Notes

fornia. The last known dumping operation was in
1982, at a site about 550 kilometres off the European
continental shelf in the Atlantic Ocean. (See map.)
Between these two dates, an estimated 63 PBq
(1.7 MCi) of radioactive waste coming from research,
medicine, and nuclear industry activities have been
packaged, usually in metal drums lined with a concrete
and bitumen matrix, and disposed of at sea.** This
inventory includes some unpackaged waste and liquid
waste which were disposed of from 1950 to 1960. Betagamma emitters represented more than 99 % of the total
radioactivity of the waste. They were fission and activation products such as strontium-90m, caesium-137,
iron-55, cobalt-58, cobalt-60, iodine-125, carbon-14,
and tritium. These represent one-third of the total radioactivity dumped in the North East Atlantic sites. The
wastes disposed of also contained low quantities of
alpha-emitting nuclides with plutonium and americium
representing 96% of the alpha emitters present.
The dumping operations were performed under the
control of national author
Features
World-wide distribution of sea dumping sites used for disposal of low-level radioactive waste
the possible damage to the marine resources. These concerns have been expressed mainly by countries which do
not share the benefits of nuclear energy. They were
expressed in 1958 in Article 48 of the Law of the Sea
which recommended "that every State shall take
measures to prevent pollution of the seas from the
dumping of radioactive waste, taking into account any
standard and regulation which may be formulated by the
competent international organizations".
As a result, since 1957, the date of its first meeting
to design methodologies to assess the safety of "radioactive waste disposal into the sea", the IAEA has
provided guidance and recommendations for ensuring
that disposal of radioactive wastes into the sea will not
result in unacceptable hazards to human health and
marine organisms, damage to amenities or interference
with other legitimate uses of the sea.
IAEA recommendations to protect man
and marine environment
Although sea dumping is essentially a strategy of dispersion/dilution rather than one of containment, IAEA
has recommended that the waste packages be designed
to ensure containment of the waste during its descent to
and impact on the sea floor and to minimize, to the
extent reasonably achievable, subsequent releases of
radionuclides to the sea. Scenarios for the releases of
radionuclides from the waste matrix and container, their
dispersion in the marine ecosystems and their transfer to
the surrounding human environment were identified.
Due to the low concentration of radionuclides expected
in the various marine components, the radionuclide
transfer back to man from the deep sea could not be
ascertained by a monitoring approach and was evaluated
using mathematical models, as is still the case today.
The subsequent development of new mathematical
models, the acquisition of improved data concerning the
oceanographic, geochemical, and biological processes
involved in radionuclide behaviour in the marine
environment have made it possible to continuously
refine the impact assessment of sea dumping of radioactive wastes on human populations and on the marine
environment.
The London Dumping Convention
Since the Convention for the Prevention of Marine
Pollution by Dumping of Wastes and Other Matter
(referred to as the London Dumping Convention, or
LDC) came into force in 1975, the dumping of waste has
been regulated on a global scale. The LDC prohibits,
inter alia, the dumping of HLW and requires that LLW
be dumped only after a special permit has been issued.
At the seventh consultative meeting (1983) of the
contracting parties to the LDC, an amendment to these
annexes was proposed to prohibit the dumping of all
radioactive waste at sea. A resolution was adopted
calling for suspension of all dumping pending a review
of the scientific basis for sea dumping of radioactive
wastes. In 1984, an independent panel of experts
reviewed the scientific and technical considerations rele48 IAEA BULLETIN, 4/1989
Features
Metal and concrete drums were used to dispose of
low-level radioactive waste at a Northeast Atlantic
Ocean site at a depth of 4700 metres. The high density
of the concrete drum (below) caused it to be half
embedded in the sediment. Traces of biological
activity can be seen near the drum.
vant to the proposed amendment. Their conclusion,
presented at the LDC eighth consultative meeting
(1985), stated that "no scientific or technical grounds
could be found to treat the option of sea dumping differently from other available options when applying internationally accepted principles of radiation protection to
radioactive waste disposal".
In 1986, as a result of the continuous improvement of
the impact assessment methodology, the IAEA
presented its third version of the definition of HLW
unsuitable for dumping at sea and its recommendations
for the control of low-level packaged waste dumping
operations.* Despite this new information, the LDC
tenth consultative meeting (1986) agreed to establish an
intergovernmental panel of experts to consider the wider
political, legal, economic, and social aspects of sea
dumping of LLW. The moratorium was extended pending the results of these new studies. At the same time,
the IAEA was requested to advise contracting parties
specifically with respect to outstanding scientific and
technical issues. Two of the studies requested from the
IAEA in this context are described below.
Comparative risk studies
Many chemicals, some of which have been identified
as carcinogens for man, are present in the marine
environment as a result of the disposal of wastes from
* Definition and Recommendations for the Convention on the Prevention of Marine Pollution by Dumping of Wastes and other Matter.
IAEA Safety Series No. 78 (1986 edition).
various industrial activities. In contrast to the extensive
knowledge of man's exposure to ionizing radiation from
all type of marine sources, the impact on human populations of non-radioactive chemicals in the oceans is not
well known. In order to fill this gap a group of experts
have been convened under IAEA auspices to compare
the risks estimated to result from the dumping at sea of
radioactive wastes with those from other uses, applications, disposals, and disseminations of potentially
hazardous substances.
In 1986, the IAEA offered guidance on an approach
for comparison of land-based disposal options with sea
dumping and the costs and risks associated with these
options. Optimizing a waste management system,
involves the review of a series of parameters specific to
the waste characteristics, the site environment, and
available resources combined with national, social, and
political factors. Currently, on behalf of the LDC, the
IAEA is undertaking a review of the published studies
dealing with comparative environmental and safety
assessments of various disposal options for different
types of solid LLW.
Toward an inventory of radioactive waste dumped
and released into the sea
On several occasions, the LDC has requested the
Agency to develop an inventory of radioactive wastes
entering the marine environment from all sources. To
date a provisional computerized database with information on the date, location, depth, quantity, weight, and
IAEA BULLETIN, 4/1989
49
Features
IAEA responsibilities in the context
of the London Dumping Convention
The ocean, a source of many resources, is international territory whose water movements know no national
boundaries. These facts imply that international collaboration is of the essence to prevent and combat global
marine pollution. In 1958, the United Nations Conference
on the Law of the Sea recommended specifically that
"the IAEA should pursue whatever studies and take
whatever action is necessary to assist States in controlling the discharge or release of radioactive materials to
the sea, in promulgating standards, and in drawing up
internationally acceptable regulations to prevent pollution of the Sea by radioactive materials in amounts which
would adversely effect man and his marine resources".
Following the United Nations Conference on the
Human Environment in Stockholm (1972), the concept of
pollution prevention took effect when, in 1975, the Convention for the Prevention of Marine Pollution by Dumping of Wastes and Other Matter (the London Dumping
Convention) entered into force. The London Dumping
Convention entrusts the IAEA with specific responsibilities for the definition of high-level radioactive wastes
unsuitable for dumping at sea, and for making recommendations to national authorities for issuing special permits for ocean dumping of low-level radioactive wastes.
IAEA was mandated to keep the definitions and recommendations under review to limit the impact of the
dumping operation.
type of containers, as well as the quantities of dumped
radionuclides, has been established. Consideration is
being given to including information on controlled
authorized liquid releases from nuclear facilities into the
coastal waters in the inventory.
The rationale for the inventory is to establish an
information base which can provide more accurate data
for assessing the impact of radioactive waste dumping
operations in the sea. Such an inventory will also serve
as a deterrent against disposal of more waste coming
from various countries than recommended in a single
oceanic basin.
Seabed disposal
The deep sea floor is one of the most stable and
predictable geologic formations on earth and has therefore been considered as a potential alternative solution to
deep geological disposal of HLW on land. If a seabed
disposal option was selected, packaged HLW could be
embedded in the sediment using penetrators or drilling
techniques. The packages would contain the wastes for
500 to 1000 years after emplacement. Long-term containment, for tens of thousands of years, would be
provided by the barrier properties of the sediment.
In 1984, the contracting parties agreed that the LDC
consultative meeting was the appropriate forum to
address the scientific and legal issues of the HLW seabed
disposal. It was also agreed that no HLW disposal into
the seabed should take place until it is proved to be technically and environmentally acceptable, including a
determination that such wastes can be effectively isolated from man and the marine environment.
In 1988, the NEA/OECD Seabed Working Group
concluded that sub-seabed burial of HLW was technically feasible, but added that its long-term safety assessment required further research to reduce the
uncertainties before the option is used.
The future
Following the voluntary moratorium, no dumping
operations have been carried out since 1982. This disposal option, however, still remains open pending a final
decision by the contracting parties to the LDC and is a
concept which can, in principle, be considered as an
alternative to disposal on land.
Through the NEA/OECD Seabed Working Group
and Co-ordinated Research and Environmental Surveillance Programme, scientific data on geochemistry,
physical oceanography, and deep-sea marine biology
continue to be accumulated on the processes controlling
radionuclide transport and dispersion in the North East
Atlantic and North West Pacific Oceans. These data, in
addition to research activities in the field of mathematical modelling of radionuclide transport processes to
marine organisms and man, have improved the capability to assess the impact of radionuclides dumped into the
sea. Next year, the NEA Committee of Radiation Protection and Public Health will conduct a review of the
suitability of the North East Atlantic Ocean NEA dumping site for the disposal of packaged LLW. * The purpose
is to ensure that new scientific data do not contradict the
conclusions of past assessments of the site.
In 1988, an IAEA/NEA Experts Group reached a
consensus on the criteria for determining which types of
radiation sources and practices may be exempted from
regulatory control on the grounds that they present a
trivial radiation risk. These criteria must now be explicitely applied to waste disposal in the marine environment to establish rules and guidelines for determining
which types of LLW may be treated as being nonradioactive for the purpose of sea disposal.
Current studies to examine the risks of sea dumping
and to compare them with those of land disposal and
with those from sea disposal of other types of hazardous
waste may give a more balanced appreciation of the real
impact of sea dumping.