General comments I appreciate that the RAP approach involves generalisations and extrapolations, that it is meant to be a flexible approach that can be modified to other organisms, and that ‘ICRP considers the CR approach to provide a good starting point from which to further develop its framework’ (line 680). I also appreciate that a generalised approach is necessary given the need for some kind of framework for environmental protection despite the enormous number of possible radionuclide-organism combinations. However, even a generalised approach must be based on a reasonable amount of hard data, and I question whether this is the case here. The sheer amount of derived data in the tables presented is a serious problem. For example in Table 4.1 – only 18 values out of 160 are real data! All the rest are derived! This seriously undermines the credibility of the approach and the report, especially in combination with section 4 that outlines in quite some detail why the CR approach does not work very well in many cases! It is repeated several times that one aim of this report is to provide reference data (line 149), points of reference (line 136), reference values (line 445) etc. However, if these values are based to such a large extent on derivations and extrapolations, I do not think they will be of much use, and will be open to serious criticism. However, I am convinced that there is a lot more published data available on CRs for these selected RAPs that could be (and should be) extracted and incorporated into this report before it is published. Instead of making more measurements as suggested in § 116, I think a concerted effort to scour the literature would reveal a lot of useful data. I did a Google search for ‘Cancer pagurus element’ and easily found many peer-reviewed papers that looked useful. Apart from a more thorough data collection to provide a more solid base for this report, I also suggest that the authors make it even clearer at the start that this is a first attempt and a starting point for the development of this proposed framework, and give much more thought to ‘the way forward’ (section 4.7). It is confusing that at the same time that this report is being prepared the IAEA are preparing their handbook of transfer factors for wildlife that contains much more data than this ICRP report. The distinction between the two should be made clearer. In addition, it is worrying that there are also inconsistencies in CR values between the two reports as Hildegarde Vandenhove pointed out in her recent comments. There are quite a few small spelling mistakes/typos that need to be fixed, and some references not in the reference list (e.g., Fisher et al (line 282), Yankovich et al 2007 (line 1002), Pröhl, 2009 (line 1180)) (these are just the ones I noticed). In several cases, paragraphs start with a general statement that then develops into a specific case (often terrestrial!) (e.g., § 18) Make clear in the first sentence if the paragraph is a general point, or if it is specific to a particular ecosystem, otherwise it is confusing. Detailed comments Fig 1.1. What exactly is the ‘sink’? The pathway of sorption from water to animals is not included. What is the box ‘detritus food chains’? Is this only bacteria? If not perhaps oversimplistic. Should be a link from detritus/food chain back to plants (release of nutrients, trace elements etc) Separating soil & sediment from detritus confusing? Herbivores and carnivores should perhaps be renamed primary and secondary consumers instead – then you could have an link from the detritus and associated food chain into the chain on the left of the diagram. § 8 Water speed, salinity, pH, oxygen levels, alkalinity etc are also important in bullets 1 and 4. First bullet. Write ‘particulate matter’ or ‘particles’ not just ‘partculate’. § 10 bioturbation can also important for resuspension of particles § 11 first sentence applies also to marine systems, not just freshwater lakes. § 12 line 229. Make clearer as follows: ‘sedimentation of uncontaminated material will also lead to the long term removal, via burial, of radionuclides…’ § 12 line 230-232. The same applies to aquatic ecosystems. § 17. Repetition in first and last sentences. § 19 line 263. Rephrase: ‘The transfer of radionuclides from TERRESTRIAL plants…’ § 19 line 267-8. ‘the body of the plant’ – strange terminology. § 19 what about the role of fungi? § 23 line 309. Soil pore water – also applies to sediment pore water. § 23 line 313. Should read ‘upwards vertical relocation’ § 26 unclear what is meant by compartments and inter-compartmental § 27 (i) this paragraph is confusing. I assume it refers only to inhalation of particles/gaseous radionuclides from air? Why single out aquatic birds? Terrestrial birds also inhale air… § 27 (iii) also applies to ingestion of sediment/detritus § 27 (iv) does this refer only to the dissolved phase or also particulate? Make clearer. Line 343. (iii) should read (iv) Lines 358-363. Exposure pathways i and v are mentioned but doesn’t this apply to iii and iv as well? § 39 first sentence. I disagree that the CR approach ‘combines’ various transfer pathways – rather it does not specifically take into account these pathways. As such, concentrations in organisms to some degree reflect these pathways but the concentrations are standardised to soil/water/air which may not be the most relevant source of radionuclides to the organism. § 40 delete last sentence (repeats an earlier one) § 46 second bullet. Insert ‘for the same radionuclide’ (I assume this is what is meant) Lines 679-681: ‘At the moment the ICRP considers the CR approach to provide a good starting point from which to further develop its framework.’ Such sentences should be included at an earlier stage (e.g. in § 6) § 53 delete last 5 words ‘for Reference Animals and Plants’ (repetition) Line 725. rephrase ‘Reference Animals that are vertebrates’ as ‘longer-lived organisms’ and include trees in the list. Line 878. replace ‘may be found’ with ‘is usually found’ Table 3.1 There are also marine ducks in the family Anatidae (e.g. eider ducks Somateria mollissima) Adult trout ecosystem may be freshwater and marine Frog ‘mass of spawn’ is an awkward phrase. Why not frog spawn? (Applies to various places in the text as well) § 62 first sentence. Rephrase as ‘..between the wildlife groups in the database (see § 60) and the….’ Table 3.2 Where do estuarine species/groups fit in this table (and in subsequent text) Line 9.1.1 Summaried should be summarised. § 65 It should be mentioned that not all data is radionuclide data – some stable element data is also used. Thus activity concentrations are sometimes concentrations instead. Line 948. ‘standard deviation of standard error’ – ‘of ‘should be ‘or’ Line 951. Remove the word ‘either’ Lines 954-6. Confusing sentence. I assume you mean that in cases where there was already a lot of existing data? Maybe write ‘many OTHER reported values’? § 68 and 70. Both combined weighted mean and arithmetic mean are mentioned. I assume these are the same? Be consistent. Lines 979 and 983. m should be M. Line 995. Suggested alternative for rephrasing: ‘…species included in the ICRP list of…’ § 74. Do we need the term ‘broad groups’ (see also Table 3.2). There are a lot of different groups – it gets a bit confusing. § 77 I don’t understand this – how is this different to what was described in § 68-70? What is the difference between these ‘baseline values’ and the values obtained in those paragraphs? Section 4. Be consistent with the use of ‘surrogate’ and ‘derived’ values. Why are no CRs for organisms in air presented? This is a very relevant pathway for terrestrial animals and plants. § 79. Compare with § 6 – there both external and internal exposures are mentioned. Line 1098. These factors are also environment-specific. § 80. What is the point/focus of this paragraph? What about the air pathway for terrestrial organisms? What about plants? Line 1055: ‘these conditions’ – do you mean the lifetime of the organism? § 81 Rephrase: ‘For some animals, many elements (and thus their radioisotopes)…’ Line 1115 – you mean constant over time?. Table 4.1 heading. ‘per Bq kg-1’ – specify that this is per kg dry weight soil (applies to ALL references to soil). Add at the end of the heading ‘(derived) according to the coding given in brackets (applies to Tables 4.2-4.4 as well) § 85. What is the point that is being made here? As it stands it sounds like you are saying that it may be more or less impossible to get reliable derived values. § 87. I am not an earthworm expert but I imagine that they are to some degree selective feeders? As such they will specifically select organic particles (and thus radionuclides associated to the organic fraction will have higher uptake rates). § 88 Why only present CR values for bee/soil? Bee/air is surely more relevant? Bees also have a relatively large home range and thus a complex exposure. Last sentence - this is exactly why the CR approach is not so good for pathways where trophic transfer is important. § 92 the question is posed ‘is this reasonable?’ The answer is no from a purely scientific point of view, but it is perhaps no worse than many other derivations that have been made for other organisms/radionuclides! Table 4.3 Heading - specify that values are per kg water. (Applies to Table 4.4 as well, and to ALL references to CRs based on water). What about marine exposures in the case of trout? In the derivations explanation at the bottom, codes are present that are not used in the table (h, j) § 97 The authors question that there are only data for 3 elements for crabs. A quick Google search for ‘Cancer pagurus element’ will quickly provide the authors with numerous peer-reviewed references giving various element concentrations in this species. I would guess that the same goes for many other of the ‘missing values’ in this dataset. § 98 Adsorbed should read Absorbed. § 99 Why such a focus on the shell? There are other important pathways such as uptake via food or gills that are hardly mentioned. The shell discussion maybe fits better in section 4.6? § 100 Flatfish are also exposed to external doses from the sediment on which (or in which) they spend much of their time. Ingestion of sediment will likely also be a factor in uptake. § 104 and 106. I would imagine that a new egg will have a similar elemental composition to the adult frog/fish that it came from, but that the longer it remains in the water (ie the older it becomes) the more it will be influenced by the element/radionuclide concentrations in the water? § 105. Co-60 is not synthesised by primary producers! Do you mean used by primary producers? This sentence needs a reference as well. § 107. Why was the bee chosen as a RAP?! It has such an incredibly complex life history! § 108. One of the larval stages is the zoea, the other is the megalopa. It is irrelevant for this document that they are transparent – delete this. I would also not describe them as having a ‘rounded body’ – they are extremely irregular and spiky in form. § 109. Doesn’t the research group at UMB Norway (Deboroh Oughton et al) have data on this? Line 1408. Suggest rephrasing as ‘…within the tissues of reference plants and animals’ (Plants don’t have organs or body parts) Line 1416-7. Change ‘accumulating organs’ to ‘accumulating organs or body parts’ (to include e.g. bone). § 110 Many algae also have actively growing areas and older more permanent parts, as well as reproductive structures and gametes, that may be of importance in a similar way as described for plants. Line 1455. Rephrase as: ‘…transfer of some radionuclides for some References Animals and Plants…’ Line 1456-7. What is meant by ‘usually been described’? Line 1459. Rephrase as: ‘…many data gaps associated with several elements and organisms’. § 110 What is this paragraph saying? § 116. I think efforts should first be put into collating data that already exists (see my general comments) Lines 1497-99. Plants are mentioned, but all tissues of interest are animal – include e.g. seeds etc.