URE YY «NG UFTNNOX
Cont. odd

Monitoring Cruise at the
Western Long Island Disposal Site
July 1992

Disposal Area
Monitoring System
DAMOS oa

Aim 0 Ss ——

DISPOSAL AREA MONITORING SYSTEM

Contribution 102
January 1996

US Army Corps

of Engineers
__New England Division

mie

\SF

DIF

he: (OZ

|

REPORT DOCUMENTATION PAGE orm approved
OMB No. 0704-0188

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any other aspect of this collection of information Including suggestions for reducing this burden to Washington Headquarters Services, Directorate for information
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.C. 20503.
1. AGENCY USE ONLY LEAVE BLANK) 2. REPORT DATE 8B. REPORT TYPE AND DATES COVERED
January 1996 Final report

. TITLE AND SUBTITLE 5. FUNDING NUMBERS
Monitoring Cruise at the Westem Long Island Sound Disposal Site, July 1992

§. AUTHOR(S)
F.C. Eller and R.W. Williams

- PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT:
Science Applications Intemational Corporation NUMBER
221 Thrid Street SAIC-C108
Newport, RI 02840

3. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 0. SPONSORING/ MONITORING AGENCY
US Army Corps of Engineers-New England Division REPORT NUMBER
424 Trapelo Road DAMOS Contribution
Waltham, MA 02254-9149 Number 102

|]11. SUPPLEMENTARY NOTES

Available from DAMOS Program Manager, Regulatory Division
USACE-NED, 424 Trapelo Road, Waltham, MA 02254-9149

12a. DISTRIBUTION/AVAILABILITY STATEMENT 2b. DISTRIBUTION CODE
Approved for public release; distribution unlimited

| |13. ABSTRACT

In July 1992, the Western Long Island Sound Disposal Site (WLIS) was surveyed as part of the Disposal Area Monitoring

System (DAMOS) Program. The survey was conducted to assess the effects of recent disposal at the site as well as to revisit areas
ithin the site and at the reference areas that had showed evidence of disturbance based on results from the last survey in June 1991.

In June 1991, the monitoring survey at WLIS showed high sediment oxygen demand and a high sulfide content at some

monitoring stations on disposal mounds “A” and “D” where dredged material has been released during the 1989/1990 disposal season.

he survey also indicated that reference area WLIS-REF may contain historical dredged material and that 2000S had experienced

|ffrequent physical disturbance. In addition, 2000S contained patchy distributions of elevated polycyclic aromatic hydrocarbons (PAH’s).

Recognizing that it is difficult to find areas of Western Long Island Sound that do not show some impact from humane activity, it was still
determined that a search for more suitable references should be conducted.

The July 1992 monitoring survey at WLIS addressed these two concerns as well as determined the topography, areal extent ,
and recolonization status of the active mound WLIS “F’. Survey methods at the WLIS “F” mound included bathymetry and REMOTS
sediment-profile photography. The bathymetric survey at WLIS “F” showed a mound approximately 200m in diameter and 1.9m in
height. The thin layer of dredged material detected by REMOTS was within a circular area 350m in diameter. The WLIS “F” mound had
recolonized rapidly with deep apparent redox potential discontinuity (RPD) values and Stage III infauna at the apex of the mound.

The benthic habitat and sediment toxicity studies for selected stations at mounds “A” and “D” included REMOTS sediment-profile
photography and a 10-day amphipod bioassay. The REMOTS data at mound “A” and “D” indicated only modest improvement in habitat

\|quality since 1991. However, the 10-day bioassay test showed no statistical difference between these sediments and those at the
||reference areas or control sediments. No remedial action is warranted based on these observations, though periodic follow-up
||monitoring should continue.

The search for reference areas to replace WLIS-REF and 2000S included a cross-shaped bathymetric survey of areas named

SOUTH and EAST to characterize the topography of these proposed areas and a 13-station cross grid REMOTS survey of each proposed
|Site. These areas were also sampled for metals, PAH’s, grain size and total organic carbon. The results showed that SOUTH was a

suitable replacement for 2000S. Area EAST was located too close to an historic dredged material disposal site and showed some of the

\|same characteristics at WLIS-REF.

||Bioaccumulation REMOTS WLIS DAMOS PAH's RPD bathymetric

16. PRICE CODE

| |17. SECURITY CLASSIFICATION OF REPORT 18. SECURITY CLASSIFICATION OF THIS 9. SECURITY CLASSIFICATION OF 20. LIMITATION OF ABSTRACT
Unclassified PAGE ABSTRACT

MONITORING CRUISE
AT THE WESTERN LONG ISLAND SOUND
DISPOSAL SITE
JULY 1992

CONTRIBUTION #102

January 1996

Report No.
SAIC-C108

Submitted to:

Regulatory Division
New England Division
U.S. Army Corps of Engineers
424 Trapelo Road
Waltham, MA 02254-9149

Prepared by:
EC. Eller
R.W. Williams

Submitted by:
Science Applications International Corporation
Admiral's Gate
221 Third Street
Newport, RI 02840
(401) 847-4210

Hist)

US Army Corps
of Engineers
New England Division

TABLE OF CONTENTS

BIST ORSTABISES Tere Str deie net, cic Mra et NA We Be tO aes, Sella ede Ng ae! od
ETSTRORIFIGURES I ratte Jase Pee OH ine FR net RE ON UAN BA ORIN. 8 GUT
Ee CUPIVESSUMMAR YS or cease Steel Sieh et ok LC Ay cake ae RON ie athe
OR aeINTRODWEMON is oar ae ene i ey Aa SA BoB Oe ees
a Naame VEE DEL OD) Saree rarest tet eet eas cay ae AU GR At ben OO eR a cee Cy
2oloe iBathymetry-and Navigationy: SF iieiiye. Siew aah AN ee ee eee a

2.2 | REMOTS® Sediment-Profile Pactra SEE cere en Ne oe iota en cle leas

Doe sclectioniorAlternatey Reference Areas) <4) 0 a1.

23k) Grain: SiZevAMAlVSISW |. Vays hasnt ene eee Se eM ane een ath

Zao emlotaliOrganic, Carbone. 1d es ee ial eagen ants Be ES

DES 239 Metals Analyses cn \eieeis i silo wae Moe Se ct OS er ese ee

2s3 Ae AMGAmAaly Ses? 2 isiWee, petals). ei 255 iret Sg Be eee

237 dhebesticides and PCBeAnaly Ses. j.)515 aaeals Ree ee

Page Loe O VVAOLO: sah aeah Py ais a I ee Ie a ce Ia RV gts

2-4 el and) Dissolved Oxygenysamplings.) =... sae eee

2.5 Benthic Habitat and Sediment Toxicity Assessment at Selected Stations . .

Sel) -- > GATORS OI 1 ESSE eek sn Aree GU ir eres se ue en mer grea Le teM ee gin Ge OT re a
Sole. bathymetry and Navigation aso cts ec suue tapes Ue ene aus ee soane aed

32 REMOTS®) Sediment-ProfilesPhotography <2... 92 ee ee

3925) DredgedsMaterialyFootprint)).)2 st 5 a: oe ee

9.222 sGraineSizesD Istrbutione ans. sks aR ea eee ae

3: 23 uu boundary“ ROUGHNESS fines sca Rea cane iets ee eee

9224 SA pparene RED Depth ways ain: ne nynecer eta die we eee ee ae

S22 SUR SUCCESSIONAlES fAgELh Hiei ech AUN aes dase PREC NGG ey calle

3*216m Organism-SedimentsIndexd(@S))ii7.) 5 See es es eee

SS eemoclection(onmAlltematepReterence-AteaSwi meee

3.3.1 Preliminary REMOTS® Survey at SOUTH and EAST ........

353-2 bathymetnc-Charactenzationyn. + ee eas ee

S055) sSeCiment) Analy sisi: mas. jue Geyer a eye ie She Ai Pen ee Ae Gollan

5:4 CiD and; Dissolved i@xygentSamplinge:.: 9 5). Neen se en

3.5 Benthic Habitat and Sediment Toxicity Assessment of Selected Stations . .

TABLE OF CONTENTS (cont.)

Page

4:0:' DISCUSSION si uk rere Cire at etree Ga ete Sars ck ete AE a eM eer 56
4.1 Dredged! Material Distribution andJEffects 29> =. 2-25 55 5 40)) 052. 56

4:2 Analysis of Selected: WLIS (D7 and 7A~ Stations 2255 7225. .-)- 5. 58

4.3) Selection‘of Alternate; ReferencevAreas. 2154-5 2-2 | 2 eee oe 59

4°35l) -Chemicalcand:Grain; Size Analyses ia 44s) en eae ee 61

4.3.2. -REMORS2 andoBathymethyan. ue cee cic ase en eee 65

5.0 CONCLUSIONS AND RECOMMENDATIONS .................-.. 67
6:0: “REFERENCES © 35 fsya yee tno Sha tes ee att eas, rane emiiner cou ete sere 69

INDEX
APPENDIX

ui

LIST OF TABLES

Table 1-1.

Table 2-1.

Table 3-1.

Table 3-2a.

Table 3-2b.

Table 3-2c.

Table 3-3.

Table 3-4.

Table 3-5.

Table 3-6.

Table 3-7.

Table 4-1.

Table 4-2.

Page
Summary of Disposal Activity at Western Long Island Sound
Disposal Site between November 1991 and May 1992 ............. 4
Physical and Chemical Analyses of Sediments Using ASTM
Method ID 422502 eae rant tox ae et ae (etn Salah a ohe aM ce OM ge nO Nee iti
Results of Sediment Grain Size Analyses and Percent Total
Organic Carbon at Reference Areas for WLIS, June 1991
andpune S992 car ayer pe Pe eae etc cee nem ara Mei hae cael eae een a 48
Metals Results for WLIS Samples as Compared to 1991 Reference
SEAGONS photic. we ea mete ON BE, cea a am ee nO RY AR 49
Aluminum Normalized Metals Results for WLIS Samples .......... 49
Iron Normalized Metals Results for WLIS Samples .............. 49
Pesticide and PCB Results for WLIS Samples ................. 51
PAH Results for WLIS Samples as Compared to 1991 Reference -
SatlO MS ap sete ees Gey cmeee <p ORL yh Pails ARs wid wii vuniniee lis ta apslne ta ca 52
Dissolved Oxygen Concentrations of Near-Surface Waters at
WLIS Reference Areas and Active Disposal Point as Determined
by Modified Winkler Titration and CTD Profiling, WLIS, July 1992 ... 54
Recommended Terminology for Low Oxygen and the Resulting
Biofacies in Marine Environments (from Tyson and
Re arsomen OO) tear rea) Mui Cire Nutt Mia ae. ie Gene oat ce ten a Ret cade th Wah rc B 55
Summary of Amphipod Ampelisca Abdita Data for 10-Day Solid
Phase Tests from Three Areas in Western Long Island Sound ....... 55
National Status and Trends Normalized PAH Data Compared to
IWAET SS 2imple sine waeeey ieee ts Na Ne UN ERNE eC RU UES RU eae kW ony lee 63
National Status and Trends Normalized Metals Data Compared
tORWAEISE Samples terrae scene enue tar tray et uee mater nen ol (ach iue Mee 64

Figure 1-1.

Figure 1-2.

Figure 2-1.

Figure 2-2.

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.

Figure 3-10.
Figure 3-11.

Figure 3-12.

LIST OF FIGURES

Page
Western Long Island Sound Disposal Site location with reference
ATEADOSIMONS eer aaw nous es oan hh shot oti a ea). cians vam nde Seay vomren ies eats may 2
Disposal barge release points at WLIS, 1991-1992 disposal season. ..... 3
Disposal site map with bathymetric survey lanes and adjacent
historicudisposalliSites;cwisds 5 eke pears ue Mich age tue cA Weitee ai ee ae 7
1 9O2VREMOUSS isunveys Of WWIETS van Wor eect sdbe rtd epee re elise canau ye semeat lara 9
Bathymetric contour plot from the 1988 WLIS survey ............ 17
Bathymetric contour plot from the 1990 WLIS survey ............ 18
Bathymetric contour plot from the 1991 WLIS survey ............ 19
Bathymetric contour plot from the 1992 WLIS survey
(NOCOrrEctedato PriOL SURVEY) ioscan ey ee ns ican en eee he ek ee eae 20
Bathymetric contour plot from the 1992 WLIS survey
(corrected to prior survey, 1200 x 800 m survey area) ........... 21
Depth difference) plot for 1992/and) 1991\surveys™] 2 3 ye 22
Dredged material footprint for 1990, 1991, and 1992 surveys,
based on REMOTS® and bathymetric surveys ................. 23
REMOTS® photographs at stations FIOOW (A), FCTR (B),
andEROOSK (EG) ree eae amiteeceisere) Oa ee Seiie yn irene I gyal Wlene nee 2S
REMOTS® photograph at Staton F300S = 927). 525.2.) 45 - o 26
Grain size distribution map, based on REMOTS® photographs ....... 27
REMOTS® photograph at Station F300N -2 =. 0 2. Pe se 29
REMOTS® photographs at stations E200W (A), W300W (B),
and! STOOSE(G) Ne yay a 2 aN Ciittc ge epee NE Sa nadie aa aetect te ON OM Retna 30

Figure 3-13.

Figure 3-14.

Figure 3-15.

Figure 3-16.

Figure 3-17.

Figure 3-18.

Figure 3-19.

Figure 3-20.

Figure 3-21.

Figure 3-22.

Figure 3-23.

Figure 3-24.

Figure 3-25.

Figure 4-1.

LIST OF FIGURES (cont.)

Boundary roughness frequency distribution at WLIS .............
Boundary roughness frequency distribution at pooled reference
areas, 1991 and 1992

Apparent RPD frequency distribution at WLIS .................
Mapped distribution of apparent RPD values at WLIS and
TELEFENCE'StALIONS 2 saciPce eac Mae ones ap ikiiey ae ae eee same Mee iene ne eames
REMOTS® photographs at stations F200W (A) and F400W (B)

showing dark subsurface sediments and associated shallow

apparent RPD sayers 266) neha Has, Una ca ees eto es dernier. Seen
Apparent RPD frequency distribution at pooled reference areas,

POO and 1992 ecient: che teovowhe eet autenante ener at chlst ei nU ata Ol ce cae
REMOTS® photographs at stations W300E (A) showing high SOD
material and poorly developed apparent RPD layers and W100E (B)
showing methane gas bubbles and dark subsurface sediments ........
Mapped distribution of successional stage values at WLIS and

reference stations

OSI-frequency (distribution ate WAS sires cles ayy ee ee
Mapped distribution of OSI values at WLIS and reference
stations

OSI frequency distribution at reference stations, 1991 and 1992

REMOTS® photographs at proposed reference areas SOUTH (A)
and EAST (B) showing relatively homogeneous sediment profiles

Depth profile of SOUTH and EAST west-to-east and north-to-south
transects

REMOTS® photographs at WLIS “D” Station 100W in 1991 (A)
and 1992 (B)

Vi

EXECUTIVE SUMMARY

In July 1992, the Western Long Island Sound Disposal Site (WLIS) was surveyed as part
of the Disposal Area Monitoring System (DAMOS) Program. The survey was conducted to
assess the effects of recent disposal at the site as well as to revisit areas within the site and at the
reference areas that had showed evidence of disturbance based on results from the last survey in
June 1991.

In June 1991, the monitoring survey at WLIS showed high sediment oxygen demand and a
high sulfide content at some monitoring stations on disposal mounds “‘A” and ““D” where
dredged material had been released during the 1989/1990 disposal season. The survey also
indicated that reference area WLIS-REF may contain historical dredged material and that 2000S
had experienced frequent physical disturbance. In addition, 2000S contained patchy distributions
of elevated polycyclic aromatic hydrocarbons (PAHs). Recognizing that it is difficult to find
areas of western Long Island Sound that do not show some impact from human activity, it was
still determined that a search for more suitable references should be conducted.

The July 1992 monitoring survey at WLIS addressed these two concerns as well as
determined the topography, areal extent, and recolonization status of the active mound WLIS
“FF”, Survey methods at the WLIS ‘“‘F” mound included bathymetry and REMOTS® sediment-
profile photography. The bathymetric survey at WLIS “‘F” showed a mound approximately 200
m in diameter and 1.9 m in height. The thin layer of dredged material detected by REMOTS®
was within a circular area 350 m in diameter. The WLIS “‘F” mound had recolonized rapidly
with deep apparent redox potential discontinuity (RPD) values and Stage III infauna at the apex of
the mound.

The benthic habitat and sediment toxicity studies for selected stations at mounds “A” and
“D” included REMOTS® sediment-profile photography and a 10-day amphipod bioassay. The
REMOTS® data at mound ‘‘A” and ‘“‘D” indicated only modest improvement in habitat quality
since 1991. However, the 10-day bioassay test showed no statistical difference between these
sediments and those at the reference areas or control sediments. No remedial action is warranted
based on these observations, though periodic follow-up monitoring should continue.

The search for reference areas to replace WLIS-REF and 2000S included a cross-shaped
bathymetric survey of areas named SOUTH and EAST to characterize the topography of these
proposed areas and a 13-station cross grid REMOTS® survey of each proposed site. These areas
were also sampled for metals, PAHs, grain size, and total organic carbon. The results showed
that SOUTH was a suitable replacement for 2000S. Area EAST was located too close to an
historic dredged material disposal site and showed some of the same characteristics as WLIS-
REF.

vil

1.0 INTRODUCTION

The Western Long Island Sound Disposal Site (WLIS) encompasses a 1 nmi? area
centered at 40°59.400’ N and 73°28.700’ W. The site is located 2.7 nmi south of Long
Neck Point, Connecticut (Figure 1-1). The discontinued Eaton’s Neck, Stamford, and
Norwalk disposal grounds border WLIS to the east, west, and northeast. Sediments dredged
from nearby harbors and shoreline communities are disposed at WLIS under permits from
the New England Division (NED) and New York District of the US Army Corps of
Engineers and monitored under the Disposal Area Monitoring System (DAMOS) Program.

Since March 1982 disposal activities at WLIS have resulted in the formation of six
sediment mounds (WLIS “A” through “F”). Disposal operations at WLIS typically occur
from October 1 to May 31. The disposal point for the 1991-1992 season (WLIS-F) was
marked by a moored taut-wire buoy located at 40°59.160’ N and 73°28.880’ W (Figure 1-
2). This position was 300 m south of the WLIS “E” mound (formed during the 1990-1991
disposal season). Based on recorded barge volumes, approximately 39,700 m3 of dredged
sediments was disposed at WLIS from November 1991 through May 1992 (Table 1-1). The
accumulation of sediment disposed during this period formed the WLIS “F” mound.

Previous monitoring surveys at WLIS have normally taken place on an annual basis,
although the site was also surveyed following the passage of hurricane Gloria (Germano,
Parker, and Williams 1993; SAIC 1987, 1988, 1990a, 1990b; Williams 1993). These
surveys have generally been conducted during the summer, following completion of an active
disposal season. The principal objectives of this monitoring have been to determine the
distribution of recently disposed dredged material, and to assess the effects of each season’s
disposal on the benthic habitat and water column. Concurrent monitoring of three reference
areas (2000W, 2000S, and WLIS-REF) has historically provided off-site data for comparison
to on-site conditions.

Following analysis of the 1991 survey data (Williams 1993) two important
observations were made concerning future monitoring at the WLIS Disposal Site:

e It was recommended that WLIS-REF and 2000S should be reassessed, and potential
replacement reference areas should be identified. Sediment chemistry analysis, grain
size information, and REMOTS® (Remote Ecological Monitoring of the Seafloor) data
indicated that two of the reference areas (WLIS-REF and 2000S) may have been
affected by historical disposal activities or have experienced greater environmental
disturbance than other reference areas.

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

Western Long Island Sound, Connecticut

2ooow

Stamford Historic
Disposal Site
(discontinued)

Figure 1-1.

73°30' W

NORWALK ISLANDS

LONG NECK POINT

Norwalk Historic
Disposal Site
(discontinued)

=
z
LS
N

41°00'N

Eaton's Neck
e Historic Disposal Site
(discontinued)

@
e
Western Long
Island Sound e
Disposal Site
@ SOUTH
@ 2000S

Long Island Sound

1 2

Nautical Miles

® REMOTS®
Reconaissance Stations

Western Long Island Sound Disposal Site location with reference area
positions

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

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Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

Table 1-1

Summary of Disposal Activity at Western Long Island Sound Disposal Site
between November 1991 and May 1992

Permit
Number Permittee Project Area
198700293 | Norwalk Cove Norwalk Cove 11/2/91 535
Marina Marina
NY14761B | Tide Mill Yacht Tide Mill Yacht 12/11/91 - 1/10/92 7990
Basin Basin
NY16225 Trust of J. Mamaroneck 1/16 - 3/3/92
McMichael
198702174 | Harbor Village 1/25 - 3/27/92
Ltd. Partnership

199010449 | Village Creek 2/14/92
Homeowners
Assoc. :

a ae | om

° Under the DAMOS Tiered Monitoring Plan (Germano, Rhoads, and Lunz 1994),
possibly deleterious effects of prior disposal at the WLIS “D” and “A” mounds
warranted further investigation. Based on REMOTS® data, one station near WLIS
“A” and several stations in the vicinity of WLIS “D” were inferred to have a high
sulphide content and a high sediment oxygen demand (SOD). Such conditions would
represent a relatively long-term influence of dredged sediments on the benthic habitat,
because these sediments were presumably deposited during the 1989-1990 season.

Disposal Dates

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

The findings and concerns generated by the 1991 survey data dictated some of the

‘objectives of the 1992 monitoring operations. The specific objectives of the 1992 survey
were

to delineate the areal distribution and topography of dredged material deposited since
the July 1991 survey;

to assess the extent of infaunal recolonization on the active WLIS “F” mound;

to investigate locations for two new reference areas to replace existing reference areas
2000S and WLIS-REF; and

to further assess habitat conditions and sediment toxicity at those stations near the
WLIS “D” mound which exhibited poor habitat conditions during the 1991 survey.

Science Applications International Corporation (SAIC) conducted field operations at

WLIS from 28 July to 30 July 1992. Field operations included bathymetric surveying,
REMOTS® sediment-profile photography, near-bottom and near-surface dissolved oxygen
(DO) measurements, and sediment sampling for metal and polycyclic aromatic hydrocarbon
(PAH) chemistry analysis, total organic carbon (TOC), and grain size determination.

The 1992 monitoring plan was designed to test the following predictions -that are part

of the DAMOS tiered monitoring protocol:

Based on a disposal simulation model, the volume of sediments disposed at WLIS
from November 1991 to May 1992 (39,700 m3) should have resulted in the formation
of a distinct mound at the disposal buoy location.

At the disposal point, benthic recolonization should be predominantly in Stage I,
while recolonization on the flanks of the mound should be primarily Stage II and/or
Stage III. Stage I consists of small pioneering polychaetes while Stage II is
characterized by tubicolous amphipods and Stage III by larger burrowing (head-down)
deposit feeders. Stage III taxa represent high-order successional stages typically
found in low disturbance habitats.

Near-bottom dissolved oxygen concentrations should be similar at stations within the
disposal site and at the reference areas.

Stage III infaunal activity and recolonization should have developed and deepened the

apparent redox potential discontinuity (RPD) boundary layer at suspect stations near
the WLIS “D” mound.

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

6

2.0 METHODS
2.1 Bathymetry and Navigation

The SAIC Integrated Navigation and Data Acquisition System (INDAS) provided the
precision navigation required for all field operations. This system uses a Hewlett-Packard
9920 series computer to collect position, depth, and time data for subsequent analysis and to
provide real-time navigation. A Del Norte Trisponder® system provided positioning data
accurate to +3 m. Shore stations were established in Connecticut at known benchmarks at
Greenwich Point and the Norwalk electric-generating facility. A detailed description of the
navigation system and its operation can be found in the DAMOS QA/QC Plan (Browning et
al. 1990).

An Odom DF3200 Echotrac® Survey Fathometer with a narrow-beam 208 kHz
transducer measured depths to a resolution of 3.0 cm (0.1 feet). Prior to the bathymetric
survey, the speed of sound was determined with a bar check apparatus. In addition, a Seacat
Model SBE 19-01 CTD (conductivity, temperature, and depth) profiler obtained a sound
velocity profile to verify the bar check measurement. Depth values transmitted to the
computer were adjusted for transducer depth. Durirg data analysis, depth measurements
were corrected for speed of sound through water and standardized to Mean Low Water
(MLW) by adjusting for changes in predicted tidal height. A complete description of the
bathymetric analysis technique is also given in the DAMOS QA/QC Plan (Browning et al.
1990).

The 1992 bathymetric survey consisted of 41 east-west lanes covering a
1200 x 1000 m area (Figure 2-1). The northern 33 lanes of this survey corresponded to the
previous 1991 bathymetry survey lanes. The buoy for the 1991-1992 disposal season (“F”)
was within 100 m of the area covered by the 1991 survey; therefore, eight additional lanes
were included in the 1992 survey to ensure complete coverage of any recently deposited
material.

2.2 REMOTS® Sediment-Profile Photography

REMOTS® photography was used to detect the distribution of thin (<20 cm),
recently deposited dredged material layers, map benthic disturbance gradients, and monitor
the progress of infaunal recolonization on, and adjacent to, the WLIS “F” mound. A
detailed description of REMOTS® image acquisition, analysis, and interpretative rationale is
given in the DAMOS QA/QC Plan (Browning et al. 1990).

The 1992 REMOTS® survey of WLIS utilized a 25-station star grid centered at the
buoy coordinates (40°59.160’ N and 73°28.880’ W) for the 1991-1992 disposal season

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

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Monitoring Cruise at the Western Long Island Sound Disposal Site,

8

(Figure 2-2). Stations were positioned 100 m apart. Triplicate photographs were taken at
each station. In addition, REMOTS® sampling at three reference areas (2000W, SOUTH,
and EAST) recorded ambient sediment conditions for comparison to on-site conditions.
Within each reference area, triplicate REMOTS® photographs were taken at each of 13
stations arranged in a cross-shaped grid and spaced 100 m apart.

2.3 Selection of Alternate Reference Areas

Geographic coordinates for several potential reference site replacement regions were
determined using National Oceanographic and Atmospheric Administration (NOAA) nautical
chart 12363. The selection criteria for choosing these areas included depth comparable to the
disposal site, location outside of the active and discontinued disposal sites, and relative
proximity to the previously utilized 2000S and WLIS-REF reference areas. The final
selection of the SOUTH reference area was based on REMOTS® sediment-profile
photography, bathymetric surveying, and sediment sampling and chemical analyses. No
adequate replacement was identified for WLIS-REF, although an initially promising area
called EAST was intensively investigated and was used as a reference for the present survey
(Figure 1-1).

Sediment samples taken with the Van Veen grab provided textural and composition
characteristics for the initial screening of potential reference areas. The presence of shell
debris and sandy or dark sediments excluded several of these regions from further
consideration. These characteristics are commonly associated with dredged or introduced
sediments or are indicative of erosional/depositional current regimes not found at WLIS.
Triplicate REMOTS® photographs were taken at the remaining areas to provide sediment-
profile data. Evidence of past disposal activity (i.e., sand over mud layering, buried
oxygenated layers, shell lag, consolidated sediments, etc.) also excluded several locations
from consideration as replacement reference areas.

A cross-shaped bathymetric survey was done to characterize the major topographical
features of the proposed SOUTH and EAST reference areas. Each survey consisted of two
lanes, approximately 800 m long, run north-south and east-west, through the center of each
area. General changes in depth and slope characteristics surrounding the potential reference
areas were noted. Evidence of significant slope would have excluded either region from
consideration.

Sediment samples were collected at the center of the SOUTH and EAST reference
areas using a 0.1 m? teflon-lined Van Veen grab sampler. Three separate grab samples were
collected for analysis at each reference area. Subsamples from each grab were obtained
using a 10 cm polycarbonate plastic core liner (6.5 cm ID). Cores (5-10 cm in length) were
composited to provide sufficient sediment to fill precleaned 250 ml glass jars for chemical
analyses of metals and PAHs, polychlorinated biphenyls (PCBs), and pesticides. Sediments

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

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for grain size and total organic carbon (TOC) were placed in plastic bags. Samples were
kept cold (approximately 4° C) and delivered to the NED lab. The triplicate samples for the
SOUTH and EAST reference areas were analyzed for TOC, PAHs, PCBs, pesticides, and a
suite of ten metals. Grain size analyses were not run in triplicate but were composited for
the SOUTH and EAST areas. Samples were composited at the NED laboratory.

2.3.1 Grain Size Analysis

Physical analysis of sediments by the NED laboratory included visual classification,
specific gravity, and grain size analysis (sieve and hydrometer) using American Society of
Testing and Material (ASTM) Method D-422 (ASTM 1990; Table 2-1). 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 tnan 62.5 wm
(<4 phi - sand and gravel), and less than or equal to 62.5 um (=4 phi - silt and clay). The
gravel and 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 wm were
combined for each sample. The silt and clay fraction was then subdivided using a pipet
technique which utilizes the differential settling rates of particles of different sizes.

2.3.2 Total Organic Carbon

Total organic carbon was measured using protocols described in the Environmental
Protection Agency’s (EPA) 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. Total organic carbon is a measurement of organic
matter (both labile and refractory) in sediments.

Six WLIS sediment samples 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%).

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

I]

Table 2-1

Physical and Chemical Analyses of Sediments Using ASTM Method D-422

Analysis | Method | Instrumentation |
ASTM D422 1 Sieve/Hydrometer
3540/8270 GC/MS

PEG | i. oe eal

7471

3051/6010
3051/6010

GC/MS = Gas Chromatograph/Mass Spectrometer

ICP = Inductively Coupled Argon Plasma Emission Spectrometry
GFAA = Graphite Furnace Atomic Absorption

CVAA = Cold Vapor Atomic Absorption

PCB = Polychlorinated Biphenyl

PAH = Polycyclic Aromatic Hydrocarbon

2.3.3 Metals Analyses

WLIS 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

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

12

analysis (Table 2-1; 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. The detection threshold associated with ICP analysis is frequently higher
than that of atomic absorption spectrophotometry (AAS). 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). AAS determinations are
completed as single element analyses which allow for low detection limit thresholds.

2.3.4 PAH Analyses

All six WLIS samples were analyzed for 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 suggested 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
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 two out of three 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
(2.3.6).

2.3.5 Pesticides and PCB Analyses

Pesticides and PCBs were analyzed using protocols described in SW-846 Method
8080 (Table 2-1; USEPA 1986). This method determines the concentration of various
organochlorine pesticide and PCB compounds from a sample extract using a GC/MS.

Detection limits for pesticides and PCBs were within limits suggested for the method.

Each sample analyzed for pesticides was spiked with two surrogates (dibutyl
chlorendate and TCMX), and each sample analyzed for PCBs was spiked with TCMX.

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

13

Surrogate recoveries did not indicate a laboratory extraction problem. 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 (2.3.6).

2.3.6 QA/QC

Results submitted by the NED lab 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 five 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
analyzed in the WLIS samples, two PAH compounds (acenaphthene and pyrene), total PCBs,
and five 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

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

14

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. The relative percent difference for all QC samples was within laboratory
control limits, indicating acceptable sample precision.

2.4 CTD and Dissolved Oxygen Sampling

A Seacat Model SBE 19-01 CTD was used to obtain vertical profiles of temperature,
salinity, and dissolved oxygen at the center of each reference area and the WLIS “F”
REMOTS® sampling grid. Prior to the survey the oxygen probe on the CTD was calibrated
using a 2-point procedure with saturated water and a zero oxygen solution. The conductivity
and temperature sensors were factory calibrated and checked with standard seawater and a
mercury thermometer. A laptop computer with Seabird instrumentation software was used to
communicate with the CTD via an RS-232 serial interface. During deployment, the SBE 19-
01 was set to record data at 2-second intervals. All profile data were archived on diskettes.

To verify the CTD dissolved oxygen measurements, near-surface and near-bottom
(within 1 m) water samples were analyzed for DO using a modification of the standard
Winkler titration method (Strickland and Parsons 1972; Parsons et al. 1984). Water samples
were collected by Niskin bottle. Immediately following collection, a 300 ml aliquot was
drawn from the bottle and preserved. ‘All preserved water samples were titrated within eight
hours of the time of collection.

2.5 Benthic Habitat and Sediment Toxicity Assessment at Selected Stations

The 1991 WLIS “A” and “D” stations (WLIS “A,” Station E400W; WLIS “D,” .
stations D200N, D300S, D100S, and D100W) that had exhibited unusually dark (highly
reduced) subsurface sediments were reoccupied during the 1992 survey. REMOTS®
sediment-profile photography and sediment toxicity were used to provide data for the
assessment of current habitat conditions. Triplicate REMOTS® photographs were taken at
each station for comparison with the photographs from the 1991 REMOTS® survey.

Sediment toxicity samples were collected with a Van Veen grab on July 30, 1992.
One 4-liter sediment sample was composited from several sediment grab samples taken at
Station E400W. A second 4-liter sediment sample was collected by compositing samples
taken from each of the WLIS “D” stations. A third 4-liter sample was collected from the
2000W reference area. Samples were placed in iced coolers for delivery to the SAIC
Environmental Testing Center (ETC), Narragansett, Rhode Island. Samples were
refrigerated at the ETC until initiation of the testing procedures. A 10-day bioassay using
the amphipod Ampelisca abdita determined toxicity of the sediment samples. Toxicity of the

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

15

three WLIS sediment samples was determined relative to a sediment sample collected from a
reference area in central Long Island Sound used for all ETC sediment laboratory control
toxicity tests. In addition, toxicity of the WLIS “A” and “D” samples was compared to
mortality rates observed with the WLIS 2000W sample.

The test organism, Ampelisca abdita, was collected from surface sediments (upper 8
to 10 cm) of the Pettaquamscutt River, Narragansett, Rhode Island. Amphipods 0.71-
1.0 mm in size were held at the ETC in chambers containing presieved, uncontaminated
sediments from their original collection location under static water conditions. During
acclimation and holding, the amphipods were fed, ad libitum (as much as they could
consume), the laboratory cultured diatom Phaeodactylum tricornutum. Fifty percent of the
water in the holding containers was replaced every day at the time of feeding.

Twenty-four hours prior to test initiation, each test sediment (WLIS “D,” WLIS “A,”
and 2000W) was press-sieved through a 2.0 mm mesh screen, homogenized, and placed into
exposure chambers. Five replicates were tested for each sediment. A fourth sediment
sample, collected from a reference area in central Long Island Sound, served as a laboratory
control sediment for the test. Each chamber received filtered seawater, was placed into
20° C water baths, and provided aeration.

On test initiation day, August 15, aeration was stopped, and 20 subadult amphipods
were distributed randomly into each test chamber. After one hour, the containers were
checked for amphipods that had not burrowed into the sediment. The test was started when
nonburrowing animals were replaced and aeration restarted. The animals were not fed
during the test.

Mortality was the endpoint for the Ampelisca toxicity test. The number of dead
amphipods in each chamber was recorded daily, and the dead organisms were removed.
Temperature was monitored daily during the test. Salinity, dissolved oxygen, and pH were
measured on Day 5 and Day 10 of the test. After ten days, the bioassay was terminated, and
the contents of each exposure container sieved through a 0.5 mm mesh screen. The material
retained on the sieve was sorted under a stereomicroscope and the recovered amphipods
counted. Any missing individuals were assumed to have died and decomposed during the
test and were counted as dead.

Mortality data from the 10-day test established the toxicity of the WLIS sediments
relative to a laboratory control sediment and the toxicity of the WLIS “A” and “D”
sediments relative to the 2000W reference area sediment. Toxicity data were reported as
mean percent survival. A t-test (arc sine-square root transformation) determined statistical
differences on proportional mortality by comparing the test sediment data to the laboratory
control.

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

3.0 RESULTS
3.1 Bathymetry and Navigation

The most recent bathymetric surveys of WLIS were conducted in 1988, 1990, and
1991 (Figures 3-1, 3-2, and 3-3). The June 1991 bathymetric survey (33 lanes) covered a
1200 x 800 m area which incorporated the five WLIS disposal mounds (WLIS “A,” “B,”
“C,” “D,” and “E”). The July 1992 bathymetric survey consisted of 41 lanes and covered a
1200 x 1000 m area (Figure 3-4). Lanes 1-33 duplicated the 1991 survey grid. This
portion of the 1992 survey incorporated the five WLIS mounds in addition to the newly
formed WLIS “F” mound. Lanes 34-41 of the 1992 survey provided bathymetric detail of
the 1200 x 200 m region southward. This southern region shoals gradually from 35 to 32
m. A shallow ridge extends approximately 200 m into the surveyed region and terminates
100 m southeast of the WLIS “F” mound.

The minimum water depths of the disposal mounds in the 1991 survey were “A,”
29.75 m; “B,” 31.00 m; “C,” 28.00 m; “D,” 28.50 m; and “E,” 29.75 m. Prior to detailed
analyses, the 1992 depth data was standardized to the 1991 survey. This procedure allowed
the comparison of the 1991 and 1992 depth data, including the assessment of changes in
mound heights and depth difference analysis. Only the 1200 x 800 m area common to the
1991 and 1992 surveys could be standardized in the 1992 survey (Figure 3-5). The data
reported in Figure 3-5 showed that the 1992 minimum water depths of the WLIS “B,” “C,”
“D,” and “E” mounds remained unchanged since the 1991 bathymetric survey; however, the
measured minimum water depth of the WLIS “A” mound increased from 29.75 to 30.25 m,
a decrease of 0.5 m in mound height.

Acoustically detected changes in water depth showed that WLIS “F” was an
elliptically shaped mound with an approximate diameter of 200 m and a height of 1.9 m
(minimum water depth 32.25 m; Figure 3-6). Based on the depth difference analysis
(comparing the 1991 and 1992 surveys), approximately 23,320 m? of sediment accumulated
at the disposal point to form the WLIS “F” mound. Barge volumes reported for the
November to May disposal period totaled approximately 39,705 m? (Table 1-1).

3.2 REMOTS® Sediment-Profile Photography
3.2.1 Dredged Material Footprint

The WLIS “F” mound was located approximately 300 m south of the WLIS “E”
mound and 350 m southeast of the WLIS “D” mound. The dredged material footprints
developed during the formation of WLIS “D” and “E” (the 1988-1990 and 1990-1991

disposal seasons, respectively) fell within 100 m of the center of WLIS “F” (Figure 3-7).
The persistence of features associated with dredged material within these older footprints

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

17

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(sand-over-mud layer, buried oxygenated layers, consolidated sediments, etc.) complicated
the mapping of the recently deposited sediments. Therefore, a combination of the
REMOTS® and bathymetric data was utilized to differentiate between relic and recently
deposited dredged material.

Dredged material, both relic and recently deposited, appeared in REMOTS®
photographs at 18 of the 25 WLIS “F” stations. REMOTS® photographs from stations on
the “F” mound showed that the recently deposited material consisted of mixtures of silt/clay
and very fine sands (Figure 3-8). Some of the sediments were deposited as consolidated
clays.

Due to the relatively small volume of material deposited during the 1991-1992 season
and the proximity of the WLIS “D” and “E” mounds to the “F” buoy, dredged materials
observed at stations F300N, F400N, and F400W were presumed to originate from the WLIS
“D” and “E” footprints or as a combination of new and old dredged materials. REMOTS®
photographs from stations F200S, F300S, F400S, and F200SE revealed thin surface layers of
cobble without evidence of dredged materials (Figure 3-9). Typically, cobble layers are
indicative of dredged sediments; however, these four stations were located on the flanks of
the ridge which extends into the survey area. This area may experience unique erosional and
depositional forces; therefore, ambient sediment characteristics along the ridge may differ
significantly from ambient sediment characteristics of the flat, level regions of western Long
Island Sound. This still does not preclude dredged material as a source for this cobble layer,
but the stations were classified as ambient.

The homogeneous REMOTS® sediment profiles at stations F200E and F400E did not
indicate past dredged material disposal. One replicate photograph from Station F300E
revealed a band of dark subsurface sediment. This sediment layer is possibly the result of an
historical disposal event.

3.2.2 Grain Size Distribution

As noted in previous monitoring surveys of WLIS, grain size analyses did not
differentiate recently deposited dredged material from ambient sediments. Sediments within
the disposal site consisted of silt/clay (>4 phi) and very fine sand (3-4 phi) (Figure 3-10).
Several stations exhibiting silt/clay sediments were clustered on the WLIS “F” mound and
within 100 m of the mound. Additional silt/clay REMOTS® stations were north and west of
the WLIS “F” mound and adjacent to the WLIS “D” and “E” mounds. Sediments at these
stations (F400N, F400W, and D100W) likely resulted from disposal operations prior to
November 1991.

The majority of the 1992 REMOTS® stations were very fine sand (3-4 phi). Sediment
profiles at these stations showed mixtures of sand throughout a predominantly silt/clay

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

REMOTS® photographs at stations F100W (A), FCTR (B), and F100S (C)

Figure 3-8.

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

26

Figure 3-9. REMOTS® photograph at Station F300S

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

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28

sediment matrix. REMOTS® photographs revealed thin surface sand overlying silt/clay
sediments at several stations within the disposal site. A similar sand-over-mud layering was
observed at several stations in the 1991 survey.

Stations F300S, F400S, and F200SW (located on the ridge in the southeast portion of
the survey) exhibited surface cobble layers. Cobble was considered to be the ambient
sediment type for the ridge although it might also have originated as dredged material.
Consolidated clay material at stations adjacent to the WLIS “E” and “F” mounds (Figures 3-
8A and 3-11) was clear evidence of dredged material. Consolidated clay material is resistant
to erosion and can persist for several years until sufficient biogenic activity breaks down
clumps and incorporates the clay into the sediment column. At the tops of disposal mounds,
shell lag is often exposed after the winnowing of unconsolidated, fine silt/clay material. The
surface shell layer at F300N (located on the WLIS “E” mound) provided evidence of this
winnowing process. This shell layer can protect the mound from further winnowing of
material and contribute to the stability of the mound.

Reference areas 2000W and EAST consisted primarily of silt/clay sediments whereas
sediments at the newly selected SOUTH reference area consisted of very fine sand (Figure 3-
12). REMOTS® photographs revealed consolidated clays and surface shell layers at some
stations within the EAST reference area. A similar surface shell layer was evident at some
stations in the 1991 reference area, WLIS-REF.

During the 1992 REMOTS® survey, reference area 2000S exhibited fine sand
sediments (2-3 phi). The 3-4 phi (very fine sand) grain size of the SOUTH reference area
resembled more closely the sediment grain size of the on-site ambient stations and, therefore,
was a more appropriate sediment type to be compared with sediment conditions in 1992.

3.2.3. Boundary Roughness

Twenty-four of the twenty-five disposal site stations had mean boundary roughness
values between 0.6 and 1.9 cm (Figure 3-13). Observed boundary roughness was attributed
to physical (as opposed to biogenic) processes. The 1991 on-site data displayed a similar
distribution: 20 of 25 stations had mean boundary roughness values between 0.6 and 1.4 cm.

Thirty-six of the thirty-nine reference stations sampled at all three reference areas
exhibited mean boundary roughness values <1.9 cm for the 1992 survey compared to 31 of
39 stations for the 1991 survey (Figure 3-14). Eight of the REMOTS® stations occupied in
1991 had boundary roughness values greater than 1.8 cm. These larger values were
attributed to sand waves at the 2000S reference area.

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

Figure 3-11. REMOTS® photograph at Station F300N

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

30

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Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

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31

WLIS
Boundary Roughness

Frequency

OoO-7A NY WwW ff OO N

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Boundary Roughness (cm)

1992 BR Values

Figure 3-13. Boundary roughness frequency distribution at WLIS

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

32

WLIS Reference Areas
Boundary Roughness

N 1991 =39

N 1992 =39
ee yoo Hate ole De clas ROO 5 eS Sine eS ee

Frequenc

i

i

j

|

i

i
i
i
i
i
i
i
i
i
i
i
H
i
i
i
i
i
i

SS

IG{BEG
T

WSC
i

0-06 1-14 1.822 263.0 3.438 42-46
Boundary Roughness (cm)

[11992 BR Values Z 1991 BR Values

Figure 3-14. Boundary roughness frequency distribution at pooled reference areas, 1991 and
1992

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

3.2.4 Apparent RPD Depth

The frequency distribution of apparent RPD depths for the 25 WLIS “F” REMOTS®
stations had a major mode in the 2.0-2.5 cm range and a mean of 2.3 cm (Figure 3-15). The
frequency distribution of the 1991 RPD depth data had a similar major mode in the 2.0-

2.5 cm range and a mean of 2.16 cm. Analysis of the 1992 RPD data revealed a relatively
even distribution of the number of stations within each 0.5 cm depth interval range for
apparent RPD depths of 1.0 to 3.5 cm. This broad distribution of the 1992 RPD depth data
was in contrast to the 1991 survey, in which mean apparent RPD depth values were clustered
in the 2.0-2.5 cm depth range. Overpenetration of the REMOTS® camera prism precluded
determining the RPD boundary layer at Station F400N.

The areal distribution of apparent RPD depths in the 1992 survey showed a
correlation between RPD depth and the proximity of the station to the designated disposal
point (Figure 3-16). Six of the seven WLIS “F” stations with apparent RPD depths
=3.0 cm fell within 100 m of the WLIS “F” mound. In addition, the majority of stations
with apparent RPD depths of =>2.0 cm encompassed the WLIS “F” mound. These results
indicated that the deepest apparent RPD depths were associated with the recently deposited
dredged material. Apparent RPD depths for the 1991 survey were moderately developed
within 100 m of the WLIS “E” mound (the active disposal point for the 1990-1991 disposal
season); however, no clear relationship between RPD depth and proximity to the mound was
apparent.

Many of the replicate photographs from stations F200W, F300W, and F400W showed
relatively dark subsurface sediments and associated shallow RPD layers (Figure 3-17).
These sediments may contain significant inventories of organic labile material which, when
processed by microbial activity, can result in decreased dissolved oxygen concentrations
within sediment pore waters. The sediments at these stations were considered to be a
mixture of past and recently deposited materials.

Sixty percent of the apparent RPD depths for the 1992 pooled reference areas were in
the 1.0-2.5 cm depth range (Figure 3-18). The mean apparent RPD depths at reference areas
2000W, EAST, and SOUTH were 1.88, 1.59, and 1.93 cm, respectively. This unimodal
distribution of the 1992 RPD data contrasted with the bimodal 1991 RPD distribution and
reflected the relative consistency. in the apparent RPD depths observed at the 1992 reference
areas. The 1991 bimodality was driven largely by the deep RPD depths noted at reference
area 2000W (mean 3.77 cm) relative to RPD depths calculated for WLIS-REF and 2000S
(mean 1.81 and 1.53 cm, respectively).

Well-defined apparent RPD boundary layers characterized sediment-profile

photographs at the 2000W reference area in 1991, whereas RPD boundary layers were not as
distinct in the 1992 data. Overall, the moderate-to-high reflectance of 1992 sediment-profile

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

34

WLIS
Mean RPD Values

J

uel icV

Frec,
Oo -]- NY & fb OT OH NN

0-0.5 1.0=1.5 * 2:02:5' 9 3/0-3:5 » 74.0-4:5 25:0-5:5
Mean Apparent RPD (cm)

1992 RPD Values

Figure 3-15. Apparent RPD frequency distribution at WLIS

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

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Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

36

B

Figure 3-17. REMOTS® photographs at stations F200W (A) and F400W (B) showing dark subsurface

sediments and associated shallow apparent RPD layers

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

ta ue
_ enlhyunrtatiery amid Robern nnd
my Lyra ss }

sit nf an ef atten A al
x - Alsi
a i v
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WLIS Reference Areas

Mean RPD Values

9
my
: cS)
i Ww)
oO Oo
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| 0
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=
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Pe I ee
io) co i<@) a N oO
e
Aouenbes 4

RPD Values
[-}1992 RPD Values Z 1991 RPD Values

Figure 3-18. Apparent RPD frequency distribution at pooled reference areas, 1991 and 1992

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

38

photographs at 2000W did not provide evidence of low dissolved oxygen concentrations in
the sediment pore waters or the overlying water column. Station W300E (within 2000W)
revealed high SOD material and poorly developed RPD layers (Figure 3-19). In addition,
methane gas bubbles and dark subsurface sediments at Station W100E provided some
evidence of either historic depositional events, earlier periods of low oxygen, or both (Figure
3-19).

RPD boundary layers were difficult to distinguish in some replicate photographs at the
SOUTH reference area due to the moderate-to-high reflectance of the subsurface sediments.
Some sediment profiles showed patchy, subsurface relic RPD layers. The reconnaissance
REMOTS® photographs taken at the center of the EAST reference area showed homogeneous
sediment profiles with moderately developed RPD boundary layers; however, REMOTS®
photographs from other EAST reference area stations showed patchy and/or relict RPD
layers. ;

3.2.5 Successional Stage

Exclusively Stage I infaunal activity was evident at six of the 25 WLIS “F”
REMOTS® stations (Figure 3-20). Four of these six stations were clustered within 100 m of
the center of the WLIS “F” mound. REMOTS® photographs from each of these stations
revealed extensive reworking of the top several centimeters of sediment by these pioneering
Stage I infauna, indicating that the initial phases of recolonization were in progress.

At least one replicate photograph from each of the remaining WLIS “F” stations
(400N was indeterminate) displayed evidence of Stage III infaunal activity (i.e., active
feeding voids, see Figure 3-8A). Five of these stations were within 100 m of the WLIS “F”
center. The presence of these Stage III organisms indicated that the newly deposited
sediments were rapidly recolonized and that incorporation of the deposited material into the
ambient sediment matrix can be expected to proceed rapidly.

Photographs from ten of the 39 reference area REMOTS® stations showed exclusively
Stage I infaunal activity. Five of these stations were located within the SOUTH reference
area. During the 1990 and 1991 monitoring surveys at WLIS, the southern reference area
(2000S) contained the greatest proportion of stations exhibiting only Stage I infaunal activity.
The remaining reference area REMOTS® stations contained Stage III or combinations of
Stage I and Stage III seres.

3.2.6 Organism-Sediment Index (OSI)
The median OSI values for 24 WLIS “F” stations ranged from +1.5 to 9. Organism-

Sediment Index values for Station F400N could not be determined due to overpenetration of
the REMOTS® camera. The unimodal frequency distribution of median OSI values had a

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

39

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Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

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Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

4]

major mode ranging from +6 to +8 (Figure 3-21). Several stations with median OSI values
= +7 were located within 100 m of the center of the WLIS “F” mound.

Based on the results of past REMOTS® surveys, OSI values of < +6 are considered
indicative of benthic habitats which have experienced recent disturbance (i.e., erosion,
dredged material disposal, hypoxia, etc.; Rhoads and Germano 1986). The areal distribution
of the 1992 OSI data showed that stations with OSI values < +6 were located primarily at
the active disposal point or along the west and south axes of the WLIS “F” grid (Figure 3-
22). The lowest median OSI values (+1.5 and +2) occurred at stations F200W and
F200NE, respectively.

Median OSI values for reference areas 2000W, SOUTH, and EAST were +5, +4,
and +6, respectively. The bimodal frequency distribution of the median OSI values for the
39 pooled reference stations show two distinct major modes at +4 and +8 (Figure 3-23).
The areal distribution of median OSI values showed the patchy, heterogeneous habitat
conditions within each reference area. Median OSI values for the 1991 reference areas
(2000W, 2000S, and WLIS-REF) were +9, +4, and +7,- respectively.

3.3 Selection of Alternate Reference Areas
3.3.1 Preliminary REMOTS® Survey at SOUTH and EAST

The results of the reconnaissance REMOTS® photographs and preliminary sediment
sampling excluded several of the proposed reference areas from further consideration as
replacements for WLIS-REF and 2000S. Shell lag and buried oxygenated layers indicated
that these areas may have been affected by past disposal activities. Triplicate reconnaissance
photographs taken from the proposed SOUTH and EAST reference sites (coordinates
40°58.700’ N, 73°29.200’ W and 41°00.200’ N, 73°27.150’ W, respectively) revealed
relatively homogeneous sediment profiles (Figure 3-24). Photographs from the center of the
proposed EAST reference area showed mud clasts on the sediment surface. Because EAST
was located approximately 3000 m northeast of the WLIS “F” mound, these mud clasts were
not considered to represent recently deposited material. Triplicate REMOTS® photographs,
taken along a 13-station cross-shaped grid, further characterized the habitat conditions within
EAST and SOUTH. REMOTS® parameters measured for these stations are presented in
sections 3.2.2 through 3.2.6.

3.3.2 Bathymetric Characterization
Two-laned, cross-shaped bathymetric surveys were run to delineate the general
topographical characteristics at the SOUTH and EAST reference areas (Figure 3-25). The

west-east bathymetric survey lane at reference area SOUTH showed that water depth
increased from 25 m (400 m west of center) to 27 m (at the center), and then decreased to

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

42

WLIS
Median OSI Values

t

Frequency
Ww

N
=

4 5 6 Te 8 9) «10
Median OSI Values

1992 OSI Values

Figure 3-21. OSI frequency distribution at WLIS

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

43

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Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

y

WLIS Reference Areas

Median OS! Values

UA

(o>)

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Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

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Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

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Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

47

24 m (400 m east of center). The south-to-north survey lane showed that water depth
increased steadily from 24 (400 m south of the center) to 30 m (400 m north of the center).
Water depth remained constant for the 800 m survey lane running east-to-west through the
center of EAST; however, depth increased from 25 m (400 m north of center) to 30 m
(400 m south of center). Although not level, the topography of SOUTH and EAST did not
exclude these areas as potential replacement reference areas.

3.3.3 Sediment Analysis

Grain Size. The results of sediment grain size analyses for samples collected during
the June 1992 WLIS survey at the two proposed reference stations are presented with the
June 1991 reference station results (Table 3-1). Sediment collected from the SOUTH station
was comparable to sediment collected from 2000S during the 1991 survey. All of the
fractions were within 3% of each other except for the percentage of fine sand. Station 2000S
in the 1991 survey contained more fine sand (45%) than the SOUTH station (38%). The
total fine-grained percentage (silt+clay) was 46% for SOUTH and 42% for 2000S.

Sediment at the EAST station was described as dark grey silty clay with sand. The
WLIS-REF station (1991) also contained dark grey clay and silt, but with a reduced sand
content (Table 3-1). The fine sand content of the EAST station was more than twice that of
the WLIS-REF station (15% vs. 7%), although WLIS-REF had a slightly higher medium
sand fraction (6% vs. 2% for EAST). The fine-grained fraction was similar for both EAST
(83%) and WLIS-REF (85%).

Total Organic Carbon. Total organic carbon was higher in both of the 1992 stations
relative to the comparable reference stations from 1991. The averaged TOC content for the
three SOUTH station replicates was 1.1%, compared to 0.6% for 2000S (Table 3-1). The
averaged TOC content for the EAST station was 1.6%, compared to 1.0% for WLIS-REF
(Table 3-1).

Metals. A suite of trace metals, Al, and Fe were measured in samples collected from
the SOUTH and EAST stations (Table 3-2a). Aluminum and Fe are common constituents of
clay minerals, and were measured for the purpose of normalizing trace metal concentrations.
Normalization to a reference element helps to determine what fraction of the metal
concentration is derived from anthropogenic sources, as opposed to naturally occurring
concentrations present in clay minerals.

All of the metals measured were detected in the six WLIS samples except for Cd,
which was below detection in all samples (Table 3-2a). Replicate variability, expressed as
one standard deviation as a percent of the mean, ranged from 9 to 22%. Considering that
the three samples were taken from three separate grab samples, the low variability suggests
relatively uniform metals concentrations in each area sampled. Normalization of metals to

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

Table 3-1

Results of Sediment Grain Size Analyses and Percent Total Organic Carbon at
Reference Areas for WLIS, June 1991 and June 1992

SOUTH 2000S EAST WLIS-REF 2000W
(June 1992) (June 1991) (June 1992) (June 1991) | (June 1991)

Dark grey Dark grey Dark grey Dark grey Dark grey
silty, clayey sand silty clay clay-silt clay-silt with
with sand shell
fragments

% Total Organic Carbon
Rep 1
Rep 2
Rep 3
Average

Grain Size’ Analysis

% Coarse Sand
(1-1 phi)

% Medium Sand
(2-1 phi)

% Fine Sand
(4-2 phi)

% Silt
(=4 phi)

% Clay
(=4 phi)

' Grain size percentages averaged for three SOUTH replicates.

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

Table 3-2a

Metals Results for WLIS Samples as Compared to 1991 Reference Stations

EAST Reference Station sont Reference Station 2000S _2000W

Values below the instrument detection limit (IDL) are shown as less than (<) the IDL.
* = Mean not calculated because of values below detection.
n.a. = Not Analyzed.

Table 3-2b

Aluminum Normalized Metals Results for WLIS Samples

| __EAST Reference Station _—__|_}_SOUTH Reference Station
1
3.35E-04 4238-04 3.05E-04 9 568-04 2 6TE-04
4.19E-05 2.76E-05 2.56E-05 3.14E-05
3.27E-03 3.10E-03 2.67E-03 2.67E-03 2.81E-03
3.42E-03 3.00E-03 3.00E-03 2.63E-03 3.10E-03
1.92E-03 2.03E-03 1.71E-03 1.85E-03 2.00E-03
1.50E-05 1.16E-05 1.48E-05 9.63E-06 1.24E-05
1.15E-03 1.06E-03 1.00E-03 1.07E-03 1.19E-03
7.69E-03_7.42E-03_7.14E-03 6.67E-03_8.57E-03

Values below the instrument detection limit (IDL) are shown as less than (<) the IDL.
* = Mean not calculated because of values below detection.

Table 3-2c

Iron Normalized Metals Results for WLIS Samples

EAST Reference Station GE al SOUTH Reference Station
1 2 3 2: Mean

2.64E-04 2.56E-04 2.56E-04 : 2.23E-04 2.07E-04
3.33E-05 3.33E-05 2.32E-05 2.23E-05 2.44E-05
2.58E-03 2.46E-03 2.24E-03 : 2.32E-03 2.19E-03

2.70E-03 2.38E-03 2.52E-03 : 2.29E-03 2.41E-03
1.52E-03 1.62E-03 1.44E-03 ; 1.61E-03 1.56E-03
1.18E-05 9.23E-06 1.24E-05 ; 8.39E-06 9.63E-06
9.09E-04 8.46E-04 8.40E-04 i 9.35E-04 9.26E-04
6.06E-03 5.90E-03 6.00E-03 : 5.81E-03 6.67E-03

Values below the instrument detection limit (IDL) are shown as less than (<) the IDL.
* = Mean not calculated because of values below detection.

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

50

aluminum and iron reduced the variability between replicates, further supporting a relatively
uniform concentration in each area sampled (Table 3-2b, 3-2c).

The only metals measured in the 1991 survey were Cd, Pb, and Zn (Table 3-2a).
The Pb concentration of sediment from 2000S was slightly higher, and Zn was in the same
range, as samples taken from the SOUTH reference area. Lead in sediment from WLIS-
REF was approximately the same as at EAST, while Zn was slightly lower (Table 3-2a).
Measured levels of Cd in the 1991 samples were within or below the detection limits of the
1992 analyses. |

Pesticides and PCBs. Only two replicates from the six WLIS samples resulted in
detectable concentrations of any pesticide: 4,4'-DDD and 4,4'-DDT were detected at slightly
above the detection limit (15 ppb) in two replicates of the EAST station (Table 3-3). No
other pesticides were detected. Total PCBs were detected in every replicate sample, ranging
from 25 to 47 ppb in EAST replicates, and 3 to 61 ppb in SOUTH replicates. Pesticides and
PCBs were not measured in 1991 reference station samples.

PAHs. Most of the PAH sample results from the WLIS 1992 samplcs were qualified
(“J”) as estimated fur results that were above the instrument detection limit and below the
practical quantification limit (PQL). These data were acceptable, but a greater degree of
uncertainty was associated with these values than with unqualified data.

PAH results were separated into low molecular weight (LMW) and high molecular
weight (HMW) compounds (Table 3-4). Means were calculated for comparison purposes;
detection limits were used in calculations using data below detection. Average LMW PAH
concentrations ranged from 30 to 170 ppb. Phenanthrene was the most abundant LMW PAH
compound at both SOUTH and EAST. Two replicates at EAST and SOUTH were below
detection in acenapthene, and one replicate of SOUTH was below detection in fluorene.
Average HMW concentrations ranged from 187 to 843 ppb. Three HMW PAHs
(dibenzo(a,h)anthracene, benzo(g,h,i)perylene, and indeno(1,2,3-cd)pyrene) were undetected
in all replicate samples except for one replicate from SOUTH (Table 3-4).

Both LMW and HMW PAHs were analyzed in reference station samples from 1991
(Table 3-4). In general, WLIS-REF PAH values were within or slightly higher than the
EAST station ranges. PAH values at 2000S were elevated for many of the compounds
measured compared to SOUTH values. The sum of LMW PAH concentrations in sediments
from 2000S was approximately three times that of the SOUTH replicates, and the sum of
HMW PAHs was approximately twice that of SOUTH.

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

51

Table 3-3

Pesticide and PCB Results for WLIS Samples

Pilcios a patente | EAST Reference Station
peicides 0 ee ee
ire ewe) Se ee ewe |

4.4-DDE| <14 | <4 | <i2| + | <4s| <x | <98 |
4,4'-DDT

aldrin | <7.2 | <o9| <5s9| + | <60| <se|<a9| + |
alpha-BHC | <7.2 | <69| <s9| * | <60| <58| <49°
beta-BHC <4.9
deita-BHC | <7.2 | <6.9 | <5.9| + | <60| <5. |

ricer e012 a eel eae
| endosulfant| <7.2 | <69| <s9| + | <60| <58| <49
| endosulfant| <14 | <4 | <v | + | <a <1 | <os

endosulfan| <14 | <4 | <i2| * | <2 | <1 | <98 |
endrin| <14 | <4 | <i2| + | <a <x | <os |
[endrin aldehyde | <14 | <4 | <a | * | <2 | <i | <os|

gamma-BHC | <7.2 | <6.9 | <5.9 <6.0 | <5.8 | <4.9
(lindane)

|

heptachlor *
methoxychlor :
[total pews 1 47 1] aa) (25) 9) ae al] anh | est aoa

Values below the instrument detection limit (IDL) are shown as less than (<) the IDL.

* = Mean not calculated because of values below detection.
PCBs = Polychlorinated Biphenyls

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

52

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Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

53

3.4 CTD and Dissolved Oxygen Sampling

Depth gradients of temperature, salinity, and DO at the reference areas and the active
disposal point are shown in the Appendix. Surface salinity at each of the four sampling
locations was approximately 27 ppt, increasing slightly (0.5 ppt) with depth. A well-defined
thermocline at 10-15 m water depth was present at each site. Surface temperatures varied
from 20.0° C to 21.5° C and decreased to about 18° C within one meter of the bottom.

Dissolved oxygen concentrations measured by the Seacat Model SBE 19-01 CTD near
the surface ranged from 7.5 to 9.2 mg:l! (SOUTH and WLIS “E,” respectively; Table 3-5).
Near-bottom DO levels ranged from 4.2 to 4.7 mg-I' (WLIS “F” and EAST, respectively).
Dissolved oxygen concentrations, as determined by Winkler titration, differed slightly from
the CTD measurements. Near-surface concentrations ranged from 7.7 to 9.6 mg-!!
(SOUTH/2000W and EAST, respectively) and near-bottom concentrations ranged from 3.6 to
3.9 mg-I' (WLIS “F” and EAST, respectively). Differences between the CTD and the
Winkler titrations were attributed to small shifts in the CTD DO calibration. All measured
dissolved oxygen concentrations were within the aerobic range as defined by Tyson and
Pearson (1991) (Table 3-6).

3.5 Benthic Habitat and Sediment Toxicity Assessment of Selected Stations

Five stations (D200N, D100S, D300S, D100W, and E400W) occupied during the
1991 survey had conspicuously dark sediment profiles and low OSI values. These stations
were reoccupied during the 1992 survey to assess benthic habitat conditions. The 1992
REMOTS® OSI values for four of these stations (D100S, D300S, D100W, and E400W) were
similar to values calculated during the 1991 survey. The median OSI value for Station
D200N increased from +5 (1991) to +7 (1992). Apparent RPD boundary layer depths
increased slightly (about 0.3 cm) at all stations except D100S, where apparent RPD depth
decreased from 1.2 cm to 0.8 cm. The benthic successional seres present for both years ,
were identical, with all stations having either Stage I or Stage I on Stage III. Although the
1992 sediment profiles did show ‘some variability among the replicate REMOTS®
photographs at each station, subsurface sediments from the 1992 survey did not appear as
dark as noted in 1991.

The results of the amphipod 10-day bioassay showed no significant toxicity in the
three WLIS sediment samples (reference area 2000W; WLIS “A,” Station E400W;; and
WLIS “D,” composite of stations D200N, D100S, D300S, and D100W) relative to the
percent survival of the laboratory control sample (Table 3-7). Mean percent survival values
for the 2000W and WLIS “A” samples (94 and 93%, respectively) were higher than the
control percent survival (89%). Mean percent survival for the WLIS “D” sample was 71%
and ranged from 95 to 25%.

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

54

Table 3-5

Dissolved Oxygen Concentrations of Near-Surface Waters at WLIS Reference Areas and
Active Disposal Point as Determined by Modified Winkler Titration and CTD Profiling,
WLIS, July 1992

SOUTH ES

2000W

EAST

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

Table 3-6

Recommended Terminology for Low Oxygen and the Resulting Biofacies in Marine
Environments (from Tyson and Pearson, 1991)

al

Table 3-7

Summary of Amphipod Ampelisca abdita Data for 10-Day Solid Phase Tests from Three Areas in
Western Long Island Sound

Sample % Survival Control % Survival as
Survival % of
Control

WLIS-D

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

56

4.0 DISCUSSION

The 1992 survey at WLIS was designed to achieve the following: first, to monitor the
physical and biological effects of dredged material distribution at the site; second, to evaluate
the benthic status of specific stations at the WLIS “D” and “A” mounds; and third, to
determine suitable replacement reference areas for WLIS-REF and SOUTH.

4.1. Dredged Material Distribution and Effects

A combination of bathymetric survey and REMOTS® data was used to delineate the
boundaries of recent deposition. Recent dredged material can be distinguished from older
deposits with these methods to accurately define the footprint of the new mound (Figure 3-7).
The recently deposited material was located in a central area of the site which has received
materials at six distinct locations from 1982 to 1992 (mounds “A” to “F”). The six WLIS
mounds are positioned within a 400 m radius, and the dredged material footprints created
during the formation of these mounds overlap. Sediment profiles from several stations in the
WLIS “F” grid (stations F200W, F300W, and F400W) revealed mixtures of old and new
dredged material deposits.

Based on the depth difference analysis between the 1991 and 1992 bathymetric
surveys, the WLIS “F” mound was approximately 200 m in diameter and 1.9 m in height.
The results of the REMOTS® survey showed that thin layers of the newly deposited
sediments extended further to cover a circular region with a rough diameter of about 350 m.
Dredged material was not apparent at stations F200E and F400E. Although these stations
had apparent RPD layers =2.0 cm, sediment-profile photographs showed no evidence of past
disposal activity. Interestingly, one of three photographs from Station F300E did reveal a
patchy, dark subsurface sediment. This is potentially remnant of historical dredged material,
or the result of historic anoxic events.

Tabulation of the recorded disposal barge volumes showed that 39,700 m3 of
sediments were disposed at the taut-wire moored buoy from November 2, 1991 to May 4,
1993 (Table 1-1). The depth difference analysis determined that 21,340 m? of dredged
sediments had accumulated in the vicinity of the WLIS “F” mound. The depth difference
analysis accounted for 54% of the reported barge disposal volume.

Processes of consolidation of dredged materials and the ambient base material,
erosion, and errors in barge disposal volume estimates are known to contribute to the
discrepancy in reported versus calculated dredged material volume. In a mass balance study
in the New York Bight, Tavolaro (1984) determined an apparent decrease in volume of
approximately 41% when comparing the disposal barge log volume and the volume
calculated through depth differencing analyses. Based only on Tavolaro’s 41% correction

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

57

factor, approximately 16,280 m3 of dredged material would be expected to be measured by
the depth difference analysis.

The 1992 survey extended 200 m further south than the 1991 survey. Bathymetric
volume calculations between the two surveys could only be based on the area common to
both surveys, in this case the area of the 1991 survey. However, it is unlikely that any
significant amount of material was present outside the 1200 x 800 m survey area, since
REMOTS® photographs did not indicate dredged sediments beyond Station F100S. In
addition, the barge disposal records show that most disposal took place north of the WLIS
“F” buoy (Figure 1-3).

Prior to the depth difference analysis and the subsequent assessment of changes in
mound height, the depths recorded during the 1992 survey were standardized to the 1991
survey. This procedure minimized variability in recorded depths resulting from differences
in the actual, observed tidal parameters and the predicted tidal parameters used for data
analysis. The depth standardization process could be applied only to the 1200 x 800 m area
common to both the 1991 and 1992 surveys. The additional 1200 x 200 m area (to the
south) covered by the 1992 survey could not be standardized to the 1990 survey. Depths
presented in Figure 3-4 (the contour plot of the entire 1200 x 1000 m 1992 survey) have not
been adjusted, whereas depths presented in Figure 3-5 (the 1200 x 800 m section of the 1992
survey) reflect changes due to the standardization process (approximately 60 cm).

Depth contours recorded for the WLIS mounds showed that the minimum water
depths of the ‘‘B,” ‘“‘C,” ‘“‘D,” and ‘“‘E” mounds remained unchanged since the 1990
survey. Closer analysis of the bathymetric depth matrix showed an approximate 0.25 m
decrease in the height of the WLIS “‘E” mound. Sediments comprising the WLIS “E”
mound were deposited during the 1990-1991 disposal season. Some settling and
consolidation of the WLIS “‘E” sediments was likely still in progress at the time of the 1991
survey. Surface shell lag observed at Station F300N (located on the ““E”’ mound) suggested
that some winnowing of the silt/clay sediment component had occurred. Similar surface
shell lag has been observed at the peaks of the other WLIS mounds. Once this shell layer is
exposed, it serves to protect the mound from further winnowing or erosion and adds to the
stability of the mound.

Depths recorded at the WLIS ‘“‘A” mound showed an apparent decrease in mound
height of approximately 0.5 m. The “A” mound is the oldest of the disposal mounds in
WLIS; therefore, depth changes of 0.5 m are unlikely to result from the continued
consolidation of sediments. Examination of the survey navigation data showed that the
horizontal position of the fathometer in the 1992 survey was shifted by approximately 7.3 m
(relative to 1991) at the point of transit across the ‘““A” mound. In areas of rough or uneven
topography the exact position of the vessel within a survey lane can have a significant effect
on the depths recorded (Williams 1993). This type of error is particularly significant within

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

58

WLIS, where the mounds are the steepest monitored under the DAMOS Program. A 6m
horizontal separation between depth measurements over a 3° slope generates a 0.4 m
difference in measured height. Therefore, the apparent changes to the height of the WLIS
“A” mound were likely the result of small differences in the horizontal transducer position
between the 1991 and 1992 surveys.

Although the range of RPD depths at the WLIS “F” mound was only moderate (from
0.1 to 4.3 cm) some of the deepest values were observed in the center region of the 1991-
1992 disposal area. RPD depths at these stations were comparable to or exceeded those in
the reference areas, indicating the relatively deep oxygenation of sediments at the center of
the WLIS “F” mound. Several of these same stations (FIOON, WLIS “F”, F100SE) were
also associated with Stage III benthic infaunal assemblages. The presence of a Stage III
community at the center of the mound indicates a rapid recolonization for at least part of
WLIS “F”. However, an equal number of central stations (F1I00W, F100SW, F100S) had
only Stage I communities present. This is more typical of recently disturbed benthic
habitats, and was predicted to be the case for the entire mound prior to the survey. This
pattern of recolonization is common for benthic areas in the process of recovery from recent
disturbance, such as dredged material mounds. Barring further disturbance, the WLIS “F”
mound is expected to exhibit a mature Stage III community by the summer of 1993.

The CTD profiles in the vicinity of the WLIS “F” mound did not indicate unusually
low dissolved oxygen levels in either the surface or bottom waters. The oxygen,
temperature, and salinity stratification observed (Appendix) was typical for this area of the
Sound (Welsh and Eller 1991). Although the western Long Island Sound region has
experienced cycles of summertime hypoxia (DO less than 3 mg:I') these conditions did not
exist during the present survey.

4.2 Analysis of Selected WLIS “D” and “A” Stations

After completion of the 1991 REMOTS® survey at WLIS, it was noted that five
stations in the vicinity of the WLIS “D” and “A” mounds exhibited very highly reduced, or
dark, subsurface sediments. As a result, these stations were resampled in 1992. Both
REMOTS® and sediment toxicity data were used to evaluate and compare the two surveys.
The REMOTS® sampling showed a modest improvement in habitat quality, but toxicity
testing demonstrated no difference between the WLIS “D” and “A” stations, and reference
areas. These results were used to evaluate the stations in the context of the DAMOS Tiered
Monitoring Plan (Germano, Rhoads, Lunz 1994).

REMOTS® sampling indicated little change in OSI between the two years, although
RPD depths were approximately 0.3 cm deeper in 1992. The increased depth of the RPD
may represent a small increase in sediment reworking by benthic organisms present at the
time of the survey. However, this change in RPD was not large enough to influence the

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

calculated OSI values. The successional sere of each station was also entirely unchanged
relative to 1991, with Stage III organisms present at three of the five stations.

In addition to the measured REMOTS® parameters, a qualitative assessment of the
photographs between the two surveys showed a lightening of the sediment fabric in 1992.
The very dark subsurface sediments noted in 1991 were not nearly as prominent in 1992
(Figure 4-1). This was interpreted to indicate that the upper sediment layers had experienced
some oxygenation and reworking during the period between the 1991 and 1992 seasons. On
the whole, REMOTS® photographs indicated only a modest improvement in habitat quality at
the stations of concern.

The amphipod bioassay showed no significant toxicity in sediment samples taken
from either WLIS ‘“‘D” or ‘‘A”’ relative to reference area 2000W. One of the five WLIS
“‘D” replicate samples had greatly reduced survivorship (25%) relative to the other four
replicates. Since each WLIS “‘D” replicate was a composite of four stations, this low value
could not be associated with any single station. This apparent outlier was also not explained
by observed conditions during the testing period, but it was not different enough to
significantly influence the mean WLIS “‘D” survivorship. Overall, the toxicity testing
clearly demonstrated a lack of difference between the stations of concern, and the reference
areas.

Within the framework of the tiered monitoring plan a failure to demonstrate
significant toxicity in the sediment bioassay tests generates a preliminary assumption that
physical or biological processes caused the unusual sediment conditions. Under these
circumstances, no immediate remedial action is required. However, the stations are
recommended to be reassessed within 12 months for further changes in the benthic
community. In addition, the tiered monitoring plan suggests that any extraneous conditions
that might affect benthic colonization also be evaluated. In the western Long Island Sound
area intermittent periods of low dissolved oxygen are a potentially important source of
disturbance to the benthos. However, low oxygen conditions were not observed during the!
present survey, and adjacent mounds and reference areas exhibited no signs of response to
seasonal anoxia.

4.3 Selection of Alternate Reference Areas

Two new potential reference areas (SOUTH and EAST) were evaluated to replace the
existing 2000S and WLIS-REF areas. This evaluation consisted of chemical and physical
analyses of grab samples, REMOTS® data, and rough bathymetric checks of the possible
new areas. The results show that SOUTH is a suitable replacement for 2000S.
Unfortunately, it was not possible to locate an area north of the disposal site that did not
exhibit some evidence of historic dredged material. Asa result, both the EAST and WLIS-
REF areas were roughly equivalent, and therefore not suitable as reference areas for ambient
bottom.

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Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

60

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Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

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The discussion below details the interpretation of the analyses done to compare the existing
and potential replacement reference areas.

4.3.1 Chemical and Grain Size Analyses

Sediment samples were collected from the two sites proposed as WLIS reference
stations and analyzed for grain size, TOC, metals, PAHs, pesticides, and PCBs. The
analysis included a comparison of the sediment data with the WLIS reference station data
from 1991, and a comparison with ambient western Long Island Sound trace metal and
organic compound concentrations. Due to the similarity of grain size and TOC, and the lack
of comparable metals data, PAH data were considered the most useful indicators of reference
applicability.

The 1992 EAST samples were slightly sandier than the 1991 WLIS-REF, although the
fine-grained fraction (which is commonly associated with anthropogenic contaminants) was
approximately the same for both sites (Table 3-1). Grain sizes between SOUTH and 2000S
were very similar in composition. TOC at EAST was slightly higher than at WLIS-REF,
and slightly higher at SOUTH than at 2000S (Table 3-1). Metals data for the two sets of
areas were similar, although the lack of several metal analyses for samples from the 1991
reference stations made this a tenuous comparison (Table 3-2).

The most complete data set for comparison purposes was the PAH data from both
areas. Raw, non-normalized PAH data indicated that EAST and WLIS-REF (1991) had
similar concentrations of PAHs, with WLIS-REF slightly higher in several LMW and HMW
compounds. PAH concentrations at 2000S (1991) ranged from two to three times higher
than the same measured compounds at SOUTH.

Natural variations in sedimentary parameters can influence the concentration of trace
metal and organic constituents measured in the laboratory. For example, an increase in both
the fine-grained fraction and in TOC can be positively correlated with metal and organic
concentrations. Normalizing to Al is increasingly being used for metals and can be
particularly useful for regional variations of sediment type (Schropp et al. 1990).

For comparison purposes, PAH values were normalized to TOC for both EAST and
WLIS-REF data. Grain size was not used, as the variation between the locations was small.
After normalization to TOC, the sum of WLIS-REF PAH concentrations was less than twice
that of EAST. Normalized PAH concentrations of 2000S samples ranged from four to six
times greater than those of SOUTH.

In order to place the potential WLIS reference stations in context, sediment data from

the area were compiled and compared with the 1992 sediment data. The NOAA National
Status and Trends (NS&T) Program has collected and analyzed coastal and estuarine

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

62

sediment data from three hundred sites since 1984. Several stations in western Long Island
Sound that had been sampled over the period of 1984-1989 (NOAA 1991) were compared to
the WLIS proposed reference stations. All of these areas were coastal (north shore of Long
Island or south shore of Connecticut) except for the western Long Island station (NS&T code
WLI) which was located approximately 5 km west of WLIS.

In comparing the WLIS results with NS&T data, several qualifications should be
made. The analytical methods used vary somewhat between the two datasets because NS&T
methods were developed for very low detection limits. For example, although pesticides
were not detected in most of the WLIS replicates, the detection limits were higher than those
of the NS&T data, so the two datasets could not be compared. PCBs were analyzed by
NS&T methods as individual isomers, and so were not directly comparable with the total
PCB measurement obtained by the NED laboratory. All NS&T data were normalized to the
fine-grained fraction since the correlation between the percentage of silt and clay and trace
chemical constituents was higher than between Al or TOC (NOAA 1991). Therefore, the
WLIS data were also normalized to the fine-grained fraction for comparison purposes.

PAHs measured at SOUTH and EAST were all within the range of the values
measured at the NS&T western Long Island Sound stations (Table 4-1). Of the NS&T sites,
two had the highest concentrations of all PAH compounds: the Throgs Neck station (the
farthest west station in Long Island Sound) and the Sheffield Island station, located northwest
of WLIS. Hempstead and Huntington Harbors on the north shore of Long Island, and the
Mamaroneck station on the southern coast of Connecticut had the lowest PAH
concentrations.

The NS&T WLI station fell between the sets of maximum and minimum PAH
concentrations measured in western Long Island Sound. The EAST and SOUTH values were
comparable to the PAH concentrations measured at the WLI station. High molecular weight
PAH concentrations from WLI were almost identical to concentrations measured at SOUTH,,
and were very similar to those at EAST (Table 4-1). Low molecular weight PAH
concentrations measured at SOUTH and EAST were slightly lower than those measured at
WLI, and were actually more similar to those measured at Hempstead Harbor (Table 4-1).

Metals results from SOUTH and EAST were, in general, similar to or lower than
metals concentrations measured at the NS&T WLI site (Table 4-2). However, of the trace
metals, As and Zn were higher than most of the NS&T stations. Zinc concentrations at both
EAST and SOUTH, and As at EAST, were higher than all of the other NS&T stations.
Categories of trace metal concentrations suggested by the New England River Basins
Commission (NERBC) were included in Table 4-2 as a guide to metals concentrations. The
metals concentrations measured at SOUTH and EAST all fell within the low to moderately
contaminated categories. Arsenic and Zn concentrations were elevated relative to other sites

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

63

Table 4-1

National Status and Trends Normalized PAH Data Compared to WLIS Samples

Low Molecular Weight
napthalene
2-methy! napthalene
acenaphthylene
acenaphthene
fluorene
phenanthrene
anthracene
Total LMW PAHs
High Molecular Weight
fluoranthene
pyrene
benzo(a)anthracene
chrysene
benzo(b)fluoranthene
benzo(k)fluoranthene
benzo(a)pyrene
dibenzo(a,h)anthracene
benzo(g,h,i)perylene
indeno(1,2,3-cd)pyrene
Total LHW PAHs

LIHH LIHU__LIMR LISI LITN

6.706 11.390 23.171
25.699

14.357

17.694

5.065

3.741

16.181

0.870 1.727 1.776
0.000 0.000 3.775
0.000 0.000 3.683
40 96 115

WLI EAST _ SOUTH

10.458
18.373
4.720
5.592
5.810

National Status and Trends (NS&T) values are averaged for each site over the period of time sampled.
A value of zero indicates the result was below the detection limit.

All data are normalized to the percent fine grain size (silt+clay) in that sample.

NS&T Location Codes:

LIHH
LIHU
LIMR
LISI
LITN
WLI

LIS-Hempstead Harbor
LIS-Huntington Harbor
LIS-Mamaroneck
LIS-Sheffield Isand
LIS-Throgs Neck

Western Long Island Sound

For specific locations of NS&T sites, see NOAA 1991.

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

Table 4-2

National Status and Trends Normalized Metals Data Compared to WLIS Samples

National Status and Trend Sites
LIHH __LIHU_LIMR__LISI_LITN WLI
979 774 1212 545 801 N.a.
0.126 0.111 0.148 0.100 0.112 : 0.1-0.2
0.015 0.018 0.013 0.023 0.012 : 0.03-0.10
1.28 1.48 1.54 2.36 1.68 : 1.1-3.3
1.23 1.29 1.57 2.07 1.60 : 2.2-4.4
458 469 558 336 499 n.a.
0.004 0.005 0.006 0.013 0.007 5 0.006-0.020
0.46 0.52 0.51 0.61 0.45 : 0.6-1.1
0.99 1.11 1.02 2.15 1.09 : 1.1-2.2
3.03 2.87 3.04 3.520 3.220 : 2.2-4.4
National Status and Trends (NS&T) values are averaged for each site over the period of time sampled.
All data are normalized to the percent fine grain size (silt+clay) in that sample.
NS&T Location LIHH LIS-Hempstead Harbor
LIHU _LIS-Huntington Harbor
LIMR_LIS-Mamaroneck
LISI —__LIS-Sheffield Isand
LITN _ LIS-Throgs Neck
WLI _—~ Western Long Island Sound
For specific locations of NS&T sites, see NOAA 1991.
NERBC = New England River Basins Commission (NERBC 1980) moderately contaminated
category for sediments (CT, NY).
All values are nomalized to a maximum estimate of 90% fine-grained percentage; see text for explanation.

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

in western Long Island Sound, but the measured concentrations were within the NERBC
moderately contaminated category.

More unusually, the normalized major element concentrations were quite different
from the NS&T data: Al was lower at both EAST and SOUTH than NS&T stations, and Fe
was higher. The statistical range of normalized Al concentrations at the NS&T sites (mean
+ one standard deviation) was 601-1044 ppm; both EAST and SOUTH Al concentrations
were below this range, and above the calculated statistical range of normalized Fe
concentrations (380-524 ppm). Assuming that these major elements (especially Al) are
reflective of regional background metals concentrations, the comparison of NS&T metals
data with the WLIS NED samples is suspect. Different digestion methods may explain part
of the difference, since incomplete dissolution of clay minerals (which release the Al and Fe)
is a common sample preparation problem.

In summary, trace metal and PAH data indicated that the newly proposed reference
stations contained similar or lower concentrations of these analytes relative to the reference
Stations sampled in 1991. Grain size distribution and TOC content were similar between the
two sets of data. PAH concentrations at the two proposed reference stations appeared to
represent western Long Island Sound ambient concentrations, as compared to several sites
measured by the NS&T program. Metals concentrations of samples from the two proposed
stations were also similar, with the exception of As and Zn. These elements were higher
than those measured in the same area by NS&T. However, the metals comparison may not
have been adequate since the reference elements (Al and Fe) demonstrated a potential
difference in laboratory results between the WLIS and NS&T samples.

4.3.2 REMOTS® and Bathymetry

The rough bathymetry done at both of the potential reference sites (EAST and
SOUTH) indicated that both areas were free of any distinct topographical features or stee
slope. Across both regions, the maximum depth change observed was 5 m depth over 800 m
in the horizontal. This was considered acceptable relief for a reference area.

REMOTS® sampling showed that grain size distribution at SOUTH was more
comparable to ambient sediments at the disposal site than was 2000S. In addition, the
photographs showed no evidence of previous dredged material disposal. However, the full
REMOTS® grid at EAST indicated distinct signs of dredged material and of sediment
winnowing. Overall, the appearance of EAST was similar to that of WLIS-REF, in that
some relic dredged material was present at both areas.

It would seem that much of the area surrounding WLIS has received dredged material
input at some point in time. Historic (prior to 1977) disposal operations were not controlled
and monitored in the manner they are today, and this material was disposed across a wide

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

66

area. This complicated the search for appropriate reference areas, since such areas should
presumably reflect ambient, undisturbed conditions.

Based on a preliminary REMOTS® survey, the EAST position was selected because it
was a) outside historic disposal site boundaries, b) of a similar depth to the disposal site, c)
appeared to have similar grain sizes to the disposal site, and d) did not show evidence of past
dredged material deposition. However, the full REMOTS® sampling grid for all stations
within EAST showed the presence of relic dredged material and some evidence of shell lags
and current scour. Moreover, the chemical analysis for PAHs (completed after the survey)
demonstrated only a minor distinction between WLIS-REF and the proposed EAST area.
This sampling, and the initial exploratory REMOTS® survey, point out the difficulty in
identifying any area north of the disposal site that has not been affected by historic dredged
material disposal.

There is no compelling reason for future surveys to relocate the WLIS-REF reference
area to the EAST position. As a result of the extensive effort made to identify a new
reference area north of WLIS, a more important question is whether a north reference area
should be used at all. Although desirable, it is not necessary to have three reference areas in
separate compass directions relative to the disposal site. Because much of the area north,
east, and west of WLIS has such an extensive history of disposal, the most realistic solution
may be to identify a third area in the vicinity of the new SOUTH reference.

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

5.0 CONCLUSIONS AND RECOMMENDATIONS

The 1992 survey at WLIS was tasked with delineating the distribution and effects of
dredged material at the WLIS “‘F” mound, with evaluating the status of selected stations at the
WLIS “D” and “‘A” mounds, and with identifying new reference areas to replace WLIS-REF
and 2000S.

Comparisons to the 1991 survey showed that a distinct mound, WLIS “F,” was created at
the 1991-1992 disposal buoy location. The amount of material at this position was
consistent with the amount reported in disposal barge logs. The benthic community in the
immediate vicinity of the new mound appeared to be recovering at a relatively rapid rate.
It is expected to achieve a mature status within the following year, barring further
disturbance.

Five stations of interest from the 1991 survey were intensively evaluated during the
present (1992) survey. In 1991 these stations exhibited unusually reduced sediment in
areas that had not experienced recent dredged material disposal. Under the DAMOS
Tiered Monitoring Plan, these stations were revisited in 1992 for both REMOTS® and
sediment toxicity testing. REMOTS® data showed mostly similar conditions in 1992,
although RPD depths were slightly increased. However, sediment toxicity testing with an
amphipod bioassay did not demonstrate any difference between these stations and control
and reference areas. Based on these results, it was concluded that no remedial action is
necessary at the WLIS “D” and “A” stations. The Tiered Monitoring Plan guidance
recommends these stations be re-evaluated within 12 months for any further changes in
community structure.

One important source of disturbance in the western Sound area is periodic hypoxia in the
bottom water. This was not observed during the present survey, but it is not known
whether low oxygen conditions occurred prior to or following the survey. Hypoxia is a
transient phenomena, and its occurrence is related to a complex interaction of temperature,
stratification, organic loading, and tidal advection. Asa result, CTD profiles taken on a
single day do not adequately describe any relationship between dredged material and water
column dissolved oxygen. However, the oxygen profiles observed during the survey were
typical of those seen in other areas of western Long Island Sound in the summer, and
these profiles did not show hypoxic conditions at the disposal site. Further, REMOTS®
results did not suggest any evidence of hypoxic events on the benthic community.

The attempt to identify new reference areas to replace WLIS-REF and 2000S was

partially successful. Sediment chemistry and REMOTS® data showed that the new
reference area, SOUTH, was a good replacement for 2000S. However, the search for a
replacement for WLIS-REF was frustrated by the nearly ubiquitous presence of historic
dredged material to the north, east, and west of the present disposal site in REMOTS®
photographs. For the purpose of the present survey a reference area designated EAST was

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

identified. However, REMOTS® data indicated that this area was only marginally
different than WLIS-REF. Future surveys at WLIS will either have to accept the use of
two reference stations (SOUTH and 2000W), or seek a third reference area south,
southeast, or southwest of the disposal site.

Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

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.

Browning, S; Revelas, E.; Germano, J.; Valente, R. 1990. QA/QC plan for the DAMOS
program. SAIC Report No. SAIC-90/7573&232. Submitted to US Army Corps of
Engineers, New England Division, Waltham, MA.

Germano, J. D.; Parker, J. H.; Williams, R. 1993. Monitoring cruise at the Western Long
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Waltham, MA.

Germano, J. D.; Rhoads, J. D.; Lunz, J. D. 1994. An integrated, tiered approach to
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Army Corps of Engineers, New England Division, Waltham, MA.

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 contaminants in sediments from the
National Status and Trends Program. NOAA Tech. Mem. NOS OMA 59. National
Oceanographic and Atmospheric Administration, Rockville, MD.

Parsons, T. R.; Maita, Y.; Lalli, C. M. 1984. A manual of chemical and biological methods
for seawater analysis. Pergamon Press, New York. 173 p.

Rhoads, D. C.; Germano, J. D. 1986. Interpreting long-term changes in benthic community
structure: a new protocol. Hydrobiol. 142: 291-308.

SAIC. 1987. Seasonal monitoring cruise at the Western Long Island Sound Disposal Site,
August 1986. DAMOS Contribution No. 61 (SAIC Report No. SAIC-87/7500&C61.)
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SAIC. 1988. Monitoring surveys at the Western Long Island Sound Disposal Site, August
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Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

70

SAIC. 1990a. Monitoring cruise at the Western Long Island Sound Disposal Site, November
1987. DAMOS Contribution No. 74 (SAIC Report No. SAIC-88/7532&C72). US
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Schropp, S. J.; Lewis, F. G.; Windom, H. L.; Ryan, J. D.; Calder, F. D.; Burney, L. C.
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Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1992

aerobic 53, 55
anaerobic 55
anoxia 56, 59, 70
atomic absorption
spectrophotometry
Peet
barge v, 1, 3, 16, 56, 57, 67
disposal v, 3, 56, 67
benthos vii, 1, 4-6, 14, 38, 41,
335) 505,96.1 595 67,
69
ampeliscids iv, 14, 15, 55
amphipod iv, vil, 5, 14,
155053, S55 S907
deposit feeder 5
polychaete 5
bioassay vii, 14, 15, 53, 59, 67
bioturbation
feeding void 38
body burden
bioassay vii, 14, 15, 53,
59, 67
boundary roughness vi, 28, 31, 32
buoy 1, 5, 6, 24, 56, 57, 67
coordinates 6
disposal 5, 67
Central Long Island Sound (CLIS)
15
Norwalk (NOR) 1, 4, 6
colonization 59
conductivity 6, 14
consolidation 56, 57
contaminant 61, 69
CTD meter iv, 6, 14, 53, 54, 58,
67
deposition 8, 24, 38, 56, 66
disposal site
Central Long Island Sound
(CLIS) 15
Western Long Island Sound
(WLIS) 1, iv, v, vi,
vii, 1-6, 8-21, 24,
Ps), ily Es

INDEX

3435458;
40-43, 47,
48, 50-70
dissolved oxygen iv, 5, 14, 15,
33, 38, 53-55, 58,
59, 67
erosion 28, 41, 56, 57
feeding void 38
fish 70
grain size iv, v, vil, 1, 5, 10, 11,
24, 27, 28, 47, 48,
61, 65
habitat vii, 1, 4, 5, 14, 41, 53, 58,
59
hurricane 1
hypoxia 41, 58, 67
methane vi, 38, 39
mud clast 41
New England River Basins
Classification
(NERBC) 62, 65,
69
organics 70
polyaromatic hydrocarbon
(PAH) iv, vii, 5, 8,
10-13, 50, 52,
61-63, 65, 66
polychlorinated biphenyl
(PCB) iv, 8, 10-13,
50, 51, 61, 62
total organic carbon vii, 5,
10, 47, 48
recolonization vii, 5, 6, 38, 58
reference area vii, 2, 8, 14, 15,
28, 33, 38, 41, 50,
53, 59, 65-68
reference station vi, 8, 28, 35, 40,
41, 43, 44, 47, 52,

61, 62, 65, 68
REMOTS®
boundary roughness vi, 28,
Sihe32

Organism-Sediment Index
(OSI) vi, 38, 41-44,
By Sissy Ob)
redox potential discontinuity
(RPD) vii, 5
REMOTS® vy, vi, vii, 1, 4-6, 8, 9,
14, 16, 23-30, 33,
36, 38, 39, 41, 45,
53, 56-60, 65-68
camera 33, 38
RPD
REMOTS®;redox potential
discontinuity (RPD)
vi, vii, 5, 33-39, 53,
56, 58, 59, 67
salinity 14, 15, 53, 58
sandy 8
sediment
chemistry 1, 67
clay 10, 24, 28, 47, 48,
57, 62, 65
cobble 24, 28
gravel 10
sand 8, 10, 24, 28, 47, 48
silt 10, 24, 28, 47, 48, 57,
62
sediment oxygen demand (SOD)
vi, vii, 4, 38, 39
sediment sampling 5, 8, 41
cores 8
grabs 8, 14, 47, 59
shore station 6
spectrophotometry
atomic absorption 11, 12
statistical testing vii, 15, 65
succession
pioneer stage 5, 38
seres 38, 53, 59
successional stage vi, 5, 38, 40
survey
bathymetry v, vii, 5-8,
16-21, 23, 24, 41,
56, 57, 59, 65

INDEX (cont.)

REMOTS® vy, vii, 6, 9, 14,
28, 41, 56, 58, 66
temperature 6, 14, 15, 53, 58, 67
thermocline 53
tide 4, 6, 57, 67
topography vii, 5, 8, 41, 47, 57,
65

toxicity vii, 5, 14, 15, 53, 58, 59,
67
trace metals iv, vii, 5, 8, 10-13,
47, 50, 61, 62, 64,
65, 70
arsenic (As) 11, 12, 62
cadmium (Cd) 11, 12, 47,
50
chromium (Cr) 11, 12
copper (Cu) 11, 12
iron (Fe) iv, 11, 12, 47,
50, 65
magnesium (Mg) 53-55, 58
mercury (Hg) 11-14
nickel (Ni) 11, 12
zinc (Zn) 11-13, 50, 62, 65
volume
estimate 56
waste 10, 70
waves 28
winnowing 28, 57, 65

APPENDIX

WLIS

Oxygen (ppm) *#*«

10

7
|

:

5
]

4

CO Fi (Ae Pa fe Fes Uf Lear Ff El fesse | fear Ue Ue | fae einai
(>) u) O uw) O uw) O ve) O
cae T= N N 9) 9) +

(Suajaw) Yydag

Depth (meters)

cn

WLIS

Sigma-t ++++
18 eS) 20
| |
Salinity (ppt) **««
26 27 28

Temperature (C) xxxx
7, 18 13 ZG Zl Zz

$e sete

WLIS SOUTH

10

Oo)

(ppm) KK 3K

Oxygen

N- TeV WU [AL Un US (SS SUS US | US UU if Ua)
S To) oO Ww oO Ww S) Ww oO
pa = WN N ny nm SSF

(Sdajaw) Yydaq

Depth (meters)

WLIS SOUTH

Sigma-t ++++
18 19 20
[ee ee Se

Salinity (ppt) ****

Temperature (C) xxxx |
iy Ke 19 Aah 21 Df
! |

Depth (meters)

WLIS 2000W

Oxygen (ppm) a Ke 3
4 5) 6 vy

| | |

(ce)
O

8
|

-(N

een
cs:

de |
1 aia

i mit i "
ve vo
Jon a
a
Bo iets
/
~ BI z 7
: {
: “
ty
\ Z
rity i
Asse

Depth (meters)

WLIS 2000W

SIQMIOS © sraraes

18 19 20
Salinity (ppt) ****

26 QT 28
Temperature (C) xxxx

a i8 1s 20 21 Za.

i i
ie,
i y
<
it
i
bs Dishiaeey Mie ire ho dana
veal
aay ~ ‘ re pat EPCRA: pee
, he ae
~
any ‘
are \e " i
i
t . >
‘ . A eypriey Deoe oath me ie
2 K
re 1
i) y
rN,
A

Depth (meters)

WLIS EAST

A

Oxygen (ppm) ****
2. S 4 S 6 7 8 9 10
0 | i | | | | ate

On

SS

40

i
i
mS ne \ eee Wa AN PMN Mh te 44 em
d )
me aie ‘
m
;
* t 7
oa I
+ ;
: ria 3
R Po
fi ss
i
3 ;
i
Ay
4
aU
te
j /
A =.
2 F
y

Depth (meters)

WLIS EAST

SIGRIG=\ sParsr ar
18 19 20
ETS a ence ER Noein rete eee |

Salinity (ppt) ****
26 27), 28

Temperature (C) xxxx
i 1g 9 20 21 22