) for SGMW-1, -2, and-3 was 10%, 8.9%, and 3.5%, respectively, in comparison to 0.5% measured at SGMW-4 (refer to Table 5-23, pages 14 to 16). / Comment No. 38: Page 5-14, Section 5.4.2, and first full paragraph: This paragraph lists daughter products of anaerobic degradation of 1,2-DCA. A figure, similar to Figure 6-1 -Aerobic Degradation Pathway of 1,2-DCA, should be included in this report showing the anaerobic degradation pathway. ' Response No. 38: Agreed. A figure depicting the anaerobic degradation pathways has been incorporated. Response to Comments -Phase I NOTS (final) 21 July I 6, 1998 I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 / Comment No. 39: Page 6-1, Section 6.0: this section neglected to discuss the numerous soil samples that did not contain viable populations of bacteria. Why? This is a significant detail that the Agency will consider when considering the implementation of the remedial action. Refer to comment #5 above and #54 below. Response No. 39: The purpose of Section 6.0 was to provide a summary of lines of evidence that support the conclusion that natural attenuation of 1,2-DCA is occurring in the vadose zone at the Site. These lines of evidence include documenting the loss of contaminant (at field scale) and the presence of degradation intermediates, which are documented in the report. Given the strength of these primary lines o(evidence and the observed variability in the bacteria enumeration data, discussion of the bacteria enumeration data in Section 6.0 was not warranted. However, a discussion of the bacteria enumeration data is presented in Section 5.3.2 of the report. / Comment No. 40: Page 6-1, Section 6.1, -second paragraph: Refer to comment #38 above. Response No. 40: A figure will be added per USEPA Comment #38. J Comment No. 41: Section 6.2.1, page 6-2, second paragraph: Assessing the different time frames and arbitrarily dropping the second six months of Plot 2 and the last 3 months of Plot 3 is inappropriate. Refer to comment #'s 34 and 35 above. Response No. 41: I Agreed. Refer to response to US EPA Comment #34. I I I I I I I / Comment No. 42: Page 6-2, Section 6.2.1, second paragraphs, last sentence: Refer to comment #33 above. Response No. 42: Acknowledged. Refer to response to USEPA Comment #33. I Comment No. 43: Page 6-2, Section 6.2.1, second paragraphs, last sentence: Refer to comment #34 above. Response No. 43: Agreed. Refer to response to US EPA Comment #34. J Comment No. 44: Page 6-2, Section 6.2.1, third paragraph: Refer to comment #35 above. Response to Comments• Phase I NOTS (final) 22 July I 6, I 998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 Response No. 44: Agreed. Refer to response to USEPA Comment #35. / Comment No. 45: Page 6-2, Section 6.2.1, third paragraph: The presentation in this paragraph is misleading. Some type of qualifying statement needs to be incorporated in this section with regard to the approximate 80% removal rate of 1,2-0CA for these soil plots. For an example, if this 80% removal rate was applied for the past IO years, then the level of 1,2-0CA in the soil back in I 988 was almost I 00%. Obviously, the past data does not support this calculation. The approximate 80% removal rate of 1,2-0CA appears artificially high which is why the Agency requires a qualifying statement to be included in this paragraph. There are other potential interpretations explaining the reported loss of 1,2-DCA in the Soil Plots. The following are two conceivable interpretations of the data collected for the soil Plots. Interpretation #1 -The Soil Plots were installed through a concrete driveway which up to that time had little to no exchange of air with the atmosphere. With the installation of these boxes, the immediate environment encompassed in each Soil Plot now had a constant exchange of air at the surface. Therefore, the majority of the loss of 1,2-0CA is associated with volatilization. Explanation #2 -When the concrete driveway was intact, there was no hydraulic head on the 1,2-0CA in the soil. When the Soil Plots were installed, water was introduced to these soils (i.e., water was poured on the soil to maintain soil moisture content and precipitation was able to infiltrate, refer to comment# 12) for the first time since the concrete driveway was poured. Therefore, the disappearance of the 1,2-DCA during the 12-month study in these Soil Plots was attributable to the migration of the 1,2-0CA down into the subsurface with the downward migration of surface water. Response No. 45: A statement qualifying the apparent 80% reduction in mass of 1,2-0CA in Plot I soil will be added to the text. Please refer to response to US EPA Comment #34. / Comment No. 46: Page 6-3, Section 6.2.2, second paragraph, first sentence: This is truly a shortcoming of the Phase I effort. This data gap needs to be eliminated during Phase II. The Agency will insist that the daughter products of aerobic degradation be analyzed for occasionally. The Agency would assume NSCC would also want to collect this data as it would be invaluable in making the case that natural degradation of 1,2-0CA is occurring in the unsaturated soil zone at the Site. Refer to comment #'s 3 and 17 above. Response No. 46: Standard EPA-approved analytical methods required to detect aerobic degradation intermediate products of 1,2-0CA currently do not exist, and ther~fore these compounds were not target analytes during Phase I of the NOTS. NSCC is investigating the feasibility of developing a method to analyze for these compounds and will consider including these compounds as analytes in Phase II of the NOTS. Response to Comments -Phase I NDTS (final) 23 July 16, 1998 I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 ./ Comment No. 47: Page 6-4, Secti_on 6.2.3: Are there any perceptions as to what is the driving force (s) causing this environment to alternate from aerobic and aerobic conditions? Can these forces be manipulated? Refer to comment #4 above. Response No. 47: The alteration in subsurface environment from aerobic to anaerobic is believed to be seasonal and is probably influenced by changes in barometric pressure, temperature and precipitation. It is not the intent of the study to influence or manipulate these forces but rather recognize and work with them during Phase IL / Comment No. 48: Page 7-1, Section 7.0, first bullet: Vinyl Chloride was also detected in a significant number of soil samples. Response No. 48: Agreed. Note: This comment highlights that VC was detected in the soil as questioned in USEPA Comment #3. ./Comment No. 49: Page 7-1, Section 7.0, fifth bullet, Item #2: There is no evidence from the laboratory Treatability study to support this conclusion (refer to comment #2 above). Response No. 49: Refer to response to USEP A Comment #2 or #4. /comment No. 50: Page 7-1, Section 7.0, fifth bullet, Item #3. Refer to comment #4 above. Response No. 50: I Refer to response to USEP A Comment #4. I I I / Comment No. 51: Page 7-2, Section 7.0, first diamond: The phrase "(no treatment)" is a misnomer. The phrase "no augmentation" may fit better. Response No. 51: Agreed. As suggested, the phrase "no treatment" will be replaced with the phrase "no augmentation". /Comment No. 52: I Page 7-2, Section 7.0, third diamond: Refer to comment #35 above. I I Response to Comments -Phase I NOTS (final) 24 July I 6, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NOTS ENVIROGEN Project No. 78504 Response No. 52: Refer to response to US EPA Comment #35. /comment No. 53: Page 8-1; Section 8.0 Soil Plot Replication and Construction Details. Although eliminating the problem encountered with rainwater (a problem which was ignored throughout the document - refer to comment #13) is important, if the pavement is left in place it would drastically reduce the aerobic conditions in the subsurface soils. Some other engineering control should be proposed to control rainwater. In addition, since the moisture content of Plot I and 2 were effectively the same due to rainwater impacts (refer to comment #13 above), the addition of moisture as a treatment option should be explored alongside a plot which has effective moisture control. In addition, if the natural aerobic condition created by exposing the soils to the atmosphere is eliminated, addition of oxygen below the concrete should be tested for comparison to the conditions noted in the first trial. Response No. 53: Natural conditions at the site would be best simulated in Phase II of the NOTS by leaving the pavement in place. if, as the agency has suggested, the aerobic conditions in surface soils were artificially created by exposing the soils to the atmosphere these conditions should not be repeated as they are not representative of natural conditions. Therefore, addition of oxygen to the subsurface will not be considered in Phase II of the NOTS. In addition, results of the Phase I NOTS indicate moisture addition, either intentional or incidental, did not significantly increase soil moisture content of the clayey soils present at the site. Given this relative stability, it is not likely that soil moisture content is a variable that significantly controls the rate ofbiodegradation of 1,2-DCA at this particular site. Therefore, further evaluation of the addition of moisture as a treatment option will not be considered in Phase II of the NOTS. /comment No. 54: Page 8-1, Section 8.0 Soil Plot Replication and Construction Details, Item #1: This item refers to Figures A-1 and A-2 of the OU #4 RD/RA Work Plan. These two figures should be incorporated into this report. Refer to comment #5 above. Response No. 54: Figures A-1 and A-2 of the OU #4 Rd/RA Work Plan has been added. / Comment No. 55: Page 8-1, Section 8.0 Soil Plot Replication and Construction Details, Item #2: This item proposes a different approach for the soil plots in Area 2 for Phase II. lfNSCC moves forward with Phase II as proposed, then NSCC will not be able to compare the data from Phase II to the data from Phase I. Response to Comments -Phase I NDTS (final) 25 July 16, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NOTS ENVIROGEN Project No. 78504 Response No. 55: The data and information gained from Phase I of the NOTS will be used to develop a program for Phase II. However, the objectives of Phase I versus Phase II do not require the comparison of data. The goal of Phase I was to confirm that natural degradation of I ,2 DCA was occurring and accomplished this goal. Phase II of the NOTS will focus on quantifying the rate of natural degradation of 1,2-DCA. /comment No. 56: Page 8-1, Section 8.0 Soil Sampling. and Item #4: This item proposes collecting more samples per sampling episode along with supporting rationale. But this item does not discuss the sampling frequency. Will it be the same as in Phase I? Response No. 56: The frequency of soil sampling in Phase II will be dependent upon the duration of the Phase II study. NSCC believes the duration of the Phase II needs to be extended to dampened seasonal or short-term variability in soil concentration and to provide a better estimate of the rate of natural degradation of I ,2-DCA in soil. NSCC will meet with US EPA and NCDENR to establish the specific approach for Phase II. / Comment No. 57: Page 8-1, Section 8.0 Soil Sampling. Item #5: An additional sentence should be added to this Item listing the analytes that are being proposed to be deleted from the Phase I analytical protocols. Response No. 57: NSCC will meet with USEPA and NCDENR to establish the specific analytes to be analyzed during Phase 11. ./ Comment No. 58: Page 8-2, Section 8.0 Soil Gas Sampling. Item #6: Refer to comment #46 above. Response No. 58: Refer to response to USEP A Comment #46. Tables /comment No. 59: In reviewing the data tables containing sample results, a wide variation in the Method Detection limit was noted (most MD Ls were very high), especially for the soils analysis. In addition, the laboratory data qualifiers were not always noted as footnotes to the tables (specific comments caught some, but not all of these). Response to Comments -Phase I NDTS (final) 26 Joly 16, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NOTS ENVIROGEN Project No. 78504 Response No. 59: The issue of method detection limits has previously been addressed by Pace Analytical Services in a letter dated December 18, 1997 which was included in the Phase I NDTS report (following page R-7). Footnotes on all tables have been verified to ensure all data qualifiers are properly referenced. / Comment No. 60: Table 5-3: Refer to comment #15 above. Based on the data presented in this table, the goal of 50 percent soil moisture content was never achieved. Why not? Why weren't the procedures specified in the approved work plan followed? Response No. 60: It should be noted that the Work Plan specified that soil moisture content be maintained at 50% of saturation which equates to a soil moisture content of approximately 20 to 25% for clays. Values reported in Table 5-3 are soil moisture contents, which are in the range specified in the Work Plan. See also response to USEPA Comment #15. / Comment No. 61: Table 5-4: The symbols"-" and "ND" need to be defined under "NOTE". Response No. 61: Table 5-4 has been amended as suggested. /Comment No. 62: Table 5-6: Not that it is imperative for this report nor does it influence the objective of the Treatability study, but the detection levels are extremely high. Response No. 62: Refer to response to USEPA Comment #59. /comment No. 63: Table 5-12: the sampling locations presented throughout the table a,re wrong and should be double checked (e.g.-page 4 of 5, Pl-D, 2-4 in the second to the last column should be Pl-X, 2-4, and where is the data for P l-x,4-6?) Response No. 63: Table 5-12 has been corrected. Pl-X, 4-6 was not analyzed. Response to Comments. Phase I NDTS (final) 27 July I 6, I 998 I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 Appendix A -Blue Planet Technologies Phase I BIOreport™#l060, dated September 17, 1996 / Comment No. 64: Has any attempt been made to correlate the presence of viable microbes to either nitrate levels or phosphate levels or both in the soils? A number of soil samples collected did not have viable microorganisms. ls there an explanation for this occurrence? Response No. 64: There does not appear to be a correlation between the presence of viable microbes and either nitrogen or phosphorous levels in soil. Refer also to response to USEPA Comment #5. Appendix A -Blue Planet Technologies Phase II BIOreport™#l060,dated November 19, 1996 (and revised 011 March 5, 1997) NOTE: As mutually agreed upon by the USEPA, NRMRL, NCDENR and NSCC, results of the Phase II BIOreport have been dismissed and therefore comments concerning this report have not been addressed. ,/ Comment No. 65: Table 2 -BIODEGRADA TION Rate of Contaminant: When calculating the correction factor for this laboratory study, why weren't all the abiotic data averaged? In taking this approach, it more clearly depicts that no degradation occurred under anaerobic conditions (i.e., the biodegradation rate for Ll8968-1D was 5.63 and the biodcgradation rate for LI8985-5A was 1.16). Response No. 65: As discussed and agreed upon with USEPA during the conference call on July 9, 1998, the Phase II Laboratory Study has been disregarded and removed from the Phase I Report. / Comment No. 66: Page 41, BT-1 (4-6 fi.) Anaerobic Biotic Ll8968-ID, first paragraph: The Agency disagrees with the conclusion stated here. The average loss of 1,2-DCA due to inherent laboratory conditions was 201.5 ppm. Therefore, it can be argued that the loss of 1,2-DCA from 500 ppm to 365 ppm over 28 days was not due to anaerobic microbial activities but laboratory conditions. Response No. 66: As discussed and agreed upon with USEPA during the conference call on July 9, 1998, the Phase II Laboratory Study has been disregarded and removed from the Phase I Report. I ✓Comment No. 67: Pages 41 + 42, BT-I (4-6 ft.) Anaerobic Biotic Ll8968-1D, carry over sentence; This sentence highlights the need of"requiring oxygen and nitrate in generous levels", however, Phase II proposes not addition of moisture or nutrients. Please explain. Response to Comments -Phase I NDTS (final) 28 July 16, 1998 I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NOTS ENVIROGEN Project No. 78504 Response No. 67: As discussed and agreed upon with USEPA during the conference call on July 9, 1998, the Phase II Laboratory Study has been disregarded and removed from the Phase I Report . ./ Comment No. 68: Page 42, BT-2 (4-6 ft.) Anaerobic Abiotic L18985°5B, first sentences; these sentence states "minor anaerobic promulgation". The data does note support this statement. The plate count at Day= 0 was <l 00 and the plate count at Day= 28 was <l 00. / ./Response No. 68: As discussed and agreed upon with USEPA during the conference call on July 9, 1998, the Phase II Laboratory Study has been disregarded and removed from the Phase I Report. Comment No. 69: Page 43, Bt-2 (4-6 ft.) Aerobic Biotic L18985-5D, Summary, first paragraph, and second sentence: Refer to comment #67 above. / Response No. 69: Refer to response to USEPA Comment #67. Response to Comments -Phase I NDTS (final) 29 July 16, 1998 I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NOTS ENVIROGEN Project No. 78504 COMMENTS FROM NATIONAL RISK MANAGEMENT RESEARCH LABORATORY (NRMRL) General Comments ./ Comment No. 1: Early in the report, a discussion is needed to explain how the data that were collected, both in the field treatability study and the laboratory treatability study, can be used and/or interpreted to determine whether the study objectives were met. For example, what changes in the field soil- gas data (i.e., oxygen, methane, carbon dioxide, and hydrogen sulfide) were the investigators looking for as evidence for biodegradation and how much of a change in each parameter is considered significant? Similarly, it is not clear how groundwater chemical data support the objectives of this study, which were aimed at determining the occurrence of intrinsic biodegradation of 1,2-DCA in the vadose zone soils. The laboratory treatability (microcosm) tests included a number of analytical parameters ( e.g., contaminants, microbial counts, hydrogen sulfide, methane, nitrate); however, the conclusions of these experiments are based almost entirely on the observed changes in 1,2-DCA concentrations over the study period. This type of infom1ation typically is included in the project work plan, but should also be included in the report so that the report can stand alone. Response No. 1: A brief discussion of the intended use of data collected, both in the field treatability study and the Phase I laboratory study, will be added to the report. Groundwater data was presented in the text at the request of the NRMRL and the approved Work Plan. NSCC agrees that the groundwater data does not support the objectives of the NDTS. A discussion of the results of the Phase I laboratory study will be added to the report. /comment No. 2: The report does not provide adequate discussion and interpretation of the results. In general, the report is focussed on delivering the data, but the task of interpretation is left largely to the reader. Response No. 2: NSCC respectively disagrees and feels the Phase I field study data were adequately presented and discussed. The interpretation of data was focused on demonstrating that the objectives of the Phase I field study were met, which in the opinion ofNSCC was achieved. /comment No. 3: The authors should provide a concise literature review of aerobic and anaerobic DCA degradation. This review should show an understanding of the reported DCA degradation pathways, the frequency of DCA degradation observed under aerobic and anaerobic conditions, and reports ofDCA degradation at different field sites. The literature review also should address natural attenuation in the vadose zone, reported for DCA or other contaminants, if available. It should also show how the work that was conducted for this study compares with work by others Response to Comments~ Phase I NDTS (final) 30 July t 6, t 998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 at natural attenuation sites. The literature review should also provide the basis for the study approach and research objectives, to demonstrate that they are founded on work that has been conducted for DCA degradation and for natural attenuation in vadose zone soils. Response No. 3: A literature review of aerobic and anaerobic 1,2-DCA degradation pathways has previously been provided to the USEPA (prepared by IT Corporation on March 31, 1994). Additionally, NSCC agrees to update the literature review of degradation pathways and include available case study information on natural attenuation of 1,2-DCA. This document will be submitted under separate cover by July 31, 1998. Section 2 -Laboratory Biotreatability Study (LBS) /comment No. 1: The location of the sample locations (i.e., BT-I, BT-IA, BT-2, BT-2A) for the LBS are not provided on a site map. Response No. 1: A site map with these sample locations will be provided. / Comment No. 2: This section of the report is light and only gives a brief overview of the two phases of the lab effort. Three objectives were slated in Section 2.1 and the results presented in Section 2.5 suggest that these objectives were met. It was not possible from reading Section 2.0 to determine that the methods were appropriate or that the data supported the claims presented in Section 2.5. There are no results presented for the Phase I LBS in Section 2.0 (i.e., the Phase I report in Appendix A was referenced only for the methods used for the listed analytes). Overall, the section is incomplete and contributed little to providing support that the three objectives were met. This led to the need to review the information reported in Appendix A. Response No. 2: A discussion of the results of the Phase I laboratory study will be added to the report. As agreed upon during the July 9, 1998 conference call, results of the Phase II laboratory study have been removed from the report. /comment No. 3: Page 2-2. What is the purpose of the partitioning experiment? It does not appear to be used after it is discussed. Is there an interest in modeling the fate and transport of DCA, or calculating total mass based on the measurement of one medium (soil, water, or air)? If so, this is not clear. It also would be interesting to compare the values measured in the laboratory with field-measured values. For example, it was interesting to see very hikh soil-gas DCA concentrations measured in the field. How do these compare with the gas/liquid DCA distribution measured in the laboratory? Response to Comments -Phase l NDTS (final) 31 July I 6, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 Response No. 3: Results of the Phase II laboratory study have been removed from the report. Section 3 -Soil Plots and Soil Gas Monitoring Wells / Comment No. 1: Eleven soil borings were drilled in the four soil plot areas to confirm the presence/absence of VOC contamination and to optimize locations for eight-soil gas monitoring wells. Only one sample was collected from the background soil boring, not two as indicated in the text. Response No. 1: The text has been corrected to reflect one soil sample collected from the background soil boring. ,I Comment No. 2: The locations of all eleven-soil borings (BT2 through BTJ 3) are not shown on Figures 3.1 and 3.2 (BT3, BT7, BTS, BTJO, BT] l, and BTJ3 not shown). Although their locations can be deducted from the information provided on Table 3.1, it would be more convenient for the reader to show their location of Figure 3.1 and 3.2. Response No. 2: The location of all eleven-soil boring has been added to Figures 3.1 and 3.2. /comment No. 3: Page 3-1 Typo: Second paragraph refers to Table 3-1 for soil sample results. The table itself says that is shows soil gas results. Response No. 3: The typo has been corrected. I Comment No. 4: Figure 3.2 shows 3 unidentified soil borings along with 1,2-DCA concentrations and the depth where the contamination was measured. These borings are not mentioned in the text. Response No. 4: Borings are soil sampling locations presented in the Final Remedial Investigation Report dated June 3, 1993. These borings will be removed from the Figure. / Comment No. 5: Figures 3.1 and 3.2 show 1,2-DCA concentration contour lines. Are these concentrations in soil (presumably)? lfso, what data were used to draw these contour lines? Response to Comments -Phase I NDTS (final) 32 July 16, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 Response No. 5: These contours are from the Remedial Investigation performed by IT Corp and presented in the Final R1 Report dated June 2, 1993. A footnote has been added to the Figure for clarification . . J Comment No. 6: The construction details for the soil plots are somewhat vague. For example, were the boxes placed in an excavation or did they sit on land surface? Are the boxes open on the bottom? What purpose did the boxes serve? Response No. 6: The term "boxes" is misleading. They are actually covers or access hatches. The covers were installed by removing the concrete (approximately 6" thick) and cementing the covers in place over the open soil. The.purpose of the covers was to prevent precipitation from entering the Plots as well as provide access to the soil for moisture and nutrient addition and soil sampling. Section 4 -Treatment and Monitoring Activities /Comment No. 1: The locations of the monitoring wells where water levels were recorded during the test period are not shown. Nor is it clear where groundwater samples were collected for chemical analyses. The text only indicates that the samples were collected in the vicinity of the soil plots. Response No. 1: A figure depicting the location of referenced monitoring wells has been added. As discussed and agreed upon with USEPA during the conference call on July 9, 1998, the groundwater chemical analyses have been removed from the Phase I report. / Comment No. 2: The text reports that 3.6L water were added per plot (plots 2 and 3). This is equivalent to 3.6 L/ (28 Lift) -0.128 ft-222 in'. The plot area is 4'x6' -24 ft= 3456 in'. Thus, the number of inches added per week in equivalent to 222/3456=0.06 inches of water added per week, or 0.25 in/month. This is only 7% of the monthly rainfall, which averaged 3.5 in/mo. Not to mention that it is only a fraction of the total water content in Plots 2 and 3. Thus, it is unlikely that the moisture addition provided a statistically significant increase in soil moisture contents of Plots 2 and 3. Response No. 2: The National Risk Management Research Laboratory was very concerned about the quantity of water added during the development of the Work Plan for the Phase I study. The NRMRL wanted to ensure soil flushing was not occurring. Consequently, water addition to Plots 2 and 3 was performed in accordance with the USEPA-approved RD/RA Work Plan for OU4. Response to Comments -Phase I NDTS (final) 33 July 16. 1998 ,, I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 / Comment No. 3: Page 4-3. How were soil samples collected? Were these 2-inch split spoons? If so, were individual borings composited before sampling? Were they stored in jars, preserved ... ? Response No. 3: Soil sample collection was performed in accordance Sampling and Analysis Plan in the RD/RA Work Plan for OU4. Soil samples were collected with 2-inch split spoons from discrete intervals (i.e., soils were not a composite), and were placed in amber jars without preservatives and store on ice. /Comment No. 4: Because the infrared gas analyzer is non-specific, one should not depend on it for methane measurements in the presence of high contaminant concentrations. Response No. 4: The potential interference of organic contaminants on the field measurement of methane was noted in the text (page 5-9, second paragraph). NSCC is investigating the use of another type of instrument to collect methane readings during Phase 11. / Comment No. 5: What was the expected impact of the NOTS on contaminant concentrations in groundwater? What analysis (e.g., statistical) was perfom1ed to determine ifan impact occurred? Was this an objective of the study? Response No. 5: As discussed and agreed upon with USEPA during the conference call on July 9, 1998, the impact to groundwater of contamination in the vadose zone soil was not an objective of the Phase 1 NOTS. The chemical analyses for groundwater has been removed from the Phase I report. J Comment No. 6: What was the purpose of monitoring SGMWs 5 through 8, which are located outside of the soil plots? Response No. 6: To monitor and establish that the natural degradation of 1,2-dichloroethane is occurring in Area 2 and near the Lagoon Area . /Comment No. 7: What were the expected changes in each of the soil parameters (see Table 4-2) and soil-gas parameters (CH,. 0 2_ CO,. H,S) that were monitored during the test period? What analyses ( e.g., statistical) were perfonned to determine if a significant change occurred? What were the detection limits for the soil gas analyses? Response to Comments -Phase I NDTS (final) 34 July 16, 1998 I I I I I I: I I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 Response No. 7: The purpose of the soil parameters listed in Table 4-2, with the exception of the volatile organic compounds (VOCs), was to establish a that the geochemical environment in the saprolite was conducive to natural attenuation. Analysis of the VOCs was to demonstrate the loss of mass of contaminant and the presence of intermediates (vinyl chloride and chloroethane) of anaerobic degradation of 1,2-DCA. A seasonal fluctuation in the soil-gas parameters listed in Table 4-2 was expected. Given the dramatic fluctuation in soil-gas parameters a statistical trend analysis was not needed. The laboratory detection limits for CH2_ 0 2_ and CO2 were 30 ppmv, 1.0% and 0.1 % by volume, respectively. H2S was not analyzed for in soil-gas samples submitted for laboratory analysis. Section 5 -Results /Comment No. 1: Water level elevations (Figure 5.2) could be better compared with the precipitation data if both had been collected at the same frequency. Also, some background information on the location and constmction of the wells (e.g., screen depth, and lithology) would be helpful in understanding the significance of the water level data. For example, how are water levels correlated with the water levels beneath the soil plots (i.e., how does the thickness of the vadose zone in the soil plots change with the changing water levels)? Response No. 1: Well location and constmction details will be added to the report. /comment No. 2: The first water quality program (with respect to time) was conducted October I 6, 1996, not January 28, 1997 as stated here (and also in Section 4). Response No. 2: This oversight has been corrected. /Comment No. 3: The summary of groundwater quality data is difficult to read and could be better presented in a table format listing the following information: well, sampling event, contaminants detected, and their maximum concentrations. What is the significance of the groundwater quality data presented here? Response No. 3: Groundwater quality data was not the focus of the Phase I NOTS study and was reported here at the request of the NRMRL and as specified in the approved RD/RA Work Plan for OU4. As agreed to during the conference call of July 9, 1998, discussion of the groundwater quality data will be removed from the text of the report. Response to Comments -Phase I NOTS (final) 35 July 16, 1998 I I I I I I I I I I I I NSCC Response to Comments on Phase I NOTS ENVIROGEN Project No. 78504 /Comment No. 4: Page 5-1 DCA byproduct concentrations, particularly VC, were inconsistently detected in groundwater; does this correspond to aerobic/anaerobic trends? Was VC measured reliably in the laboratory? A significant fraction of the VC measurements appear to be qualified by U or J qualifiers in the data tables. Response No. 4: See response to NRMRL [Section 5 -Results] Comment #3 / Comment No. 5: ls there a possible source of the methylene chloride and acetone that was detected in the groundwater? (It was suggested that they could be laboratory contaminants, based on the detection of these compounds in a lab blank associated with samples from NS-35/46 (acetone) and NS-39 (methylene chloride). However, they apparently were not detected in lab blanks associated with other samples/wells that contained acetone and methylene chloride). Response No. 5: See response to NRMRL [Section 5 -Results] Comment #3 /comment No. 6: What is the suspected source of carbon disulfide detected in wells NS-35 and NS-36? Response No. 6: See response to NRMRL [Section 5 -Results] Comment #3 /' /Comment No. 7: The soil moisture data do not appear to follow significant trend, especially in plots I (natural conditions) and 2 (moisture only). Was a statistical trend analysis perfom1ed on these data? Response No. 7: I A statistical trend analysis was not performed on the soil moisture content data. I I I I I I / Comment No. 8: I-low was soil moisture determined (i.e., method)? This parameter is not listed on Table 4.2 with the other soil parameters that were monitored during the test. Presumably, each soil moisture data point represents an average of 3 soil samples collected in the respective soil plot. Response No. 8: Soil moisture contents were determined using a gravimetric method (mass basis). As specified in Table 5-3, reported soil moisture contents are an average of 3 soil samples collected in the respective soil plot. Response to Comments -Phase I NDTS (final) 36 July I 6, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 -comment No. 9: Page 5-3. As pointed out in the text, the bacterial enumeration's that were performed for anaerobic heterotrophs are of limited value because they do not account for organisms that are involved with the reductive dechlorination pathway. At the end of the page, the authors note that the numbers of cultivable bacteria in samples vary considerably with the media used and incubation conditions. The authors also should note that these results have no direct correlation to 1,2-DCA-degrading bacteria in soils. Unless the heterotrophs or ferrnenters are tested against 1,2-DCA, all that these results can say is whether there are high or low heterotroph or fermenter populations in the soils. Other reasons for these bacteria could be natural organic matter or other contaminants. Furthermore, it doesn't appear that tests were conducted on clean soils, for comparison, so there is no way to know whether bacterial concentrations are higher in the contaminated plots than in uncontaminated plots. Response No. 9: NSCC acknowledges the fact that specific 1,2-DCA degrading bacteria were not enumerated in soil samples collected from the site. ✓comment No. 10: Tables 5-4 and 5-5 suggest extremely low bacterial populations. These results suggest either relatively sterile soils or experimental error. It is possible that the high DCA concentrations could be toxic? How would this fit with the conclusions that there was significant biodegradation at the site? lfthe authors believe that biodegradation was significant, then the bacterial counts cannot be correct. If this is the case, and due to the problems discussed in the previous comment, it is suggested that these results be moved to an appendix. Their presence in the body of the report suggests that the results provide some significant findings, but they are not referred to again in the report Response No. 10: The purpose of the NOTS was to provide lines of evidence that support the conclusion that natural attenuation of 1,2-DCA is occurring in the vadose zone at the Site. These lines of evidence include documenting the loss of contaminant (at field scale) and the presence of degradation intermediates, which are documented in the report. Given the observed variability in the bacteria enumeration data, use of this data to further support a natural attenuation argument was not warranted. However, these data do document the presence of total heterotrophic bacteria in the subsurface at the Site and therefore will be left in the main body of the report. /comment No. 11: Page 5-4. How do the isolate profiles compare with DCA-degrading bacteria reported in the literature? A more interesting test than the profile test, and better use of time, would have been to test the isolates for DCA degradation. Response to Comments -Phase I NDTS (final) 37 July 16, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NOTS ENVIROGEN Project No. 78504 Response No. 11: The genera of bacteria identified at the site included Pseudomonas, Micrococcus, Bacillus and Corynebacterium. Of these bacteria, which are commonly found in soils', at least five facultative strains of Pseudomonas that are able to utilize 1,2-DCA as a sole carbon source for growth have been isolated'. /comment No. 12: Page 5-5. At the end of this section, increases in DCA concentrations in plots 2 and 3 are discounted, suggesting that they are an aberration -a result of a few highly contaminated, non- representative soil samples. This statement is not supported by the data, suggested by the following review of Table 5-10.1) This table shows ratios of standard deviation to average values reported for each date, in Table 5-10. The ratios remain relatively constant for each site, reputing the authors' argument that 'the increase during the last three to six months ... may be a result of the collection of a few highly contaminated soil samples that may not be representative of the Soil Plots as a whole." If this were the case, one would expect much higher relative standard deviations for the last three months of data than the first six months of data. In fact, for Plot 3, the relative standard deviation for total DCA concentrations decreases from the first to the last sample point, except for the 9/11 data. In soil plot 2, the values remain relatively constant except for the G/17 data, and in Soil Plot 1, they increase. The increase in Plot 1 is not surprising, since more scatter is expected with lower measured concentrations. Thus, Soil Plot 1 provides the only real evidence for decreasing DCA concentrations. It is also of interest to note that soil gas concentrations remained much more constant over time than the soil concentrations. In some ways, soil-gas concentrations may provide a stronger indication ofDCA reductions, because of their averaging affect due to soil gas diffusion and mixing. On the other hand, they tend to be relatively nonspecific because of soil gas migration. Response No. 12: NSCC agrees that data collected from Soil Plot 1 provides the best evidence for decreasing 1,2- DCA concentrations. /comment No. 13: Page 5-8. Explain why metals and inorganic anion and cations were measured and what the results suggest, if anything. Response No. 13: These analytes were measured in accordance with the approved RD/RA Work Plan for OU4 and provide supporting infom1ation that the geochemical conditions in the saprolite are suitable for natural attenuation. ' Alias, R.M, and R. l3artha. 1981. Microbial Ecology: Fundamentals and Applications. Addison-Wesley Publishing Co., Reading Massachusetts. pg. 215. 2 Jassen, D.B., J.R Plocg, and F. Pries. 1994. "Genetics and biochemistry of l,2-dichloroethanc degradation." Biodcgradation Vol. 5 pp:249-257. Response to Comments -Phase I NDTS (final) 38 July 16, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 /comment No. 14: Page 5-9. The high methane concentrations could be due in part to the non-specific infrared analyzer. The Summa canister gas analyses showed much lower methane analyses. Response No. 14: Refer to response to NRMRL [Section 4-Treatment and Monitoring Activities] Comment #4. /Comment No. 15: The authors reported difficulty measuring soil gas in the deeper soil gas wells. This is not at all surprising, when the depth to groundwater was less than 5 ft for most of the year. Consider moving the soil gas well up one foot. Response No. 15: During Phase I of the NOTS, depth to water in monitoring well NS-39 and NS-40 ranged between 8.08 and 12.25 feet. These monitoring wells are located near Lagoon 2 or Soil Gas Monitoring Wells 7 and 8 .. Depth to water in monitoring well NS-35 and NS-36 ranged between 3.42 and 4.56. The surveyed elevations of the top of these wells are 746.11 and 745.59, respectively. These wells arc located near the Northeast Tributary at a topographic low. Ground surface of Area 2 is approximately 20 to 25 feet higher in elevation than the Northeast Tributary. Consequently, the depth to water in wells NS-35 and NS-36 indicate that the water table is approximately 20 to 25 feet below ground surface in Area 2. For your information, depth to water in monitoring well NS-47 was recorded at 23.5 feet in January 1997. This well is located next to Soil Gas Monitoring Well 5 and 6. This well is screened between IO and 40 feet below ground surface and the surveyed elevation of top of casing for this well is 769.92 feet. This well also indicates that the water table is located approximately 20 below the ground surface in Area 2. Section 6 -Discussion ✓ Comment No. 1: Figure 6-1 would be much more appropriate in the beginning of the report. It would be nice to have a briefliterature review of DCA degradation. Also, it would be nice to show anaerobic DCA transformation reactions in a similar figure to 6-1 Response No. 1: A literature review of 1,2-DCA degradation pathways will be submitted under separate cover and a figure depicting the anaerobic degradation pathways will be added to the report. / Comment No. 2: Page 6-2. Last paragraph. This conclusion should be corrected because there was no evidence for just a few highly contaminated soils, any more than previous samples. Response to Comments -Phase I NOTS (final) 39 July 16, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NOTS ENVIROGEN Project No. 78504 Response No. 2: The paragraph in question will be deleted and the conclusions regarding mass estimates of 1,2- DCA in soil revised to reflect the response to USEPA Comment #34. / Comment No. 3: It's unfortunate that aerobic metabolites were not measured. ls this because they are difficult to measure, because of their short half-lives, or because, as the text says, they are not commonly measured? If the latter, then it is suggested that they be measured during the next phase of sampling. They need only be measured in selected samples, for a qualitative confirmation of aerobic DCA degradation. Response No: 3: Refer to response to USEPA Comment #46. /Comment No. 4: Page 6-3. The authors conclude that no CO, increase was measured because DCA was incompletely degraded to chloroacetate or chloroacetaldehyde. This is speculative, and there is no direct evidence for this conclusion from the field data. It is also possible that there was less degradation than expected. Also, this dead end would not be expected under cometabolic degradation, where CH, is used as the cosubstrate, which the authors argue is possible due to the high soil gas CH, and 0 2 concentrations. !fit is true that the mass ofDCA degraded is as high as reported, and most of the DCA does not go to CO2 it should not be difficult to measure these aerobic metabolites. Response No. 4: The discussion only put forth a possible explanation of aerobic degradation of 1,2-dichloroethane without the fonnation of the final product carbon dioxide. This phenomenon is supported by the referenced literature. /comment No. 5: There is no discussion of the bacterial counts and DCA soil gas measurements. If these results have little significance, it may be more appropriate to put them in an appendix. Response No. 5: Refer to response to US EPA Comment #39 concerning soil bacterial counts. The primary purpose of the Summa canister sampling was to detect anaerobic 1,2-DCA degradation products that arc very volatile (chloroethane, ethane, chloroethene, ethcne, and methane), which arc discussed on Page 6-3, last paragraph. These data will therefore be left in the main body of the report. Response to Comments -Phase I NDTS (final) 40 July 16, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NOTS ENVIROGEN Project No. 78504 Section 7 -Summary and Conclusions /comment No. 1: I. Soil gas samples suggest that degradation may be relatively slow. They do not correspond well with the soil concentrations, which showed dramatic OCA decreases. This should be discussed. Response No. 1: The soil gas data demonstrates a dynamic system in the vadose zone. This fact is recognized and will be considered when a developing a program for Phase II. Section 8 -Recom111endatio11s /comment No. 1: While it is likely that a larger number of samples will improve the study, no further sampling should be conducted without first developing a statistically based sampling plan (i.e., how many samples are required to meet the data quality objectives of the study? What are the data quality objectives of the study?). Otherwise, the shortcomings of the current study will be repeated. Suggest adding chloroacetate and chloroacetaldehyde analyses. Response No. 1: NSCC will consider the Agency's recommendation when preparing the scope of work for the Phase II study and is prepared to meet with the Agency to discuss and agree upon an approach and work plan to execute Phase II of the NOTS. /comment No. 2: The soil data collected during the first phase of the study should be used to estimate the number of soil samples required to reliably quantify the average contaminant concentration in the soil plots. lfthe number of samples is prohibitive, consider homogenizing the samples before analyses are performed. Because of the volatile nature of the contaminant(s), consideration should be given to how this could be accomplished with minimal loss of the contaminant(s). I Response No. 2: NSCC will consider the Agency's recommendation when preparing the scope of work for the Phase II study. NSCC will meet with the Agency to discuss an approach to execute Phase II of the NOTS. / Comment No. 3: To properly evaluate the effectiveness of intrinsic biodegradation for remediating contaminated soils at this site, the study should also quantify mass removal via mechanisms other than biodegradation. In fact, from the data that were collected during the phase I field treatability study, it is not certain whether the (apparent) decreases in OCA soil concentrations that were ' observed were due to biodegradation or if they were the result of other processes (i.e., leaching, volatilization). Volatilization losses could be assess~d measuring contaminant concentrations in Response to Comments -Phase I NDTS (final) 41 July 16, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 the soil gas over time. Suction lysimeters or similar devices could be considered for collecting leachate samples to assess contaminant removal via leaching. This is especially important for Phase II, which is aimed at determining the rates of intrinsic biodegradation. Response No. 3: NSCC will consider the Agency's recommendation when preparing the scope of work for the Phase II study. NSCC will meet with the Agency to discuss an approach to execute Phase II of the NOTS. /Comment No. 4: The percent oxygen and percent methane plots demonstrate a dynamic system in the vadose zone soi I gas. There are several qualitative conclusions that can be drawn from this information. First, the repeated depletion of oxygen demonstrates that there is aerobic degradation in the vadose zone. It remains unclear how much of that oxygen uptake is due to OCA, toluene or other aerobically degraded contaminants, or natural organic matter (NOM). However, because the oxygen depletion in the contaminated plots (Plots I, 2 or 3) is greater than in the uncontaminated plot (Plot 4), it appears that at least part of the oxygen depletion is due to soil contaminant degradation. It would be useful to analyze these trends more carefully, using the existing data and/or collecting additional data. One type of additional data that could be collected would be oxygen data from an additional clean area soil gas well to provide a replicate for SGMW-4. Response No. 4: NSCC will consider the Agency's recommendation when preparing the scope of work for the Phase II study. NSCC will meet with the Agency to discuss an approach to execute Phase II of the NOTS. /comment No. 5: The fact that oxygen is repeatedly replenished after it is depleted is likely due to soil gas flushing from winds or differential gas pressures in the vadose zone. Although this is not unusual, often continuously depressed soil gas oxygen concentrations are common at sites where there is a very high oxygen demand. For example, at sites with high BTEX concentrations in the vadose zone, one would not expect oxygen levels to return to 20%, but would expect anaerobic conditions to persist (i.e., less than 5% oxygen with high methane concentrations). The implication here is that DCA degradation, if it is occurring, is relatively slow. Thus, other processes, such as leaching or stripping, may play relatively important roles in OCA attenuation. Response No. 5: NSCC will consider the Agency's recommendation when preparing the scope of work for the Phase ll study. NSCC will meet with the Agency to discuss an approach to execute Phase II of the NOTS. Response to Comments -Phase I NDTS (final) 42 July 16, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NOTS ENVIROGEN Project No. 78504 / Comment No. 6: The authors also may attempt to quantify the OCA mass degraded due to oxygen depletion at the site. The oxygen mass loss would have to be estimated, and a certain percentage of this mass would have to be attributed to OCA. Clearly, this is a difficult task, especially if air flux rates are not known. However, this kind of calculation can give the reader an idea of the approximate OCA degradation values and whether OCA degradation is expected to be significant. How do these values compare to the aerobic laboratory OCA degradation rates? Response No. 6: NSCC will consider the Agency's recommendation when preparing the scope of work for the Phase II study. NSCC will meet with the Agency to discuss an approach to execute Phase II of the NOTS. / Comment No. 7: ls there ant way of assessing the OCA mass degraded via oxygen uptake tests? For bioventing sites, oxygen uptake rate tests are commonly conducted to assess the oxygen demand and to establish the air injection rates. Similar tests may be considered for this site. Response No. 7: NSCC will consider the Agency's recommendation when preparing the scope of work for the Phase II study. NSCC will meet with the Agency to discuss an approach to execute Phase II of the NOTS. / Comment No. 8: We would suggest adding chloroacetate and chloroacetaldehyde analyses. Response No. 8: NSCC will consider the Agency's recommendation when preparing the scope of work for the Phase II study. NSCC will meet with the Agency to discuss an approach to execute Phase II of the NOTS. Appendix A -Laboratory Biotreatability Study (LBS) -Phase I B/Oreport #1060 Comments marked with'***' will not be addressed per the direction ofUSEPA's letter of May 26, 1998. / Comment No. 1: *** This report is simply a compilation of tables containing results from various soil analyses that were conducted on the samples collected from the site. No discussion is provided of the data that were collected during this phase of the LBS and/or their importance with regards to biological activity in the soils. In particular, the primary objectives of the Phase I LBS, in addition to confinning the presence of 1,2-0CA and characterizing the microbial consortium, was to determine whether nutrients are available in sufficient quantity to promote biodegradation, and; Response to Comments -Phase I NDTS (final) 43 July I 6, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NOTS ENVIROGEN Project No. 78504 whether other factors (e.g., moisture, pH, metals) could be limiting biodegradation. It appears that the data were use in the second phase of the treatability study. / Comment No. 2: *** In reviewing the data, it was assumed that the letter A in the Sample I.D. represented a replicate sample. For example, BT-lA 4-6 was a replicate ofBT-1 4-6. If this is the case, the following observations were made. / Comment No. 3: *** The repeatability between replicates for DCA, phosphorus, iron and TOC concentrations, microbial counts, pH, and moisture content was poor. There was no discemable trend in the lack of repeatability. This led to some concern as to the replication of sampling and/or the repeatability of the analyses. There was no quality control data presented, making the data suspect. / Comment No. 4: *** The tables should include columns listing the method detection limits. /comment No. 5: *** The microbial counts should be in scientific notation. Appendix A -Laboratory Biotreatability Study (LBS) -Phase II B/Oreport #1060 ./ Comment No. 1: Page 3. Objectives. The first objective was to determine the feasibility of successfully implementing bioremediation at the site in question. This objective was not met. The second objective was to confirm that indigenous microorganisms were capable of degrading DCA. The soils from BT-I were bioaugmented with an enriched culture from BT-2. It appeared that the two soils were from two distinctly different locations and the organisms from BT-2 were not indigenous to BT-I. Therefore, the objective was not met for BT-1. Response No. 1: As agreed upon during the conference call of July 9, 1998 all results of the Phase II laboratory study will be disregarded and therefore this comment has not been addressed. ./ Comment No. 2: *** Page 3. Methods. A major weakness of the study was the lack ofreplicates for each experimental condition and statistical validation of the difference between treatments and controls. In general, the methods section is weak and provides insufficient information to adequately support the data. Response to Comments -Phase I NOTS (final) 44 July I 6, 1998 I I I I I I I I I I. I I I I I I I I I NSCC Response to Comments on Phase I NOTS ENVIROGEN Project No. 78504 /Comment No. 3: ••• Bacterial enumerations were performed using a standard spread plate technique. It was not apparent that the plates from the anaerobic flasks were performed under anaerobic conditions. If this was not the case, the data from the anaerobic flasks are meaningless. ·/comment No. 4: ••• Nutrient Analysis. If the point is that the nutrients were not limiting, why was nitrate added to the flasks? /comment No. 5: ••• Carbon Dioxide Generation. How was the sample collected and the analysis performed? ./ Comment No. 6: ••• Confirmation of Contaminant Degradation. This section should explain the sampling and analytical methods used to monitor the fate of the DCA and the production of intermedtates. The discussion of the flask setup is incomplete. How much soil was in each flask? What were the pH and soil moisture? Was the soil added as a slurry? If not, what was the purpose of rotating the flasks? / Comment No. 7: Page 4. Addition of Indigenous Microorganisms. Why were BT-! soils inoculated with BT-2 organisms? Doing this provides some information on the bioaugmentation potential but excludes data on the ability of indigenous organisms to degrade DCA. Was the same enrichment procedure (aerobic is assumed) used for both the aerobic and anaerobic conditions? If so, what was the reasoning behind this? How much nutrient remained in the culture broth that was added in the IO mL of culture? This could account for the increase in microbial numbers seen at the beginning of the experiment. Response No. 7: As agreed upon during the conference call ofJuly 9, 1998 all results of the Phase II laboratory study will be disregarded and therefore this comment has not been addressed. /comment No. 8: ••• Where is the addition of nitrate explained and why was this done? It would be necessary to compare DCA degradation in microcosms with and without nitrate to evaluate any potential benefit. ✓Comment No. 9: ••• Where is the spiking ofDCA described? One soil from Bt-1 4-6 showed 7,400 ppb DCA and the replicate was non-detect. Was DCA measured in the BT-! 4-6 soil prior to spiking? If there was no DCA, was it assumed that the microbes in this soil had previously been exposed to the compound? If the soil wasn't contaminated, what was the reasoning for including it in the lab study? Response to Comments -Phase I NDTS (final) 45 July 16, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NOTS ENVIROGEN Project No. 78504 Appendix A -Laboratory Biotreatability Study (LBS) -Phase II BIOreport #1060: AerobidAbiotic Results / Comment No. 1: *** Page 5. If the flasks were effectively killed, the CO2 data show significant variation. It would be beneficial to know how the CO2 was sampled and analyzed. /comment No. 2: *** Page 6. The DCA loss under abiotic conditions is high. It would be beneficial to know the design of the modified biometer flasks, how the microcosms were set up, and how they were sampled and maintained aerobic. With I 00 grams of soil in a I-liter flask, there is a large potential for volatile loss during headspace exchanging. Appendix A -Laboratory Biotreatability Study (LBS) -Phase II BIOreport #1060: AerobidBiotic Results ✓Comment No. 1: Page 9. The large decrease in microbial counts suggests that the soil was not capable of supporting the dense population of organisms. The brief increase suggests that the substrate and nutrient in the transfer fluid may have supported limited growth. What did the bacterial identification look like in the inoculum and the soil both before and after incubation? Response No. 1: As agreed upon during the conference call of July 9, 1998 all results of the Phase II laboratory study will be disregarded and therefore this comment has not been addressed. Appendix A -Laboratory Biotreatability Study (LBS) -Phase II BIOreport #1060: AnaerobidAbiotic Results /comment No. 1: *** Pages 13 and 14. The CO2, nitrate, and DCA data suggest that these microcosms were not effectively killed. Was an aerobic plate count method used to enumerate the microbial population? If so, why? (Note: Similar comments can be made throughout the presentation of the results. Overall, insufficient detail was provided on the experimental setup and the sampling I and analytical procedures to readily accept the trends seen in any of the data). ' / Comment No. 2: *** Page 39. Discussion. The opening paragraph is lacking in technical validity. Response to Comments -Phase I NDTS (final) 46 July 16, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 / Comment No. 3: *** Third paragraph. It is not clear why DCA was added to achieve 500 ppb in the BT-I soils. If there was no DCA present, why were these soils included in the test? The study should have been conducted using soil from a contaminated area. / Comment No. 4: Fourth paragraph. Why was 500 ppm nitrate added to the soil? Is it recognized that adding enriched cultures from BT-2 negated the effect of indigenous microbes in BT-I? Response No. 4: As agreed upon during the conference call of July 9, 1998 all results of the Phase II laboratory study will be disregarded and therefore this comment has not been addressed. ,/ Comment No. 5: *** Fifth paragraph. Where are the results of the mass balance? It is not clear how the flasks were sampled or what matrix (soil, headspace, or water) was sampled. Based on the results from the abiotic losses, it appears that a mass balance would be very difficult without analysis ofDCA in all of these matrices. ./ Comment No. 6: *** Sixth paragraph. This text is not clear and contributes nothing to the findings of this study. /comment No. 7: Page 40, second paragraph. If the soil was not "fresh," what was done to it between the time of sampling and the time of Phase II study? The sample holding method can have a dramatic effect on the microbiology as well as the contaminant characteristics of soils. In addition, the argument is made that it is not possible to add contaminant to a soil to stimulate actual conditions that are encountered in the field; but if that is the case, then why conduct this study? It is stated that part of this in-depth study was to determine if the microorganisms recovered are capable of degrading DCA because of consortium plasmid transfer, genetic lending, or bond transfer. These phenomena were not part of this study. Response No. 7: As agreed upon during the conference call of July 9, 1998 all results of the Phase II laboratory study will be disregarded and therefore this comment has not been addressed. Appendix A -Laboratory Biotreatability Study (LBS) -Phase II BIOreport #1060: BT-I (4-6) Aerobic Abiotic /4omment No. 1: ••• Page 40, fourth paragraph. The last sentence lacks scientific validity. Response to Comments -Phase I NDTS (final) 47 July 16, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 Appendix A -Laboratory Biotreatability Study (LBS) -Phase II BIOreport #1060: BT-I (4-6) Aerobic Biotic /comment No. 1: *** Page 40, fifth paragraph. The term "planted indigenous organisms" is incorrect. The increase and subsequent decrease of microorganisms could be due to the availability then disappearance of substrate transferred into the microcosm with the 10 mL inoculum. It was not clear whether the cells were centrifuged and washed prior to innoculation. It is not apparent that nitrate was used as an electron acceptor. There are no oxygen data to make this apparent. The term ''N03 radical" should be deleted. /comment No. 2: *** Page 40, last paragraph. The CO2 data are similar to the abiotic microcosm; if the abiotic microcosms were sterile, the data provide no evidence of microbial activity. Appendix A -Laboratory Biotreatability Study (LBS) -Phase II BIOreport #1060: BT-I (4-6) Anaerobic Abiotic /comment No. 1: *** Page 41, second paragraph. There seems to be some confusion between aerobic and anaerobic metabolism. Under anaerobic metabolism, electron acceptors other than oxygen are used. The soil contained plenty of iron and nitrate was added at 500 mg/L. Perhaps the lack ofDCA degradation in abiotic flasks was due to the lack of viable cells. /comment No. 2: *** Page 41, third paragraph. This argument for CO2 production is hard to accept. Based on the CO2 data, it seems more likely that the CO2 analytical method is flawed. / Comment No. 3: *** Page 41, fourth paragraph. In the abiotic control, one would like to assume that the DCA loss was nonbiological. The report needs more description on the experimental setup and the sampling methods to support the claim. I Appendix A -Laboratory Biotreatability Study (LBS) -Phase II BIOreport #1060: BT-I (4-6) Anaerobic Biotic / Comment No. 1: *** Page 41, fifth paragraph. This is the definition of "anaerobic metabolism." Response to Comments -Phase I NDTS (final) 48 July 16, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 /comment No. 2: ••• Page 42, second paragraph. While the data may suggest that aerobic metabolism is more rapid than anaerobic metabolism for DCA degradation, it is not clear that the microcosms were not manipulated to not reflect actual conditions in the field and that the results from this study are valid. Were the soils anaerobic in the field? Were they sampled anaerobically? Were they stored under anaerobic conditions at a temperature close to the in situ temperature? Appendix A -Laboratory Biotreatability Study (LBS) -Phase II BIOreport #1060: BT-2 (4-6) Anaerobic Biotic / Comment No. 1: ••• Page 42, fourth paragraph, second sentence. This statement is incorrect. / Comment No. 2: ••• Page 42, fourth paragraph, third sentence. This statement is incorrect. Nitrate and iron were both present in the soil. / Comment No. 3: ••• Page 42, fourth paragraph, last sentence. Do they mean anaerobic degradation? Methanogenesis is a strictly anaerobic process. Appendix A -Laboratory Biotreatability Study (LBS) -Phase II BIOreport #1060: BT-2 (4-6) Anaerobic Abiotic / Comment No. 1: ••• Page 42, sixth paragraph. What is the nitrogen radical? Appendix A -Laboratory Biotreatability Study (LBS) -Phase II BIOreport #1060: BT-2 (4-6) Aerobic Abiotic / Comment No. 1: ••• Page 43, third paragraph. Again, mixing probably had nothing to do with the loss of volatiles unless the soil was in a slurry and the flasks were open to the atmosphere. /comment No. 2: ••• Page 43, fifth paragraph. What alternate electron donor? · Response to Comments -Phase I NDTS (final) 49 July 16, 1998 I I I I I I ' I I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 Appendix A -Laboratory Biotreatability Study (LBS) -Phase II BIOreport #1060: BT-2 (4-6) Aerobic Biotic / Comment No. 1: *** Page 43, sixth paragraph. This is not surprising, because the cultures are aerobic. Appendix A -Laboratory Biotreatability Study (LBS) -Phase II BIOreport #1060: Summary (page 43) / Comment No. 1: *** The data suggest that aerobic degradation ofDCA can be supported. The anaerobic results are suspicious and more detail is needed to evaluate the results. The effects of nutrients cannot be evaluated based on the results from this study. There were no data on the indigenous o!ganisms in BT-I soils. There are no data to support the claims of apparent symbiosis, plasmid ·sharing, or individual species specificity. / Comment No. 2: *** Overall, this was a poorly designed and executed treatability study. The report is incomplete and inconclusive. It appears that the data required to meet the stated objectives were not obtained in the described experiments. Response to Comments -Phase I NDTS (final) 50 July I 6, I 998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 NCDENR Comments on Phase I Natural Degradation Treatability Study Progress Report For Operable Unit 4 List of Tables /comment No. 1: The titles given for Table 5-17 and Table 5-18 are Summary of Soil Ammonia Nitrogen Concentrations and summary of Soil Nitrate Nitrogen Concentrations, respectively. However, the titles for Table 5-17 and Table 5-18 is summary of Soil Nitrogen Ammonia Concentrations and summary of Soil Nitrogen Nitrate Concentrations, respectively, Please clarify this discrepancy. Response No. 1: Titles of tables have been revised to be consistent with List of Tables. /Comment No. 2: The title for Table 5-23 should be Monthly Summa Canister Sampling Results, Soil Gas Monitoring Wells 1, 2, 3 and 4. Please correct this oversight. Response No. 2: Table title has been corrected. / Comment No. 3: The title given for Figure 3-2 is Location of Soil Plots and Soil Gas Monitoring Wells in Lagoon Area. However, the title for Figure 3-2 is Location of Replication Plots and soil Gas Monitoring Wells in the Lagoon Area. Please correct this oversight. Response No. 3: Figure title has been corrected. / Comment No. 4: The titles given for Figure 5-15 and Figure 5-17 are Soil Concentration of Ammonia Nitrogen- Plot 1, Soil Concentration of Ammonia Nitrogen -Plot 2 and Soil Concentration of Ammonia Nitrogen-Plot 3, respectively. However, the titles for Figure 5-15, Figure 5-16 and Figure 5-17 are Soil Concentration of Nitrogen Ammonia-Plot 1, Soil Concentration of Nitrogen Ammonia -Plot 2 and Soil Concentration of Nitrogen Ammonia-Plot 3, respectively. Please clarify this discrepancy. Response No. 4: Titles of figures have been revised to be consistent with List of Figures. Response to Comments -Phase I NDTS (final) 51 July 16, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NOTS ENVIROGEN Project No. 78504 /comment No. 5: The titles given for Figure 5-18, Figure 5-19 and figure 5-20 are Soil Concentration ofNitrate Nitrogen -Plot 1, Soil Concentration of Nitrate Nitrogen -Plot 2 and Soil Concentration of Nitrate Nitrogen -Plot 3, respectively. However, the titles for Figure 5-15, Figure 5-16 and Figure 5-17 are Soil Concentration of Nitrogen Nitrate -Plot 1, Soil Concentration of Nitrogen Nitrate -Plot 2 and Soil Concentration of Nitrogen Nitrate -Plot 3, respectively. Please clarify this discrepancy. Response No. 5: Titles of figures have been revised to be consistent with List of Figures. NSCC Responses to USEPA and NCDENR Comments -USEPA General Comments / Comment No. 6: The title to this section should state 'NSCC Responses to USEPA and NCDENR Comments". Please correct this oversight. Response No. 6: Section title has been corrected. / Comment No. 7: The second sentence in response to US EPA General Comment No. 1 should state" ... (Refer to Figures 5.33 through 5.56)". Response No. 7: Sentence has been edited as suggested. / Comment No. 8: Response No. 5 states that Figure 3-1 was revised to indicate the location of soil sample BT-7. However, Figure 3-1 indicates the location of soil sample BT-6. Please clarify this discrepancy. Response No. 8: Figure 3-1 will be revised to include all boring holes, including BT-6 and BT-7. / Comment No. 9: Response No. 9 states that Table 5-14 (page 1 of5) has been revised to indicate that soil sample SP3-34-68 was sampled on November 13, 1996. However, Table 5-14 (page 1 of5) was not revised. Please correct this oversight. Response No. 9: SP3-34-68 was only analyzed for volatile organic compounds and not nutrients, metals, and other parameters. Therefore, it does not appear in Table 5-14. Response to Comments -Phase I NDTS (final) 52 July I 6, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 / Comment No. 10: Response No. 10 states that Table 5-14 (page 1 of5) has been revised to define the symbol"-". However, Table 5-14 (page I of 5) was not revised. Please correct this oversight. Response No. 10: Table 5-14 has been revised accordingly. /Comment No. 11: Response No. 12 referred to the letter submitted by Pace Analytical Services, Inc. on December 18, 1997. This letter included two attached chromatographs, which were inadvertently omitted. Please correct this oversight. Response No. 11: The chromatographs were intentionally omitted. The discussion in the text of the letter explains · the reasons for elevated detection limits. / Comment No. 12: Response'No. 29 should state "See page 39". Please correct this oversight. Response No. 12: Edited as suggested. LBS Results /comment No. 13: The second item in this section state that "Indigenous soil microorganisms are able to degrade 1,2-DCA under both aerobic and anaerobic conditions with the addition of nitrate to the soil". This statement is in sharp contrast to the conclusions presented in the Phase II BIOreport included in Appendix A. The Phase II BIOreport concludes, " ... the evidence weighs heavily for an aerobic form ofbiodegradation ... ". The anaerobic results obtained in the laboratory biodegradation study (LBS) indicated the lack of anaerobic biodegradation or, at a minimum, provided highly inconclusive results. Please clarify this discrepancy. Response No. 13: As agreed upon during the conference call of July 9, 1998 all results of the Phase II laboratory study will be disregarded and therefore this comment has not been addressed. Soil Plots and Soil Gas Monitoring Wells / Comment No. 14: The last paragraph of this section provides only a'portion of the information regarding the water infiltration dilemma as presented in the last paragraph of Section 3.0 in the previous submittal of the Natural Degradation Treatability Study, Revised Progress Report for Operable Unit 4. Please Response to Comments -Phase I NDTS (final) 53 July I 6, I 998 I I I I I I I I I I I I I I I I I I II NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 clarify this discrepancy. Furthermore, please provide additional detail regarding the approximate amounts of water removed from the soil plots, the time frame for removal in regards to the rain event, the method of removal, and the current status of the soil plots regarding rainfall infiltration. Response No. 14: Refer to response to USEPA Comment #12. Treatment and Monitoring Activities / Comment No. 15: The fourth paragraph of this section detail the addition of water and ammonium phosphate to Soil Plot 3. Furthermore, this paragraph states that the water and ammonium phosphate amendments were increased during the last three months. Please provide the technical-> justification for this change to the work plan. Response No. 15: Refer to response to USEPA Comment #15. Precipitation and Groundwater Elevation Monitoring /comment No. 16: This section details the collection of precipitation data at the NSCC site. However, it is unclear as to the purpose of this activity as the soil plots are covered and are intended to be sealed from rainfall events. Please clarify the intent of this activity. Response No. 16: Precipitation data for the site was included to show that incidental infiltration into the Soil Plots had minimal impact on the Phase I Study. Soil Gas Monitoring /tomment No. 17: ' The fourth sentence of the third paragraph of this section should state " ... was allowed to enter the canister at a predetermined flow rate." Please borrect this oversight. Response No. 17: Oversight has been corrected. Response to Comments -Phase I NDTS (final) 54 July 16, I 998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NOTS ENVIROGEN Project No. 78504 Groundwater Quality Data / Comment No. 18: The third sentence of the third paragraph of this section states that methylene chloride was detected at monitoring well NS-40 at a concentration of 180 micrograms per liter (ug/1). However, the last sentence of this paragraph states that methylene chloride was detected at monitoring well NS-40 at a concentration of 460 ug/l. Please clarify this discrepancy. Response No. 18: Chemical analyses for groundwater has been removed from the report as agreed upon during the conference call on July 9, 1998. / Comment No. 19: The third sentence of the fourth paragraph of this section states that the detection of acetone in monitoring well NS-40 at a concentration of 2,400 µg/1 was a laboratory artifact. The NC DENR questions the validity of this statement. Laboratory quality assurance/quality control procedures should have been implemented to prevent the detection of laboratory artifacts at this high of a concentration. Response No. 19: Groundwater quality data was not the focus of the Phase I NDTS study and was reported here at the request of the NRMRL and as specified in the approved RD/RA Work Plan for OU4. As agreed to during the conference call of July 9, 1998, discussion of the groundwater quality data will be removed from the text of the report. Bacterial Enumeration and Identification Data / Comment No. 20: The third paragraph of this section details the inability of the laboratory to properly incubate anaerobic bacteria. However, this section should be revised to include a statement that, at a minimum, the laboratory is able (or should be able) to properly count the amount of anaerobic bacteria present in a given soil sample at the onset of the biodegradation study. Response No. 20: NSCC believes that there is adequate discussion concerning the method used to incubate anaerobic bacteria. Therefore, no revision to the text has been made. Volatile Organic Compounds -Mass Estimates of 1,2-Dichlorethane (1,2-DCA) in Soil / Comment No. 21: The first sentence in the fourth paragraph of this section is repeated twice. Please correct this oversight. Response to Comments -Phase I NDTS (final) 55 July 16, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NOTS ENVIROGEN Project No. 78504 Response No. 21: Duplicate sentence will be deleted. / Comment No. 22: The fourth and fifth paragraphs of this section provide estimates of the 1,2-DCA losses incurred at each of the soil plots. However, the fourth paragraph indicates that the increase in 1,2-DCA concentrations is due to the spatial variability of the contaminants. Please provide some indication of the relative amount of error that may be attributed to the spatial variability of the contaminants. This discussion should also address the relative amount of error due to spatial variability regarding the large percentages of contaminant degradation noted in this section. Response No. 22: The main point here is to recognize that there is variability due to spatial distribution and this variation will be considered when developing Phase II. Inorganic Compounds / Comment No. 23: Pages 5-7 through 5-10 have been included twice. Please correct this oversight. Response No. 23: Duplicate pages will be deleted. Mass Estimates of 1,2-DCA in Soil / Comment No. 24: The second and third paragraphs of this section provide estimates of the 1,2-DCA losses incurred at each of the soil plots. However, the third paragraph indicates that the increase in 1,2-DCA concentrations is due to the spatial variability of the contaminants. Please provide some indication of the relative amount of error that may be attributed to the spatial variability of the contaminants. This discussion should also address the relative amount of error due to spatial variability regarding the large percentages of contaminant degradation noted in this section. Response No. 24: Refer to response to NCDENR Comment #22. Summary and Conclusions / Comment No. 25: The second item in the section entitled, Results of the laboratory biotreatability study indicate, states that "Indigenous soil microorganisms are able to degrade 1,2-DCA under both aerobic and anaerobic conditions with the addition of nitrate to the soil." This statement is in sharp contrast to the conclusions presented in the Phase II BIOreport included in Appendix A. The Phase II Response to Comments -Phase I NDTS (final) 56 July 16, 1998 I I I I I I I I I I I I I I I I I I 'I NSCC Response to Comments on Phase I NOTS ENVIROGEN Project No. 78504 BIOreport concludes that" ... the evidence weighs heavily for an aerobic form of biodegradation ... " The anaerobic results obtained in the laboratory biodegradation study (LBS) indicated the lack of anaerobic biodegradation or, at a minimum, provided highly inconclusive results. Please clarify this discrepancy. Response No. 25: Refer to response to NCDENR Comment #13. Recommendations / Comment No. 26: The fifth item in this section indicates that NSCC is proposing to reduce the list of analytical parameters in estimating the biodegradation rates. However, there is not mention of the analysis of the oxygenated, water-soluble compounds that are the products of aerobic degradati\O'e pathway. Please clarify why these parameters are not included considering that the laboratory biodegradation study indicated that the soils preferred the aerobic degradative pathway. Furthermore, the field biodegradation study indicated that, at a minimum, the aerobic degradative pathway was used in conjunction with the anaerobic pathway. Please provide additional information to indicate how the statistical analysis/regression analysis will be employed to determine the complete biodegradation rates. Response No. 26: NSCC will consider the Agency's recommendation when preparing the scope of work for the Phase II study. NSCC will meet with the Agency to discuss an approach to execute Phase II of theNDTS. Summary of Soil Sampling Locations and Sample I.D. / Comment No. 27: Table 4-3 (page 1 of 4) indicates that two soil samples were collected from soil sampling location 12, Soil Plot 1 on September 11, 1997. However, Figure 4-5 indicates that the two soil samples should have been collected from soil sampling location 22. Please clarify this discrepancy. Response No. 27: Table 4-3 (page 1 of 4) contained a typo. SPl-12-24 and SPl-12-68 should have been listed as SPl-22-24 and SPl-22-68, respectively, and have been changed. /comment No. 28: Table 4-3 (page 3 Of 4) does not indicate the collection of the soil sample SP3-34-6 on November 13, 1996. However, laboratory documentation and Table 5-8 indicate that this sample was indeed collected. Please clarify this discrepancy. Response to Comments -Phase I NDTS (final) 57 July 16, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 Response No. 28: Table 4-3 (page 3 of 4) has been revised. ./Comment No. 29: Table 4-3 (page 4 of 4) indicates the collection of soil sample PLOT4, 4-6. However, there is no indication as to the location where this soil sample was collected. Please clarify this discrepancy. Response No. 29: A figure indicating the soil sampling locations in Plot 4 will be added to the report. Summary of Soil Aerobic Bacteria Counts J Comment No. 30: Please amend Table 5-4 to include the sample identification as originally submitted to the laboratory. ' Response No. 30: Table 5-4 has been amended as suggested. ./comment No. 31: Please define the symbol "--" as included in Table 5-4 Response No. 31: The symbol "--" has been defined in Table 5-4. Summary of Soil Anaerobic Bacteria Counts /Comment No. 32: Please amend Table 5-5 to include the sample identification as originally submitted to the laboratory. Response No. 32: Table 5-5 has been amended as suggested. ./Comment No. 33: i Please define the symbol"--" as included in Table 5L5 I Response No. 33: The symbol "--" has been defined in Table 5-5. Response to Comments -Phase I NOTS (final) 58 July 16, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 Plot I: Soil Concentration of Volatile Organic Compounds /comment No. 34: Table 5-6 indicates that two soil samples were collected from soil sampling location 12, soil plot I, on September 11, 1997. However, Figure 4-5 indicates that the two soil samples should have been collected from soil sampling location 22. Please clarify this discrepancy. Response No. 34: Table 5-6 contained a typo. SPl-12-24 and SPl-12-68 should have been listed as SPl-22-24 and SPl-22-68, respectively, and have been changed. Comment No. 35: The following discrepancies were noted in Table5-6. Please clarify these discrepancies. /Response No. 35: Table 5-6 reflects validated data. The majority of the discrepancies between the March 1998 and January 1998 reports are a result of the validation process. The January data was submitted in a progress report prior to data validation. Subsequently, the March report included validated data that can change the qualifiers and concentrations. Plot 2: Soil Concentration of Volatile Organic Compounds / Comment No. 36: The following discrepancies were noted in Table5-7. Please clarify these discrepancies. Response No. 36: Table 5-7 reflects validated data. See Response #35. Plot 3: Soil Concentration of Volatile Organic Compounds / Comment No. 37: The following discrepancies were noted in Table5-8. Please clarify these discrepancies. Response No. 37: Table 5-8 reflects validated data. See Response #35. Summary of Soil 1,2-Dichloroethane Concentrations ' I /Comment No. 38: j Please amend Table 5-10 to include the sample idenfification as originally submitted to the laboratory. i Response to Comments -Phase I NDTS (final) 59 July I 6, I 998 I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 Response No. 38: Table 5-10 has been amended as suggested. Plot 1: Soil Concentrations of Nutrients, Metals, and Other Parameters /comment No. 39: Please amend Table 5-12 (pages 4 and 5 of5) to define the qualification "EQ." Response No. 39: Table 5-12 has been amended as suggested. Plot 2: Soil Concentrations of Nutrients, Metals, and Other Parameters_, / Comment No. 40: Please amend Table 5-13 (page 4 of 5) to define the qualifications "B" and "EQ". Response No. 40: Table 5-13 has been amended as suggested. / Comment No. 41: Please amend Table 5-13 (page 5 of 5) to define the qualification "EQ". Response No. 41: Table 5-13 has been amended as suggested. Plot 3: Soil Concentrations of Nutrients, Metals, and Other Parameters I / Comment No. 42: I I I I I I Please amend Table 5-14 (pages 4 and 5 of5) to define the qualification "EQ". Response No. 42: Table 5-14 has been amended as suggested. Summary of Soil Kjeldahl Nitrogen Concentrations /comment No. 43: Please amend Table 5-16 to include the sample identification as originally submitted to the laboratory. Response to Comments -Phase I NDTS (final) 60 July 16, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NOTS ENVIROGEN Project No. 78504 Response No. 43: Table 5-16 has been amended as suggested. / Comment No. 44: Table 5-16 indicates that the soil samples collected from the deep (6 to 8 ft) interval in Soil Plot 3 on December 11, 1997 contained no detectable concentrations ofKjeldahl nitrogen. However, Table 5-14 indicates that the soil sample collected from location Z contained 410 milligrams per kilogram (mg/kg) Kjeldahl nitrogen; the soil sample collected from location AM contained 190 mg/kg Kjeldahl nitrogen; and, the soil sample collected from location E contained 340 mg/kg Kjeldahl nitrogen. Please clarify these discrepancies. Response No. 44: Table 5-16 has been corrected to reflect the proper concentration ofKjeldahl nitrogen as the specified locations. /Comment No. 45: Table 5-16 indicates that zero concentrations were used in those instances where no detectable concentrations ofKjeldahl nitrogen were found. Please provide the detection limits used in the laboratory analysis ofKjeldahl nitrogen as well as an analysis of the data variability when the detection limits are used for zero concentrations. Response No. 45: Table 5-16 has been revised to include detection limits and an analysis of variability using detection limits for reported zero concentrations. Summary of Soil Ammonia Nitrogen Concentrations /comment No. 46: Please amend Table 5-17 to include the sample identification as originally submitted to the laboratory. Response No. 46: Table 5-17 has been amended as suggested. ✓ Comment No. 47: Table 5-17 indicates that zero concentrations were used in those instances where no detectable concentrations of ammonia nitrogen were found. Please provide the detection limits used in the laboratory analysis of ammonia nitrogen as well as an analysis of the data variability when the detection limits are used for zero concentrations. Response No. 47: Table 5-17 has been revised to include detection limits and an analysis of variability using detection limits for reported zero concentrations. Response to Comments -Phase I NDTS (final) 61 July 16, 1998 I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 Summary of Soil Nitrate Nitrogen Concentrations / Comment No. 48: Please amend Table 5-18 to include the sample identification as originally submitted to the laboratory. Response No. 48: Table 5-18 has been amended as suggested. / Comment No. 49: Table 5-18 indicates that the soil sample collected from location F, deep (6 to 8 ft) interval, in Soil Plot 1 on June 17, 1997 contained 0.9 mg/kg nitrate nitrogen. However, Table 5-12 indicates that this soil sample contained not detectable concentrations of nitrate nitrogen. Please clarify this discrepancy. Response No. 49: Value reported in Table 5-18 is correct; Value reported in Table 5-12 has been corrected. / Comment No. 50: Table 5-18 indicates that zero concentrations were used in those instances where no detectable concentrations of nitrate nitrogen were found. Please provide the detection limits used in the laboratory analysis of nitrate nitrogen as well as an analysis of the data variability when the detection limits are used for zero concentrations. Response No. 50: Table 5-18 has been revised to include detection limits and an analysis of variability using detection limits for reported zero concentrations. Summary of Soil Total Phosphorous Concentrations / Comment No. 51: Please amend Table 5-19 to include the sample identification as originally submitted to the laboratory. Response No. 51: I Table 5-19 has been amended as suggested. I I I / Comment No. 52: Table 5-19 indicates that the soil sample collected from location U, deep (6 to 8 ft.) interval, in Soil Plot 1 on March 26, 1997 contained 110 mg/kg total phosphorous. However, Table 5-12 Response to Comments -Phase I NDTS (final) 62 July 16, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NOTS ENVIROGEN Project No. 78504 indicates that this soil sample contained 280 mg/kg total phosphorous. Please clarify this discrepancy. Response No. 52: Value reported in Table 5-12 is correct; Value reported in Table 5-19 has been corrected. /comment No. 53: Table 5-19 indicates that the soil sample collected from location Y, deep (6 to 8 ft.) interval, in Soil Plot 2 on June 17, 1997 contained 16 mg/kg total phosphorous. However, Table 5-13 indicates that this soil sample contained 110 mg/kg total phosphorous. Please clarify this discrepancy. Response No. 53: Value reported in Table 5-13 is correct; Value reported in Table 5-19 has been corrected. / Comment No. 54: Table 5-19 indicates that the soil sample collected from location X, deep (6 to 8 ft.) interval, in Soil Plot 3 on September 11, 1997 contained 1.2 mg/kg total phosphorous. However, Table 5-14 indicates that this soil sample contained no detectable concentrations of total phosphorous. Please clarify this discrepancy. Response No. 54: Value reported in Table 5-14 is correct; Value reported in Table 5-19 is the method detection limit. / Comment No. 55: Table 5-19 indicates that zero concentrations were used in those instances where no detectable concentrations of total phosphorous were found. Please provide the detection limits used in the laboratory analysis of total phosphorous as well as an analysis of the data variability when the detection limits are used for zero concentrations. Response No. 55: Table 5-19 has been revised to include detection limits and an analysis of variability using detection limits for reported zero concentrations. Summary of Soil Total Alkalinity Concentrations /comment No. 56: Please amend Table 5-20 to include the sample identification as originally submitted to the laboratory. Response No. 56: Table 5-20 has been amended as suggested. Response to Comments -Phase I NDTS ( final) 63 July 16, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 / Comment No. 57: Table 5-20 indicates that the soil sample collected from location U, shallow (4 to 6 ft.) interval, in Soil Plot 3 on March 26, 1997 contained 160 mg/kg total alkalinity. However, Table 5-14 indicates that this soil sample contained 1600 mg/kg total alkalinity. Please clarify this discrepancy. Response No. 57: Value reported in Table 5-20 is correct; Value reported in Table 5-14 has been corrected. / Comment No. 58: Table 5-20 indicates that zero concentrations were used in those instances where no detectable concentrations of total alkalinity were found. Please provide the detection limits used in the laboratory analysis of total alkalinity as well as an analysis of the data variability when the detection limits are used for zero concentrations. Response No. 58: Table 5-20 has been revised to include detection limits and an analysis of variability using detection limits for reported zero concentrations. Summary of Soil Chloride Concentrations / Comment No. 59: Please amend Table 5-21 to include the sample identification as originally submitted to the laboratory. Response No. 59: Table 5-21 has been amended as suggested. / Comment No. 60: Table 5-21 indicates that the soil sample collected from location Z, shallow ( 4 to 6 ft) interval, in Soil Plot 1 on December 11, 1997 contained 320 mg/kg chloride. However, Table 5-12 indicates that this soil sample contained 90 mg/kg chloride. Please clarify this discrepancy. Response No. 60: Value reported in Table 5-12 is correct; Value reported in Table 5-21 has been corrected. / Comment No. 61: Table 5-21 indicates that the soil sample collected from location AM, shallow (4 to 6 ft) interval, Soil Plot on December 11, 1997 contained 430 mg/kg chloride. However, Table 5-12 indicates that this soil sample contained 320 mg/kg chloride. Please clarify this discrepancy. Response No. 61: Value reported in Table 5-12 is correct; Value reported in Table 5-21 has been corrected. Response to Comments -Phase I NDTS (final) 64 July 16, 1998 I I I I I I I I I I I I I I a I I I NSCC Response to Comments on Phase I NOTS ENVIROGEN Project No. 78504 /comment No. 62: Table 5-21 indicates that the soil sample collected from location E, shallow ( 4 to 6 ft) interval, in Soil Plot I on December 11, 1997 contained 450 mg/kg chloride. However, Table 5-12 indicates that this soil sample contained 180 mg/kg chloride. Please clarify this discrepancy. Response No. 62: Value reported in Table 5-12 is correct; Value reported in Table 5-21 has been corrected. /Comment No. 63: Table 5-21 indicates that the soil sample collected from location G, deep (6 to 8 ft) interval, in Soil Plot I on March 26, 1997 contained 190-mg/kg chloride. However, Table 5-12 indicates that this soil sample contained 130 mg/kg chloride. Please clarify this discrepancy. Response No. 63: Value reported in Table 5-12 is correct; Value reported in Table 5-21 has been corrected. /comment No. 64: Table 5-12 indicates that the soil sample collected from location Z, deep (6 to 8 ft) interval, in Soil Plot I on December 11, 1997 contained 620 mg/kg chloride. However, Table 5-12 indicates that this soil sample contained 260 mg/kg chloride. Please clarify this discrepancy. Response No. 64: Value reported in Table 5-12 is correct; Value reported in Table 5-21 has been corrected. /comment No. 65: Table 5-21 indicates that the soil sample collected from location AM, deep (6 to 8 ft) interval, in Soil Plot I on December 11, 1997 contained 860 mg/kg chloride. However, Table 5-12 indicates that this soil sample contained 110 mg/kg chloride. Please clarify this discrepancy. Response No. 65: Value reported in Table 5-12 is correct; Value reported in Table 5-21 has been corrected. /comment No. 66: Table 5-21 indicates that the soil sample collected from location E, deep (6 to 8 ft) interval, in Soil Plot 1 on December 11, 1997 contained 570 mg/kg chloride. However, Table 5-12 indicates that this soil sample contained 3 70 mg/kg chloride. Please clarify this discrepancy. Response No. 66: Value reported in Table 5-12 is correct; Value reported in Table 5-21 has been corrected. /comment No. 67: Table 5-2 I indicates that the soil sample collected from location AM, shallow ( 4 to 6 ft) interval, in Soil Plot 2 on December 11, 1997 contained 54 mg/kg chloride. However, Table 5-13 indicates that this soil sample contained I 00 chloride. Please clarify this discrepancy. Response to Comments -Phase I NOTS (final) 65 July 16, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 Response No. 67: Value reported in Table 5-12 is correct; Value reported in Table 5-21 has been corrected. / Comment No. 68: Table 5-21 indicates that zero concentrations were used in those instances where no detectable concentrations of chloride were found. Please provide the detection limits used in the laboratory analysis of chloride as well as an analysis of the data variability when the detection limits are used for zero concentrations. Response No. 68: Table 5-21 has been revised to include detection limits and an analysis of variability using detection limits for reported zero concentrations. Monthly Summa Canister Sampling Results, Soil Gas Monitoring Wellil, 2, 3 and4 Jcommeilt No. 69: The first entry for Freon 113 and the second entry for Toluene are incorrect duplicates and should be deleted from Table 5.23, Soil Gas Monitoring Well I (6 to 8 ft), page 3 of 16. Additionally, the second entry for Freon 113 and the first entry for Toluene are incorrect duplicates and should be deleted from Table 5.23, Soil Gas Monitoring Well I (6 to 8 ft), page 4 of 16. Please correct these oversights. Response No. 69: The incorrect duplicates in Table 5-23 have been deleted. ./ Comment No. 70: Due to the detection of benzene in soil gas monitoring well 3 (6 to 8 ft) on November 18, 1997, benzene should be added to the list of parameters included on Table 5.23, Soil Gas Monitoring Well (6 to 8 ft), page 12 of 16. Please correct this oversight. Response No. 70: Benzene has been added to Table 5-23, page 12 of 16, to correct this oversight. / Comment No. 71: The following discrepancies were noted in Table 5.23. Please clarify these discrepancies. Response No. 71: Table 5-23 reflects validated data. See Response #35. Response to Comments -Phase I NDTS (final) 66 July 16, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 Monthly Summa Canister Sampling Results, Soil Gas Monitoring Wells 5, 6, 7 and8 / Comment No. 72: The following discrepancies were noted in Table 5.24. Please clarify these discrepancies. Response No. 72: Table 5-24 reflects validated data. See Response #35. Groundwater Elevations: Wells NS-14, NS-35, NS-36, NS-39, NS-40, NS-42 /comment No. 73: Figure 5-2 indicates that the groundwater elevations for monitoring wells NS-14 and NS-42 are depicted. However, the groundwater elevations for these two monitoring wells were ' inadvertently omitted. Please correct this oversight. Response No. 73: Wells NS-14 and NS-42 are not included on Figure 5-2. They have been omitted from the figure name. /comment No. 74: Figure 5-2 is very congested in the four-month period from August through December 1997. Please reconfigure this figure into two figures, or whatever may be required, in order to clearly depict the groundwater elevations for the monitoring wells during this time frame. Response No. 74: The line types and line weights have been adjusted to help clarify Figure 5-2. Shallow (2-4 ') Soil Gas Concentrations (SGMW-4), Field Measured w/GA-90 / Comment No. 75: The word "Concentrations" is misspelled in the title for Figure 5.39. Please correct this oversight. Response No. 75: The misspelled word has been corrected. Response to Comments -Phase I NDTS (final) 67 July 16, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 APPENDIX A -Blue Planet Technologies, Phase I B/Oreport #1060, September 17, 1996 /comment No. 76: The word "Cadmium" is misspelled in the table, Factors that Limit Microbial Growth, throughout the Phase I BIOreport. Please correct this oversight. Response No. 76: As suggested, the tables have been revised. / Comment No. 77: The table, Analytical Results for 1,2-Dichloroethane, indicates that the soil sample BT-1, 4-6', contains 7400 ug/1 1,2-DCA. However, NSCC has made many comments stating that this soil sample only contained 500 ug/1 1,2-DCA. Please clarify this discrepancy by providing the actual laboratory analytical report generated during the analysis of this soil sample. ·' Response No. 77: The concentration of 1,2-dichloroethane in soil sample BT-1, 4-6' used in the Phase I Laboratory Study was 7,400 µg/L. The disputed concentration of500 µg/L at the onset of the Phase II Laboratory Study is inconsequential since the results of the Phase II Laboratory study have been omitted from the Phase I NDTS report as agreed to during the July 9, 1998 conference call. / Comment No. 78: The chain of custody documentation for the soil samples collected for the Phase I BIOreport was inadvertently omitted. Please correct this oversight. Response No. 78: The reference chain of custody documentation will be provided. Blue Planet Technologies, Phase II BIOreport #1060, November 19,1996 As agreed upon during the conference call ofJuly 9, 1998 all results of the Phase II laboratory study will be disregarded and therefore comments regarding this report have not been addressed. / Comment No. 79: I The second sentence of the Methods -Confirmation of contaminant Degradation section should be corrected to read "The closed system is rotated at 200 rpm at 25 degrees centigrade ... " Please correct this oversight. Response No. 79: As agreed upon during the conference call of July 9, 1998 all results of the Phase II laboratory study will be disregarded and therefore this comment has not been addressed. Response to Comments -Phase I NDTS (final) 68 July I 6, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NOTS ENVIROGEN Project No. 78504 /comment No. 80: The second sentence of the Discussion-BT-1 (4-6ft) Anaerobic Biotic Ll8968-1D section does not make sense. Please clarify the meaning of this sentence. Response No. 80: As agreed upon during the conference call of July 9, 1998 all results of the Phase II laboratory study will be disregarded and therefore this comment has not been addressed. /comment No. 81: The last sentence of the Discussion-BT-2 (4-6 ft) Anaerobic Biotic Ll8985-5A section states that" ... the decrease of substrate ( e.g.) 60 ppb of 1,2 Dichloroethane in 28 days, after subtraction of the abiotic losses ... " However, the decrease of substrate for the Bt-2 anaerobic sample should be 70 ppb. Please correct this oversight. Response No. 81: The second sentence of the Discussion-BT-I (4-6ft) Anaerobic Biotic L18968-1D section does not make sense. Please clarify the meaning of this sentence. APPENDIXC -Field Activity Daily Logs (FADL'S) / Comment No. 82: The Borehole Log for soil boring BT-3 indicates that the decontamination procedures for the split spoons were as follows: soap; water rinse; isopropanol; organic-free water; distilled water; and tap water. However, these procedures are not in accordance with the US EPA Region IV Environmental Investigations Standard Operating Procedures and Quality Assurance Manual (EISOPQAM). Please provide justification for noncompliance with the US EPA Region IV EISOPQAM. Response No. 82: The split spoons were decontaminated in accordance with the OU4 RD/RA Work Plan. The boring Jog BT-3 does show the proper decontamination equipment but inadvertently in the wrong order. ./ Comment No. 83: The F ADL for November 11, 1996 (page 2 of 5) indicates that the decontamination procedures for the well casing were as follows: isopropanol; distilled water; and air dry. However, these procedures are not in accordance with the US EPA Region IV EISOPQAM. Response No. 83: The actual procedure was in accordance with the OU4 RD/RA Work Plan. The FADL shows the materials used to decontaminate the stainless steel probes and not the specific order. Response to Comments -Phase I NOTS (final) 69 July 16, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 /comment No. 88: The List of Samples includes sample SP2246. This sample should be shown as sample SP2346. Please correct this oversight. Response No. 88: The sample ID has been amended as suggested. / Comment No. 89: The second paragraph listed in the section entitled, Method Blank Contamination, indicates that soil samples SPl 194 and SPl 196 should be associated with a "U" qualification at the reported value for acetone and 2-butanone. However, these samples were not associated with the appropriate qualification. Please clarify this discrepancy. Response No. 89: The discrepancy in this paragraph has been clarified. /comment No. 90: One of the soil samples listed in the section entitled, Initial Calibration, is sample 2220. This sample should be shown as 3220. Please correct this oversight. Response No. 90: The sample ID has been amended as suggested. /comment No. 91: The fourth paragraph listed in the section entitled, Continuing Calibration, indicates that soil samples SP 1226, 1346, 3196DL, 3342DL, 3344, 3220, and 3226 should be associated with a "J" qualification for all the associated positive results for acetone and "UJ" qualification for all the associated nondetects for acetone. However, none of these qualifications were associated with any of the above samples. Please clarify this discrepancy. Response No. 91: The oversight has been corrected and the appropriate qualifiers have been added to the data in the tables. / Comment No. 92: The word, "dichlorethene" was misspelled in the fouhh sentence of the Matrix Spike/Matrix Spike Duplicate, MS/MSD section. Please correct this oversight Response No. 92: The misspelled word has been corrected. Response to Comments -Phase I NDTS (final) 71 July 16, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 APPENDIXD -Blue Planet Analytical Reports ./Comment No. 84: The title page for appendix D should state that the date of the June 1997 report is June 31, 1997. Please correct this oversight. Response No. 84: The title page has been amended as suggested. September 29, 1997 Blue Planet Technologies Report /comment No. 85: Table I, Anaerobic Plate Counts, indicates that two samples that have the same sample identification (SP3-17-6-8) were collected. Additionally, Table 1 does not indicate the'collection of soil sample SP2-22-6-8. Please clarify these discrepancies. Response No. 85: The discrepancies in Table I have been clarified. APPENDIX E -Data Validation, Pace Analytical, Inc. Report #72221 / Comment No. 86: The word "Analytical" is misspelled on the cover page of this report. Please correct this oversight. Response No. 86: The misspelled word on the cover page has been amended as suggested. / Comment No. 87: The List of Samples does not include all of the samples collected on November 13, 1996 and submitted to Pace laboratories for laboratory analysis. Specifically, soil samples SP3346, SP3196, SP322D6, SP412, SP424, SP425, SP432, SP436 and PLOT44 were not included in the data validation report. Please provide justification f6r not including these samples in the data validation report. ' Response No. 87: NSCC selected not to validate these samples. Page B-22 of the OU4 RD/RA Work Plan stated that a minimum of20 percent of the soil samples would be validated. Actually, NSCC validated approximately 90% of the soil samples. Response to Comments -Phase I NDTS (final) 70 July 16, 1998 I I I I I I I I I I I I I I I I I I I NSCC Response to Comments on Phase I NOTS ENVIROGEN Project No. 78504 Data Validation, Pace analytical, Inc. Report #3089 / Comment No. 93: One of the soil samples listed in the List of Samples section is sample SP77. This sample should be shown as SP! 77. Please correct this oversight. Response No. 93: The sample number has been amended as suggested. ./comment No. 94: The third paragraph in the section entitled, Method Blank Contamination, indicates that chloroform was detected in method blank VBLK095A. However, laboratory documentation indicates that 1,2-dichloroethane, not chloroform, was detected in method blank VBLK095A. Please clarify this discrepancy. Response No. 94: The discrepancy in this paragraph has been corrected. / Comment No. 95: The first paragraph in the section entitled, Field or Rinse Blank Contamination, indicates that methylene chloride and acetone were detected in the equipment blank, EB032697. However, laboratory documentation indicates that I, 2-dichloroethane was also detected in the equipment blank, EB032697. Please clarify this discrepancy. Response No. 95: The discrepancy in this paragraph has been corrected. Data Validation, Pace Analytical, Inc. Report #SPJ65 /comment No. 96: The word "Analytical" is misspelled on the cover page of this report. Please correct this oversight. Response No. 96: The misspelled word has been corrected. / Comment No. 97: The word "were" is misspelled in the third sentence of the section entitled, Method Blank Contamination. Please correct this oversight. Response No. 97: The misspelled word has been corrected. Response to Comments -Phase I NDTS ( final) 72 July 16, 1998 I I I I I I I I I a I I I I I NSCC Response to Comments on Phase I NDTS ENVIROGEN Project No. 78504 Data Validation, Pace Analytical, Inc. Report #3333 ✓comment No. 98: One of the soil samples listed in the List of Samples section is sample SP3668. This sample should be shown as SP3468. Please correct this oversight. Response No. 98: The sample ID has been amended as suggested. /Comment No. 99: The third paragraph of Section B of the Blank Contamination section indicates that soil samples SP1466 and SP1466DL should be associated with a "U" qualification for acetone. Please clarify and correct this section about whether this is soil sample SP1446 or soil sample SP1468. Response No. 99: The discrepancy in this paragraph has been corrected. /comme~t No. 100: The last sentence of the Matrix Spike/Matrix Spike Duplicate, MS/MSD section should state that 'MS/SMD WAS PERFORMED ON SAMPLE SP32268, CRJTERIA WAS MET." Please correct this oversight. Response No. 100: The sentence has been amended as suggested. /comment No. 101: The laboratory documentation for sample SP3468 is incorrectly cited as that for sample SP3668. Please correct this oversight. Response No. 101: The sample number has been corrected. Data Validation, Pace Analytical, Inc. Report #105089 /comment No. 102: The laboratory documentation for soil samples SP21624 and SP21624DL have been incorrectly I corrected to SP21626 and SP21626DLm respectively. Please correct this oversight. Response No. 102: I The sample numbers have been corrected. I I Response to Comments -Phase I NDTS (final) 73 July 16, 1998