Day 038 - 19 Oct 94 - Page 12

     
     1        conclusion that, in practice, actions do not conform with
     2        what nominally is supposed to be their approach.
     3
     4        They claim that time and again they give the benefit of the
     5        doubt to consumers.  But, my reading of the literature, if
     6        that were the case, their policy recommendations would be
     7        radically different from those that they advance.
     8        Therefore, I do not find the claim they give of the benefit
     9        of the doubt to consumers at all compelling or convincing.
    10
    11   Q.   Professor Walker argued that your analysis was
    12        unscientific, because you do not appreciate the
    13        significance of the dose at which adverse effects occur.
    14        Is there any comment you would like to make in terms of
    15        that?
    16        A.  Yes, I am prepared to comment on that.  Well, put most
    17        baldly, I think it is simply false to suggest, the
    18        statement suggests that I do not recognise the importance
    19        of dose; I certainly do.  I think dose is important and
    20        I checked the frequency which with the word "dose" appeared
         in the computerised text of my statement.  I found it was
    22        present on 34 occasions.
    23
    24        So, I certainly think dose is important, but I do not
    25        accept the way in which Walker and his colleagues on the
    26        regulatory committees use it.  I think it is important to
    27        appreciate why the particular types of doses that are used
    28        in tests are indeed adopted.
    29
    30        The position, as I understand it, goes something like
    31        this:  Take the UK, where we have a population of, perhaps,
    32        55 million people; the European Union, where we have,
    33        perhaps, 350 million people; we are endeavouring to protect
    34        the public health of these very large groups.  Tests are
    35        being conducted on laboratory animals in an attempt to
    36        identify the effects that the compounds might have on
    37        humans.
    38
    39        Now, the average life expectancy of an adult human may be
    40        more than 70 years, whereas a mouse on average lives 18
         months in a laboratory, a rat perhaps for two and a half
    42        years.  So, firstly, we are dealing with small groups of
    43        animals that are supposed to serve as a model for very
    44        large populations, and animals with a relatively short
    45        life-span for humans with a relatively long life-span.
    46
    47        Now, the toxicology profession have chosen (for reasons
    48        I do not find particularly convincing) to scale up the dose
    49        in the tests supposedly to compensate for the relatively
    50        small size of the laboratory animals and the relatively 
    51        short life of laboratory animals.  I have yet to see any 
    52        evidence, convincing or otherwise, that scaling up the dose 
    53        does compensate for or appropriately model -- rodents or
    54        laboratory animals appropriately to model the effects on
    55        humans.  But the relatively high doses that are sometimes
    56        used in chemical toxicological tests are used for those
    57        reasons.
    58
    59        The official committees will then sometimes perhaps, by my
    60        likes all too often, disregard the effects that occur in