T-1110 Radioactive pollution in northern ocean areas

Historical archive

Published under: Brundtland's 3rd Government

Publisher: Miljøverndepartementet

Guidelines/brochures | Date: 05/07/1995

The Norwegian Ministry of Environment

Radioactive pollution in northern ocean areas

Introduction

Norwegian-Russian research expeditions to the northern ocean areas show that radioactivity in the sea is low, and is lower than in other ocean areas. The radioactive substances found are primarily due to radioactive fallout produced by testing of nuclear weapons and the transport of radioactivity from the south by the ocean. Dumping has had little effect on general radioactivity content. Protection of the environment and future generations calls for continued efforts to curb radioactive pollution. Because several potential sources of pollution exist in the area the content of radioactive substances in the northern ocean areas should also be monitored in the future.

In the autumn of 1990 there were unofficial reports that the former Soviet Union had dumped radioactive materials in the Barents and Kara Seas. The reports received wide coverage throughout the world and raised concerns about ocean pollution. The Barents Sea is one of the most productive ocean areas on the face of the earth. The annual catch in this area varies between 1.5 and 3 million tons.

Radioactive pollution in the northern ocean areas can be a threat to both people and the environment. Norwegian authorities took the unofficial reports seriously, and in 1992 Russian and Norwegian environmental authorities joined forces to investigate radioactive pollution in the northern ocean areas. The purpose of the studies is to determine the potential consequences of the dumped materials and other radioactive waste in the northern ocean areas on the environment and people.

Little radioactivity and limited effects

Fish from the Barents Sea contain about 1 Bq/kg of human-generated radioactivity. This is a low value, and is under the activity levels we find in fish from the Baltic Sea for example. The level is also far under international limits for permitted activity levels in food. In European Union countries, the limit for radioactivity in fish has been set at 600 Bq/kg.

With the aid of models, scientists can calculate how radioactivity distributes itself over time in the ocean. Model calculations can also be expanded to include how radioactive substances migrate in the food chain from fish to people. It is possible to calculate the doses to humans if one knows which radioactive substances have been dumped, how fast the substances are filtering into the sea and the level of fish consumption. The calculations show that even under extreme conditions where it is assumed that all radioactivity dumped into the sea occurs simultaneously, the radiation doses to humans will be quite low.

Brief introduction to radiation and radioactive substances

Certain types of matter emit radiation. These substances are called radioactive. Radioactivity is measured in becquerel (Bq). The unit is named after the French physicist Henri Becquerel, who discovered radioactivity in 1896. The number of becquerel gradually diminishes as the radioactive substances emit radiation.

After a certain amount of time the number of becquerel drops by half. This span of time is called half-life, and is characteristic for each radioactive substance. For example, the half-life of radioactive cesium (Cs-137) is 30 years. Because of its prolonged half-life, cesium is a pollution problem long after its discharge.

Radiation doses are expressed in millisievert (mSv). The radiation dose is decided by the amount of radioactivity (Bq) one is exposed to. The radiation dose from, e.g., polluted food is determined by the total number of becquerel one takes in through one's diet. We all receive an annual radiation dose of about 5 mSv from radiation from outer space and from natural radiation from radioactive matter in our surroundings and in our own body.

Possible contributors to radioactive pollution in the northern ocean areas

Radioactive matter can be transported long distances in the air and water. In addition to dumped radioactive material, a number of other known sources of radioactive pollution exist in the northern ocean areas:

Fallout from nuclear-weapons tests in the 1950s and '60s.
Transport of radioactive matter by ocean currents from European recycling plants for spent nuclear fuel.
River transport of radioactive substances from nuclear plants and nuclear installations in Russia.
Fallout and transport of radioactive substances after the Chernobyl accident.

The studies in the Barents and Kara Seas show traces of all these pollution sources.

The majority of the radioactive pollution in the ocean areas is due to fallout from earlier nuclear-weapons tests in the atmosphere. This fallout is distributed throughout most of the world.

Part of the radioactive discharges from European recycling plants is transported by ocean currents to northern areas. New technology, international pressure and more stringent emission limits have substantially reduced discharges over the past few years.

Rivers in the Russian interior, including the rivers running by nuclear installations in Tomsk, Chelyabinsk and Krasnoyarsk, can carry radioactive substances to the sea. Much of the radioactivity is deposited en route in the river bottom. It is still uncertain how much the rivers contribute to the total radioactive pollution of the ocean areas.

The Chernobyl accident in 1986 caused the discharge of large amounts of radioactivity into the atmosphere. The fallout was registered in most European countries, with to some extent considerable variations between the countries. The northern ocean areas saw little fallout after the accident, but radioactive fallout is transported by ocean currents from other areas.

"Komsomolets", the nuclear-powered submarine that sank in the Norwegian Sea in April 1989, contains both fuel and nuclear warheads. Extensive measurements by the submarine and in the surrounding area show that the leakage is insignificant. Norwegian and Russian environmental authorities agree that the sunken submarine does not represent any threat to the environment in its present condition, but are monitoring the situation.

Both liquid and solid radioactive material has been dumped into the Barents and Kara Seas. While the liquid material has been diluted and transported further in the seawater, the solid dumped material still lies on the bottom of the sea. On the basis of information from Russian authorities the dumping sites for radioactive material are now known.

What has been dumped?

From 1959 to 1991 the Russian navy and the civilian Russian nuclear icebreaker fleet have dumped both solid and liquid radioactive waste on several occasions. Reactor parts and spent reactor fuel are probably the biggest pollution risk. The activity level of the liquid waste is generally lower.

The solid radioactive waste is dumped in areas along the east coast of Novaya Zemlya and in the Kara Sea. Along with fluid material, a large number of containers, six reactors with spent uranium fuel and 10 reactors without fuel were dumped here. In addition, the Russian northern fleet sank a total of 17 ships with radioactive waste in the Barents and Kara Seas. Most of the material on board the ships consists of containers of radioactive waste, reactor parts and other polluted equipment.

Liquid radioactive waste has been dumped in five defined areas in the Barents Sea. The waste has been dumped directly in the ocean from moving ships. There have also been smaller discharges of liquid material outside these areas, mainly in the Kara Sea.

Dumped radioactivity

According to official Russian sources a total of 0.45 PBq of liquid radioactive material has been dumped in the Barents Sea and 0.32 PBq in the Kara Sea.

Most of the solid radioactive waste has been dumped along the east coast of Novaya Zemlya and in the open Kara Sea. Most of the fuel-containing reactors that have been dumped are protected by material to guard against leaks. In addition, other material with a lower level of radioactivity has been dumped in metal containers or special barges:

Solid radioactive waste in the Kara Sea
Reactors with fuel: 85.0 PBq
Reactors without fuel: 3.7 PBq
Metal containers with radioactive material: 0.6 PBq

Solid radioactive waste in the Barents Sea
Metal containers with radioactive material: 0.002 PBq

These values are estimated by Russian authorities. International calculations show that the actual amount of radioactivity dumped is probably less.

Research expeditions

Since 1992 three expeditions have been carried out to study the amount of radioactivity in the northern ocean areas and the condition of the dumped waste. During the expeditions Norwegian and Russian researchers have taken joint samples of seawater, sediments, flora and fauna. Representatives from the European Union and the International Atomic Energy Agency (IAEA) also accompanied the expeditions.

The expeditions have been particularly concentrated on areas where reactors and other solid radioactive material are dumped. About half of the solid radioactive waste lies in the Abrosimov fjord south-east of Novaya Zemlya. It has therefore been important for researchers to concentrate on this fjord in particular.

The dumped waste was localised with the help of sonar equipment and examined with an underwater camera, and the amount of rust on the containers was simultaneously measured. The inspection showed that many of the containers are rusty and that some have holes. Some of the holes probably occurred during the actual dumping.

The underwater camera also made it possible to take samples of the water and sea floor immediately by the dumped material. Sediment samples of the sea bed were taken at about 100 different places during the expeditions, and about 100,000 litres of water have been analysed.

Measurements

The current radioactivity content in the open Barents and Kara Seas is low, and is lower than the levels shown by earlier studies from 1963 to 1992. The radioactive substances found indicate that the pollution in the northern ocean areas is primarily due to global fallout produced by testing of nuclear weapons and transport of radioactivity via ocean currents. Dumping has so far had very little impact on the radioactivity content in the ocean areas.

Higher radioactivity content has been measured in the sea bed of some of the dumping sites. These local variations are limited in scope; a few metres away from the waste the radioactivity content drops back to a low level.

The radioactivity content in the Abrosimov fjord is somewhat higher than the level otherwise found in the Kara Sea. The radioactivity in the fjord water appears to be primarily due to radioactive material leaking from the dumped containers. Little radioactivity is leaking from the reactors, which from the outset represent the biggest threat.

The samples were analysed at nine different laboratories in Norway, Russia and other countries. The measurements from the various laboratories correspond well.

Some measurements from the expeditions

Amounts of radioactivity in the open Kara Sea:

Cesium (Cs-137):
3-32 Bq/m3
Strontium (Sr-90):
3-25 Bq/m3
Plutonium (Pu-239, 240):
0.002-0.03 Bq/kg

Amounts of radioactivity in the upper layers of the sea bed in the open Kara Sea:
Cesium (Cs-137):
2-53 Bq/m2

The radioactive cesium in sediments close to some of the dumped waste is higher. Some radioactive cobalt (Co-60), and plutonium (Pu-239, 240) were also measured in these sediments. All measurements and results are described in detail in the scientific reports from the expeditions.

International co-operation

Methods that will protect the environment and resources in the northern ocean areas.

On the basis of the results from the Norwegian-Russian expeditions and a thorough evaluation of the future effects of dumping, IAEA will prepare recommendations for further international efforts.

IAEA's recommendations will be presented to member nations of the so-called London convention in the course of 1996. The convention is a global agreement to limit ocean pollution from dumping. Seventy-one countries have signed the treaty, including Russia.

The dumping by Russia has ceased, but Russia is the only member country that has not accepted a total ban on dumping. Several countries are actively working to get Russia to agree to a total prohibition on dumping.

Efforts to prevent future radioactive pollution of ocean areas

The current radioactivity content in the northern ocean areas is low and probably diminishing as the result of reduced emissions from European recycling plants and the present halt in nuclear-weapons testing. Protection of the environment and future generations nevertheless requires continued efforts against radioactive pollution.

Dumped reactor materials and fuel are cause for concern with respect to future pollution. Discharges are mainly dependent on the quality of the protective material enveloping the reactors. The protective material around the sources will rust away with time and more radioactivity could filter out into the ocean in the long term.

Sources on land and along the coast could also lead to more radioactivity in the ocean areas. Civil and military use of nuclear power carries with it the risk of new accidents and emissions. Simultaneously, inadequate storage of radioactive waste and scrapped nuclear-powered submarines along the Kola peninsula could jeopardise the ocean environment in the future.

The existence of several potential pollution sources means that radioactivity in the northern ocean areas must be continuously monitored. Control of radioactive pollution ensures that the correct precautions can be taken at an early stage. The activities in the northern areas also require a holistic approach, including increased efforts to counter radioactive pollution on land. This will be a main area of concentration for Norwegian authorities in the years ahead.

The monitoring programme and continued mapping of radioactive sources will therefore form an important basis for Norwegian-Russian control of the radioactive pollution in our northern ocean areas.

Terms

Activity
Gives the amount of radioactivity. Activity is measured in becquerel (Bq) and diminishes as time passes. The curie (Ci) was previously used to measure activity.

Atmosphere
The whole mass of air surrounding the earth.

Atomic activity
The production of energy with the aid of nuclear reactors.

Bq
Abbreviation for becquerel. Becquerel is a small unit, and activity is therefore often stated in petabecquerel. 1 petabecquerel (PBq) is equal to one million billion becquerel.

mSv
Abbreviation for millisievert. Measure of radiation dose.

Fallout
Radioactive substances in the atmosphere that fall to earth.

Food chain
Food and energy from the earth can be transported through plants and animals into the food of humans. Radioactive matter can also be transported in the food chain.

Radioactive matter
Some substances are unstable and will be transformed into new substances. Energy is emitted to the surroundings during this transformation. Unstable substances such as these are called radioactive.

Radiation dose
The energy from radioactive substances will hit other matter. The radiation dose is a measurement of the amount of energy absorbed by the radiated substance. The bigger the radiation dose the bigger the damage. The radiation dose is stated in millisievert (mSv).

Radiation
Energy and particles emitted by radioactive substances.

Information about the publication

Reports from the research expeditions in the Barents and Kara Seas can be obtained by contacting:

Norwegian Radiation Protection Authority
Environmental Protection Department
P.O. Box 55, N-1345 Østerås, NORWAY
Tel: +47 67 16 25 37
Fax: +47 67 14 74 07

Additional copies of this brochure can be ordered from:

Norwegian Pollution Control Authority (SFT)
P.O. Box 8100 Dep., N-0032 Oslo, NORWAY
Tel: +47 22 57 34 00
Fax: +47 22 67 67 06

The brochure is also available on the Internet: http://odin.dep.no/md/md.html

Editor in chief:
Sylvi Oftstad
Text:
Morten Bremer Mærli
Scientific contribution:
Institute of Marine Research, Norwegian Radiation Protection Authority and Institute for Energy Technology
Production: Svein Magne Fredriksen
Graphic design and illustrations:
Skomsøy Grønli as
Repro: Lito-print Print: Aktiv trykk as
Copies: Norwegian: 15.000, English: 6.000, Russian: 2.500, Lapp: 3.000
This document was last updated 31 July 1995 by the ODIN-editors