Day 244 - 03 May 96 - Page 23
1 Q. In the second paragraph on that page 2:
2
3 "It is thus my view that any exposure to OP residues is
4 undesirable in that damage may be caused, the damage rather
5 than the toxins being cumulative."
6
7 Can you explain what you mean?
8 A. Yes. This is the difference, and it is a subtle but
9 important difference between the two main groups of
10 pesticides, the organochlorines. They build up in fat and
11 as long as they sit there in relatively stable fat they are
12 doing nothing to the body system. In fact, the body is
13 shunting them out on to a siding where they are actually
14 not doing very much, at least short-term.
15
16 OPs work differently in that they are absorbed by -- their
17 structure is such that they of a predilection to the
18 nervous system, and it is also important to note the
19 metabolites. It is not just the question that the chemical
20 itself is converted in the digestion system into a
21 secondary product, i.e. the metabolite. That has the
22 capability to do harm.
23
24 The point is that we are not dealing with a poison, say,
25 like cyanide, or a fraction doses is relatively easily
26 neutralised by the body. We are dealing with something
27 which is a molecule which at any level will do damage, will
28 actually physically damage the nervous system. Obviously
29 very small doses of the chemical will do very small amounts
30 of damage.
31
32 Now, the trouble is that the one system in the human body
33 which does not repair itself is the nervous system.
34 Therefore, continued exposure to very, very, very small
35 levels of OPs gives you very, very, very small amounts of
36 damage to the nervous system. Over the years, that damage
37 accumulates. As I have said here, it is about -- you have
38 in the human body about 30 per cent redundancy. That
39 varies individual to individual. You can find different
40 routes -- the nervous system can find different routes,
41 ways around blockages; but it comes to a point where the
42 damage builds to a level where first you start suffering a
43 wide variety of ill-health effects and then, latterly, you
44 start exhibiting detectable, recognisable signs of that
45 damage.
46
47 Thereby, you can say, that in a multi-faceted exposure,
48 where you are receiving it environmentally, from food, from
49 fairly innocuous or apparently innocuous home insecticide
50 products, that cumulative dose from those variety of
51 sources can do harm. Therefore, it is extremely desirable
52 to reduce one's exposure overall, in which context it is
53 undesirable to expose yourself to a dietary source of
54 pesticide residues.
55
56 MR. JUSTICE BELL: Do you put yourself forward as an expert so
57 far as the central nervous system is concerned?
58 A. No, I rely on other work and I can cite it and bring it
59 forward. I rely very much on the work of Dr. Jamal from
60 Edinburgh -- no, sorry Glasgow -- who has done an enormous
