AEMY. NE PAMOS Cort, Hieg Monitoring Cruise at the Portland Disposal Site July 1992 Disposal Area Monitoring System DAMOS D A|M O § DISPOSAL AREA MONITORING SYSTEM Contribution 108 January 1996 US Army Corps of Engineers New England Division , ee | ho. (0§ REPORT DOCUMENTATION PAGE OMB No. 0704-0188 Public reporting concern for the collection of information Is estimated to average 1 hour per response including the time for reviewing Instructions, searching existing data sources, gathering and measuring the data needed and correcting and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information including suggestions for reducing this burden to Washington Headquarters Services, Directorate for information Observations and Records, 1216 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302 and to the Office of Management and Support, Paperwork Reduction ect (0704-0188), Washington, D.C. 20503. i. AGENCY USE ONLY (LEAVE BLANK) p. REPORT DATE B. REPORT TYPE AND DATES COVERED January 1996 Final report 4. TITLE AND SUBTITLE 6. FUNDING NUMBERS Monitoring Cruise at the Portland Disposal Site, July 1992 6. AUTHOR(S) M. B. Wiley . PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Science Applications International Corporation 221 Thrid Street Newport, RI 02840 8. PERFORMING ORGANIZATION REPORT NUMBER SAIC-C110 19. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) US Army Corps of Engineers-New England Division 424 Trapelo Road Waltham, MA 02254-9149 10. SPONSORING/ MONITORING AGENCY REPORT NUMBER DAMOS Contribution Number 108 41. SUPPLEMENTARY NOTES Available from DAMOS Program Manager, Regulatory Division USACE-NED, 424 Trapelo Road, Waltham, MA 02254-9149 42a. DISTRIBUTION/AVAILABILITY STATEMENT Approved for public release; distribution unlimited 42b. DISTRIBUTION CODE 13. ABSTRACT Between October 1991 and June 1992, a capping project was conducted at the Portland Disposal Site (PDS) as part of the Disposal Area Monitoring System (DAMOS) Program. Fine-grained dredged material from the US Coast Guard project in South Portland (13,270 m3) was capped with cleaner fine-grained sediment from the same project (19,451 m?), as well as with sandy material from the Northeast Petroleum project (18,310 m?) Science Applications International Corporation (SAIC) conducted a monitoring cruise at PDS in July 1992. The survey was designed to map the areal extent of dredged material at the site, to determine the effectiveness of the capping operation, and to obtain sediment chemistry data on the cap and at the reference areas. The field work included a REMOTS® sediment-profile survey, a bathymetric survey, an acoustic sediment density study, and sediment sampling for chemistry and grain size. Based on the REMOTS® survey, the areal extent of dredged material at PDS ranged from 200 m west of the disposal buoy to 700 m southwest of the buoy location. The bathymetric survey, when compared to the previous bathymetric survey in January 1989, showed accumulations up to 0.75 m thick within 200 m of the buoy. The comparison of the 1989 and 1992 bathymetric surveys also indicated an area of accumulation 500 m south of the buoy. This corresponded to the southernmost detection of dredged material from the REMOTS® survey in an area that received dredged material after 1989. The acoustic sediment density survey showed that, in general, the coarser grained sediment was concentrated in water depths shallower than 54 m, and the finer grained sediment was concentrated in the deeper areas. The acoustic data were patchy and, after smoothing, precluded identification of the project cap material. The patchiness was attributed to both the heterogeneity of dredged material and the rapidly changing slopes in the survey area. Sediment chemistry data from the surface of the cap showed that contaminant concentrations were within the ranges measured at PDS reference areas, indicating that the cap was effectively isolating contaminants. Two stations, F7/ and H5 near the location of a historical (1984) disposal buoy, showed elevated levels of several metals, though these levels were similar to the cap material and much less than the contaminated material that was disposed. delete the following [potentially attributed to the disposal of contaminated material at.] A comparison of the metal and polycyclic aromatic hydrocarbon (PAH) baseline chemistry data from PDS reference areas and data collected by the National Oceanographic and Atmospheric Administration (NOAA) National Status and Trends (NS&T) Program for the Gulf of Maine showed that the PDS reference areas were well within the ambient values for metals and PAHs in the area (NOAA 1991). 14. SUBJECT TERMS DAMOS PDS REMOTS-~ SAIC bathymetric 17. SECURITY CLASSIFICATION OF REPORT 18. SECURITY CLASSIFICATION OF THIS Unclassified PAGE 15. NUMBER OF PAGES sie 16. PRICE CODE 19. SECURITY CLASSIFICATION OF 20. LIMITATION OF ABSTRACT ABSTRACT j ws “ % APaity ere aes Ye ts are MONITORING CRUISE AT THE PORTLAND DISPOSAL SITE JULY 1992 CONTRIBUTION #108 January 1996 Report No. SAIC-C110 Submitted to: Regulatory Division New England Division U.S. Army Corps of Engineers 424 Trapelo Road Waltham, MA 02254-9149 Prepared by: Mary Baker Wiley Submitted by: Science Applications International Corporation Admiral's Gate 221 Third Street Newport, RI 02840 (401) 847-4210 US Army Corps of Engineers ‘oes Te @iie' ' he. 7 _. =a _ TABLE OF CONTENTS | Page ISCO} hg AN 8) CASES 9s alls de ale ela a a 1s tae RL eet eee Ill BISIMORSEIG URES ayers ene ee ee Pinel Sie eyed tes TINA e? Ai Sees Ph een Le pears eo IV EXE CUPIVESSUMMARY her. reeei ts on reeee IAL. IER tena, coe We aati e e ye eth deaoal ema vi 120k GINTRODUGCTION MAG fo, Prey PE, AEN EO INS STE re, belle hts 1 He) ln 0 BBS (CD B Icy ae een eS moi: Gk Ae op ae I ae Rae es Lc aren Nn ai Rca aR CP 4 2el' .Bathymetry and Navigation 2%. io. eS eee ey) 2 es 2S a ee, 4 2.2 REMOTS® Sediment-Profile Photography .................... 4 eS ee SEGIMEME DENSITY ey cts esta Rter meal Alene ERO Re Rae OM Ag ce: 2 aad rete 5 -2.4 Sediment Sampling and Analysis FETE ie aes | SARIN URE AED yet le 9 24 leGrainsSizevAnalysis hs sc -eue as ye Me ak ee ee 9 2.4.2 Total Organic Carbon’ iis. 0s os le he a ee eens aie ee 27435 \Metals\and PAH ‘Analysis. 2.018 A2k028G OR a se ewe ak 12 DRATA RT OVAY OCH BERPON Sb oie oie he Mates, ee les RENE Bm rie i eR 13 SAOMO SRES USES A eee re eae hy EL, OS DN AE SI 8 soos ao eta 15 Solis Bathymetiya 28 et. eee vaca yhe aoe cries Re rotten. LA ker ne ane 15) Seen IRE MOT Sear hens clan cite rat Malstiat alidayacce Vein vai ananliteh era oupnd Oya ng Marek gaara 15 355) Sediment Density 330-445 5 4 Ales WE neite kat SNe. OR Reet crs RUNES a See 26 3.4 Sediment Grain Size and Chemistry ...... pt fates Norte OR rea 26 3.4.1 Grain Size and Total Organic Carbon .......... Ateee ev eeee 26 3.4.2 Metals and PAHs ....... ane ize se c2ey ge Oey seated ele at ee oer 30 AN ORD ISCWSSION se Stich hese Aik, ah Ouch weeiieoau aunts Udaee en Shee saree 38 SOc CONCEUSIONS: fictted canoe eae we ee ee0a0c0ccensa008s 44 GRO eR PE RIEIN GES? Baneyits Ge sotee Oxtiin Po alstale et testa ohn euie o ne Meme a aseone pera a 45 INDEX bh wie owe: oa) e: LIST OF TABLES Table 2-1. Table 2-2. Table 3-1. Table 3-2. Table 3-3. Table 3-4. Table 3-5. Table 4-1. Page Portland Disposal Site Reference Stations ..................... 5) Summary of Laboratory Analytical Work, 1992 ................ 11 Sediment Grain Size Analyses for Reference Stations and Cap Stations at the Portland Disposal Site, July 1992 ................ 28 Total Organic Carbon Values at the Portland Disposal Site FRELETENCE PATE AS irre tet acre) eo hy hse eae fare ene een ae Re tl ere eS 30 Non-normalized Metal Analyses for the Portland Disposal Site StauonsvandReferenceAreas® 23-5 Wa, ne oe eee os oe 31 Normalized Metal Analyses for the Portland Disposal Site StationsvandReference Areas’ 05. 6) so eae se bh we ee 33 Normalized Portland Disposal Site Reference Area Sediment Sample Results for Polycyclic Aromatic Hydrocarbons (PAHs) ....... 37 Metals and PAH Data Normalized to % Silt/Clay for NS&T Stations Casco Bay(CSC): andi Stover/Point)(MSSP)it fee... Se ee ee 42 ul narare tu oh seis isieabat: se a * oe yeaah re ae hi . — iP eadioadit mance 9 iene a, "een abe om ic ate Figure 1-1. Figure 2-1. Figure 2-2. Figure 2-3. Figure 2-4. Figure 3-1. Figure 3-2. Figure 3-3. Figure 3-4. Figure 3-5. Figure 3-6. Figure 3-7. Figure 3-8. Figure 3-9. LIST OF FIGURES Page Location of the Portland Disposal Site in relation to Caper Elizabeth MME wie Ac Se Oat, PN ee Se ee PR aia 2 REMOTSS station locations at the Portland Disposal Site, AMULET 1992 aha roars Pate svat aaah tee nt war Sa lseD eH Meee my eae shoe toeeke ake 6 Dredged material location at the Portland Disposal Site, January 1992 Wes Re ee en OM EE are LES DES enh MEE Ae 7 July 1992 REMOTSS® stations at the Portland Disposal Site .......... 8 Sediment sample locations at the Portland Disposal Site, July 1992 10 Contoured bathymetric chart of the Portland Disposal Site, July 1992 (depthsinumeters) woh eists Canc Ruy einer ae ie tere tober ene era cos 16 Contoured bathymetric chart of the Portland Disposal Site, January LOSS X(Gepthtinimeters)r ho ee ee ee eee ne we ame eee te se ee 17 Positive depth difference contour chart (in meters) based on the comparison of 1989 and 1992 Portland Disposal Site bathymetry ...... 18 Negative depth difference contour chart (in meters) based on the comparison of 1989 and 1992 Portland Disposal Site bathymetry ..... . 19 Dredged material location, based on REMOTSS®, at the Portland Disposal Site uly 1992 oes Bs eee ee eich oe ce eee yy eee 21 RPD values at the Portland Disposal Site and reference stations, Uva OOD Riemann erenen eee ee fiat nce rats meme Tekin en USSR? ara ee ae eae nD Frequency distribution of RPD values at the Portland Disposal SitevandtreferenceareaSir; cnt tee ee) eee eee oe etn oes 7233 Successional stage values at the Portland Disposal Site and reference areas, Julym1992) Se. ee ee Se Wench eae tg ape ANH te hy 24 OSI values at the Portland Disposal Site and reference areas, TET RP Mole Po A ar dete ihalecamice dee sia Aceon Beenie ror tien ea oe nila A ear Der 25 Figure 3-10. Figure 3-11. Figure 3-12. Figure 218) Figure 4-1. Figure 4-2. LIST OF FIGURES (cont.) Surface sediment density (g-cc’') for the Portland Disposal Site....... P| Normalized zinc values in surface sediments at the Portland Disposal Site, Duly 19922. Seeeee See re Ce ee ee ER ete soars 34 Normalized lead values in surface sediments at the Portland Disposal Site, Muh y G92 sae eS pene es ite i eee ea Ae ere, ae whee ene 35 Normalized copper values in surface sediments at the Portland Disposal Site, uly 1992) Fear Pre oat Tee nee WN eee 36 Barge disposal release points at the Portland Disposal Site, October ROO Mito Tune 992 ers. mess Genin oases sel ee ree re ae elie 39 Accumulation of sediment, distribution of dredged material, and barge release locations at the Portland Disposal Site between January 1989 and uneplO92 woh: Saar. Ce eine PIS Go ERS ne 40 EXECUTIVE SUMMARY Between October 1991 and June 1992, a capping project was conducted at the Portland Disposal Site (PDS) as part of the Disposal Area Monitoring System (DAMOS) Program. Fine-grained dredged material from the US Coast Guard project in South Portland (13,270 m?) was capped with cleaner fine-grained sediment from the same project (19,451 m3), as well as with sandy material from the Northeast Petroleum project (18,310 m3). Science Applications International Corporation (SAIC) conducted a monitoring cruise at PDS in July 1992. The survey was designed to map the areal extent of dredged material at the site, to determine the effectiveness of the capping operation, and to obtain sediment chemistry data on the cap and at the reference areas. The field work included a REMOTS® sediment-profile survey, a bathymetric survey, an acoustic sediment density study, and sediment sampling for chemistry and grain size. s Based on the REMOTS® survey, the areal extent of dredged material at PDS ranged from 200 m west of the disposal buoy to 700 m southwest of the buoy location. The bathymetric survey, when compared to the previous bathymetric survey in January 1989, showed accumulations up to 0.75 m thick within 200 m of the buoy. The comparison of the 1989 and 1992 bathymetric surveys also indicated an area of accumulation 500 m south of the buoy. This corresponded to the southernmost detection of dredged material from the REMOTS® survey in an area that received dredged material after 1989. The acoustic sediment density survey showed that, in general, the coarser grained sediment was concentrated in water depths shallower than 54 m, and the finer grained sediment was concentrated in the deeper areas. The acoustic data were patchy and, after smoothing, precluded identification of the project cap material. The patchiness was attributed to both the heterogeneity of dredged material and the rapidly changing slopes in the survey area. Sediment chemistry data from the surface of the cap showed that contaminant concentrations were within the ranges measured at PDS reference areas, indicating that the cap was effectively isolating contaminants. Two stations, F7 and H5, showed elevated levels of several metals, although metal levels were overall within the range measured in samples collected in the cap material prior to dredging. A comparison of the metal and polycyclic aromatic hydrocarbon (PAH) baseline chemistry data from PDS reference areas and data collected by the National Oceanographic and Atmospheric Administration (NOAA) National Status and Trends (NS&T) Program for the Gulf of Maine showed that the PDS reference areas were well within the ambient values for metals and PAHs in the area (NOAA 1991). vi ~~ del ae ype, | Cane arn ce nv ites ue Pros . te plied ih ee me yatta be eeramier. we pala ie Sea a sag ih eet Oh vib eas epee avec da ie ly ad ie yrs nighieneail — he ned iene fhewiaa weal — wave Hos vee etd Hee ‘ay c ¥ As me it rite ie i ml jnelths i | Ries ey yo me "ia mi iit int WA) ! ie rind AAA NTE foot inns ae ae ae on ‘IY AG ies ey bang wen ere ae ta | itt Mole Wola 1G, WR yd 4 ey Nh hae, eile weil. srg alt Vi nes _ Fash je Pk @ ie. ; ie ae Wigs al i, pay sl tad aha ~ 1.00 INTRODUCTION The Portland Disposal Site (PDS) is located in Bigelow Bight, 7.1 nmi east of Dyer Point on Cape Elizabeth, Maine (Figure 1-1). It is one of ten regional dredged material disposal sites in New England managed by the US Army Corps of Engineers, New England Division (NED), as part of the Disposal Area Monitoring System (DAMOS) Program. The Portland Disposal Site was first used for the disposal of dredged material in 1979. Since then, it has been periodically monitored as part of the DAMOS Program. The site is a 1 nmi square with sides running true north-south and east-west, centered at 43°34.100’ N, 70°02.000' W, North American Datum 1927 (NAD 27). It is characterized by a flat, sandy valley, surrounded by rocky outcrops. Water depths range from 42 m on the hard rock ridges to 64 m in the valleys. In January 1989, a bathymetric survey and a REMOTS® survey were conducted at the site. From January 23, 1989 to November 15, 1990, 14,810 m3 of dredged material was released near the PDS buoy location (43°34.270’ N, 70°01.968’ W). Most of this material came from the Portland International Terminal and the Royal River Boatyard. On January 31, 1989, one barge load of material (412 m3) was recorded as being released at 43°34.100’ N, 70°01.900' W. The next series of disposal events, from March 18 to April 30, 1991, (6,193 m3) was also released near 43°34.100’ N, 70°01.900’ W. Navigational charts and the USCG light list do suggest that a buoy may have been at that location during these disposal events. In October 1991 a capping project was begun at PDS. This project at PDS set a precedent among DAMOS capping projects since the water depths at the site are much greater than 20 m (20 m is the average water depth for Long Island Sound sites). From October 1991 through January 1992, 13,270 m3 of material that was determined to be unsuitable for unconfined open ocean disposal was released at or near the buoy (43°34.270' N, 70°01.968’ W). One barge load of this material (625 m?) was reported released at 43°34.100’ N, 70°01.900’ W on November 8, 1991. All material unsuitable for unconfined open water disposal came from the US Coast Guard (USCG) project in South Portland and consisted of 75-86% silt/clay contaminated with moderate to high levels of metals. In January 1992, Science Applications International Corporation (SAIC) conducted postdisposal, precapping bathymetric, and REMOTS® surveys at PDS for C&B Marine. The results of these surveys were used to map the location of the dredged material and to determine disposal points for subsequent cap placement. Capping began in January 1992 and was completed in June 1992. The cap material (37,761 m3) consisted of fine-grained material from other portions of the USCG project (19,451 m3) and sandy material (70-86% sand) from the Northeast Petroleum project Monitoring Cruise at the Portland Disposal Site, July 1992 LS) Portland, Maine O©\NNER GREEN IS. PORTLAND PEA 2 OUTER GREEN IS. (aes S. 6 SOUTH PORTLAND Casco Bay 43°35'N CAPE 7 hel Ceci IS. Portland Disposal Site 70°10'W Figure 1-1. Location of the Portland Disposal Site in relation to Cape Elizabeth, ME Monitoring Cruise at the Portland Disposal Site, July 1992 wy (18,310 m3). The cap materials from both projects, coarse- and fine-grained, were released concurrently, confounding physical differentiation between the silt/clay contaminated material and the silt/clay and sand cap. Additional material (about 2,700 m3) from a project at the Merrills Marine Terminal was released at the same location during late June and early July 1992. Once finished, the capping project was expected to cover the material that was unsuitable for unconfined open ocean disposal with at least 30 cm of cap. Because the cap material was released at the site within a few months of the survey, the benthic community around the buoy was expected to be in a relatively early stage of colonization, with the frequency of Stage I organisms at the buoy being greater than at the reference areas. Monitoring Cruise at the Portland Disposal Site, July 1992 4 2.0 METHODS The July 1992 survey at PDS was designed to map the extent of dredged material at the site, to evaluate the status of benthic recolonization, and to determine the effectiveness of the capping operation by obtaining sediment chemistry data on site and at the reference areas. To accomplish this, SAIC conducted a bathymetric survey, a REMOTS® sediment-profile survey, an acoustic sediment density study, and sediment sampling for chemistry and grain size. 2.1 Bathymetry and Navigation The precision navigation required for all field operations was provided by the SAIC Integrated Navigation and Data Acquisition System (INDAS). This system uses a Hewlett- Packard 9920 series computer to collect position, depth, and time data for real-time navigation. Contribution No. 60 (Parker and Revelas 1989) contains a detailed description of INDAS and its operation. Positions were determined to an accuracy of +3 meters from ranges provided by a Del Norte Trisponder® System. All positions are in datum NAD 27. For the present survey, shore stations were established at known benchmarks: Cape Elizabeth - Light (43°33.959’ N, 70°12.034’ W) and Portland Head Light (43°37.381' N, 70°12.502' W). The July 1992 PDS bathymetric survey was set up over the same area used in January 1989. The 900 x 1100 m area consisted of 45 lanes oriented east and west with 25 m lane spacing. An ODOM DF3200 Echotrac® Survey Recorder with a narrow-beam 208 kHz transducer recorded depth to a resolution of 3.0 cm (0.1 ft) as described in DAMOS Contribution No. 48 (SAIC 1985). At the beginning of the survey, a surface-to-bottom cast of a Sea-Bird Electronics, Inc., Model SBE 19-01 conductivity-temperature-depth profiler (CTD) was done to obtain accurate speed of sound data for the analysis. Analysis of the bathymetric data was conducted using the Hydrographic Data Analysis System (HDAS). All depth values were converted to Mean Low Water (MLW) after compensating for vessel draft and tidal fluctuations that occurred while surveying. During analysis, position and depth data were checked to identify and eliminate any outlying values before producing an accurate contour plot. 2.2 REMOTS® Sediment-Profile Photography A REMOTS® survey was conducted at PDS and reference stations on July 22 and 23, 1992. The orthogonal REMOTS® sampling grid at the disposal site was designed to map the areal extent of the dredged material deposit and to confirm predictions about benthic recolonization. Forty-two stations were surveyed at the disposal site. The three reference areas, SEREF, SREF, and EREF (Table 2-1), were each surveyed in a 13-station cross- shaped grid. Triplicate photographs were taken at all stations. Monitoring Cruise at the Portland Disposal Site, July 1992 Table 2-1 Portland Disposal Site Reference Areas Water Depth SEREF 43°32.802' N 70°00.193'W | cm | 43°33.346’ N 70°01.753'W | 60m si 43°34.429’ N 69°59.732' W In January 1992, as part of the USCG capping project, a 64-station orthogonal REMOTS® survey around the disposal buoy mapped the distribution of dredged material at PDS (Figure 2-1). Ambient sediment formed the western boundary of the dredged material deposit in January, and hard rock was found in the northeast, leaving the location of the dredged material boundary unclear on the east, and north and south (Figure 2-2). The REMOTS® stations surveyed in July were chosen to further define the boundaries of the dredged material and to determine the status of benthic recolonization at the site. Fourteen REMOTS® stations were surveyed on July 22 (Figure 2-3). Seven of these stations (El, G2, F3, E4, HS, G7, E8) were also surveyed in January. The seven stations outside of the boundary of the January survey (14, J5, 17, D9, I9, M9, E10) were surveyed to further delineate the dredged material boundary. After reviewing the REMOTS® photographs from these 14 stations for the presence of dredged material, an additional 28 REMOTS® stations were sampled to demarcate further the dredged material boundary and to gain more information on benthic recolonization on the cap. 2.3. Sediment Density A 24 kHz acoustic survey was conducted concurrent with the July 21 bathymetric survey. The survey interfaced the 24 kHz sound source with the Acoustic Core System® (model CE-IB-100; Caulfield Engineering Group, Oyama, BC, Canada). The Acoustic Core System® is a combination hardware/software package designed to provide quality control during shallow seismic data acquisition. It provided acoustic impedance and density predictions based on signal amplitude in the shallow seismic field. The system calculated impedance values relative to seawater, and generated density estimates based on the work of Hamilton (1970, 1971). Surface sediment grab samples were collected to ground truth sediment density estimates. Monitoring Cruise at the Portland Disposal Site, July 1992 ‘o 766] Aienues ‘aug jesodsiq puryi0g ay) 38 SUOTJEIO] UONRIS gSLOWAU ‘T-Z ainsiy s1a}aIN QO€ O02 O01 —a ad ajeoS 2 72) vu io) w = > - 2 = m wo fe) Cc z i) > a < M.0S° L002 SNOILVLS oSLOWsAd C66L AYVNANVE “ALIS 1VSOdSIG GNV1LYOd Monitoring Cruise at the Portland Disposal Site, July 1992 N 766] Alenueg ‘ajig jesodsiq puepyog oy) 38 UOTJVOO] [elIajeW pespolq °7-7 sinsIg s10}oyy : QOOE O02 00 w qwWaN WON WON le Vv ] Vv Bje9S rr =| m fo} Cc ra is) > a x M.0S°to0Z eJeulwsajapuj = ONI scons ieuoren pepsiaues=3=wa NOLNEIHYLSIG IWIHSLVIN GaD0gHa ae A ieraeiian A d A @ i) N.SZ L002 M.S2°700L SNOILVLS si9oyy oo€ O02 OOL Ere @je9S N.G2 vEoEv M.0S°20o0Z @SLOWSY C66L AINE “ALIS 1WSOdSIG GNV1LYOd Monitoring Cruise at the Portland Disposal Site, July 1992 Data output from the Acoustic Core System® included amplitude and acoustic impedance values. Acoustic impedances have been reliably assigned to different sediment types and, therefore, can be used to detect changes between sediments with dissimilar impedance characteristics (Hamilton 1970, 1971). Impedance values were converted to density values and mapped to quantify changes in sediment type. For a more detailed discussion of the analysis procedure, see Caulfield and Yim (1983) and Caulfield (1984). The density values converted from the impedance values were compared to the density values calculated for the surface sediment samples at the cap site to ground truth the data. 2.4 Sediment Sampling and Analysis : Sediment samples were collected from the center of the three PDS reference areas (SREF, SEREF, and EREF) and from 13 stations located within the lateral limits of the cap at PDS (H5, F5, DS, BS, H7, F7, El, F3, G3, E3, C3, D7, B7). The stations on the cap correspond to the REMOTS® stations. The sediment samples were collected with a 0.1 m2 teflon-lined Van Veen grab sampler. Three samples were collected for analysis at SEREF, and two were collected from EREF and SREF due to difficulty in collecting sediments. One grab sample was collected from each of the 13 stations on the cap (Figure 2-4). Each grab. at the reference stations was subsampled for metals, polycyclic aromatic hydrocarbons (PAHs), and grain size and % total organic carbon. The grabs from the surface of the cap sediment were subsampled for metals and grain size. Sediment to be analyzed for metals and PAHs was placed in precleaned (acid-washed) glass jars. Sediment to be analyzed for grain size and % total organic carbon (TOC) was placed in plastic bags. Samples were kept cold (approximately 4° C) and delivered to the NED laboratory. 2.4.1 Grain Size Analysis Physical analysis of sediments by the NED laboratory included visual classification, and grain size analysis (sieve and hydrometer) using ASTM Method D-422 (ASTM 1990; Table 2-2). Grain sizes were classified using the Wentworth (phi) scale: -2 to -1 phi for gravel, between -1 and +4 phi inclusive for sand, between +4 and +8 phi inclusive for silt, and greater than or equal to 9 phi for clay. Prior to initiating the grain size analysis, a subsample (approximately 5-20 g) was taken for total solids analysis for determination of moisture content. A sieve analysis was then performed in which the sample was separated into size fractions greater than 62.5 wm (<4 phi - sand and gravel), and less than or equal to 62.5 um (=4 phi - silt and clay). The gravel/sand fraction was subdivided further by mechanically dry sieving it through a graded series of screens. The wet sieved and dry sieved fractions less than 62.5 um were combined for each sample. The silt/clay fraction was then subdivided using a pipet technique which utilizes the differential settling rates of particles of different sizes. Monitoring Cruise at the Portland Disposal Site, July 1992 266 I Aing ‘aug jesodsiq puepiog oy) 38 suOTe.0] a[duIes JUSUIpag = *p-7 9ANSI N.0O'GE 0b 9543YSO5 e434S N.0O'PEoED M.0S°Lo0L N,OS'VEoEP SNOILVIDOT FIdWVS LNAWIGAS C66L AIN “ALIS 1VWSOdSIG GNV1LYOd Monitoring Cruise at the Portland Disposal Site, July 1992 1] Table 2-2 Summary of Laboratory Analytical Work, 1992 EPA Test Method No. en eR Fe Pree a ne iu Sample Prenig, xuAmaljtical |? ints avai) ae Ee a re 20 eR Te ere] Polynuclear Aromatic Hydrocarbons (PAHs) 3540 8270 GC/MS Total Organic Carbon 9060 Carbonaceous Analyzer STU BES evap velba GC/MS = Gas Chromatograph/Mass Spectrometer ICP = Inductively Coupled Argon Plasma Emission Spectrometry GFAA = Graphite Furnace Atomic Absorption CVAA = Cold Vapor Atomic Absorption Monitoring Cruise at the Portland Disposal Site, July 1992 12 2.4.2 Total Organic Carbon Total organic carbon, a measurement of organic matter (both labile and refractory) in sediments, was measured using protocols described in the Environmental Protection Agency’s (EPA’s) Test Methods for Evaluating Solid Waste (SW-846) Method 9060 (USEPA 1986). Organic carbon in the samples was converted by the analyzer to carbon dioxide (CO,), which was subsequently measured by an infrared detector. The amount of CO, is directly proportional to the concentration of carbonaceous material in the sample. Inorganic forms of carbon (carbonate and bicarbonate) are not included as part of the reported total organic carbon value... Three PDS sediment samples from the reference areas were analyzed for TOC; results were accompanied by one method blank which was below detection (<0.1% TOC). In addition, eight EPA Standard Reference Material (SRM) sample results were submitted with the TOC samples. The recovery of TOC from these samples ranged from 91.2 to 103.5%, well within acceptable limits (80-120%). 2.4.3 Metals and PAH Analysis Portland Disposal Site sediment samples were analyzed for a suite of eight trace metals as well as aluminum and iron. All metals were analyzed using standard SW-846 procedures for metals analysis (Table 2-2; USEPA 1986). Sediment samples were digested using nitric acid in a microwave oven (Method 3051) except for mercury analysis (Method 7471). Aluminum (Al), cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), nickel (Ni), and zinc (Zn) were analyzed by inductively coupled argon plasma emission spectrophotometry (ICP, Method 6010). Digestates can be heated in several stages allowing removal of unwanted matrix components. Analysis by ICP allows simultaneous or rapid sequential determination of many different metals. Atomic adsorption determinations are completed as single element analyses which allow for low detection limit thresholds. Arsenic (As) and lead (Pb) were analyzed using graphite furnace atomic adsorption techniques (GFAA), and mercury (Hg) was analyzed using cold vapor atomic adsorption (CVAA). The three PDS reference station samples were analyzed for polynuclear aromatic hydrocarbons (PAHs) using SW-846 Method 8270 (Table 2-1; USEPA 1986). This method determines the concentration of semivolatile organic compounds from a sample extract using a gas chromatograph with a mass spectrometer detector (GC/MS). Detection limits for PAH compounds were within limits recommended for the method. Each PAH sample was spiked with three system-monitoring or surrogate compounds (2-fluorobiphenyl, nitrobenzene-D,, and terphenyl-D,,) as a measure of accuracy. Surrogate samples are analyzed as a check on the laboratory’s ability to extract known concentrations of compounds not found normally in the sample. All PAH surrogate recoveries were within Monitoring Cruise at the Portland Disposal Site, July 1992 acceptance limits except for high recoveries of terphenyl-D,, in all samples except the method blank.. The high surrogate recoveries were potentially caused by matrix interference. The acceptable recoveries of 2 out of 3 surrogate compounds indicate no laboratory extraction problem (USEPA 1988a). Specific QC samples for the PAH analyses included a method blank, a spiked sample, and a spiked duplicate sample. These results are discussed in the QA/QC section below (2.4.4). 2.4.4 QA/QC Results submitted by the NED laboratory were found to be acceptable and supported by appropriate documentation. Sample data were evaluated using protocols developed by the EPA (USEPA 1988a, 1988b). Quality control checks from the NED laboratory consisted of method blanks, matrix spikes, duplicate samples, and laboratory control samples. Method blanks are laboratory QC samples processed with the samples but containing only reagents. Method blanks test for contamination which may have been contributed by the laboratory during sample preparation. Matrix spike sample analyses provide a measure of the efficiency and effectiveness of sample preparation and analysis procedures, in addition to an indication of how tightly a compound is bound to its matrix. Matrix spikes are also used to assess the accuracy of analytical measurements. Duplicate samples indicate variability in laboratory procedures and degrees of difference between individual samples. Duplicate blank spike and duplicate matrix spike samples were used to measure precision in laboratory procedures. Laboratory control samples used by the NED were EPA standard reference material (SRM) samples analyzed using identical procedures as with the samples. All samples submitted for metals analysis were extracted and analyzed within EPA recommended holding times, except for Hg samples which were extracted 32 days after collection and analyzed the following day. EPA guidelines suggest a maximum holding time of 28 days for Hg (USEPA 1988b). The Hg results were not qualified because of the short time delay and the refrigeration of the samples. Samples analyzed for PAHs, PCBs, and pesticides were extracted and analyzed within EPA recommended holding times (USEPA 1988a). Method blanks were below detection for all metals except for Zn (13 ppm). All samples contained zinc in concentrations greater than 5 times the concentration detected in the method blank, so no qualifications were necessary (USEPA 1988b). The method blank samples for PAHs, PCBs, and pesticides were below the practical quantitation limit for all compounds. Spike and spike duplicate samples were analyzed as an evaluation of laboratory accuracy and precision. Duplicate spike samples were analyzed for all of the metals Monitoring Cruise at the Portland Disposal Site, July 1992 14 analyzed in the PDS samples, two PAH compounds (acenaphthene and pyrene), total PCBs, and six pesticide compounds (lindane, heptachlor, aldrin, dieldrin, endrin, and 4,4'-DDT) using the same methods described above. All spike recoveries were within control limits except for low recoveries of endrin in both pesticide spike samples (51% and 55%; the acceptance range is 56-121%). Since four out of five pesticide recoveries were within control limits, the endrin results indicate no laboratory extraction problem. Precision was measured as a relative percent difference between the spike and spike duplicate results. Relative percent differences for all QC samples were within laboratory control limits, indicating acceptable sample precision. Monitoring Cruise at the Portland Disposal Site, July 1992 15 3.0 RESULTS 3.1 Bathymetry The Portland Disposal Site varies in depth from 42 to 64 m (Figure 3-1). The higher elevations are hard rock ridges with steep slopes that enclose more gently sloping sandy valleys. The ridges are located in the southwest corner of the site (minimum water depth of 43 m), at the northern border of the site (minimum water depth of 45 m), and to the east (minimum water depth of 49 m). These ridges enclose two main valleys. One, centered at approximately 43°34.167’ N, 70°02.167’ W, trends northwest to southeast and has a maximum depth of 60 m. The other valley trends north to south in the center of the site and slopes to a maximum water depth of 64 m. The July 1992 bathymetric survey identified a well-defined mound just south of the buoy location. The mound is approximately 100 m in diameter and 7 m in height (minimum water depth 49 m; Figure 3-1). The location and shape of the mound appear to have remained unchanged since 1989 (Figure 3-2). A depth difference comparison between the January 1989 and the July 1992 bathymetric surveys shows extensive areas of accumulation (Figure 3-3) and isolated areas of loss (Figure 3-4). Accumulations of 0.75 m and 1.0 m are located within a 300 m radius of the buoy location. Below 43°34.083’ N, another broad area of accumulation with similar values is seen. Large (>1 m) positive differences in depth between 1989 and 1992 occur in very localized areas and are marked by dense contour lines. Most areas of negative depth differences are localized around areas of steeply sloping ridges. Two areas of negative depth difference (southeast of 43°34.250’ N, 72°02.250’ W and northeast of 43°34.000’ N, 70°01.750’ W) are located on the southwest slopes of ridges. 3.2 REMOTS® The REMOTS® photographs from the 42 stations were analyzed for the presence of dredged material and a variety of parameters indicative of the health of the benthic environment. Previous REMOTS® surveys at PDS have been hampered by the hard rock bottom which can inhibit data collection (SAIC 1990). Because the general location of the dredged material was known in July, more usable images were collected from the disposal site than in January. Due to the rocky bottom, there were still difficulties in collecting data from the reference areas, and no data was obtained at 16 out of 39 stations. The January 1992 PDS REMOTS® survey outlined the dredged material boundary within 250 m of the disposal location (Figure 2-2). The REMOTS® stations in the present survey were chosen to repeat some of the dredged material stations surveyed in January and to further define the dredged material footprint by expanding the survey into ambient bottom. Monitoring Cruise at the Portland Disposal Site, July 1992 (s1ajoul ul yIdap) 7661 Ang ‘aS jesodsiq puepiiog ay) JO Wey dINoWIAYIeq ponoOD ‘“J-¢ sans 0008/5 :3t@25 : evel M.SZ 4.02 M .00'Z00Z M .G2Z'Ze0Z e66r. ATN£ puetjuod N .00 VEot¥ aiS 1VSOdSIG =~ = N SZ Veoev joe] 2) Cc z s) y > D < M..0S'b00Z M SL'boOL M..00'2002 mean Monitoring Cruise at the Portland Disposal Site, July 1992 M7, (siojaut ul yidap) 636] Arenues ‘ayIg Jesodsiq pueloOg ay) Jo WEY oINOWAYIEG poinojuoD = *7-¢ ANSI WOSe "10 010 hO0S "10 020 ROSL10 010 h000"cO 020 KOS2“cO 010 hO0S"cO 0/0 : S514 OGY ij Gog 005 0 a s—— gh mice f je + + N wre. Ai a) AYVONNOE ALIS IvSOasia N000"vE Ev -|- te ED. 5 AYWONNOE SIS TwSOdsia -weieer -|- i ape Wa PELOPILN AG WOS250 020 W008 "50 020 WOSL'10 010 h000'20 0/0 Monitoring Cruise at the Portland Disposal Site, July 1992 AyjaurAyjeq aug jesodsiq puepyiodg Z661 PUB 686] JO UOsIIedUIOD oY) UO paseq (SID}aUI UT) WRYD INOJUOD aoUaIOIJIP dap SATISOg QOOB/F ‘3fe2S 533m M.SLZ 4002 M .00'2.0Z M .S@'%o02 6861 02 J3tP UZdap + e66t Atn€ puetzuod N .SC vEoey +- M..0S'400Z MSZ 4002 M .00'2002 M.S2200Z ifs Settee. BSS EIS of [ is [ioe "€-€ Jind N .00 VEEP N SC veoty Monitoring Cruise at the Portland Disposal Site, July 1992 AnawiAyyeq ays jesodsiq pueyjo0g 7661 PU 686 JO UOSIIedUIOD dy) UO paseq (SJ9}9N UI) WeYD INOWUOD doUaIaJJIP dap aaNeSaN *p-E VANSI OOOB/F :ate2s su0am MSZ +002 M .00'2002 6865 uel ystP uZdap— e66t Atn€ puetzuo0d N SC veoey S38 q a ef) ~ aa 0-862 M.0S't.02 M.SZ 4.02 M .00°2.02 M .S2 2002 tr N 00 VEEP N SZ poole M .S@'eo02 Monitoring Cruise at the Portland Disposal Site, July 1992 20 Twenty REMOTS® stations were surveyed in both January and July. In July, fourteen remained dredged material, four remained ambient sediment, one (B2) was ambient and became covered with dredged material, and one (G2) was ambient in January, but the camera did not penetrate the sediment in July (Figure 3-5). In general, penetration depths were shallower for ambient sediment than dredged material. In January, the dredged material boundary was undefined at the north central point and to the east and south. REMOTS® Station EO was surveyed in July, and dredged material was detected, extending the undefined boundary to the north. Stations J3, J5, K4, and J6 were chosen in July to determine the extent of the dredged material boundary to the east. Ambient sediment was detected at these stations and more clearly defined the eastern boundary of the dredged material. Additional stations to the south (J8, D9, F9, 19, B10, E10, H10, J10, C11, K11, E12, and G12) all exhibited dredged material, leaving the southern boundary undefined. These stations are near the location of the disposal buoy from 1979 to 1984 (43°34.110’ N, 70°01.910’ W). Stations K9, M9, I7, and N10 were water or surface photos, providing no clear information. Parameters that indicate the health of the benthic environment in the REMOTS® photographs include the Redox Potential Discontinuity (RPD) depth and the successional stage. The multiparameter REMOTS® Organism-Sediment Index (OSI) is used to characterize habitat disturbance. The parameters used to calculate the OSI values are the mean apparent RPD depth, the presence of methane or low dissolved oxygen, and the successional stage (Parker and Revelas 1989). RPD values at PDS in July ranged from 0 to 3.28 cm (Figure 3-6). Most RPD values (21 stations) were between 1.5 and 3.4 cm. Seventeen stations on the disposal site had indeterminate values due to condensation on the camera lens. At the reference stations where data was collected (23 stations), 17 stations had RPDs between 1.5 and 3.4 cm (Figure 3-7). At PDS, 18 out of 42 REMOTS® stations had indeterminate successional stage values due to condensation on the camera lens. Where the successional stage could be determined, 21 out of 24 stations had Stage III organisms (Figure 3-8). Stage I organisms were found at three stations: El, F3, and F9. At the reference stations, Stage III seres were found at 17 out of 23 stations. Stage I taxa were found at SREF stations 200E and 300E. Three stations were indeterminate. OSI values at PDS ranged from 3 to 9.5. Since the OSI value is dependent on the RPD and successional stage values, as well as other factors, 19 stations at the disposal site were indeterminate (Figure 3-9). Of the remaining 23 stations, five had OSIs less than +6, indicating areas that were stressed. At the reference areas, OSIs at two out of 23 stations were indeterminate, three were below +6, and the remainder ranged from six to 11. The Monitoring Cruise at the Portland Disposal Site, July 1992 21 7661 Alng ‘ayg [esodsiq puejiog ay) I ‘gS LOWAY UO paseq ‘uONeD0] [eLIa}eUI paspalq “s-¢ aINSIY "eep gSLOW3Y Asenuer pue Ajnr uo peseq UO!INQIISIP jel4a3ewW peBpep sjiwijep inojuOD N.00°'VEoEP sia}eyy Oo€ O02 OOL a ae9S N.G2 VE oEV d22 ppm for As, >92 ppm for Ni), and in the "moderate" category for Cr (112-513 ppm). Four metals results at H5 are elevated above reference values (Cu, Pb, Hg, and Zn); Cu is in the "low" NERBC category, while Pb, Hg, and Zn are within the "moderate" category. Other than F7 and H5, there are several measured values that are slightly elevated relative to reference values including Cr at D5, Cu at D5 and D7, Pb at B7, D7, F5, and H7, and Ni at D5; all of these values are within the "low" NERBC categories (NERBC 1980). All results were then normalized to the percent silt/clay. For stations with gravel (F7, EREF, and SREF), the gravel was removed before the sample was homogenized for Monitoring Cruise at the Portland Disposal Site, July 1992 3] 0cI €€ £L80'0 0€ 000'8¢ ‘181 €9 ss> 8L v7 {vs0'0 91 000° TE f0l +) 4 €c> S16 00S‘91 us S'0¢ x sos 00701 Oot (44 £8€0°0 {LI 000°€I 87 *pazijewiiou-uou 34sIam Alp uldd jje oe syiup ‘uondajap MOTI SANjeA Jo vsnedaq payejNojed jou ukay = *(1Od) Wu] UONBoNUeNb jesoRId ay MOjaq Inq JUN] UONII}ap JUSWINAYSUT ay) AOE :anjeA payewNsy = 6£ {s°8 fevo'o0 L6 000°LI yS> 07 €c> os 000°TT oUIZ 1949!N Aind1ayy peoT uol] jaddop winiwo1y9 wniwped o1uasiy wnuiwinyy aed |dey Baly aoualajay oUuIZ 1249!N Anda pea] uol] jaddop waAlwo0ly9 87> winiwiped) 6L auasly 000°02 wouluinty Sealy dUalajay pue SUOIIeIS aI1g [esodsiq puepOg oY) JO} sasdjeuy [RII poziyeutou-uoyy €-€ FGeL * f Monitoring Cruise at the Portland Disposal Site, July 1992 a 32 chemical analysis. Therefore, the results for these stations were normalized to the percent silt/clay in the fraction of the sample that was analyzed (F7=15%, EREF=20%, SREF=21%). Results from normalization of samples with <20% fine-grained material should be treated with caution as artificially inflated values can result (NOAA 1991). The normalized results for metals analysis for both cap sediments and the reference stations are listed in Table 3-4. There are fewer normalized values that are above the maximum normalized reference values, especially for Hg. Again, the significantly elevated values are concentrated in Stations F7 (As, Cr, Cu, Pb, Ni, and Zn) and H5 (Cu, Pb, and Zn). The number of elevated normalized values at F7 is partially a function of normalization, where the data are normalized to a very small fraction of fine grained sediment. Both F7 and HS are located along the southern edge of the sampled cap stations (Figures 3-11, 3-12, and 3-13). PAHs were analyzed at the reference areas as part of the baseline chemistry survey. The total Low Molecular Weight (LMW) and High Molecular Weight (HMW) PAHs, not including values below detection, are listed for each reference area. SEREF had the lowest values for total LMW and HMW PAHs, and SREF had the highest values. The results for all replicates at each reference area are listed in Table 3-5. 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The depth difference comparison of these two surveys (Figure 3-3) indicated an accumulation of 1 m about 25 m east of the 1992 buoy. Below 43°34.100’ N, another broad area of accumulation is also seen. Negative depth differences between 1989 and 1992 (Figure 3-4) are clustered along steep slopes. These are most likely caused by surveying lane offsets over steeply sloping hard rock ridges (Germano et al. 1993). The extensive areas of dredged material accumulation are not on the steep slopes and are therefore not affected by lane offsets. The pattern of sediment accumulation at PDS between January 1989 and June 1992 must be viewed in conjunction with the positions recorded in the barge logs for disposal _ locations. From January 1989 to November 1990, 21 barge loads of material were recorded as being released within 400’ of the buoy (43°34.270' N, 70°01.968’ W). During this time, one barge load was recorded with a disposal position of 43°34.100’ N, 70°1.900’ W. In March and April 1991, 17 barge loads of material were again released within 200’ of that point. The release areas around these disposal points are shown in Figure 4-1. The disposal position at 43°34.100’ N was the location of the US Coast Guard deployed buoy prior to 1985. Since that time, navigational charts and the US Coast Guard light list continue to denote a buoy at that location. Reported disposal points for the contaminated project material released from October to December 1991, and the cap material released from January to June 1992, are also indicated on Figure 4-1. Most of the contaminated project material was released just north of the buoy location; one barge load on November 8, 1991 was released at 43°34.100’ N, 70°01.900’ W. Cap material was released at various points over the project mound. However, three barge loads were released to the east of the project area. These barge loads were released at a buoy location that was recorded by vessels in the area on January 30, 1992 (Figure 4-2). The disposal locations for the material released in 1989/1990 and for the USCG Capping project correspond to the areas of accumulation between the 1989 and 1992 surveys (Figure 4-1). There is no apparent accumulation at the release point recorded for the spring of 1991, but there is accumulation approximately 100 m to the south. The July REMOTS® survey detected dredged material around the designated disposal area as well as to the south. The material detected along the southern edge of the deposit may have been a thin layer deposited since 1989 (and therefore undetectable to bathymetric surveys), but it may also have been material that was released prior to 1989 that is still visible in REMOTS® sediment profile photographs. i The silt/clay material from the USCG project that was unsuitable for unconfined open water disposal was capped with cleaner silt/clay material as well as with sand from the Northeast Petroleum project. The concurrent release of these two types of cap material made Monitoring Cruise at the Portland Disposal Site, July 1992 PORTLAND DISPOSAL SITE % = Seaman Sampling Station DISPOSAL POINTS Copier aterial 43°34.25° N 43°34.00° N Meters 70°02.00° W 70°01.75° W Figure 4-1. Barge disposal release points at the Portland Disposal Site, October 1991 to June 1992 Monitoring Cruise at the Portland Disposal Site, July 1992 %* = Sediment Sampling Stations A = Contaminated Matenal Disposal Point PORTLAND DISPOSAL SITE 0 = Cap Material Disposal Point ——_ — =— —— = Dredged Material Boundary Delineated by REMOTS® OD Reported Buoy ; Location 3/29/92 Reported Buoy Location 1/30/92 43°34.00° N Figure 4-2. Accumulation of sediment, distribution of dredged material, and barge release locations at the Portland Disposal Site between January 1989 and June 1992 Monitoring Cruise at the Portland Disposal Site, July 1992 it impossible to differentiate between the cap and the disposal mound based on grain size or density. The 24 kHz survey of sediment density did not differentiate between the cap material and other dredged material. The acoustic sediment density survey showed that, in general, the higher density sediment (coarser grain size) was concentrated in water depths shallower than 54 m, and the lower density sediment (silt and clay) was concentrated in the deepest areas. This overall pattern indicates that potentially the finer-grained materials are settling in the deepest areas of the site. The patchy data, however, prevented a conclusive identification of the project dredged material, and the smoothing of the data tended to inhibit the identification of smaller features related to dredged material disposal. The patchiness was due, in part, to the variability due to rapidly changing slopes in the survey area (as in bathymetry), and the heterogeneity of dredged material and, in particular, of the cap material that was being mapped. Finally, the acoustic method of characterizing bottom sediment is still being refined; the strength of the bottom reflection is a function of the acoustic impedance contrast between . the water column and the bottom sediments and is, in theory, directly related to sediment: density. More recent work has shown, however, that the strength of the return is also affected by such sediment properties as porosity, surface "roughness" (particularly a problem with heterogeneous dredged material), and grain size, among other factors (LeBlanc et al. 1992). A capping project is designed to isolate contaminants in the dredged material by covering the dredged material with cleaner sediment which may have contaminant concentrations comparable to, or somewhat greater than, reference. Reference data collected at the PDS were compared to ambient sediment chemistry values (metals and PAHs) as measured by the NOAA National Status and Trends Program in two areas near PDS: Casco Bay (CSC) and Stover Point (MSSP). Metals and PAH data normalized to silt/clay were collected from 1984 to 1986 for CSC and in 1988 for MSSP (Table 4-1). Mean metals values for the three PDS reference areas (Table 3-4) are within the ranges for the NS&T stations. Based on the average concentrations of metals in the NS&T stations and at the reference areas, it appears that the reference areas chosen for PDS are representative of the ambient sediment in the Gulf of Maine. The total LMW and HMW PAHs at reference areas EREF and SEREF (Table 3-5) are below the average total PAH values found at the NS&T stations. At reference area SREF, the total HMW PAHs were 11.00 ppb compared to 9.90 ppb at MSSP. The total LMW PAHs at SREF, 2.39, was within the ranges found at the NS&T stations. Given that the reference areas appear to be representative of the area, metals concentrations from samples taken on the cap (Table 3-4) can be compared to the reference areas. In general, all stations on the cap except for F7 and HS had normalized metals values within the ranges found at the reference areas, indicating that the cap has effectively isolated Monitoring Cruise at the Portland Disposal Site, July 1992 42 OE! 0bO0 8 8£'0 000 6: 000 190 95°0 $629 i i i PI'L6E O07 9% 8£0 i i i seo 870 ssl gsi ki ! i 760 000 6©6.000 j i 100 000 610 L470 i i 610 910 B19SZ OO'FZI 09°SZI i i 00:0 7 ces cwLE ; Th 26 (dSSW) lod J9A0}¢ pue all seo 00'0 10 L8 16£ 8£°0 sol 00'0 Wo 81021 O£ 9L ‘uO}99}ap MOJaq SANjeA JO asnedaq paye[nsjed jou ueaW] = ‘wydiam Ap qdd ul sHWd “qydiom Ap wid ut sjeiayy ouaiAd(po-¢'Z' | )ouapur auaArad(i‘y'3)ozuaq QuadeIIpUe(Yy'e)OZUIqIp aua1Ad(e)ozuaq auatpjuesonij(4)ozuaq auatpuesonij(q)ozuaq auas Aly ausaesIjue(e)Ozuaq 670 000 Le0 eL Liv ! j TL PEE #70 i i ZA) 601 : ; £01 A . 00:0 810 ‘ 710 8h618 S9°166 i ee 188 $9'¥9 (DSO) Aeg oaseD suOHeIS LSN Joy Ae[D/TIS % 0) pazt[eUON we HVd pur s[eIoW Tp P1921 Monitoring Cruise at the Portland Disposal Site, July 1992 43 the contaminants from the underlying material. A few measured non-normalized values fell within the "moderate" or "high" values for Maine as defined by the NERBC (NERBC 1980) at Stations F7 and H5. Plotting normalized values of three metals (Figures 3-11 through 3- 13) showed that the highest values are concentrated in the southeastern portion of the surveyed area. Although the effect of normalization using a small value for the fine-grained fraction at Station F7 contributes to the elevation of normalized metal concentrations there, the elevation at that station and Station H5 warrants closer inspection. The variability of the metals data could be a function of variability within the cap material itself, or of variability within historical dredged material placed prior to the capping project at the 1984 buoy location. Either of these hypotheses are possible; metal levels at F7 and H5 are within the Tange of samples collected in the cap material except for As, Cr, and Ni. Because F7 and H5 are not located near the center of disposal, however, it is possible that no project material was placed at these stations and that the metals concentrations are a result of historical disposal. It is unlikely that the samples were collected in uncapped Coast Guard material, because in samples collected from Coast Guard material prior to dredging, the entire suite of metals had much higher concentrations than measured in F7 and H5. As a reasonable management precaution, however, additional sediment from future projects should be directed to the 1984 buoy location where a small quantity (625 m*) of contaminated material may have been disposed. Monitoring Cruise at the Portland Disposal Site, July 1992 44 5.0 CONCLUSIONS The July 1992 monitoring survey at PDS succeeded in further delineating the dredged material within the site boundaries. Two apparent disposal mounds were found by - comparing the 1989 and the 1992 bathymetric surveys, one representing the capped mound around the 1989/1992 buoy location and one to the south nearer the 1984 buoy location, an area that received material after 1989. Dredged material distribution, as detected by the REMOTS® sediment-profile survey, includes these two areas of accumulation and extends over a broad area to the south as well. The distribution of dredged material in the REMOTS® photographs may reflect historical (pre-1989) dredged material as well as material released between 1989 and 1992 that was not thick enough to be detected acoustically. The 24 kHz survey was not effective in distinguishing the cap material. The heterogeneity of the cap, a mix of coarse and fine-grained sediment, resulted in patchy data over a large area. The high degree of smoothing necessary during data processing decreased the ability to identify specific features in this data set. The "density" as measured by the system is only related to the strength of the acoustic signal. Recent evidence that other factors may influence signal strength (i.e, surface roughness, porosity) make the attempt to distinguish the cap material by this method alone even more difficult. The effectiveness of the cap in isolating contaminants was determined by examining the sediment chemistry values and the benthic biology. Normalized sediment chemistry results from samples on the cap, with the exception of stations F7 and H5, show metals and PAH values within the ranges found in the ambient sediment at the reference areas. Further, these values were generally similar to or lower than values measured in cap material prior to dredging. The location of F7, near the site of the 1984 buoy where a small volume (625 m°) of contaminated material was disposed, suggests that additional cap material should be placed there as a precautionary measure. Stage III organisms were prevalent on the cap, indicating that the benthic environment on the cap is healthy and that the cap material has most likely isolated contaminated material from the sediment/water interface. Monitoring Cruise at the Portland Disposal Site, July 1992 45 6.0 REFERENCES ASTM. 1990. Annual book of ASTM standards, part 19: Natural Building Stone, Soil and Rock, Peat Mosses, and Humus. American Society for Testing and Materials, Philadelphia, PA. Caulfield, D. D.; Yim, Y. C. 1983. Prediction of shallow sub-bottom sediment acoustic impedance while estimating absorption and other losses. J. Can. Soc. Expl. Geophys., Vol. 19(1):44-5S0. Caulfield, D. D. 1984. Shallow seismic derived acoustic core logs. Offshore Technology Conference, Houston, TX, 7-9 May. Germano, J. D.; Parker, J.; Williams, R. 1993. Monitoring cruise at the Western Long Island Sound Disposal Site, July 1990. DAMOS Contribution No. 85 (SAIC Report No. SAIC-90/7598&C92). US Army Corps of Engineers, New England Division, Waltham, MA. Hamilton, E. L. 1970. Reflection coefficients and bottom losses at normal incidence computed from Pacific sediment properties. Geophysics, Vol. 35:995-1004. Hamilton, E. L. 1971. Elastic properties of marine sediments. J. Geophys. Res., Vol. 76:579-604. LeBlanc, L. R.; Mayer, L.; Rufino M.; Schock, S. G.,; King, J. 1992. Marine sediment 3 classification using the chirp sonar. J. Acoust. Soc. Am. 91(1):107-115. NERBC. 1980. Interim plan for the disposal of dredged material from Long Island Sound. New England River Basins Commission, Boston, MA. NOAA. 1991. Second summary of data on chemical concentrations in sediments from the National Status and Trends Program. National Oceanic and Atmospheric Administration Technical Memorandum NOS OMA 59, Rockville, MD. Parker, J. H.; Revelas, E. C. 1989. Monitoring cruise at the New London Disposal Site, August 1985 - July 1986. DAMOS Contribution No. 60 (SAIC Report No. SAIC- 89/7554-C60). US Army Corps of Engineers, New England Division, Waltham, MA. SAIC. 1985. Standard operating procedure manual for DAMOS monitoring activities: volume I. DAMOS Contribution No. 48 (SAIC Report No. SAIC-85/7516& C48). US Army Corps of Engineers, New England Division, Waltham, MA. Monitoring Cruise at the Portland Disposal Site, July 1992 46 SAIC. 1990. Monitoring cruise at the Portland Disposal Site, January 1989. DAMOS Contribution No. 78 (SAIC Report No. SAIC-89/7560&C80). US Army Corps of Engineers, New England Division, Waltham, MA. USEPA. 1986. Test methods for evaluating solid waste (SW-846): physical/chemical methods. Environmental Protection Agency, Office of Solid Waste, Washington, D.C. USEPA. 1988a. Laboratory data validation: functional guidelines for evaluating organics analyses. US Environmental Protection Agency, Office of Emergency and Remedial Response, Washington, D.C. USEPA. 1988b. Laboratory data validation: functional guidelines for evaluating inorganics analyses. US Environmental Protection Agency, Office of Emergency and ESL Response, Washington, D.C. . Monitoring Cruise at the Portland Disposal Site, July 1992 atomic absorption spectrophotometry 11 barge v, 1, 38-40 benthos 3-5, 15, 20, 44 buoy vi, 1, 3, 5, 15, 20, 38, 42, 44 disposal vi, 5, 20 Capping vi, 1, 3-5, 38, 41, 42 colonization 3 Conductivity 4 contaminant vi, 41, 44 CTD meter 4 density v, vi, 4, 5, 9, 26, 27, 38, 41, 44 disposal site New London 45 Portland 1, iii, iv, v, vi, 1, 2, 4-8, 10, 12, 15-19, 21-25, 27, 28, 30, 31, 33, 34, 35-37, 39, 40, 46 Western Long Island Sound (WLIS) 45 dissolved oxygen 20 grain size iii, vi, 4, 9, 11, 26, 28, 29, 38, 41 habitat 20 methane 20 New England Rivers Basins Classification (NERBC) 30, 41 organics 46 polyaromatic hydrocarbon (PAH) iii, vi, 9, 11-14, 30, 32, 37, 41, 43, 44 polychlorinated biphenyl (PCB) 13, 14 total organic carbon iii, 9, 11, 12, 26, 30 recolonization 4, 5 reference area iii, 32, 37, 41 INDEX reference station iii, iv, 4, 9, 20, 22, 26, 28, 30, 32 REMOTS® Organism-Sediment Index (OSI) iv, 20, 25, 26 redox potential discontinuity (RPD) 20 REMOTS® iv, vi, 1, 4-6, 8, 9, 15, 20, 21, 38, 44 RPD REMOTSS®;redox potential discontinuity (RPD) iv, 20, 22, 23 RPDs REMOTS®;redox potential discontinuity (RPD) 20 sandy vi, 1, 15, 28, 29 sediment chemistry vi, 4, 41, 44 clay iii, 1, 3, 9, 26, 28-30, 32, 38, 41, 43 gravel 9, 26, 28-30 sand 1, 3, 9, 26, 28, 29, 38 silt iii, 1, 3, 9, 26, 28-30, 32, 38, 41, 43 sediment sampling vi, 4, 9 cores 5, 9, 45 grabs 5,9 seismic 5, 45 shore station 4 spectrophotometry atomic absorption 11 succession seres 20 successional stage iv, 20, 24 survey baseline vi, 26, 32 bathymetry iv, vi, 1, 4, 5, 15-19, 26, 38, 41, 44 postdisposal 1 REMOTS® vi, 1, 4, 5, 15, 38 sub-bottom 45 temperature 4 tide 4 trace metals iii, vi, 1, 9, 11-13, 30-33, 41-44 arsenic (As) 11, 12, 30 cadmium (Cd) 11, 12 chromium (Cr) 11, 12, 30, 32 copper (Cu) v, 11, 12, 30, 32, 36 iron (Fe) 11, 12 mercury (Hg) 11-13, 30, 32 nickel (Ni) 11, 12, 30, 32 zinc (Zn) v, 11-13, 30, 32, 34 waste 12, 46 INDEX (cont.) i 7 Ths iy