controlling the mean external dose are the settlement type (rural or urban) and the level of 137Cs soil deposition (in kBq/m2). For internal exposures, the most important factors are the soil type and the level of 137Cs soil deposition. On average, effective doses to the inhabitants of rural settlements are higher than those to urban dwellers.

(18)The average total annual doses to the inhabitants of settlements located in the Chernobyl accident areas, caused by environmental 137Cs and 90Sr, range from 0.1 to about 5 mSv. In many tens of settlements the average annual exposure level still exceeds the national action level of 1 mSv.

(19)Dosimetric models have been developed and tested to estimate past, present and future radiation exposures from all Chernobyl related pathways. The models predict that, by 2001, people in affected areas had already received at least 75% of their lifetime internal dose due to 137Cs, 134Cs, 90Sr and 89Sr in Chernobyl fallout. Dose rates will decrease slowly with time over the next 50 years as deposited 137Cs (half-life 30 years) decays and is made less available by soil redistribution processes.

(20)For critical groups in Chernobyl contaminated areas, wild foods (e.g. forest mushrooms, game, forest berries and fish) can make an important contribution to dose; for example, in one study in the Bryansk region of the Russian Federation, ‘natural’ foods contributed from 50% to 80% of 137Cs intake. The average annual internal dose due to 137Cs was estimated to be 1.2 mSv for men and 0.7 mSv for women.

(21)In most cases, aquatic pathways (drinking water, fish consumption and irrigation) make only a small contribution to the total dose from Chernobyl sources. At times of flooding of the Pripyat floodplain, dose rates increase somewhat due to washout of 90Sr. Furthermore, in some closed lakes the concentration of 137Cs remains high, and high levels of contamination are found in fish species. People who illegally catch and eat contaminated fish may receive internal doses in excess of 1 mSv/a from this source.

(22)Routine releases of radionuclides from operating nuclear reactors in the Dnieper River basin do not contribute significantly to

radiation exposure of communities living in their vicinity.

(23)More data are required in order to make reliable estimates of exposures of people living in uranium affected areas. Estimates of exposure from the drinking water pathway suggest low dose rates, except in small areas that are unlikely sources of drinking water.

(24)Further work is needed to assess the potential short term and long term doses that might be received if uranium tailings impoundments adjacent to waterways in Ukraine were to fail and release tailings and/or contaminated water into adjacent rivers.

1.10.6. General

(25)Monitoring data are collected by various agencies for different purposes; different methodologies are used, some of which are outdated. There needs to be harmonization of results between the various organizations engaged in monitoring.

1.11. RECOMMENDATIONS

1.11.1. Chernobyl affected areas

Within the CEZ:

(1)The engineering works on the right bank of the Pripyat River within the CEZ should be completed. The works were started in 1998 but were suspended due to lack of funding.

(2)A diversionary canal should be constructed along the Belarus–Ukraine border between the settlements of Krasne and Zimovische to prevent inundation of the heavily contaminated areas on the Pripyat River’s left bank.

(3)After 2007 the heavily contaminated Chernobyl cooling pond should be safely decommissioned.

(4)Appropriate measures need to be taken to monitor and prevent releases of radioactivity from the Chernobyl shelter.

(5)Technical measures should be taken to prevent significant radionuclide dispersion from the sites of temporary radioactive waste storage in the floodplain of the Pripyat River.

(6)The monitoring system for surface and underground waters in the CEZ should be improved and optimized.

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Within inhabited areas:

(7)In order to reduce population exposure in the most contaminated areas, the following measures should be considered:

(i)Restrict consumption of local foods (wild game, fish, berries, mushrooms, etc.);

(ii)Restrict grazing and use of vegetation on floodplains;

(iii)Provide safe water to rural communities.

(8)The monitoring system for surface and underground waters should be optimized. In particular, screening studies on closed lakes in the most contaminated areas should be performed and their impact on population exposure assessed.

(9)The radiological criteria in the Chernobyl affected countries should be harmonized.

1.11.2. Nuclear power plants

(10)Rules and regulations should be harmonized within the Dnieper River basin and made consistent with international best practice.

(11)Cooperation and information exchange between regulatory organizations should be strengthened to make use of experience gained in implementing safety upgrade programmes.

(12)To improve preparedness for a possible nuclear accident, technical measures (early warning systems, decision support systems), institutional measures (logistics) and links between nuclear power plant and regional administrative units should be improved.

(13)The scope of safety analysis reports should be compliant with national requirements and consistent with the IAEA safety standards and current international practice.

(14)Comprehensive plant specific probabilistic safety assessments need to be finalized for all nuclear power plants in the region and subjected to thorough regulatory review. The countries with nuclear power plants would benefit from participation in activities organized by the IAEA on comparison of probabilistic safety assessment studies for similar reactors.

(15)Plans established for safety improvements should be carried out as a matter of urgency.

1.11.3. Uranium mining and processing

(16)An ongoing system for radioecological monitoring of the environment (water, soil, vegetation, air and food products) in the affected regions (Zhovti Vody, mining areas and Dniprodzerzhinsk) needs to be established. This should involve provision of appropriate equipment and coordination of the efforts of the external monitoring organizations.

(17)The pollution resulting from past and present operations in the Dniprodzerzhinsk industrial complex needs to be considered holistically in order to understand its respective contribution to pollution of the Dnieper River basin and the effects of interactions between the major waste storage areas. Essentially, there needs to be an overall plan for the site, which will include rehabilitation of sites along with possible further industrial development.

(18)Rehabilitation of non-operational uranium tailings impoundments at Zhovti Vody and Dniprodzerzhinsk needs to be completed in order to ensure that they provide long term containment. In any rehabilitation plan, particular attention should be given to tailings D and to the Konoplyanka River, which is acting as a conduit for the transfer of pollutants from the tailings impoundment into the Dnieper River.

(19)Current and future operations need to be carried out in accordance with an environmental plan that includes funding provisions to ensure progressive rehabilitation of closed mines, dumps and other facilities.

1.11.4. General

(20)Existing laws, regulations and guidelines should be reviewed and revised:

(i)To ensure that radiation safety provisions are consistent within the region and compliant with the latest international standards;

(ii)To apply risk assessment methodologies to account for radioactive, chemical and biological contamination.

(21)More detailed impact analysis of actual and potential hot spots should be undertaken within the framework of a specialized project.

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(22)Monitoring of the environmental radioactive contamination in the Dnieper River basin should be improved and harmonized among Belarus, the Russian Federation and Ukraine.

(23)Scientific research that contributes to the assessment, understanding and solution of radiological problems in the Dnieper River basin should be supported.

REFERENCES TO SECTION 1

[1.1] UNITED NATIONS, Sources and Effects of Ionizing Radiation (Report to the General Assembly), Annex J: Exposures and Effects of the Chernobyl Accident, United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), UN, New York (2000).

[1.2] INTERNATIONAL ATOMIC ENERGY

AGENCY, The Principles of Radioactive Waste

Management, Safety Series No. 111-F, IAEA,

Vienna (1995).

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