Select Committee on Science and Technology Minutes of Evidence



Examination of witnesses (Questions 60 - 79)

WEDNESDAY 9 JUNE 1999

PROFESSOR ROGER CLARKE and DR JOHN STATHER

Dr Turner

  60. To continue on the question of levels and variations. If my memory serves me right, you have, as far as ionising radiation is concerned, lowered your own guidelines of minimum doses over the years.
  (Professor Clarke) Yes, indeed.

  61. In fact, it is more or less accepted that you cannot with confidence say that there is any such thing as a minimum safe level of ionising radiation. In the light of that do you think you are being a little cavalier in the answer to the last question about differences in the levels?
  (Professor Clarke) I would like you to believe we were not being cavalier in this. There is a difference in that with ionising radiation there is a well-established dose response relationship for the induction of cancer. Any single ionisation event has an associated probability of causing a cancer. So you are into a risk management situation and we are dealing with acceptable levels of risk which may change from time to time and estimates of the risk of the exposure from the ionising radiation. With the non-ionising radiation we are not in that biological situation at all. It is this cliff I mentioned to you that at the low levels there is no damage to DNA, as far as we are aware and there are no carcinogenic effects that we are aware of, so we are in a situation of keeping below a threshold rather than managing a level of risk which is inevitable.

  62. But there have been published assertions that such damage can occur whether they are correct or not.
  (Professor Clarke) And we keep those reviews under surveillance. The Non-Ionising Radiation Advisory Group under Sir Richard Doll has looked at all the epidemiological reports published and concluded that there is no evidence from that to suggest a carcinogenic risk from these non-ionising radiations. In fact, I believe today in the journal Radiation Research a comprehensive review of the possible carcinogenic effects of mobile telephone transmissions has been published and that review has concluded that all of epidemiological studies so far do not give any credence to there being a carcinogenic effect. I can give you the reference.

  Dr Jones: What about in vitro studies though?

  Chairman: We will ask our Clerk to pick up that article and circulate it to the Committee. Back to Mr Beard who was doing the main questioning.

Mr Beard

  63. On a similar theme, why are only the thermal effects of radiation considered worth regulating for? What can be said about the non-thermal effects of microwaves?
  (Dr Stather) Really it is the thermal effects where there is an established health concern that we feel we need to protect people against so that provides the basis for setting standards. We do it nationally but the international organisations that have looked at the issue have the same approach. We are doing the same thing as every other organisation would do. The athermal effects do not provide any basis for setting standards.

  64. The scientific foundation for that is what?
  (Dr Stather) It is based on heating effects, the demonstrated effect of heating of tissue when the temperature rises above a degree or two when you can see effects on tissue function so you want to ensure that any heating is well beneath that level at which heating effects may occur and that is the basis for setting standards.

  65. What can be said about the non-thermal effects of microwave radiation on tissue?
  (Dr Stather) There is not the same body of evidence for giving any credence for using that information as a basis for setting standards.

  66. I am not asking you to set standards. I am saying what can be said about it? Is the evidence not strong?
  (Dr Stather) There is no strong evidence for an effect on cancer induction.

  67. It is not just cancer, it is also brain function.
  (Dr Stather) Or effects on brain function that would cause a health effect.

  68. No evidence whatsoever?
  (Dr Stather) No evidence that we believe is sufficient to give us any cause for concern in terms of a health effect as a result of effects on the brain function.

  69. What is your assessment of the report by Lai and Singh of DNA fragmentation effects caused by mobile phone exposure?
  (Dr Stather) They have used an assay of potential damage to DNA and that is one thing they have looked at but the studies that they have done have not been reproduced by other groups who have also used the same model system. I think one important aspect of any studies in this area, whether it is an experiment or epidemiology, is that there needs to be a body of evidence that demonstrates there is a clear effect.

  70. You are saying their work is flawed?
  (Dr Stather) We feel the work needs to be reproduced by other organisations before you could use that in any way for setting standards.

  71. Has that been attempted and failed?
  (Dr Stather) Yes, people have attempted it and have failed to do it.

  Dr Gibson: They were not in fact a similar type of experiment, there were clear differences between them—

Dr Jones

  72. There were other experiments that showed an adverse effect or a more serious effect of known carcinogens and also effects on other cellular functions equally, and they have been replicated. Does it not concern you that there have been peer-reviewed reports published which do indicate other damage to cells from this type of radiation?
  (Dr Stather) It certainly concerns us that there have been a few studies (unreplicated) that suggest there may be other effects which is why, if you go back to 1996, we were very much involved in looking at what the European Community should be funding in terms of research in a comprehensive way to look at the possible effects of cell phone radiation on the body.

Mr Beard

  73. Are you as a board funding research?
  (Professor Clarke) We are. Thank you very much for prompting me to give that reply. I was just about to say that we are undertaking studies in vitro and in vivo as well as working with epidemiological groups so that we can continue to bring the totality of the evidence to people like our advisory group. In fact, Chairman, I might just leave with you the latest document from my board which is a statement from the board on the advice of the International Non-Ionising Radiation Protection Committee's guidelines and the board has concluded on the lack of overall evidence of effects, other than heating, in setting guidelines for restrictions on exposure.

Chairman

  74. Since you have brought up the subject of the Advisory Group on Non-ionising Radiation, which you tell us in your submission was formed in 1990 to support the board and its staff on advice on health-related matters, can you tell us who is on that board? You have mentioned that Sir Richard Doll is the Chairman. Who else is on the board and how are they selected, appointed?
  (Professor Clarke) The membership of the group has changed from time to time because the topics which I have asked them to look at for us have changed. Initially the concern was very much about power lines and low frequency electro-magnetic fields. It then moved on to ultraviolet radiation and giving advice on the health dangers from exposure to ultraviolet radiation.

  75. Meaning sunlight or meaning other things?
  (Professor Clarke) Meaning sunlight in particular but industrial UV use is also covered.

  76. Fly-killers and that sort of thing?
  (Professor Clarke) Yes, and sewerage sterilisation, for example. The membership I can leave with you but currently it consists, under the chairmanship of Sir Richard Doll, of Professor Colin Blakemore from the University of Oxford, Professor Ted Grant from Imperial College and Microwave Consultants, London, Professor David Harnden from Manchester, Professor Malcolm Harrington from the Institute of Occupational Health, Birmingham, Professor Meade from St Bartholomew's and the Royal London Medical School, and Professor Tony Swerdlow from the London School of Hygiene and Tropical Medicine. They currently have sub-groups on ultraviolet radiation, which I mentioned, chaired by Professor Swerdlow, on the effects of radiation on the eye, which is important with infrared from furnaces, for example, and things like that, which is chaired by Professor Marshall from London, and on radio frequencies and mobile phone work, which is chaired by Professor David Harnden from Manchester. These eminent experts are appointed by myself on the advice of Sir Richard Doll and other members of the group who feel that these individuals will have expertise which will help to address the particular issue of concern.

Mr Beard

  77. One follow-up from the previous line of questioning: you are doing this work on the non-thermal effects of radiation. When do you believe you will be in a position to say there are not any?
  (Professor Clarke) As a scientist I will probably never be able to say that.

  78. To arrive at a conclusion from this work?
  (Professor Clarke) The results of the first experiments have not shown anything.
  (Dr Stather) These are behavioural studies.
  (Professor Clarke) Behavioural studies, brain function. We hope to be participating in the Fifth Framework Programme of the European Commission. There is to be a Europe-wide co-ordinated programme of research into this end-point. This will be a four-year programme of research.

  79. Beginning this year?
  (Professor Clarke) Yes, although it is late starting.
  (Dr Stather) And one of the specific things we will be looking at in this programme, and have put in the proposals, is the damage to DNA in cells, which is the end-point that Professor Lai was interested in, and you may be interested to know that he is to come to see us at NRPB because he is in this country, and we have a good opportunity to discuss these matters with him.


 
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