|Comments on the updated Draft Recommendations of the ICRP
(02/276/06 – 5 June 2006)
1. The distinction between three types of exposure situations (planned situations, emergency situations and existing exposure situations) is presented very clearly in the updated draft and it provides a solid framework to replace the "practices and interventions".
2. Justification is treated in the updated draft much more adequately than in the first draft. Further improvement could be achieved by removing some redundancy: some sentences appearing in paragraph 5.7.2 (Justification for medical exposure of patients) are repeated in Section 6.1 (Justification of radiological procedures).
3. The topics of optimisation of protection and constraints are adequately treated. Consistency could be improved if more coordination could be achieved between Section 5.8 (Optimization of protection) and the paragraphs dealing with optimization in the following Chapters (6, 8 and 9).
4. It seems that there are some inconsistencies in the structure of Chapter 6 (Medical exposure of patients):
• Subsections 6.4.1 (Volunteers for research) and 6.4.2 (Medico-legal exposures) are treated under Section 6.4 (The optimization of protection for patient comforters and carers), although those subjects do not seem to belong to the topic of Section 6.4. They should be treated separately or it should be explained why they are connected to Section 6.4.
• Section 6.5 (Release of patients after therapy with unsealed radionuclides) could be treated as a subsection of Section 6.4, since the subject is presented in (265)-(266) as belonging to it.
• Section 6.4 should precede Section 6.3 (Exposure of pregnant patients), since both Section 6.2 and Section 6.4 deal with optimization.
5. Adoption of the exclusion levels of 1,000 Bq/kg (heads of U and Th series) and 10,000 Bq/kg (40K) mentioned in (294) for unmodified concentrations of naturally occurring radionuclides in commodities has a potential to disturb international trade in phosphate rock and potash, which are used as fertilizers or as raw materials in the fertilizer industry. (Since phosphate rock and potash are produced in some countries, but are consumed universally, a considerable amount of these commodities is involved in international trade.)
In those commodities produced in Israel, for instance, the activity concentration of 40K in potash is 16,000 Bq kg-1 and the activity concentration of 238U in phosphate rock is 1,700 Bq kg-1, respectively. In the case of potash, the same activity concentration of 40K applies to all producers of high-grade material (as KCl). With regard to phosphate rock an activity concentration of 1,000 Bq kg-1 would discriminate against the material produced in part of the producing countries. According to a survey conducted by the IAEA, reported values range from 15 to 5,000 Bq kg-1 (Extent of environmental contamination by naturally occurring radioactive material (NORM) and technological options for mitigation. Technical Reports Series No. 419. International Atomic Energy Agency, Vienna, December 2003).
It also came to my attention that the reader is referred in (47) to the foundation document "The Scope of Radiological Protection" for detailed guidance on exclusion and exemption.
Although the consultation period for this document is over, the above-mentioned comment may also be appropriate for it, due to the fact that it is a foundation document supporting the Recommendations.
In (124) of the Scope document it is mentioned: "non-edible naturally occurring radioactive materials may be generically exempted when the activities are as high as 1000 Bq kg-1 for any of the radionuclides of the primordial chains and 10000 Bq kg-1 for potassium-40", whereas it is mentioned in (138): "The conditions for such generic exemption would be that the activity concentrations of the radionuclides in the primordial uranium and thorium series should be lower than around 1000 Bq kg-1 and of potassium-40 lower than around 10000 Bq kg-1."
In order to tackle the problem of potash and phosphate rock, it could be stated (in the Recommendations as well as in the Scope document) that the mentioned values indicate orders of magnitude and a deviation from the values by a factor of 2-3 is considered as acceptable (reflecting the wording "around" in (138) of the Scope document). It could also be stated, as in the IAEA Safety Guide No. RS-G-1.7, that exemption can be granted even when the activity concentrations exceed the values "by several times (e.g. up to ten times)" (Application of the concepts of exclusion, exemption and clearance. Safety Guide No. RS-G-1.7. International Atomic Energy Agency, Vienna, July 2004).
6. References in the text to other Sections should be checked, since they are not always correct (see for instance reference to Section 10 in (225), to Section 11 in (240) or to Section 2.2 in (280)).
(55) last line: For the sake of consistency, "absorbed" should be omitted, since 100 mSv is mentioned in line 4.
(57) line 3: "unambiguously" instead of "ambiguously".
(58) last sentence: the end of the sentence should be changed to: "… will remain, not only until the demonstration of their relevance to cancer development in vivo, but also until knowledge of the dose-dependence of the cellular processes involved is gained".
(59) line 14: "firmer" instead of "more firm".
(63) line 3: "cancers" instead of "cancer".
Last sentence: the end of the sentence should be changed to: "cancers and not for leukaemia, for which a linear-quadratic response is seen, i.e. a lower risk per unit dose at low doses than at high doses".
(64) line 8: "overall cancer" instead of "cancer overall".
(65) line 7: "survivors" should be added after "A-bomb".
(71) first sentence: "detriment adjusted nominal risk coefficients for cancer of" instead of "nominal risk coefficients for detriment adjusted cancer risk as".
Table 2: first column: "Whole population" instead of "Whole" and "Adult workers" instead of "Adult".
Sixth column: "5.7" instead of "6" and "4.2" instead of "4".
(76) last line: "of low LET radiation" instead of "low LET".
(79) line 1: "survivors" should be added after "A-bomb".
(88) lines 9-10: the varying sensitivity of organs and tissues is mentioned twice in the sentence. "variations in the response of organs and tissues of the body to radiations" should be replaced by "the biological effectiveness of different radiations".
(93) line 2: the content of the parentheses could be omitted, since it was already mentioned in (88).
(94) The first sentence is a repetition of the last sentence of (88).
Fig.1: In order to make a distinction between the first two lines of the legend, "(step function)" and "(continuous function)" should be added to the first line and the second line, respectively.
(105) last line: "charged pions" instead of "neutrons".
(110) It seems that the words "due to" should be omitted from the second sentence.
(120) line 5: "Table 4" instead of "Table 4.2".
(122) lines 6-7: It looks as if "these dose quantities …respectively" refer to HP(10) and HP(0.07), but these are mentioned for the first time in (125).
(133) first two lines after formula (4.11): "by inhalation" should be moved after "radionuclide j".
(136) In the second sentence: "as well as from the use of different technologies for the same medical examination" should be moved after "therapeutic procedures".
(137) In the second sentence: "considering the low tissue weighting factor for skin" instead of "with low tissue weighting factors for skin".
(145) line 8: "person sievert" is preferable to "man sievert".
(157) line 9: "categories" instead of "types" (types is used in Section 5.2 to characterize exposure situations).
Lines 12 and 13: "categories" instead of "groups".
Section 5.3. Since public exposure is defined as exposure other than occupational and medical (167), one would expect the subsection on medical exposure to precede the subsection on public exposure. This order would also fit the order in Section 5.4.
(165) First sentence: In the definition of occupational exposure, "with the exception of excluded exposures and exposures from exempt practices or exempt sources" could be omitted. If the exposure of a worker is monitored, the dosimeter will not distinguish between exposure from excluded/exempt practices/sources and non-excluded/non-exempt ones.
Fig.2 "normal situations" should be changed to "planned situations".
(184) "within a class of exposure" should be changed to "within a category of exposure".
(185)-(186) Although it is mentioned in (185) that "the Commission … has now formulated a set of principles that apply equally to planned, emergency and existing controllable situations", it is said in (186) that the third principle does not apply to emergency situations and to existing situations.
(190) It would be useful to mention the other considerations, apart from radiological protection, that are important in judging the justification.
(191) It would be useful to mention (as in the BEIR VII report) that some radiation-intensive procedures, such as screening exams by whole-body CT scans, are not necessarily justified.
(193) The sentence "where these are not certain to be received" (lines 3-4) is not clear and can be omitted.
(198) The last sentence is somewhat ambiguous ("to protect … from all identified controllable sources"), since it was stated in Figure 2 that dose constraints are intended to protect the individual from single sources, whereas dose limits are used to protect from all sources.
(202) lines 2-3: "risk of cancer or hereditary effects in exposed organs or tissues" should be replaced by "risk of cancer in exposed organs or tissues or of hereditary effects".
(205) It should be made clearer that the last sentence, which deals with emergency situations, does not relate to the circumstances described in the first sentence that apply to planned situations.
(207) line 3: "to restrict or avoid" should be replaced by "to restrict".
Lines 4-5: "…from all sources": same ambiguity as described for (198).
(213) first bullet, line 6: "lesser" instead of "other".
(215) last line: "Sections 6.4 and 6.5" instead of "Section 6.4".
(219) The first sentence is too long. Its ending ("in order to reduce … below the constraint") could be omitted.
The end of the last sentence should be changed to: "… this constraint, which typically should not exceed around 20 mSv per year and should in no case exceed 100 mSv per year".
(231) The first sentence implies only part of the second sentence ("more weight could be given to doses given in the near future"), but it does not imply that "more weight could be given to moderate and high doses".
(232) line 6: "operational" should be replaced by "operating".
(255) line 1: "levels" has been omitted after "diagnostic reference".
(266) The two first sentences are a repetition of the two sentences in (265).
(269) Medico-legal exposures (required by insurance companies) do not seem to be justified, especially not at levels of a few mSv per episode.
(285) line 4: "mSv" instead of "mGy".
(286) line 5: It seems that the word "variable" is missing after "are more".
(287) line 5: "for" is to be added before "others".
(294) line 8: "at" is to be added after "set".
(310) It seems that waste disposal should be mentioned in the third sentence, since the last sentence deals with the disposal system. For instance, "as in the case of radioactive waste disposal" could be added after "in the future,".
(328) line 2: "their exposures" should be added after "standards and".
(329) line 2: "iodide" instead of ""iodine".
(330) line 1: "a" should be added after "seen as".
(331) lines 3-4: "neither recognised nor reported" instead of "either not recognised or reported".
(386) line 8: "affect" instead of "effect".
(395) The third sentence is a repetition of the second sentence.
(135) last line: "see" instead of "se".
(146) line 4: "doses" instead of "dose" (first occurrence).
(220) line 7: "any decision" instead of "any a decision".
(299) line 8: "month" instead of "moth".
(300) lines 12-13: "200-600" and "500-1500" instead of "600-200" and "1500-500", respectively.
(315) line 6: "some" instead of "s0ome".
(354) line 13: "experience" instead of "experienced".
(382) line 4: "emergencies" instead of "emergences".
(384) line 3: "to make" instead of "to a make".