United States
           Environmental Protection
           Office of
           Washington, DC 20460
July 1988
The Use of Geophysical
Monitoring Systems
and Data  to Identify and
Designate  Ocean Sites for
Disposal of Low-Level
Radioactive Wastes

                                                 EPA 520/1-88-012

                     James Neiheisel

                        July  1988
              Office of Radiation Programs


                 Washington,  D.C.   20460

     In 1972 Congress enacted the The Marine  Protection,
Research and Sanctuaries Act  (PL 92-532).   The Act  required  the
Environmental Protection Agency  (EPA) to develop  regulations to
control ocean disposal of all wastes, including low-level
radioactive wastes  (LLW).  The EPA Office  of  Radiation  Programs
(ORP) initiated specific studies to  develop criteria  directly
applicable to ocean disposal of LLW.

     The ORP has conducted feasibility  studies to determine
whether present-day technologies could  be  applied to  determine
effects from previous  (1946 to 1970) U.S.  disposals of
radioactive wastes  in the oceans.  After successfully locating
LLW containers in three previously used  disposal  sites,  the  ORP
initiated characterization studies to:  (1)  determine  the
biological, chemical, and physical parameters within  each  of the
sites;  (2) monitor  for the presence  and  distribution  of
radionuclides in each site, including their concentration
levels; and,  (3) assess the performance  of past packaging
techniques and materials.

     The purpose of this report  is to provide information
applicable to using geophysical  instruments and survey  methods,
and the data collected, in the process  of  designating sites  for
ocean disposal of LLW.  The geophysical  ocean survey  methods
described in this report are envisioned  as preceding  any
sediment sampling required to characterize disposal sites.

     The Agency invites all readers  of  this report  to send any
comments or suggestions to Mr. David E.  Janes, Director,
Analysis and Support Division, Office of/Radiation  Programs
(ANR-461), Washington, D.C.  20460.
                                   / Richard  «K7\3u\^njond,  Director
                                      Office /of/Radiation  Programs

                   TABLE  OF  CONTENTS

FOREWORD                                                  in

ACKNOWLEDGMENTS                                           vii

1.       Introduction                                      1

2.       Geophysical Instruments                           2

2.1.     Side-Scan Sonar Systems                           3

2.2.     Seismic Profiling Systems                         4

2.2.1.   Airgun Profiler                                   5

2.2.2.   High-Resolution Profiler                          5

3.       Disposal Site Monitoring                          6

FIGURE 1                                                   7

    Graphic 3.5-kHz, High-resolution Sediment Profile,
    Mid-Atlantic Slope - Lower Baltimore Canyon.

REFERENCES                                                 8

     The author wishes to thank Dr. James Booth of the United
States Geological Survey (USGS) for the opportunity to
participate in the March 1987 mid-Atlantic, Exclusive Economic
Zone (EEZ)  survey cruise.  During this cruise, the author was
able to observe the Geological, Long-Ranged, Inclined Asdic
(GLORIA) seafloor mapping system in operation and to assess  its
applicability to designating sites for ocean disposal of LLW.
Thanks is also extended to Dr. James Robb, Chief Scientist for
that cruise, for his helpful suggestions on using geophysical
instruments/methods applicable to site characterization and
designation studies.  The information provided in this report is
based directly upon the author's at-sea experience in assessing
state-of-the-art geophysical instrumentation and data.

     I also wish to thank Mr. Robert S. Dyer and Mr. William
Curtis of the Office of Radiation Programs, U.S. Environmental
Protection Agency, for critical review of this report and for
the many helpful suggestions and discussions during the course
of this work.  The critical review and comments also provided by
Dr. William Forster of the U.S. Department of Energy and
Dr. James Booth of the U.S. Geological Survey are gratefully
acknowledged.  Typing of this document by Ms. Phoebe H. Suber is
also acknowledged with appreciation.

1.   Introduction
     The Environmental Protection Agency  (EPA)  is currently
revising its 1977 Ocean Dumping Regulations.  The revised
regulations will incorporate criteria applicable to any  ocean
disposals of low-level radioactive wastes  (LLW), as recommended
by the International Atomic Energy Agency  (IAEA).  The IAEA
recommends, pursuant to Annexes I  (Sec. 6) and  II (Sec.  B.)  of
the London Dumping Convention  (LDC), that  any LLW disposed in
the oceans should be properly packaged and disposed in deep
ocean sites where the average water depth  exceeds 4000 meters.
Thus, the Agency, in revising the regulations for all wastes,
will also include waste package performance and site designation
criteria that are specific to LLW.

     In addition to including siting and packaging performance
criteria in the revised regulations, the Agency is preparing a
series of technical reports that provide LLW disposal site
monitoring recommendations.  Sediment monitoring requirements >
for ocean disposal of all wastes, as listed in  Part 228  of the
existing Ocean Disposal Regulations  (42 FR 2462 of January 11,
1977), include organic carbon, texture, particle size
distribution, major mineral constituents,  and settling rate.
Because of the unique character of LLW, their potential  for
migration in sediments, and the different  environmental  stresses
that the waste packages will be subject to from disposal in  the
deep ocean, additional disposal site sediment monitoring
parameters are recommended.  These include determining:  (a)  the
sorptive distribution coefficient  (Kd) of  radionuclides; (b)
sediment redox potential by the nitrate method  and other
supporting techniques; (c) pH; (d) geotechnical parameters;  and
(e) the composition of sediment core samples by the x-radiograph
technique.  Specific rationale for recommending each of  these
additional sediment monitoring parameters, and  disposal  site
characterization data applicable to immobilizing LLW, are
presented in two of the referenced technical reports  (Neiheisel,
1988 and U.S. EPA, 1988).  In general, determining these
additional sediment parameters in LLW disposal  sites will
provide data for predicting the capability of sediments  to
retain radionuclides.  Calculating the radionuclide retention
factor of sediments in potential LLW disposal sites is very
important because it can indicate whether  a sufficient natural
barrier to radionuclide migration exists in case the primary,
engineered-barrier (waste container) fails.

     This report is another in the Agency's series of technical
documents that provide specific recommendations applicable to
any future ocean disposal of LLW.  It provides  information about
using geophysical instrumentation and survey methods  in
designating disposal sites.

     In March 1987, the EPA Office of Radiation  Programs  (ORP)
participated in the U.S. Geological Survey  (USGS)  mapping  of  the
mid-Atlantic Exclusive Economic  Zone  (EEZ)  using the  geological,
long-ranged inclined asdic  (GLORIA) system  to  obtain  sonographs
(rough images)  of the sea floor.  Data  from that survey  shows
that use of the GLORIA system can significantly  improve  the
process for locating and designating potential LLW disposal
sites.  Within those portions of the mid-Atlantic EEZ  (33.5°N
to 39°N latitudes), where water  depths  exceeded  4000  meters,
the GLORIA data identified no less than  three  sites with  little
or no indication of debris flow  or other detrimental  phenomena.
Smaller-scale geophysical surveys, at each  of  the three  sites
identified from the GLORIA data, could  provide more specific
resolution of seafloor topography and a  better assessment  of
environmental conditions within  each site.   The  more  specific
data could be obtained from detailed sonographs  provided  by
high-resolution seismic reflection profilers,  from sea floor
photographs, and from sediment characterization  studies.

2.   Geophysical Instruments

     State-of-the-art geophysical instruments  used to obtain
reconnaissance plan-view imagery of large sections of the  ocean
floor have been compared to the  first high-resolution photos  of
earth taken from space by the Landsat satellite  (Hill, 1986).
Side-scan sonars, seismic profilers and  other  geophysical
instruments, supplemented by in-situ sediment  monitoring,
provide a means for assessing potential  LLW disposal  sites in
the deep ocean.  The full potential for  applying such
instruments to locating possible LLW disposal  sites began  in
1984 when the USGS initiated monitoring  surveys  of the EEZ,
which extends to 200 nautical miles offshore.  During these
surveys, the long-range side-scan sonar  system GLORIA mapped  the
seafloor.  The first phase of GLORIA mapping in  the EEZ,  off  the
U.S. west coast, was completed in 1984.  The data from the
initial surveys, including  interpretations  of  seafloor
topography at a scale of 1:500,000, were published in atlas
format  (EEZ - SCAN 84, 1986).  Mapping  of the  EEZ off the  U.S.
east coast was completed in 1987.  Publication of that data  is
expected in 1989.  The EPA participation in the  mapping  of the
mid-Atlantic EEZ was motivated by an opportunity to obtain
supplemental data pertinent to earlier  EPA  studies at the
previously used 2800m and 3800m  LLW disposal sites that  are
located in the mid-Atlantic EEZ.  The insight  gained  on  the
capabilities and limitations of  geophysical instruments  during
the USGS mid-Atlantic survey was invaluable in preparing  this

     The remainder of this report briefly discusses various
side-scan sonar systems and seismic profilers that can  be  used
to identify geologically stable, deep-water areas for potential
designation as LLW disposal sites.

2.1. Side-Scan Sonar Systems

     The GLORIA system is a specialized side-scan sonar capable
of large-scale reconnaissance mapping of deep-ocean seafloor
topography.  GLORIA can map seafloor areas of approximately  the
same size as the state of New Jersey in a single day  (MacGregor
and Lockwood, 1984), while towed by ship at a speed of  8 - 10
nautical miles per hour (knots).  Developed into a digital data
collection system  in 1981 by the United Kingom Institute of
Oceanographic Sciences, this unique side-scan sonar operates at
a nominal frequency of 6.5 kHz and a 100 Hz band width  from  a
transducer array towed at 50 meters depth.  The recorded pulses
received are corrected in real time aboard the ship and used to
produce sonographs which are images that show entire  surfaces of
topographic features at 50-m resolution.  The advantages of  the
GLORIA mapping over conventional mapping techniques is  that
correlations and trends of features such as ridges and  channels
can be made with confidence between seismic profiles, and  that
the patterns of such features as meandering channels  and
dendritic canyons  can be clearly defined  (Cacchione,  et al,
1988) .

     As the GLORIA imagery on the mid-Atlantic EEZ survey  was
being assembled aboard the RV FARNELLA in March 1987, it became
apparent that major slumping areas and submarine canyons with
interconnecting drainage patterns were more numerous  and more
complex than had been previously depicted on existing contoured
bottom charts.  Local tectonic structures and tonal differences
that reflected a variation in sediment types also added to the
interpretation of  the bottom topography.  The detailed  GLORIA
imagery provided an interpretative means of identifying areas of
transport and erosion that could reflect on the suitability  of
considering an area for LLW disposals.

     The GLORIA data obtained from the mid-Atlantic EEZ, in
locations deeper than 4000 m, reveals three areas  (one  off New
England and two off the Carolinas) that show relatively static
geologic environs, free from debris flows or other indications
of instability.  These three areas, observed in unprocessed
GLORIA data made available to EPA by the USGS, will be  assessed
in greater detail  after final processing of all data  which
should provide improved resolution over the unprocessed
imagery.  These areas could be candidates for potential LLW
disposal sites.  Further study of these locations would require
the use of more detailed, narrower ranged side-scan sonar  and
other geophysical  instruments.

     The National Oceanic and Atmospheric Administration (NOAA)
utilizes a hull-mounted side-scan  sonar  system,  SEA  BEAM,  that
maps a smaller seafloor area, but  in more detail,  than the
GLORIA system.  The 5 km mapping "swath" of  SEA  BEAM is much
narrower than the 30 km trackline  spacing of  the GLORIA system
but the resultant map is much more detailed.

     In addition to using GLORIA,  the USGS has deployed the  SEA
MARK I, a mid-range side-scan sonar, to  collect  detailed
topographic data of slump zones on the continental slope and
rise off North Carolina  (Cashman and Popenoe, 1985)  and for
surficial geological studies  in the Northern  Baltimore Canyon
(Robb et al, 1982).

     Seafloor maps provided by the SEA BEAM  and  SEA  MARK I
side-scan sonar systems, in conjuction with  data obtained  from
high-resolution seismic profilers, have  yielded  excellent
details of bottom features in selected areas  of  mapping.   The
use of SEA MARK I or SEA BEAM is recommended  to  enhance bottom
features observed in GLORIA data and especially  in the process
of characterizing a site for consideration as a  potential  LLW
disposal site.

     The long-range  (GLORIA) and medium-range  (SEA BEAM and  SEA
MARK I) side-scan sonar imagery systems  are  valuable tools to
the researchers, enabling them to  focus  on ocean bottom features
that can indicate the degree of geologic stability in  deep ocean
environments.  Areas of bottom surface stability or  active areas
of erosion and deposition can be identified  from the sonograph
imagery.  Vertical stability of a  seafloor area  is not always
discernable from side-scan sonar imagery, but the use  of
high-resolution seismic profilers  can provide vertical stability
data.  The fact that six times as  many seismic data  profiles are
available from SEA BEAM or SEA MARK I surveys, as compared to
GLORIA, is a decided advantage with the  more  detailed  surveys.

2.2. Seismic Profiling Systems

     Continuous seismic profiling  methods complement the
side-scan sonar imagery and permit a more certain interpretation
of the geological stability of a potential LLW disposal site.
Combined use of a 3.5-kHz Sub-Bottom Profilier with  a  deep
penetrating seismic system, using  a 160  in3  air  gun  or similar
sound source, provides a detailed  resolution  of  sediment
layering and subsurface geologic structures,  extending from  the
seafloor surface to underlying basement  rock.

2.2.1.   Airgun Profiler

     During the GLORIA survey -of the mid-Atlantic EEZ, deep
penetration mapping of the ocean sediments and basement  rock  was
obtained by using a 160 in^ airgun with a hydrophone  streamer
of French-Italian design.  The airgun was fired at  10-second
intervals and at a 6-second sweep.  Incoming data was  fed  in
parallel to a special USGS computer (MASSCOMP) which  digitized
and displayed the data in real time on a monitor and  recorded
the data on nine-track magnetic tape.  This type of deep
penetrating seismic profiling is considered essential  to
assessing the stability of a candidate LLW disposal site and
adjacent areas.

     Deep penetrating seismic profiling provides a  means of
correlating surface bottom relief with reflectors found  in the
subsurface geology.  Structures have been identified  by  the
deeper penetrating seismic reflection systems that  could
eliminate a potential site for LLW disposal.  An example is seen
in data from the Atlantic continental slope and rise  off North
Carolina where a salt diapir complex was observed  (Cashman and
Popenoe, 1985).  Salt diapirs are related to instability as they
normally indicate areas of extensive slumping.  The slumping
appears to be a result of uplift and faulting associated with
the vertical intrusion of the diapir.

     Seismic reflection profile data, from along the  edges of
buried rift basins in the Long Island Basin, show low-angle
border faults, tilted sedimentary horizons, and high-angle cross
faults (Hutchinson et al, 1986).  Such structures of  instability
are reported from Nova Scotia to South Carolina in  the Atlantic
continental margin.  Although these structures were observed  in
shallower areas than the 4000-m depth recommended by  the IAEA
for LLW disposal sites, they are examples of utilizing deep
penetration seismic profilers to obtain interpretative data.

     Preliminary releases of Atlantic GLORIA survey data by the
USGS  (Ocean Science, 1987) report two fields of apparent salt
domes off the Carolinas and northern New Jersey.  These  salt
dome fields, and other features observed in the seismic  profile
data that will be published in the forthcoming EEZ  Atlas of the
Atlantic, will likely exclude otherwise potentially favorable
LLW disposal sites from further consideration.

2.2.2.   High-Resolution Profiler

     A high-resolution 3.5-kHz profilier provides a graphic view
of sediment layering in the upper 25-100 m of bottom  sediment.
The 3.5-kHz system is sometimes termed the sediment profiler

since it presents a vertical profile  of  layered  soft sediment.
A 12-kHz system is also used with  the 3.5-kHz  profiler  to obtain
bathymetry data.

     A typical 3.5-kHz system consists of  a  transceiver
(transmission and receptor device)  towed from  the  bow,  and a
recorder aboard ship.  A  3.5-kHz sediment  profile,  recorded
aboard the RV FARNELLA during the  USGS mapping survey of  the
mid-Atlantic EEZ, is  shown in Figure  1.  This  profile was
obtained from an area in  the lower  seaward portion  of the
Baltimore Canyon.  The profile  shows  the continuity and
regularity of multiple layers in the  upper 25  m  of  bottom
sediments along a section of the ship's  track  in this area.
Using Figure 1 as an  example, one  can readily  see  the utility of
using geophysical instruments during  LLW site  selection or
designation surveys to evaluate the degree of  geologic  stability
and sediment uniformity in a prospective deep-sea  location.

3.   Disposal Site Monitoring

     Monitoring surveys to select  deep-ocean candidate  LLW
disposal sites should include the  use or collection of
geophyscial data and  sediment samples.   Identification  of
relatively large-scale, static  or  stable seafloor  areas can be
made by examining available USGS reconnaissance  imagery data
obtained from the GLORIA  surveys of the EEZ.   More  detailed and
smaller scaled data  (for  example,  from the SEA BEAM and SEA MARK
I mid-range side-scan sonar systems)  can then  be used,  in
conjunction with extensive seismic  reflection  profiling data,  to
delineate bottom features in potentially static  areas identified
by the GLORIA data.   It should  be  noted here,  however,  that,
although a relatively large volume  of side-scan  sonar and
seismic relection profile data  has  been collected  in the  U.S.
east and west coast EEZ areas,  one  of the  criteria  for
designation of LLW disposal sites  requires an  average water
depth in excess of 4000 meters.  This depth  is recommended by
the IAEA and is accepted  by the United States  as a  signatory to
the LDC.  Thus, potential areas for consideration  as LLW
disposal sites will be limited  by  this criterion within the  U.S.
EEZ, particularly in  the  Atlantic  Ocean.

     It is also important to note  that assessments  of potential
LLW disposal sites should not be based solely  upon  side-scan
sonar and seismic profile data.  Site selection/designation
processes will require in-situ  sediment sampling.   Accordingly,
the EPA has prepared  a report recommending sediment monitoring
methods for LLW disposal  sites  (U.S.  EPA,  1988).

                                     '" 4"... -p- '.tT*.»••',;ji',,,  • ' K!I-* •.'.•.', .i.\ .'A1' •'.'!.';•< "'."K
ill0fe-Jjf'-i'.•'"> ^1.0 a; r'l?*«"{»'

   Figure 1.  A  graphic  3.5-kHz,  high-resolution  profile  of
               sediment  layers along the  continental slope in
               the lower  reaches  of the Baltimore  Canyon.   Data
               obtained  on March  12, 1987,  during  a USGS  survey
               of the mid-Atlantic EEZ.

Cacchione, et al, 1988, Physiography of the Western United
States Exclusive Economic Zone, Geology, v. 16, p. 131-134.

Cashman, K.V. and Popenoe, 1985, Slumping and Shallow Faulting
Related to the Presence of Salt on the Continental Slope and
Rise off North Carolina, Marine and Petroleum Geology, v. 2,
p. 260-271.

EEZ - SCAN 84, Scientific Staff, 1986, Atlas of the Exclusive
Economic Zone Western Conterminous United States:  U.S.
Geological Survey Miscellaneous Investigation Series 1-1792,
p. 152.

Hill, G.W.,  1986, U.S. Geological Survey Plans for Mapping  the
Exclusive Economic Zone using GLORIA., Proceedings of Exclusive
Economic Zone Symposium Exploring the New Ocean Frontier,
Washington,  DC, October 2-3, 1985.

Hutchinson,  D.R., Klitgord, K.D., and Detrick, R.S., 1986,  Rift
Basins of the Long Island Platform, Geological Society of
America Bulletin, v. 97, p. 688-702.

McGregor, B.A., and Lockwood, M., 1984, Mapping and Research in
the Exclusive Economic Zone, U.S. Department of Interior and
U.S. Department of Commerce Bulletin, Washington, DC, 40 p.

Neiheisel, J., 1988, Sediment Monitoring Parameters and
Rationale for Characterizing Deep-Ocean Low-Level Radioactive
Waste Disposal Sites, U.S. Environmental Protection Agency,
EPA 520/1-87-011.

Ocean Science News, 1987, More Specific Results, of the East
Coast GLORIA Survey, v. 29, n. 18, May 12, 1987, Washington, D.C.

Robb, J., Hampson J.C., and Kirby, J.R., 1982, Surficial
Geological Studies of the Continental Slope in the Northern
Baltimore Canyon Trough Area - Techniques and Findings, 14th
Annual Offshore Technology Conference, Houston, TX, May 3-6, 1982
p. 39-43.

U.S. Environmental Protection Agency, 1988, Methods Manual  for
Sediment Monitoring at Deep-Ocean Low-Level Radioactive Waste
Disposal Sites, edited by J.W. Booth, U.S. Geological Survey,
EPA 520/1-88-002.