United States
Environmental Protection
Agency
Office of Water
(WH-556F)
EPA 842-S-92-005
June 1992
Final Revision to Initial
Report on Results of
Studies Conducted  in
the Vicinity of 106-Mile
Deepwater Municipal
Sludge Site
                           U

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                 FINAL
       REVISION TO INITIAL REPORT
     RESULTS OF STUDIES CONDUCTED
 IN THE VICINITY OF 106-MILE DEEPWATER
         MUNICIPAL SLUDGE SITE
               May 3, 1988
U.S. ENVIRONMENTAL PROTECTION AGENCY
                Region II
            New York, New York
                  and
    Office of Marine and Estuarine Protection
              Washington, DC
    Prepared Under Contract No. 68-03-3319

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                              TABLE OF CONTENTS
                                                                         Page



1,  INTRODUCTION	     1

2.  SUMMARY OF STUDIES	     6

3.  HYPOTHESES WITHIN TIERS OF MONITORING PROGRAM  	 .  .    14

     3.1  TIER 2: NEARFIELD FATE AND SHORT-TERM EFFECTS  ........    14
     3.2  TIER 3: FARFIELD FATE	    IS
     3.3  TIER 4: LONG-TERM EFFECTS	.  .	    17

4.  STUDY RESULTS APPLICABLE TO MONITORING PROGRAM .....  	    19

     4.1  PHYSICAL OCEANOGRAPHY  ..... 	    19
          4.1.1  Pycnocline Depth  	    21
          4.1.2  Currents	    24

     4.2  MARINE CHEMISTRY	    36
          4.2.1  Metals	    37
          4.2.2  Organic*	'	    39
          4.2.3  Dissolved Oxygen and pH 	  ......    41

     4.3  MARINE BIOLOGY	    42
          4.3.1  Plankton Communities  .	    43
          4.3.2  Commercial, Prey, and Endangered Species	    44
          4.3.3  Btnthic Communities	    45
          4.3.4  Pathogens	    47

5.  LITERATURE CITED	    48

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                               LIST OF FIGURES

                                                                      £§!§

Figure 1.  Implenientation of the 106-Mile Site Monitoring Program
           Involves a Tiered Approach to Address Assessuent of
           Permit Compliance and Potential Impacts . . 	     2
Figure 2.  Areal Coverage of Studies Conducted in the Vicinity
           of the 106-Mile Site (Shaded Area) ...
Figure 3.  Schematic Representation of Season*! Variations in
           Pyenoeline Depth at the 106-Mile Site. Three Ctses
           Are Illustrated: the Permanent Pycnoclinej the Seasonal
           Pycnocline; and a Pycnocline Caused by a Surface Layer
           of Shelf Mater . . ...................     25

Figure 4.  Conceptual Model of the Circulation in the Slope Water
           Region, as Presented by Csanady and Hamilton (1988) ...    28

Figure 5.  Trajectories of Subsurface Drifters Launched in the Gulf
           Stream Offshore North Carolina (near 35% 7S°W)t from
           Bower, O'Gara and Rossby (1985) ...... . . .....    35

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                                LIST OF TABLES
Table 1.  Impact Categories In Ocean Dumping Regulations and
          Predictions for Potential Impacts of Sludge Dumping
          at the 106-Mile Site	 . . .
Table 2.  Background Summary of Studies Conducted Within the
          Vicinity of the 106-Mile Site	
Table 3.  Summary of the Technical Objectives of Studies Conducted
          in the Vicinity of the 106-Mile Site .... 	
Table 4.  Data Issues Contained in the Null Hypotheses Associated
          with the Assessment of Potential Impacts 	
Page



   4


   7


   9


  20

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                               1.   INTRODUCTION

     The United States Environmental Protection Agency (EPA), under the
Marine Protection, Research, and Sanctuaries Act of 1972 (MPRSA, PL 92-532),
is responsible for regulating disposal of wastes, including sewage sludges,
in ocean waters.  Under MPRSA, EPA has published ocean dumping regulations
(40 CFR Parts 92-532), which require EPA to develop and maintain monitoring
programs for designated ocean disposal sites.
     EPA has developed a monitoring plan (  EPA   , 1992a)  for the 106-Mile
Deepwater Municipal Sludge Site (106-Mile Site), located beyond the
continental shelf off the New York/New Jersey coast.  The objective of the
monitoring program is to ensure that regulatory requirements are met.  Data
generated through the monitoring program will be used by EPA to make
decisions about site redesignation or dedesignationj continuation,
termination, or modification of permits; and continuation,  termination, or
modification of the monitoring program itself.  The plan for implementing
the monitoring program (   EPA  > 1992a) is summarized in Figure 1.
     The monitoring strategy focuses on two areas of concern: assessment of
compliance with permit conditions and assessment of potential impacts of
sludge disposal on resources or other aspects of the marine environment.  The
approach used to address assessment of permit compliance and potential
impacts uses a series of monitoring tiers.  Each tier represents a series of
null hypotheses, or questions, to be tested through monitoring activities.
The tiered approach organizes the null hypotheses into a hierarchy, whereby
data collected in each tier form the basis for the design and extent of
monitoring activities in the next tier.  Such an approach ensures that only
information needed for making decisions will be obtained (leller and Wastler,
1987).
     The purpose of this report, which is an updated revision of a previous
report  (   EPA   , 1986), is to review studies conducted in the vicinity of
the 106-Mile Site.  Those study results that pertain to or can be used to
test the null hypotheses directed at the assessment of potential impacts
(Tiers  2, 3, 4) will be summarized.  Some of the information provided by the
studies reviewed  for this report can be used to establish baseline
conditions within the vicinity of the site.  Although not used  in the

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Implementation of
Monitoring Program
                                         Assessment of
                                       Permit Compliance
                                         Assessment of
                                       Potential Impacts
                                                                                   TIER 1

                                                                          Waste Characteristics and
                                                                             Disposal Operations
                                                                                   TIER 2

                                                                              Nearfield Fate and
                                                                              Short-Term Effects
   TIER 3

Parfield Fate
                                                                                   TIER 4

                                                                              Long-Term Effects
  FIGURE 1.  IMPLEMENTATION OF THE 106-MILE SITE MONITORING PROGRAM INVOLVES A TIERED APPROACH
             TO ADDRESS ASSESSMENT OP PERMIT COMPLIANCE AND POTENTIAL IMPACTS.

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assessment of permit compliance, baseline conditions provide a frame of
reference against which to compare the results of monitoring activities
directed at the assessment of potential impacts (Tiers 2, 3» and 4).
     The objectives of the monitoring tiers that address assessment of
potential impacts are founded in the ocean dumping regulations, which specify
the impact categories listed in Table 1.  The monitoring plan (  EPA   ,
1992a) describes the regulatory basis for the monitoring program and how the
site and sludge characteristics have been used to predict potential impacts
(Table 1) for each impact category resulting from sludge disposal.  The
predicted potential impacts have, in turn, been used to formulate the null
hypotheses that have been organized into tiers (Figure 1) for testing through
monitoring activities.
     Because the emphasis in this report is on study results that provide
information that can be used in the assessment of potential impacts, this
report has been organized into sections corresponding to the monitoring
tiers associated with assessment of potential impacts.  Brief summaries of
the studies reviewed for this report are presented in Section 2.
     Section 3 lists the null hypotheses associated with Tier 2 (Nearfield
Fate and Short-Term Effects), Tier 3 (Farfield Fate), and Tier 4 (Long-Term
Effects) of the monitoring program.  In addition to the null hypotheses,
Section 3 includes the scientific issues relevant to each hypothesis,  or the
type of information needed to test each null hypothesis.
     Summaries of study results are included in Section 4.  Only those
results that relate directly to the scientific issues of the null hypotheses
are discussed.  Because the null hypotheses contain issues that fall into
three general scientific areas, Section 4 is organized into subsections for
physical oceanography, marine chemistry, and marine biology.

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TABLE 1.  IMPACT CATEGORIES IDENTIFIED IN OCEAN OWING REGULATIONS AND PREDICTIONS FOR
          POTENTIAL IMPACTS OF SLUDGE DURING AT TOE 106-MILE SITE.
Impact Categories
Predicted Potential Iifjacts
Impingement of sludge onto
shorelines
Movement of sludge into marine
sanctuaries or shell fishery or
fishery areas
Effects of sludge on commercial
fisheries
Accumulation of sludge constituents
in biota
Progressive changes in water quality
P-l: Sewage sludges dumped at the 106-Mile Site
will probably not impact any shoreline in
detectable quantities.

P-2; Marine sanctuaries and shellfishery areas will
probably not be impacted by shoreward movements of
sludge.

P-3: Sewage sludge may be transported to the
continental slope and shelf where fishery
activities exist.

JMj Tht impact of sludge dumping on commercial
fisheries, expressed as direct decrease in fish
stocks or decrease in eggs or larvae,  will probably
not be detected, and the use of any area for
fishing will not be reduced.

P-5: Bioaccumulation of low levels of contaminants
associated with sewage sludge from the 106-Mile
Site will occur, from time to time, at the site or
directly adjacent to the site, by migrating fishes
or invertebrates, but may be difficult to
distinguish from other potential sources.

P-6: Bioaccumulation of low levels of contaminants
by resident continental shelf/slope fishes or
invertebrates may occur, depending on direction and
extent of transport of sludge to these areas, but
may be difficult to distinguish from
bioaccumulation from other potential sources.

P-7t Sewage sludge movement and transport beyond
the site boundaries may result in significant
impact on the water quality beyond the site.

P-8: Sludge constituents may be found in
significant quantities within the site at all times
and may persist beyond 4 hours after disposal.
Chronic effects on marine biota are possible.

P-9; Though certain sludge constituents may be
detectable well outside the site, their levels are
not expected to have significant effects on marine
biota.

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                                         TABLE 1.  (continued)
Impact Categories
Predicted Potential Impacts
Progressive changes in sediment
composition
Impacts on pollution-sensitive
species
Impacts on endangered species
Progressive changes in biological
communities
P-10: Sludge particles may settle outside the
disposal site boundaries.  However, this settling
will occur over a very large and as yet undefined
area.  The resultant changes in sediment
composition, the destruction of habitat, and/or the
accumulation of sludge constituents in surficial
sediments will probably be nil to minimal.

P-ll: The disposal of sewage sludge probably will
not cause long-term impacts on pollution-sensitive
species or life-cycle stages in the water column or
the sediments of the 106-Mile Site region.  Effects
may be detectable, but local and short-lived.

P-12: The sea-surface microliyer in the disposal
site and in an undefined area adjacent to the site,
as well as the sensitive life stages of marine
biota within may be affected by the surface-active
consonants and nonpolar pollutant compounds present
in sludges.

P-13: Endangered species of mammals or reptiles
will probably not be impacted by sewage sludge
disposal at the 106-Mile Site.

P-14: Due to nutrient enrichment in the upper water
column, there may be a localized increase in
primary productivity related to individual sewage
plumes.

P-15: There will probably be no long-term or large-
scale impact on the plankton community as a result
of sludge disposal at the 106-Mile Site.

P-16; Because ol the expected absence of sewage
sludge particles in the demersal or benthic
environment, no  effects on the benthic or demersal
community structures are likely.

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                            2.   SUMMARY  OF  STUDIES

     Much information on physical characteristics and baseline chemical and
biological conditions at the 106-Mile Site is available from studies
conducted during the past decade.  This information was used to develop the
framework of the 106-Mile Site monitoring plan.  It also represents a
valuable resource that can be used to test the various hypotheses of the
monitoring plan.  The purpose of the initial version of this report, the
Studies Document, (   EPA   , 1986) was to summarize the pertinent results of
these major studies, but because the final  project results were not available
at that time, the Studies Document presented only an overview of individual
project objectives and a summary of the field measurements.  This report
presents an update of the scientific results from the major studies that were
identified in the initial Studies Document.  Some additional studies have
also been reviewed for this report because they provide information that is
relevant to the issues at the 106-Mile Site.
     In this section, the sampling design and scientific objectives of each
of the reviewed studies are briefly summarized, with supporting information
provided in Table 2.  Each study has been numbered to facilitate simple
reference in the text; locations of measurements for each study are shown in
Figure 2.  Table 3 summarizes important types of data obtained from each
study.  The data topics included in Table 3 have been specifically selected
because they correspond to scientific issues raised by the null hypotheses,
which are discussed in Section 3.

     Study 1: Mid-Atlantic  Slope and Rise Physical Oceanography Study
 (MASAR).  This  study, funded by the U.S. Department of the Interior (DOI),
Minerals Management Service (MMS), was conducted by Science Applications
 International Corporation  (SAIC) between September 1983 and September  1986.
The  study area  (see Figure  2) was bounded by the shelf break to the west, the
outer continental rise area to the east, 36°N to the south, and 40°N to the
north.  Current measurements, hydrographic measurements, and remote sensing
data were used  to evaluate  potential impacts of petroleum exploration  on the
continental  shelf,  slope,  and rise.  The program was designed with the
 following objectives:

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TABLE 2.  BACKGROUND SUMMARY OF STUDIES CONDUCTED WITHIN THE VICINITY OF THE
          106-HILE SITE.
Study
Sponsor
Prine
Contractor
Date of
Measurement
1. Mid-Atlantic Slopi and     DOI, MMS
Rise Physical Oceanography
Study (MASAR)

2. Shelf Edge Exchange        DOE
Processts Program (SEEP)
                SAIC
                BNL,  L-DGO,
                UHOI,  Yale
                  9/83 - 9/86
                  1982 - 1992
3A. Study of Biological       DOI, MMS
Processes on the U.S. Mid-
Atlantic Slope and Rise

3B. Analysis of Trace         DOI, MMS
Metals in Bottom Sediments
on the U.S. Mid-Atlantic
Slope and Rise

4A. Study of Biological       DOI, MMS
Processes on the U.S.
North Atlantic Slope and
Rise

4B. Analysis of Trace         DOI, MMS
Metals in Bottm Sediments
on the U.S. North Atlantic
Slope and Rise

5. four Studies of            EPA
Baseline* Conditions at
the 106-Mile Site
6. Study of Baseline          EPA
Conditions at the North
Atlantic Incineration Site

7. Current Meter              EPA
Measurements at the 106-
Mile Site in Support of
Municipal Waste Disposal

8. Analysis of Circulation    NOAA
Characteristics in the
Vicinity of Deepwater
Dumpsite 106
                Battelle
                USGS
                Battelle
                uses
                5A. JRB
                SB. Battelle
                5C. Battelle
                50, BattelU

                Battelle
                  3/84 - 7/86
                  3/84 - 7/86
                  11/84 - 4/87
                  11/84 - 4/87
                  5A. 7-8/84
                  5B.   8/85
                  5C.   2/86
                  5D. 8-9/86

                    11/85
                Battelle, SAIC    9/86 - 4/87
                EG&G
                  1968 - 1981

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FIGURE 2.   AREAL  COVERAGE OF STUDIES CONDUCTED IN THE VICINITY OF THE
           ,«  — SITE (SHADED AREA). STUDIES ARE IDENTIFIED BY NUMBER  IN
                                      8

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TABLE 3.  SUMMARY OF THE TECHNICAL OBJECTIVES OF STUDIES CONDUCTED IN THE
          VICINITY OF THE 106-MILE SITE.
                                                Studies
Objectives                 1   2   3A  38  4A  4B  5A  58  5C  50  6   7   8
Physical Oceanography

     Pycnocline Depth      x   x
     Currents              x   x
     Participates              x                       x   x   x

Marine Chemistry

     Metals                        x   x   x   x   x       x   x
     Organics                      x       x       x   x   x   x   x
     Dissolved Oxygen      x       x       x               x   x   x
     pH Levels                                             x   x   x
     Bioaccumulation               x       x                       X

Marine Biology

     Plankton Communities      x                           x   x   x
     Endangered Species            x       x           x   x   x   x
     Benthic Communities           x       x

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     •    Determine general seasonal ocean circulation features,
     •    Quantify and describe ocean circulation processes that produce
          variability.
     •    Determine the degree to which continental slope and rise
          circulation features influence the physical oceanography of the
          adjacent Mid-Atlantic continental shelf.

     Results of MASAR have been presented in a final program report (Science
Applications International Corporation, 1987).   Further analysis of the
MASAR results with a model of the circulation in the slope water region has
been presented by Csanady and Hamilton (1988).
     Study 2:  Shelf Edge Exchange Processes Program (SEEP).  This program,
funded by the U.S. Department of Energy, is an ongoing, multidisciplinary
study conducted by Brookhaven National Laboratory (BNL), Lamont-Doherty
Geological Observatory (L-DGQ), Woods Hole Oceanographic Institution (WHQI),
and Yale University.  The program is designed as a multiphase study along the
U.S. east coast from south of Nantucket Shoals to Cape Hatteras.  The first
phase (SEEP-I) consisted of a 1-year (1983-1984) physical,  chemical, and
biological measurement program across the outer continental shelf and upper
slope south of New England (see Figure 2).  Although each component of this
multidisciplinary program has specific scientific objectives, the primary
theme of the study is to define the processes that govern the distribution
and fate of "energy-related pollutants" that might be introduced into the
marine environment of the coastal United States. (Department of Energy,
1982).  Measurements were specifically directed at resolving the fate of
fine-grained particles from the continental shelf.
     Scientific results of SEEP-I will be presented in a series of articles
to appear in a special issue of Continental Shelf Research during the next
few months.  To facilitate review of the SEEP-I results prior to publication,
the editor of Continental Shelf Research kindly made draft copies of selected
articles available to Battelle.
     SEEP-II, a companion monitoring program to SEEP-I, is being conducted in
                                      10

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the middle-Atlantic region (37° to 38°N), but these results will not be
available for at least 2 years.
     Study 3At  Study of Biological Processes on the U.S. Mid-Atlantic Slope
and Rise;  Study 3B?  Analysis of Trace Metals in Bottom Sediments in Support
of Deepwater Biological Processes Studies on the U.S. Mid-Atlantic Slope and
Rise.  Study 3A was conducted by Battelle, in conjunction with WHOI and
L-DGQ, for the U.S. DOI, MMS.  The analysis of trace metals in sediments
(Study 3B), performed by the U.S. Geological Survey (USGS), was supported
under a separate interagency agreement.  The studies were developed as a
multidisciplinary monitoring program that focused on two deepwater
exploratory drilling sites.  Six sampling surveys were conducted between
March 1984 and July 1986.  The primary objectives of the monitoring program
were the following:

     •    Characterize predrilling biological, geological, and chemical
          properties of benthic environments at 14 stations in the general
          vicinity of two exploratory drilling sites.
     *    Monitor potential changes in these properties with time, and to
          determine whether the changes are caused by drilling-related
          activities, or whether they are the result of other phenomena
          including natural temporal or spatial variation.
     •    Determine the distribution and fate of discharged drilling-
          related materials that have accumulated above background levels.
     •    Estimate recovery rates of deep-sea benthic communities
          potentially impacted by drilling-related activities,

     Results of the monitoring program have been reported by Maciolek et al.
(1987a) and Bothner et al. (1987a).

     Study 4A:  Study of Biological Processes on the U.S. North Atlantic
Slope and Rise;  Study 4Bt  Analysis of Trace Metals in Bottom Sediments in
Support of Deepwater Biological Processes Studies on the U.S. Worth Atlantic
Continental Slope and Rise.  Studies 4A and 4B were developed as a companion
program to the U.S. Mid-Atlantic Slope and Rise program (Studies 3A and 3B),
The program was conducted by Battelle, in conjunction with WHOI and L-DGO.
Analyses of metals in sediments by the USGS was supported under a separate
interagency agreement.  The multidisciplinary program, which included six
                                      11

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seasonal surveys between November 1984 and April 1987, had the following
objectives:

     •    Characterize predrilling biological, geological, and chemical
          properties of benthic environments at a limited number of stations
          within areas of potential oil and gas development on the North
          Atlantic Slope and Rise.
     •    Monitor potential changes in those properties with time to
          determine the extent of natural temporal and spatial variation.
     •    Determine the background distribution of materials (such as trace
          metals and hydrocarbons) that may accumulate at elevated levels due
          to future drilling operations.

     Results of these studies have been presented by Maciolek et al. (1987b)
and Bothner et al. (1987b).

     Study 5:  Studies of Baseline Conditions at the 106-Mile Site.  Study 5
actually refers to a series of four baseline surveys of the 106-Mile Site
funded by EPA.  The July/August 1984 survey (Study 5A) was conducted for EPA
by JRB Associates; the August 1985 (Study 5B), February 1986 (Study 5C), and
August/September 1986 (Study 5D) surveys were conducted for EPA by Battelle.
Although the four surveys were conducted as separate studies, they all shared
a common objective: to obtain information concerning baseline conditions at
the 106-Mile Site.  Results for each individual study have been presented in
several reports (  EPA   , 1986;    EPA  , 1987a;   EPA   , 1988a).

     Study 6:  Study of Baseline Conditions at the North Atlantic
Incineration Site.  This EPA-funded study was conducted by Battelle in
November 1985 as part of the ocean incineration program.  The primary
objectives of the study were to field-test sampling equipment and analytical
methods for use during the monitoring of a research burn and to collect
baseline data for water, air, and biota at the site.  Results of the
analysis of samples collected during the study have been reported by    EPA
(1987b).

     Study 7:  Current Meter Measurements at the  106-Mile Site in Support of
Municipal Haste Disposal.  This EPA-funded study was conducted by SAIC  under
                                      12

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sybcontract to Battelle.  From September 1986 to April  1987,  two current
meter moorings were deployed on the 2500-m isobath northeast  and southwest of
the 106-Mile Site (Figure 2) .  The moorings were designed to monitor the
current and temperature structure of the upper layers of the  ocean in the
vicinity of the 106-Mile Site.  The primary objective of the  study was to
assess the effects of various current regimes on sludge disposal.  Results of
the study have been reported by EPA (1992

     Study 8t  Analysis of Circulation Characteristics in the Vicinity of
Deepwater Dumpsite 106.  This study was performed by EG&G for the National
Oceanic and Atmospheric Administration (NOAA),  The scope of  the study
consisted of a review and analysis of more than 300 months of current meter
data collected between 1968 and 1981.  The primary objective  was to describe
the long-term mean circulation patterns in the continental slope region along
the U.S. east coast.  Investigators have reported on the general pattern of
slope circulation based on monthly averaged data (National Oceanic and
Atmospheric Administration, 1985).

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              3.  HYPOTHESES WITHIN TIERS OF MONITORING PROGRAM

     This section presents the null hypotheses associated with the monitoring
prograi tiers introduced in Section 1.  Because this report focuses on
studies that may provide baseline information to be used in the assessment of
potential impacts of sludge disposal, this section addresses only those null
hypotheses within the following monitoring tiers:

     •    Tier 2:  Nearfield Fate and Short-Term Effects
     •    Tier 3:  Farfield Fate
     *    Tier 4j  Long-Term Effects

The null hypotheses within Tier 1 (Waste Characteristics and Disposal
Operations), which are related to assessment of permit compliance,  are not
addressable by any of the studies under consideration.  Thus,  the Tier 1 null
hypotheses are not discussed in this report.
     In addition to presenting null hypotheses, this section lists types of
measurements or information that must be obtained in order to test each
hypothesis.  For example, Ho6, which is stated in Section 3.1, concerns the
settling of sludge particles in relation to the pycnocline.  In order  to test
H06, information is needed about the depth of the pycnocline,  the settling
rates of sludge particles, the background levels of particles in the
vicinity of the 106-Mile Site, and regional current characteristics.  Thus,
the types of measurements relevant to H
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those occurring within 24 hours.  Knowing the behavior and movement of sludge

immediately following disposal  is necessary to test assumptions,  regarding

dispersion and dilution, that are used in permit-issuance decisions.   Knowing

the short-term effects of sludge disposal is necessary to test the assumption

that permit compliance is sufficiently protective of the marine environment.

The Tier 2 null hypotheses are as follows:


NEARFIELD FATE

H06:      Sludge particles do not settle in significant quantities to the
          seasonal pycnocline (50 w) in the summer or to the SO-* depth at
          any tine, within the site boundaries or in the area adjacent to the
          site.
          Relevant information:
                    Pycnocline depth
                    Sludge settling rates
                    Background particulate levels
                    Currents


H07:      The concentration of sludge constituents within the site does not
          exceed the limiting permissible concentration (LPC) or water
          quality criteria (HQC) 4 hours after disposal and is not
          detectable in the site 1 day after disposal.
          Relevant information:
                    Metals concentrations within the site
                    Concentrations of organic compounds within the site


Ho8:      The concentration of sludge constituents at the site boundary or in
          the area adjacent to the site does not exceed the LPC or WQC at
          any time and is not detectable 1 day after disposal.
          Relevant information:
                    Metals concentrations outside the site
                    Concentrations of organic compounds outside the site


Ho9:      The disposal of sludge does not cause a significant depletion in
          the dissolved oxygen content of the water column nor a significant
          change in the pH of the seawater in the area.
          Relevant information:
                    Oxygen concentrations in the area
                    pH levels in the area


SHORT-TERM EFFECTS

HQ10:     No significant biological effects in the water column are
          measurable within the site within 1 day after disposal.

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          Relevant information:
                    Biological conditions within the site


H011:     Ho increase in primary productivity or any changes in planktonlc
          biomass or species composition will occur.
          Relevant information;
                    Primary productivity
                    Planktonic bionass


H012:     No evidence of short-tern bioaccunulation of sludge constituents by
          commercially important species found at or adjacent to the site or
          in important prey species found it or adjacent to the site will be
          found within 1 day after disposal.
          Relevant information:
                    Commercially important species
                    Important prey species
                    Bioaccumulation of metals
                    Bioaccumulation of organic compounds


H013:     Sludge constituents do not accumulate in the surface nicrolayer in
          the vicinity of the site.
          Relevant information:
                    Surface microlayer concentrations of sludge
                    constituents
                         3.2  TIER 3; FARFIELD FATE


     Before any estimation of long-term effects  resulting from sludge
disposal at the 106-Mile Site can be made, it is necessary to determine where
the sludge goes, the area of the seafloor that may be influenced by sludge
particles, and the cumulative concentrations that may be expected in the
water column and sediments after many years of disposal.  The null  hypotheses
within Tier 3 relate to where the sludge goes over the long term.
     Null hypotheses concerning farfield fate address impact issues that
pertain to potential movement toward and subsequent impact to shorelines
(predicted potential impact P-l, refer to Table 1), to marine sanctuaries and
fisheries (P-2), and to the continental shelf/slope (P-3).  The Tier 3 null
hypotheses also address information necessary in deciding whether studies
should be conducted under Tier 4 to determine whether there is a potential
for long-term impacts from sludge disposal, and if so, where those studies
should be conducted.  The Tier 3 null hypotheses are as follows:
                                      16

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H014:     Sludge constituents do not settle beneath the pycnocltne outside
          the disposal site.
          Relevant information;
                    Pycnocline depth outside the site
                    Sludge settling rates
                    Currents
                    Metals concentrations outside the site
                    Concentrations of organic compounds outside the site


H015:     Ocean currents do not transport sludge to any adjacent shoreline,
          beach, Marine sanctuary, fishery, or shell fishery.
          Relevant information,*
                    Onshore currents via the slope circulation,
                    warm-core eddies, or other processes.

HolSj     Sludge recirculation through the site is not significant.
          Relevant information:
                    The hypothesized slope sea gyre or
                    recirculation via warm-core eddies that
                    revisit the site


Hol7:     Sludge particles do not settle to the sea floor in  the vicinity of
          the site or in the region predicted as a possible settling region
          based on laboratory settling measurements and current trajectory
          analysis.
          Relevant information:
                    Sludge settling rates
                    Currents
                    Metals concentrations in sediments
                    Concentrations of organic compounds in sediments


                       3.3  TIER 4t  LONG-TERM EFFECTS


     The objective of Tier 4 is to assess whether there are long-term impacts

of sludge disposal at the 106-Mile Site.  Long-term effects may occur within
or outside the site.  An example of long-teri effects within  the site would

be a progressive decline in water quality, although such an effect is not
predicted.  Long-term effects outside the site, such as bioaccumulation of
sludge constituents, would only be expected if sludge is regularly
transported 1n a given direction  (determined through studies  of farfield

fate).
     Because the null hypotheses within Tier 4 are related to  long-term

effects, the studies results summarized  in Section 4 are not sufficient to

                                      17

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test the Tier 4 hypotheses.  However,  baseline data provided by some of the

studies may be used as a reference against which to compare data obtained

through monitoring activities.  The Tier 4 null hypotheses are as follows;


H018:     Sludge constituents have no significant long-ten effect on the
          distribution of endangered species in the vicinity of the site.
          Relevant information:
                    Endangered species distributions


H019:     Sludge constituents do not accumulate in the tissues of
          commercially important species resident in shelf/slope areas
          adjacent to the site.
          Relevant information;
                    Commercially important species
                    Bioaccymulation of sludge constituents


Ho20:     Benthic community structure does not change significantly due to
          sludge disposal.
          Relevant information;
                    Benthic community structure
Ho21:     Sludge disposal has no effect on the sensitive eggs  and larval
          stages of indigenous animals.
          Relevant information:
                    Indigenous animals (i.e.,  important  commercial,
                    important prey,  endangered,  and benthic  species)
                    Effects of sludge constituents  on  eggs and larvae  of
                    indigenous animals


H022:     Sludge disposal has no measurable long-term  impact on offshore
          plankton communities.
          Relevant information:
                    Plankton communities
Ho23:     Pathogen levels will not increase in the water column or in the
          biota.
          Relevant information:
                    Pathogen levels
                                      18

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              4.   STUDY RESULTS APPLICABLE TO MOHITORINS PROGRAM

     This section focuses on those study results that are applicable to the
null hypotheses that form the framework of the monitoring program.  Table 4
lists the data issues associated with each hypothesis (refer to Section 3).
The information needed to address the null  hypotheses used in the assessment
of potential impacts can be divided into the following general categories:

     *    Physical oceanography
     *    Marine chemistry
     *    Marine biology

     This section is organized according to the three general categories of
relevant information, rather than by hypothesis, because many of the data
issues are contained in several  hypotheses (see Table 4).   In this manner,
results that may be applicable to several hypotheses may be related to the
information common to those hypotheses, rather than repeated for each of the
hypotheses.

                          4.1  PHYSICAL OCEANOGRAPHY

     The null hypotheses directed at the assessment of nearfield (Tier 2) and
farfield.(Tier 3) fate require,  as input, information on the physical
oceanographic processes and conditions at the 106-Mile Site and surrounding
regions.  Although there exist a myriad of processes that ultimately affect
the dynamics of this region, only those that will have a significant effect
upon the vertical and horizontal transport of sludge dumped at the site will
be addressed in the present review of studies results.  Table 4 illustrates
that there are two scientific issues/processes within the category of
physical oceanography that are expected to have a major effect on the
behavior of sludge dumped at the 106-Mile

     •    Pycnocline depth
     *    Currents
                                      19

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TABLE 4.  DATA ISSUES CONTAINED IN THE NULL HYPOTHESES ASSOCIATED WITH THE
          ASSESSMENT OF POTENTIAL IMPACTS.
                                              Hypotheses
Issues                      6 7 8 9 10 11 12 13 14 15 16 17 18 19 21 22 23
Physical Oceanography

     Pycnocline Depth       x                    x     x
     Currents               x                    x  x  x  x

Marine Chemistry

     Metals                   xx          x  x           x     x
     Organic Compounds        x x          x  x           x     x
     Dissolved Oxygen             x
     pH Levels                    x
Hanne Biology

     Plankton Communities            x
     Primary Productivity            x  x
     Planktonic Biomass              x  x
     Commercial Species              x     x                 x        x
     Important Prey Species          x     x                          x
     Endangered Species              x                    x           x
     Benthic Communities             x                          x     x
     Pathogens                       x
                                      20

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     Pycnocline depth 1s known to play a major role in the settling
(vertical transport) of sludge, whereas, currents govern the dispersion and
advection (horizontal transport) of sludge, both in the nearfield and the
farfield.  In the following subsections, a summary of recent (and site-
specific) results is presented for each oceanographic process: pycnocline
depth (subsection 4.1.1) and currents (subsection 4.1.2).  Results are
presented by individual study; synthesis of all study results for a specific
process was beyond the scope of this review project.  The individual results
illustrate that much is known about the physical processes that will
ultimately affect the transport of sludge dumped at the 106-Mile Site.  It is
also important to note that these processes will not be affected by the
sludge, in contrast to local chemical and biological characteristics which
may be significantly altered by sludge disposal.   The knowledge of physical
processes that has been gained from the past studies is, thus, directly
applicable to the conditions that will be encountered during sludge disposal,
whereas chemical and biological measurements from past surveys represent
only baseline data from which to make short-term (Tier 2 and 3) and long-term
(Tier 4) assessments of the effects of sludge disposal at the site.

                           4,1.1  focnocline Depth

     The term pycnocline refers to a layer in the water column where vertical
gradients of density are strong relative to the remainder of the water
column.  With regard to ocean dumping of seawage sludge, the pycnocline is an
important factor affecting sludge behavior because 1t represents a potential
barrier to vertical mixing and settling of sludge particles.  In extreme
cases where the pycnolcine is very intense, particles may be prohibited from
settling through the pycnocline and accumulation will be significant at this
depth.  In practice, however, particle settling is difficult to predict as it
is highly dependent upon particle characteristics (e.g., size, density)
pycnocline intensity, and seawater viscosity.
     The depth of the pycnocline off the U.S. east coast varies according to
three principal factors*. (1) location,  (2) season, and  (3) resident water
mass and/or oceanographic feature.  At any given site,  there is a smoothly
varying seasonal cycle to pycnocline depth; this cycle  is a difect result of
                                      21

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solar radiation.  In simmer, a near-surface seasonal pycnoeline separates the
warm surface waters from the underlying, relatively cool, dense water that
comprised the upper water column during the prior winter and spring*  As the
overlying atmosphere cools in autumn, and increased winds and waves cause
intense vertical mixing in the near-surface layers, the seasonal pycnoeline
is eroded from the surface and a relatively cool, surface mixed layer is
formed.  The depth of this winter mixed layer varies greatly from year to
year, in relation to the number and intensity of the storms passing over the
region.  This winter mixed layer often extends to depths of 100 m or greater,
such that the base of the mixed layer coincides with the top of the permanent
pycnocline.  Thus, the depth of the pycnoeline in summer refers to the depth
of the seasonal pycnocline, whereas in winter when the seasonal (summer)
pycnocline is absent, pycnocline depth refers to the depth of the permanent
pycnocline.

MASAR and SEEP (Studies 1 and 2)

     To determine the seasonal variability of pycnocline depth in a
particular region such as the 106-Mile Site,  it is necessary to analyze a
large number of vertical density (temperature and salinity)  profiles from
each season, and preferably, from a number of years to address interannual
variability.  A large number of hydrographic  profiles were made across the
continental shelf and slope during the MASAR  and SEEP programs (see Figure
2), but because pycnocline depth was not one  of the principal analysis
topics, the density profile results are not presented in a form that allows
simple interpretation of seasonal variability in pycnocline depth.
     The MASAR hydrographic program consisted of eight cruises, with one
cruise per season in both 1984 and 1985.  These data would yield a fair
representation of the seasonal cycle within 2 consecutive years, but two
observations from each season do not represent a good statistical sample of
pycnocline depth for all years.  Similarly, the relatively small number of
hydrographic surveys made during SEEP would not yield a good statistical
representation of seasonal and interannual variations in pycnocline depth
because of the limited sampling program.
                                      22

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Analyses of Historic Data

     An accurate, statistical determination of pycnocline depth and its
seasonal variability at the 106-Mile Site can only be derived from a
numerical analysis of many years of hydrographic profile results,  such as
the data archives maintained by the National Oceanographie Data Center
(NODC).  For example, a less extensive yet informative analysis of historical
hydrographic data from the 106-Mile Site has been presented by Warsh (1975)
in NOAA Dumpsite Evaluation Report 75-1.  Warsh has presented monthly
averaged temperature and salinity profiles from which seasonal variations in
pycnocline depth can tasily be interpreted.  Figure 3 presents the seasonal
cycle of pycnocline depth as derived from the results presented by Warsh
(1975).  In this figure, the permanent pycnocline exhibits considerable depth
variability ranging from a maximum of 200 m in April to a minimum  of 100 m
throughout the remainder of the year.  The upper boundary of the seasonal
(summer) pycnocline is, in contrast, very shallow (10 to 30 ro) and present
only from May through October*  This figure illustrates that although the
permanent pycnocline exists throughout the year, the seasonal pycnocline will
be the limiting factor in the initial mixing and vertical penetration of
sludge dumped at the 106-Mile Site during summer.  A more comprehensive
numerical analysis of historic NODC hydrographic data will be required to
refine these statistical estimates of pycnocline depth and its seasons!
variability.  Spatial variations in pycnocHne depth can also be investigated
in conjunction with the temporal analyses of pycnocline depth.

Hearfteld Monitoring Studies

     In addition to seasonal variations, pycnocline depths can also be
affected by the passage of anomalous water masses and/or oceanographic
features.  At the 106-Mile Site, warm-core eddies of Gulf Stream origin and
displaced parcels of shelf water can have major impacts on the vertical
profile of density in the upper water column.  For example, under Sustained
northerly wind conditions, shelf water has been observed as far offshore as
the 106-Mile Site, and when this occurs, large vertical density gradients can
arise  at the interface between the shelf and slope water masses.  Such an
                                      23

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event was observed during the Winter 1988 nearfield monitoring survey of the
106-Mile Site (   EPA  , 1988b)': a 40-m thick layer of relatively fresh shelf
water lay above the resident slope water creating a temporary pycnocline that
was much shallower than the permanent pycnocline.  This "shelfwater"
pycnocline would greatly reduce the vertical penetration  of sludge dumped at
the 106-Mile Site during winter conditions.  This hypothetical (yet
previously observed) case is superimposed on the seasonal cycle of pycnocline
depth presented in Figure 3.
     Similar temporary (3- to 15-day), nonseasonal variations in pycnocline
depth can also be caused by the passage of warm-core eddies.  The waters
within these eddies are less dense than typical slope waters, and
consequently, vertical density profiles on the edge of these eddies may
exhibit near-surface pycnoclines that are much shallower than ambient
pycnoclines.  This occurrence is especially true during winter when the
surface temperatures within the eddies are much greater than surface
temperatures of the ambient slope water.  In summer, surface temperatures
within the eddies are similar to those of the surrounding waters, and
pycnocline depths may not be affected as much as during winter.
Nevertheless, warm-core eddies must be viewed as an important physical
mechanism for large, short-term changes in pycnocline depth at the 106-Mile
Site.  Additional data analyses will be required to quantify their potential
effects during all seasons,

                               4.1.2  Currents

     Information on currents at the 106-Mile Site is required for two primary
purposes: (1) to determine the rates at which sludge is transported out of
the site after discharge (nearfield fate studies), and (2) to predict the
pathways and rates of farfield transport.  The likelihood of sludge
recirculation through the site is also a major topic of interest.
     Results from a variety of recent current measurement programs and
numerical modeling studies have greatly increased the knowledge of currents
and circulation along the U.S. east coast and in the vicinity of the  106-Mile
Site.   These results are summarized below according to individual research
programs! however,  it is informative to first provide a brief  introduction to
                                      24

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                              M
                                           MONTH

                                           J      J      A
            100-S
Wl
I
h-
0_
LU
Q
                                                    Seasonal

                                                    Pycnocline
                                                                         Permanent
                                                                         Pycnociine
    150 —
            200
           250
                    FIGURE 3.  SCHEMATIC REPRESENTATION OF SEASONAL VARIATIONS IN PYCNOCLINE
                              DEPTH AT THE 106-MILE SITE. THREE CASES ARE ILLUSTRATED:  THE
                              PERMANENT PYCNOCLINEf THE SEASONAL PYCNOCLINE: AND A PYCNOCLINE
                              CAUSED BY A SURFACE LAYER OF SHELF HATER.

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the four major oceanographic processes that govern the currents of the

regiont the slopewater circulation, warm-core Gulf Stream eddies, mesoscale

and subiesoscale eddies that frequent the shelf/slope front,  and events

where shelf water reaches as far offshore as the 106-Mile Site.  Specific

issues concerning sludge transport for each of these current  regimes include

the following:


     Slopewater Circulation


     •    Do the weak, southwestward currents within the slope water
          represent the "normal" current pattern such that farfield transport
          of sludge will almost always be directed toward the southwest?

     •    During the slopewater current regime,  is sludge transported onto
          the continental shelf or toward major fisheries or  sanctuaries?

     *    Can sludge be recirculated through the site by the  hypothesized
          slopewater gyre?

     *    Will sludge contained within the slope water ultimately be injected
          into the Gulf Stream and transported northeastward  away from the
          site?


     Warm-Core Gulf Stream Eddies


     *    Can eddies transport sludge from the 106-Mile Site  onto the
          continental shelf or into important fishery areas?

     *    Do strong eddy-induced currents increase nearfield  sludge dilution?

     *    Will sludge dumped within an eddy remain trapped inside the eddy
          for a period of months?

     *    Do individual eddies revisit the 106-Mile Site and  thus represent a
          mechanism for sludge recirculation through the site?


     Mesoscale Eddies at the Shelf/SIope Front


     *    Do the mesoscale and submesoscalt eddies that are found at the edge
          of the continental shelf represent an important mechanism for the
          transport of slope water through the shelf/slope front and onto the
          continental shelf?
                                      26

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     Shelfwater Events

     •    Does the shelfwater/slopewater front move offshore  as  far as  the
          106-Mile Site?
     •    Will sludge discharged within a shelfwater event at the site  be
          transported back onto the shelf?

Project results that help to answer these technical questions/issues are
summarized below.

MASAR (Study 1)
     Using the extensive hydrographic and moored current meter data sets
generated by the MASAR program, and historic data from previous measurement
programs in the region, Csanady and Hamilton (1988)  have developed a
conceptual model of the circulation within the slope sea,  the region that
lies between the Gulf Stream and the continental shelf (Figure 4).  The
prominent western component of this slope sea gyre is expected to vary in
size and intensity, as a result of with changes in the large-scale wind
forcing, the location of the Gulf Stream, and variations in the inflow of
Labrador Sea water from the northeast.  The 106-Mile Site is situated in  the
strongest part of the southwestward-f lowing inshore arm of the anticlockwise
(cyclonic) slope sea gyre.  This result is consistent with the predominantly
southwestward ("10 cm/s) mean currents that were observed near the 106-Mile
Site during MASAR and other studies.
     This conceptualized model of the circulation within the slope sea
(Figure 4) is intended to represent the "mean" circulation in the absence of
eddies spawned from the Gulf Stream and the she If /slope front.  The MASAR
results suggest that this elliptical circulation is present on the slope
roughly 85 percent of the time; eddies and other short-lived, small-scale
processes are present at the site for the remainder of the time (roughly  15%
on an annual basis).  Currents associated with these "transient" (2- to 20-
day) events can be 5 to 15 times greater than the typical southwestward
slopewater flow, and current directions can vary by 180° over periods of a
day or  less during these events.

                                      27

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50°-
45°-
                                  Slope Sea Gyre
                                                             Shelf Edge
                  70'
60'
50°
    FIGURE 4.  CONCEPTUAL MODEL OF THE CIRCULATION IN THE SLOPE HATER REGION, AS
              PRESENTED BY CSANADY AND HAMILTON (1988).
                                   28

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     These and other significant MASAR results  that  pertain  to  the  currents

and circulation at the 106-Mile Site are summarized  below:

     *    In the absence of eddies and other transient  features,  currents  at
          the site are primarily directed toward the southwest, with  mean
          speeds that vary from 20 cm/s above 250 m  to  about i  cm/s near
          1000 m.  This southwestward flow is consistent  with existing
          theories of a cyclonic slope sea gyre whose inshore,  southwestward
          flow coincides with the location of the 106-Mile Site.

     *    The strength of the slope sea gyre may have a seasonal  dependence,
          with strong flow during winter and apparent stagnation  during
          summer.

     *    The position of the Gulf Stream has an indirect, yet  significant
          effect on the strength of the southwestward flow of slope water  in
          the vicinity of the 106-Mile Site. When the  axis  of  the  Gulf
          Stream is displaced northward of its  mean  position, the slope sea
          gyre is constricted and southwestward currents  at  the site  are
          intensified.

     *    Analyses of satellite thermal imagery suggest that water  from the
          106-Mile Site often travels southwestward,  to a point near  Cape
          Hatteras, where the slope water is constricted  between  the
          continental shelf and the Gulf Stream.  At this location, slope
          water is believed to be advected toward the northeast along the
          northern side of the Gulf Stream,  thus creating the southern arm of
          the cyclonic slope sea gyre.

     *    During the passage of warm-core Gulf  Stream eddies, current speeds
          above 100 m can exceed 1 m/s, whereas maximum speeds  at 1000 ra are
          on the order of 30 cm/s.  Current  directions  during the passage  of
          eddies may vary greatly over a period of a few  days.

     •    In the absence of large perturbations such as warm-core eddies,
          currents may be spatially coherent over horizontal  scales of 100 to
          200 km.  During eddy events, currents lack spatial  coherence beyond
          a few tens of kilometers.

     •    Submesoscale (30 to 50 km diameter) eddies are  a common feature  at
          the edge of the continental  shelf. These  eddies represent  a
          significant mechanism for driving  intrusions  of slope water onto
          the shelf.  Cross-frontal transfer of water (and potentially,
          sludge) is more likely during summer  than  winter,  on  account of
          seasonal variations in horizontal  temperature and  density
          gradients.
                                     29

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SEEP (Study 21

     The primary focus of phase 1 of the multidisciplinary Shelf Edge
Exchange Program (SEEP-I) was to determine the fate of fine-grained particles
in the continental shelf water column south of New England.  The dynamics in
the adjacent slopewater region was also a topic of investigation because of
its supposed effect upon the sedimentation of particles onto the slope.
Commensurate with these objectives, the majority of the SEEP-I moored current
measurements were made on the outer shelf and upper slope region south of New
England (near 71°W).   Although SEEP-I generated a relatively large number of
year-long records of currents, temperature, and turbidity throughout the
water column inshore of the 500-m isobath, only one current record was
obtained from the upper 250 m of the wat.er column offshore of the 500-m
isobath.  Thus, with regard to the currents and circulation at the 106-Mile
Site, the SEEP-I results are useful for resolving the dynamics at the
shelf/siope front, but they contribute little to our knowledge of the current
variability further offshore, in the vicinity of the 106-Mile Site.
     The SEEP-I results that pertain to currents and exchange of water
masses at the shelf/slope front are summarized below.  These results have
been presented in the following articles: Walsh et al. (1988); Houghton et
al. (1988); Aikman et al. (1988)j and Flagg (1988).

     •    At the shelf break south of Hew England, the SEEP-I results
          confirmed a net offshore flow in the surface layer (0 to 40 m) as
          well as in the bottom (~30 m thick) Ekman layer.  Onshore flow was
          observed at mid-depth.
     •    Hind-induced upwelling within the slope sea is weak, such that only
          20 percent of the slope water eventually enters the shelfwater
          region.
     •    Mean currents are westward (alongshore) on both the shelf and
          slope, but current speeds are significantly greater on the shelf
          than further offshore.
     •    There is a clear minimum in kinetic energy (current speed) on the
          mid-slope compared to sites further inshore and offshore.  This
          minimum would support the hypothesis of increased particle
          settling on the mid-slope and eventual down-slope transport of
          particles within the bottom nepheloid layer.
                                      30

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          Horizontal exchange of water (and temperature)  through the
          shelf/slope front exhibits a strong seasonal  dependence.  In winter,
          the front is characterized by a sharp temperature gradient that
          fluctuates over distances of 10-20 km on time scales of 4 to 20
          days.  Cross-frontal exchange exhibits high short-term variance  in
          winter, but zero net transfer.  In summer,  shelf and slope waters
          become connected along isopycnal surfaces,  with the result of
          significant onshore mass ana heat flux across the shelf/slope
          front.

          Internal waves generated at the shelf/slope front can produce a
          significant bottom mixed layer that can result in significant
          cross-frontal exchange of shelf and slope waters, and suspended
          particulate mttter,

          During the passage of a warm-core Gulf Stream eddy along the slope,
          the eddy-induced onshore heat flux was large, and 3 times greater
          than the offshore flux, but its effect was  not detected on the
          continental shelf.
EPA Current Measurements at the 106-Mile Site  (Study 7)


     Under contract to EPA, Battelie and SAIC conducted a 7-month moored
current measurement program to monitor the current structure in the upper

1000 m of the water column in the vicinity of the 106-Mile Site.   The

measurements were intended to provide more site-specific  current information,

with increased vertical resolution, than that resulting from the MASAR

program.  Current meters were situated at depths of 50, 100, 250, and IQOO m

on each of the two moorings bracketing the 106-Mile Site.  Although only two

current records were obtained from depths above 250 m during this measurement

program, a number of interesting results arose from this  7-month (September

through April) program.  The results pertinent to the issue of sludge

disposal at the 106-Mile Site are summarized below:


     *    During the 7-month deployment period, currents  were highly variable
          due to a wide variety of physical processes including a large
          warm-core Gulf Stream eddy, two smaller warm eddies, cool
          filaments of shelf water extruded from the shelf by the eddies,
          warm parcels of water extending from Gulf Stream meanders, moderate
          southwestward flow of the slope sea gyre, and strong inertial
          currents associated with intense winter storms.

     *    Some of these processes had not been detected during previous

                                      31

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          current measurement programs in the vicinity of  the  106-Mile Site
          (e.g.,  MASAR)  because of the lack  of sampling above  100  m.

          For the duration of the 7-month records  the  mean current speed was
          6,5 cm/s directed toward the southwest  (along the isobaths);  the
          mean current was remarkably uniform with depths  between  50  and 1000
          m.

          During  the passage of the warm-core Gulf Stream  eddy, mean  currents
          in  the  upper 250 m of the water column were  on the order of 15 cm/s
          and directed toward the northeast.   The  mean current speed  at 1000
          m during this  event was 5 cm/s  toward the southwest.

          Southwestward  currents during the  EPA measurement program were
          roughly half the speed of currents  observed  during the MASAR
          program.  The  intensification of the slope sea gyre  during  MASAR
          was a result of a prolonged northward displacement of the Gulf
          Stream.

          Intense current oscillations having amplitudes of 30 cm/s were
          observed during the passage of  the  warm-core Gulf Stream eddy.
          These intense  current "jet" structures have  been previously
          observed at the outer edges of  eddies (Joyce and Stalcup, 1984).

          Spectral analysis of the current records illustrates that warm-core
          eddies  are responsible for the  major portion of  current
          variability, at periods greater than 10  days. Inertial  currents
          dominate the high frequency current variability, with lesser
          contribution from the M2 semidiurnal  tidal constituent.

          Along-shore currents at the two mooring  sites were not coherent
          over the ?5-km mooring spacing, presumably because of the current
          variability imparted by the eddies.  For low frequencies, onshore
          currents were  highly coherent yet  180° out of phase  at the  two
          mooring sites.
Analysis of Historical Current Records (Study 8)
      •

     This study represents the most comprehensive numerical  analysis  of the

large number of moored current measurements that  were made along the

continental slope region of the U.S. east coast (between 69* and 73°W)  during

the period from 1968 through 1981.  This Eulerian database consisted  of 150

separate records constituting roughly 300 months  of current data.  A  major

result of this extensive analysis of historic current data is that, to a

first approximation, it is reasonable to use the  long-tern statistics

gathered from a wide array of station locations along the U.S. east coast to

                                      32

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describe the basic features of the slope circulation in the vicinity of the

106-Mile Site.  On this basis, the following results can be applied to the
current regime at the 106-Mile Site:

     •    Monthly averaged current data reveal  an isobath-parallel  flow
          toward the west or southwest in the slopewater region.  This mean
          current system extends throughout the water column and  across the
          width of the slope water region from the shelf break to at least
          150 km offshore.

     *    Monthly mean currents are strongest above 200 mt  with speeds
          ranging up to 50 cm/s and averages in excess of 10 cm/s.
          Variations in current speeds and directions are also greatest near
          the surface.

     *    Warm-core Gulf Stream eddies reprtsent the major source of current
          variability within the slopewater region.  Current speeds in
          excess of 1 m/s may persist for periods of several days during
          these events.

     •    Although current speeds decrease consistently with depth  over the
          water column, there does not appear to be a consistent  pattern to
          the depth dependence of current direction.  This  variability of the
          vertical current structure  is significant because it implies that
          shear dispersion is an effective mechanism for the dispersion of
          sludge dumped at the 106-Mile Site.

     *    Mean residence time of water within an area corresponding to the
          106-Mile Site is expected to be less  than a few days.  Periods of
          weak currents (e.g., <5 cm/s) are observed on an  infrequent basis
          (~10%) and generally do not persist for periods of more than 2
          days.

     *    Periods of shoreward currents are infrequent,  with an incidence of
          roughly 15 percent.  The speed of these currents  would  be
          sufficient to carry sludge  from the 106-Mile Site to the  edge of
          the continental shelf within a period of several  days.

     *    Short-term recirculation events, which would return sludge to the
          106-Mile Site within periods of a few weeks or less,  are  rare.

     •    The long-term fate of sludge dumped at the 106-Mile Site  appears to
          be entrainment by the Gulf Stream within a period of roughly 1
          month, with little likelihood of subsequent large-scale
          recirculation to the slopewater region.
                                     33

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PHfter Trajectory Studies

     Over the past 10 years, Or. Thomas Rossby at the University of Rhode
Island has conducted a variety of lagrangian drifter studies to investigate
the mid-depth circulation within the Gulf Stream and throughout the western
North Atlantic.  The initial studies used neutrally buoyant SOFAR (sound
fixing and ranging) floats that transmitted low-frequency sound signals to
allow tracking via submerged, coastal, acoustic receivers.  Since 1984,
Rossby has used RAFOS (the inverse of SOFAR) floats to further investigate
the dynamics within the Gulf Stream.  RAFOS floats listen to moored sound
sources, which is opposite to SOFAR floats, which are transmitters.  RAFOS
floats also have the added advantage that they actively follow isopycnal
(constant density) surfaces, which yields a better three-dimensional
trajectory of water parcels.
     Bower et al. (1986) have presented a summary of RAFOS data from the
vicinity of the Gulf Stream which were compiled during 1984 and 1985.   Figure
5 presents a "spaghetti diagram" of float trajectories that were acquired
from floats deployed in the Gulf Stream offshore Cape Hatteras (near 35°N).
The majority of these trajectories followed the core of the Gulf Stream
toward the northeast, but three floats exited the stream near 38°N, 72°W and
entered the slope water near the 106-Mile Site.  These floats moved northward
until they reached the continental slope (~2QOQ-ra isobath in Figure 5), then
began to move southwestward along the isobaths in agreement with typical
slope water flow.  Curiously, these floats turned southward to reenter the
Gulf Stream about 2 weeks after having entered the slope water.  Although
these few trajectories do not provide a statistical representation of float
trajectories in the vicinity of the 106-Mile Site, these results illustrate
that sludge dumped at the 106-Mile Site may, on occasion, enter the Gulf
Stream relatively soon after disposal.  In this scenario, sludge would be
transported rapidly toward the northeast with little possibility of
recirculation through the site.
                                      34

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                                                                                                              SSW
CO
Ul
           4 ON
          35N
                 76H
70N
6SH
                                                                                                                 40N
                                                                                                                 3SN
                                                                                       BOH
                                                                                                               S6H
                     FIGURE 5.   TRAJECTORIES OF  SUBSURFACE DRIFTERS LAUNCHED  IN THE GULF  STREAM
                                OFFSHORE NORTH CAROLINA (NEAR 35% 75°W),  FROM BOWER.  O'GARA AND
                                ROSSBY (1985).

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                            4.2  MARINE CHEMISTRY

     The null hypotheses directed at the assessment of nearfield and farfield
fate raise the following information issues that come under the general
category of marine chemistry;

     *    Metils
     *    Organics
     *    Dissolved oxygen
     *    pH levels
     Analyses for metals and organic compounds are an integral  part of the
106-Mile Site monitoring plan.  As implied by references to LPC and HQC in
H07 and Ho8, bioaccumulation of sludge constituents in Hol2 and H019,
settling of sludge particles to the sea floor in Hol7, and surface microlayer
accumulation in Hol3, measureients of concentrations of dissolved metals and
organic compounds are needed to determine the fate of sludge constituents.
Dissolved oxygen concentrations and pH, referenced in H09, address impacts to
the water column in the immediate vicinity of disposal activity.
     Data available from the studies reviewed for this report are not
sufficient to test the applicable null hypotheses.  However, these studies,
particularly the baseline surveys (Studies 5 and 6), provide important
baseline data for comparison with the results of future monitoring
activities.
     Because none of the studies reviewed for this report specifically
sampled the surface microlayer, there are no baseline data available to
address the issue, raised in Ho20, of accumulation of sludge constituents in
the surface microlayer.
     The issue of bioaccumulation of sludge constituents in the tissues of
commercially important/important prey species is raised in Hol2 and H018.
Although bioaccuinulation is monitored to provide an indication of change in
biological conditions, the topic is included in this subsection because
bioaccuiulation studies involve chemical measurements.  Although Studies 3A

                                      36

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and 4A, included analyses of benthic fauna!  tissues,  none of the studies
specifically targeted tissue analyses of commercial  and prey species.   Thus,
there are insufficient baseline data against which to compare the results of
future chemical analyses of these species.
     Because it is beyond the scope of this report to present the chemical
data generated in the studies reviewed, this section will describe the types
of data available (e.g., metals in sediments, surface water) and reference
reports where data are presented.  Wherever possible, this section will
summarize study conclusions.
                                4.2.1  Metals

     Analyses of metals were conducted in many of the studies reviewed for
this report (Table 3).  For purposes of obtaining baseline data for testing
monitoring hypotheses, the matrices of interest are the surface microlayer
(H013), the water column (H07 and H08), the tissues of commercially important
and prey species (H012 and Hol9), and sediments (H017).  Because none of the
studies reviewed included microlayer sampling, data are not available for
metals concentrations in this matrix.

Studies 3A and_4A

     The studies of biological processes on the Mid- and North Atlantic slope
and rise included analyses of metals in brittle stars (Ophiomusium lymani),
sea urchins (Echinus affinis). and red crabs (Geryon quinquidens). which are
fished commercially in some areas (Maciolek et a!., I987a; Maciolek et aU,
1987b).  The metals analyzed in the whole body tissue samples (A1, Ba, Cd,
Cr, Cu, Fe, Mn, Ni, Pb, V, Zn, and Hg) were near detection limits with the
exception of aluminum, iron, and zinc.  The authors reported that the higher
levels of aluminum, iron, and zinc may have been associated with ingested
sediment.
                                     37

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Studies 36 and 4B

     Studies 31 and 4B provide results from the analyses of trace metals in
bottom sediments from the Mid- and North Atlantic slope and rise (Bothner et
a!., 1987a; Bothner et al., 1987b).  Twelve metals (AT, Ba, Cd,  Cr,  Cu,  Fe,
Hg, Mn, Ni, Pb, V, and Zn) were analyzed in sediments collected  over a 2-year
period.  Metal concentrations in samplts from the Mid- and North Atlantic
slope and rise were lower than those reported for world average  shales,
indicating no major contamination.  In sediments from some stations  adjacent
to drilling rigs, barium, a major element in drilling mud, exhibited a small
increase (< 32 percent) in concentration over the study period ,  An
enrichment of lead was detected in surface sediments relative to deeper
sediments.  This enrichment was presumed to result from the onshore
combustion of leaded fuels.

Baseline Surveys (Studies 5A, 5C. 5D)

     As part of the August 1984 survey of the 106-Mile Site (Study 5A),
filtered seawater and seawater particulates were analyzed for silver, iron,
Itad, and zinc (   EPA   , 1987a).  Only line was detected in the filtered
stawater samples, although the accuracy of the results is questionable
because of the high concentrations of line in the field blanks.   Zinc and
iron were the only metals detected in seawater particulates, with the Hudson
Canyon station having higher metals concentrations than the other areas.
Sediments were analyzed for iron, mercury, lead, and zincj measurable
concentrations were reported for all sediment samples.
     The February  1986 survey to the 106-Mile Site (Study 5C) included
analyses of metals in unfiltered seawater (i.e., including particulates) and
in sediments  (   EPA  , 1987a).  For stawater samples, copper, lead, mercury,
silver, and zinc were not detected above the field blank levels.  Cadmium was
only detected below the thermocline.  Chromium concentrations were slightly
higher in the slope water than on the shelf.  Iron concentrations were
significantly higher at the shelf station than at the shelf break or on the
slope.  Most trace metal concentrations were more than a thousand times lower
than IPA's WQC for seawater.  Sediments were analyzed for silver, cadmium,
                                      38

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chromium, copper, iron,  mercury,  lead,  and zinc.  Concentrations were
generally lower than those reported from the 1984 survey for comparable
metals.  However, the authors suggested that the variability was most likely
due to differences in analytical  technique.
     The August 1986 survey to the 106-Mile Site (Study 5D)  included analyses
of unfiltered seawater samples for silver, cadmium,  chromium, copper, iron,
lead, and 2inc (  EPA   ,  1986).   Silver and lead were not detected in any of
the samples.  The reported concentrations for cadmium, chromium, iron, and
zinc were higher than generally accepted values for  the area.  Copper
concentrations were consistent with previously reported values.
     In summary the studies reviewed herein provide  some baseline data for
concentrations of metals in the water column and in  sediments.  Because many
metals were not found in samples  above detection limits, additional data and
lower detection limits are needed to establish actual baseline
concentrations.  The studies do not provide data on  metals concentrations in
the surface microlayer nor in the tissues of prey and commercially important
species, with the exception of red crabs, indicating a need for baseline data
of this type.

                           4.2.2   Organic Compounds

     Analyses of organic compounds were performed in many of the studies in
the vicinity of the 106-Mile Site (Table 3).  As with metals, the matrices
of interest for relating results  to the null hypotheses are the surface
microlayer  (Hol3), the water column (H07 and Ho8), the tissues of
commercially important and prey species  (H012 and H019), and sediments
(H017).

Studies 3A  and 4A

     Some sediments and tissues from the Mid- and North Atlantic slope and
rise were analyzed for organic constituents as part of Studies 3A and 4A
(Maciolek et al.( 1987a; Maciolek et al., 1987b).  Total hydrocarbon
concentrations  in sediments ranged between 2.9 and 27.1 pg/g dry weight at
North  Atlantic  stations and between 2.9  and 52.9 pg/g dry weight at Mid-
                                      39

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Atlantic stations (see Figure 2).  Concentrations of polynuclear aromatic
hydrocarbons (PAH) in general covaried with total hydrocarbon concentrations,
ranging between 10 and 364 ng/g dry weight at North Atlantic stations and
between 66 and 11S7 ng/g dry weight at Mid-Atlantic stations.  The
concentrations at the Mid-Atlantic stations appeared similar to, but higher
than, concentrations found in earlier studies in the same geographic area.
Sediments from both studies were also analyzed for total organic carbon,
hydrogen, and nitrogen.  In general, sediments from the Mid-Atlantic stations
contained higher levels of organic carbon, hydrogen, and nitrogen.
     Tissues of brittle stars (Ophiomusium lymani) and red crabs (Geryon
quinquidens) from North Atlantic stations contained very low hydrocarbon
concentrations.  Total hydrocarbon concentrations in brittle stars ranged
between 29.S and 54.6 ^9/g wet weight whereas concentrations in red crabs
ranged between 5.5 and 11.8 pg/g wet weight.  Hydrocarbon concentrations in
brittle stars and sea urchins (Echinus affinis) froi Mid-Atlantic stations
ranged between 27.4 and 163.1 /ig/g wet weight.
Baseline Surveys (Studies 5A. SB. 5C. 5D. and 6)

     Sediment samples were collected for analyses of organic compounds during
the August 1984 (Study 5A) and August 1985 (Study 5B) surveys to the 106-Mile
Site (   EPA  , 198?a).  With the exception of 4,4'-DDT, which was detected
in trace* amounts along a southwest transect through the 106-Mile Site, no
organic pollutants were detected in any sediments.
     Filtered seawater and seawater particulates were collected for organics
analyses during the February 1986 (Study 5C) survey to the 106-Mile Site
(Battelle, 1987c).  Samples were analyzed for PAH, polychlorinated biphenyls
(PCB), pesticides, and coprostanol.  With the exception of aldrin, a
pesticide found in the slope samples, and coprostanol in the shelf sample, no
pollutants of interest were found in seawater particulate samples.  PCB were
not detected in any of the samples in either the particulate or filtrate
phase.  Filtered seawater samples did contain some analytes in concentrations
above method detection limits.  Naphthalenes, phenanthrenes, and
dibenzothiophenes were only found in shelf waters.  A pesticide, a-BHC, was
                                      40

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found In both shelf and slope waters.  Heptachlor and aldrin were also found
in several samples.
     Filtered seawater and seawater particulate samples were collected for
organics analyses during the August 1986 (Study 50) survey to the 106-Mile
Site (   EPA   ,  1992b).  Filtered seawater samples were analyzed for PAH;
particulate samples were analyzed for PCB, pesticides, and coprostanol.
Seawater samples from all stations at both sampling depths (surface and
subpycnocline) contained naphthalene and alkylated naphthalenes.  The only
other PAH detected, Ci-phenanthrene, was detected in some seawater samples.
Mo PCB or coprostanol were detected in any particulate samples.  Some
pesticides U-BHC, £-BHC, f-BHC, S-BHC, 4,4>-DDE, 4,4'-DDT, and heptachlor)
were detected in some particulatt samples.
     The November 1985 (Study 6) baseline survey of the North Atlantic
Incineration Site included sampling of filtered seawater and seawater
particulates.  Results were reported for analyses of PCB, PAH, pesticides,
chlorobenzenes,  polychlorinated dibenzo-p-dioxins (PCDD), and
polychlorinated dibenzofurans (PCDF}(   EPA  ,  1987b),  In all cases but two,
no PCDD nor PCOF were detected in seawater samples*  Measurable PCB were
detected in only one seawater sample.  Chlorobenzenes were not detected in
any seawater samples.  Low levels of PAH were detected in seawater samples
from all but one station; no PAH were detected in any particulate samples.
Low levels of pesticides were detected in seawater and particulate samples
from two out of the five stations sampled.

     In summary the data generated in the studies reviewed herein provide
much baseline data for organics in seawater, particulates, and sediments.
The studies do not provide baseline data for the surface microlayer or, with
the exception of red crabs, the tissues of commercially important and prey
species.

                        4.2.3  Dissolved Oxygen  and pH

     The effects of sludge disposal on dissolved oxygen concentration and pH
in the vicinity of disposal are issues raised in H09.  Because these
parameters are expected to be routinely measured during all monitoring
                                      41

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activities, the value of historical results are limited.  Dissolved oxygen
concentrations have been reported for Studies 1, 3A, 4A, SCf SO, and 6.  A
typical range for reported dissolved oxygen concentrations is 7.0 - 7.8 mg/l
(   EPA  , 1987b) in surface water and 4.9 - 6.6 mg/L (   EPA   , I9BBa) at
250-ro depths.  Measurements of pH have been reported for Studies 5C, 5D, and
6.  Typically, pH ranges between 7.8 and 8.3 (   EPA  , 1988a).
                             4.3  MARINE BIOLOGY

     The null hypotheses directed at the assessment of short- and long-term
effects (Tiers 2 and 4) focus on changes in biological conditions within and
near the 106-Mile Site.  The specific marine biological measurements dictated
by the hypotheses are as follows;

     *    Plankton communities
     *    Primary productivity
     •    Planktonic biomass
     *    Commercially important species
     •    Important prey species
     *    Endangered species
     •    Benthic communities
     •    Pathogens

     Because none of the studies reviewed in this report were specifically
directed at monitoring short- or long-term effects of sludge disposal at the
106-Mile Site, none of the null hypotheses in Tiers 2 and 4 can be tested
using available data.  However, the data that are available provide a
baseline against which future monitoring data can be compared.
                                      42

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                         4.3.1  Plankton Communities

     The issue of the long-tern effects of sludge disposal on plankton
communities is raised in H022.  Primary productivity and planktonic bioiass,
issues found in Holl, are Issues that are also related to plankton
communities.

Baseline Surveys (Studies 5C. 5D. and 6)

     The most recent baseline surveys-(Studies 5C and 5D) of the 106-Mile
Site and the baseline survey to the North Atlantic Incineration Site (Study
6) have included measurements of chlorophyll (as chlorophyll a),
phaeophytin, and adenosine triphosphate (ATP).  ATP is used as an indication
of the biomass of live microorganisms, including bacteria, phytoplankton, and
zooplankton; chlorophyll is used as an indication of the quantity of
phytoplankton 1n seawaterj and phaeophytin is a degradation product of
chlorophyll.  Whereas ATP and chlorophyll provide an indication of
planktonic biomass and primary productivity, the ratio of chlorophyll to
phaeophytin provides an indication of the health of the phytoplankton
population.  The ratio of chlorophyll to phaeophytin decreases in
phytoplankton at depths below the euphotic zone or in areas of heavy
zooplankton grazing.     EPA   (1987a, l§87b» 1988a) has reported results of
these measurements at stations within and in the vicinity of the 106-Mile
Site,* normal chlorophyll/phaeophytin range between 1.4 and 1.7.

SEEP (Study 2)

     As part of Study 2, Walsh et al.  (1988b) conducted high-frequency
sampling of the 1984 spring bloom within the Mid-fttlantic Bight.  Data were
obtained from moored fluoroieters, transmissometers, thermistors, and current
meters deployed south of Martha's Vineyard and Long Island,* airborne sensors,'
and shipboard bottle and fluorescence-conductivity-temperature-depth (F/CTD)
casts.  Data were used  to estimate the export of phytoplankton from the Mid-
Atlantic during the  1984 spring bloom and to provide validation data for a
simulation model  (Walsh et  al., 1988c).  The results suggested a seaward
                                      43

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export of perhaps 0.20 mg chlorophyll nr3 day! at depths of 75-81 m during
February to April 1984.  This horizontal loss of algal  carbon would represent
19-67 percent of the March-April 1984 primary production within the overlying
euphotic zone.  Estimates of the vertical flux of organic carbon suggested
that approximately 50 percent of the carbon export at the shelf break might
be derived from the adjacent overlying water column,  with the rest derived
from lateral injections of near-bottom particles originating on the inner
shelf.
     Although the data generated in Study 2 may be of limited value in
testing the null hypotheses associated with plankton  communities,  the data
generated from Studies 5C, 5D,  and 6 provide important  baseline information
for comparing results of future monitoring at the 106-Mile Site.

               4.3.2  Commercial. Prey, and Endangered  Species

     The issue of bioaccumulation of sludge constituents by important
commercial or prey species is raised in H012 (short-term effects)  and Hol8
(long-term effects).  The long-term effect of sludge  constituents  on the
distribution of endangered species is addressed in H017.
     As indicated in Table 3, observations of cetaceans, marine turtles, and
seabirds have been conducted by the Manomet Bird Observatory as part of
several surveys to the 106-Mile Site and the North Atlantic Incineration Site
(Battelle, 1984;   EPA   , 1987a;    EPA   , 1987b;   EPA   , 1988a).
Cetaceans and marine turtles observed In the vicinity of the 106-Mile Site
include sperm, minke, fin, pilot, and possibly sei whales; dolphins, grampus,
and leatherback turtles.  Several species of seabirds,  which are not expected
to be directly affected by sludge disposal, were also observed.  It should be
noted that not all of the species observed (e.g., pilot whales, dolphins,
grampus) are on the endangered list.  Endangered species distributions were
also reported as part of the Northeast Monitoring Program (NOAA, 1983).
     The National Oceanic and Atmospheric Administration (NOAA, 1983) has
reported on the distribution of fish and fisheries in the vicinity of the
106-Mile Site.  The survey, conducted as part of the  Northeast Monitoring
Program, includes commercially important and important  prey species.
                                      44

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     Because results of the Northeast Monitoring Program are not recent,
this program was not selected as one of the primary programs (Table 3)
reviewed for this report.  More recent data on distributions of endangered
species are available (Battelle, 1984;   EPA   , 1987«;    £PA   , 1987b;
  EPA   ,  1988a) and provide more relevant baseline data for comparison with
future monitoring studies.  None of the studies reviewed for this report
specifically address distributions of important commercial  or prey species.

                          4.3.3   Benthie Communities

     The issue of long-tern effects on benthic community structure is raised
in H020.  Comprehensive studies of benthic community structure along the
Atlantic slope and rise in the vicinity of the 106-Mile  Site have been
conducted  as part of Studies 3 and 4,  A wealth of baseline data has been
generated  and reported by Maciolek et al.  (1987a,  1987b).

Benthic Infauna

     The diversity of benthic infaunal species was evaluated by Hurlbert
rarefaction, species accumulation over increasing area,  and Shannon-Wiener
methods.  For the Mid-Atlantic study (Maciolek et al.,  1987a), diversity  at
the mid-slope (2020 - 2195m) stations (176 to 184 species per 1000
individuals) was greater than that at the remaining stations (144 to 171
species per 1000 individuals).  A similar result was reported for the North
Atlantic study (Maciolek et al, 1987b) where the raid-slope stations (1220 -
1350m) exhibited higher diversities than either shallower or deeper stations.
Polychaetes comprised the majority of dominant species  at all depth intervals
within the Mid- and North Atlantic study areas.  The top dominant at stations
deeper than 2020 m was the spionid polychaete Aurospio  dibranchiata«
Infaunal communities at the shallower, mid-slope stations were dominated  by
the sipunculan Aspidoslphon zinni and the aplacophoran  mollusc Prochaetoderma
yengei.  Water depth and sediment grain size were significant determinants of
infaunal community structure.  The diversity of the benthic infaunal
community was stable over all sampling seasons.  Wet, dry, and ash-free dry
                                      45

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weights were also reported for both the Mid-Atlantic and North Atlantic
studies.
     Benthic recolonization experiments were conducted as part of Studies 3A
and 4A.  In a significant result from the Mid-Atlantic study, the 6-month
experiment conducted in 1985 showed recolonization by a different fauna than
was observed over the same time period in 1984 (Maciolek et al.( 1987a).
Results from both studies suggested that recolonization of disturbed or
defaunated sediments is very slow (on the order of years) in the deep sea
relative to shallow coastal water depths (weeks to months).
     Benthic epifaunal community structure was also examined as part of
Studies 3A and 4A.  The results of the Mid-Atlantic study indicated trends in
epifaunal trophic structure and species composition which were related to a
combination of depth and topography (Maciolek et al., 1987a).  The highest
density of total megafauna (5-6 individuals/m2) was observed at depths
between 1800 and 1900 m.  Fauna! density was lower (3-4 individuals/m2) at
depths between 1900 and 2350 m.  Higher densities were also found on shallow
ridges and in flat valleys than on steep slopes and in deep valleys.  Similar
densities of total megafauna were recorded for the western transect of the
North Atlantic study at depths between 1800 and 2200 m (Maciolek et al.,
1987b).  Although filter feeders and deposit feeders were both dominant,
their relative proportion shifted according to bottom topography.  A higher
proportion of filter feeders was found on ridges and in flat valleys; a
higher proportion of deposit feeders was found on steep slopes and in deep
valleys.- No consistent seasonal or yearly differences in epifaunal community
structure were reported for either study.

     The data obtained as part of the studies of biological processes on the
U.S. Mid- and North Atlantic slope and rise provide much recent baseline
data on  benthic communities in the vicinity of the 106-Mile Site.  Although
these data are not sufficient to test the relevant null hypothesis H020»
they may be used to compare results of future monitoring studies.
                                      46

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                              4.3.4  Pathogens

     None of the studies reviewed for this report included baseline
information regarding pathogens  in the vicinity of the 106-Mile Site.  This
lack of information will be addressed in future monitoring studies in order
to test the related null hypothesis,  Ho23.
                                     47

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                              5.  LITERATURE CITED

Aikman, F., H.H. Ou, and R.W. Houghton.  1988.  Current Variability
      Across the New England Continental Shelf Break and Slope.  Contin.
      Shelf Res.  In Press.

Battellt.  1184.  Cruise Report MMS Mid-2 R/V GYRE 31 July - 9 August, 1984
      Study of Biological Processes on the U.S. Mid-Atlantic Slope and Rise,
      Final Report.  Environmental Protection Agency Oceans and Coastal
      Protection Division (formerly QNEP), Washington, DC.

Bothner, M.E., E.Y. Campbell, 6.P. DiLusio, C.M. Pirmeter, R.R. Rendlgs,
      J.R. Gil 11 son, W. Dangelo and J.A. Commeau.  1987.  Analysis of
      trace metals In bottom sediments in support of deepwater
      biological processes studies on the U.S. Mid-Atlantic Continental
      Slope and Rise.  Final Report submitted to U.S. Department of
      Interior, Minerals Management Service.

Bower, A., R. O'Gara, and T. Rossby.  1986.  RAFOS Float Pilot Studies
      in the Gulf Stream 1984-1985.  Technical Report. Graduate School
      of Oceanography, University of Rhode Island. Ref No. 86-7.

Csanady, 6.T. and P. Hamilton.  1988.  Circulation of slopewater.
      Contin. Shelf Res.  In Press.

Departient of Energy.  1982.  DOE Northeast Ten-Year Plan: A Joint
      Effort on Shelf Energy Exchange Processes (SEEP) by Brookhaven
      National Laboratory, Lamont-Doherty Geological Observatory, Woods
      Hole Oceanographic Institution, and Yale University.

EPA.  1986.  Studies Conducted in the Vicinity of the 106-Mile Deepwater
      Municipal Sludge Site (Revision No. 1).  Final Report.
      Environmental Protection Agency Oceans and Coastal Protection
      Division (formerly OMEP), Washington, DC.

EPA.  1987a.  Final Report on Analysis of Baseline Seawater and Sediment
      Samples from the 106-Mile Deepwater Municipal Sludge Site.
      Environmental Protection Agency Oceans and Coastal Protection
      Division (formerly OMEP), Washington, DC.

EPA.  19870.  Final Report on Analytical Results of Samples Collected
      During the 1985 North Atlantic Incineration Site (NAIS) Survey.
      Final Report.  Environmental Protection Agency Oceans and Coastal
      Protection Division (formerly OMEP), Washington, DC.

EPA.  1988a.  Final Report of Analytical Results of the 106-Mile
      Deepwater Sludge Dumpsite Survey - Summer 1986.  Environmental
      Protection Agency Oceans and Coastal Protection Division  (formerly
      OMEP), Washington, DC.

EPA.   1988b.  Draft Site Condition Report for Nearfield Fate Monitoring

                                      48

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      at the 106-Mile Deepwater Sludge Site: Winter 1988 Oceanographic
      Survey,  Environmental Protection Agency Oceans and Coastal
      Protection Division (formerly OMEP), Washington, DC.

EPA.  1992a.  Final Draft Monitoring Plan for the 106-HHe Deepwater
      Municipal Sludge Site.  Environmental Protection Agency.  EPA 842-
      S-92-009.

EPA.  1992b.  Final Draft Implementation Plan for the 106-Mile Deepwater
      Municipal Sludge Site Monitoring Program.  Environmental
      Protection Agency. EPA 842-S-92-010.

EPA.  1992c.  Final Report on Current Meter Measurements at the 106-Mile
      Site in Support of Municipal Waste Disposal.  Environmental
      Protection Agency.  EPA 842-S-92-012.

Flagg, C.N.  1988.  Internal waves and mixing along the Hew England
      shelf-water/slope-water front.  Contin. Shelf Res.  In Press.

Houghton, R.W., F. Altaian, and H.H. Ou.  1988.  Shelf/Slope Frontal
      Structure and Cross-shelf Exchange at the New England Shelf Break.
      Contin. Shelf. Res.  In Press.

Joyce, T.M., and  H.C. Stalcup.  1984.  An upper ocean current jet and
      internal waves In a Gulf Stream warm core ring.  J. Geophy. Res.
      89:1997-2994.

Maciolek, N., J.F. Grassle, B, Keeker, P.D. Boehtn, B. Brown, B. Dade, W.
      6. Steinhauer, E. Baptists, R.E. Ruff, and R. Petrecca.  1987a.
      Study of Biological Processes on the U.S. Mid-Atlantic Slope and
      Rise.  Executive Summary Prepared for the U.S. Department of the
      Interior, Minerals Management Service under Contract No. 14-12-
      0001-30064.

Maciolek, N., J.F. Grassle, B. Hecker, P.D. Boehm, B. Brown, J.A. Blake,
      R. Petrecca, S. Duffy, E. Baptiste, and R.E. Ruff.  1987b.  Study
      of Biological Processes on the U.S. Mid-Atlantic Slope and Rise.
      Executive Summary Prepared for the U.S. Department of the
      Interior, Minerals Management Service under Contract Ho. 14-12-
      0001-30064.

National Oceanic and Atmospheric Administration.  1985*  Analysis of
      Circulation Characteristics  in the Vicinity of Deepwater Dumpslte
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