Letters : . . . . .
by e-mail
The oceans are an extremely dilute solution of virtually every known chemical
compound (in addition to being obviously strong solutions of a few salts). Thus
a glass of seawater is presumably a universal homeopathic dose?
Letters : No cause for alarm
Chilton, Oxfordshire
Rob Edwards quotes comments relating to the possible role of
radiation-induced genomic instability in the development of human diseases
(“Radiation roulette”, 11 October, p 36).
In spite of the great concern expressed, it is evident that this phenomenon,
observed in a few cellular and animal experimental systems, has not been
scientifically linked with any adverse health effect in humans exposed to radiation.
The article proposes that it is “highly unlikely” that induced genomic
instability is irrelevant to the development of cancer, and gives the impression
that other health effects are manifest in a wide range of diseases which escape
the notice of epidemiologists. Concern is also expressed that the human gene
pool is being “permanently polluted” as a result of low-dose, radiation-induced
genomic instability.
Stated simply, there is no evidence for such profound and widespread health
effects after low-dose radiation exposure, and a solid body of evidence argues
against many of the proposals made (see http://www.nrpb.org.uk). Indeed,
if there were to be such effects it is difficult to envisage how human life
could have evolved under conditions of exposure to natural background radiation
received over thousands of generations.
Given their social and economic implications, internationally and nationally
agreed recommendations in the area of radiological protection need to be based
on established scientific findings rather than individual conjecture and
speculation. It is not that the phenomenon of radiation-induced genomic
instability is being ignored, it is simply that its role in radiation-induced
human disease remains obscure.
Letters : Molecule memories
Regarding your comments on claims made for homeopathy
(Editorial, 27 September, p 3
and Letters, 18 October, p 58):
criticisms centred around the
vanishingly small number of solute molecules present in a solution after it has
been repeatedly diluted are beside the point, since advocates of homeopathic
remedies attribute their effects not to molecules present in the water, but to
modifications of the water’s structure.
Simple-minded analysis may suggest that water, being a fluid, cannot have a
structure of the kind that such a picture would demand. But cases such as that
of liquid crystals, which while flowing like an ordinary fluid can maintain an
ordered structure over macroscopic distances, show the limitations of such ways
of thinking. There have not, to the best of my knowledge, been any refutations
of homeopathy that remain valid after this particular point is taken into
account.
A related topic is the phenomenon, claimed by Jacques Benveniste’s colleague
Yol猫ne Thomas and by others to be well established experimentally, known
as “memory of water”. If valid, this would be of greater significance than
homeopathy itself, and it attests to the limited vision of the modern scientific
community that, far from hastening to test such claims, the only response has
been to dismiss them out of hand.
Letters : Cough scare
Bilthoven, The Netherlands
In your article on the outbreak of whooping cough in the Netherlands, you
state that a new “mutant” strain of Bordetella pertussis is expected to
spread over Europe causing a large epidemic
(This Week, 11 October, p 5).
This is not the case. We have observed antigenic shifts in the B.
pertussis populations in the Netherlands, but also in other European
countries (some of which do not show an upsurge of disease). Whether or not
these shifts affect vaccine efficacy and play a role in the upsurge of disease
in vaccinated populations has not been established and is the subject of further
investigations.
Letters : Trash and ash
London
Fred Pearce’s article on dioxin contamination is essentially correct as far
as it goes but has missed two crucial factors
(This Week, 4 October, p 21).
The regulatory action by the Environment Agency has indeed significantly
reduced the quantity of dioxins emitted into the air from incinerators, and this
has resulted in increased quantity of dioxin-containing ash. Disposal of the ash
is strictly regulated and takes place at properly managed landfill sites. There
is no evidence that dioxins escape from these sites.
Dioxins released into the air can be deposited on crops and pasture and thus
enter the human food chain. This aerial route is the most significant source of
human exposure to dioxins. Based upon current knowledge, modifying processes to
capture dioxin-containing ash and ensuring it is disposed of to landfill
represents the best practicable environmental option. This strategy has proved
to be a very successful way to reduce exposure to dioxins.
The article notes that many recycling operations have the potential to
produce dioxins and indeed other pollutants, implying that they are not as
environmentally friendly as is generally thought. However, properly operated,
the environmental impact of recycling plants need not be significant. What is
vital is that for every material, proper environmental risk assessment is
undertaken for all the possible technical options before decisions are made as
to the merits of recycling versus new production.
Letters : Downhole dumping
Beijing, People’s Republic of China
Jonathan Cardy raises some concerns about disposing of nuclear waste in
depleted oilfields (Letters, 20 September, p 62).
I would like to answer them.
As he points out, current technology leaves a large percentage of the original
oil in place, and this may be removed by future advances in recovery methods.
This is not true for gas fields, as the mobility of the gas and its expansion as
the reservoir pressure drops allows the maximum amount to be recovered.
Again, Cardy is correct in saying that only fields that are sealed in every
direction could be used for waste storage, otherwise there is a remote
possibility that water sources will be contaminated. With gas fields, a plot of
the decline in reservoir pressure versus the amount of gas produced shows if the
field is completely sealed (this can also be done with oilfields).
Cardy is concerned about erosion exposing the reservoir. I would suggest that
if several thousand metres of rock have eroded away in such a short
(geologically speaking) time-frame, we will have far more pressing problems to
sort out.
He is also worried about the concentration of fissile material causing a
critical event. The material will have to be reduced to extremely small
particles to allow it to be pumped away. The material then can be pumped in
cement or resin, so it is held in place once pumped. In any case, a gas field is
produced through many wells, so the waste can be distributed equally between
them. I cannot conceive of a mechanism that would allow it to become
sufficiently concentrated for criticality to occur.
Cardy states that the extraction of oil disrupts the rock and may cause
subsidence. This is true, but only for certain types of reservoirs (fractured
chalk), the problems of platform subsidence at Ekofisk being the prime example.
However, even in the case of Ekofisk, where the subsidence is measured in feet,
there is no evidence that it has opened a path through several thousand metres
of rock to the surface.
Several of Britain’s southern North Sea gas fields that are nearing the end
of their lives would be prime candidates for nuclear waste disposal.
Letters : Badger bias
Dublin
The gardener’s opinion of badger conservation as given by Willie Stanton
(Letters, 13 September, p 56)
was alarming. The “threats” that the badger once
posed to the rural populace have all but vanished in these days of mechanisation
and monoculture. The wanton destruction of a wild species (badger “harvesting”)
hails back to days of persecution through sheer ignorance which brought several
species of British animals to the brink of extinction and beyond.
Up-to-date research on the prey preferences of badgers is hard to come by, as
in many parts of Britain (and Ireland) badger populations have shrunk to barely
quantifiable levels. Little may be concluded from Stanton’s garden survey, as no
indication of garden type is given, nor any details of the methods used to
detect hedgehogs.
As its traditional habitat is eaten up by green deserts, motorways and
development, it is small wonder that the hapless 20th-century badger seeks out
nourishment in gardens. Rather than condemn a native wild species to the
unsubstantiated status of pest, gardeners may more usefully examine their plots
and determine how much refuge the modern garden offers to wildlife.
Letters : Trees and eagles
Belford, Northumberland
Your article on the possible effect on two golden eagles of the plan to plant
trees on the Kintyre peninsula in Scotland appeared to me to be highly selective
with the facts (This Week, 20 September, p 5).
The Forestry Authority press release stated that the regional advisory
committee for Strathclyde “concluded in the light of the evidence that it had
not been demonstrated whether or not there would be an adverse impact on this
pair of golden eagles”. The regional advisory committee comprises 12 people: an
independent chairman, four members from a forestry background, four from a range
of environmental backgrounds, and the others from farming, local authority and
trade union interests. As I understand it, Scottish Natural Heritage and the
Royal Society for the Protection of Birds were the only objectors, while the
others on the committee, including at least one eminent ecologist, were not
impressed.
The decision now lies with Lord Sewel, forestry and environment minister for
Scotland, and I hope that whichever way that goes, there is a more balanced
report, possibly meriting some more background detail.
Letters : No plankton, please
Glasgow
I was very interested to read about three hungry sperm whales swimming into
Marseille harbour to gorge themselves on plankton
(Feedback, 11 October). I can
only think that they must have been ravenous to give up their normal diet of
mesopelagic squid (about the only thing they have ever been recorded to eat) to
feed on such small substitutes.
Can I suggest that either they were not feeding on plankton or they were not
sperm whales.
However, if the report is correct, maybe this sheds some light on the recent
theory put forward by some cetologists that sperm whales are actually more
closely related to the plankton-eating baleen whales than they are to other
fish/squid-eating toothed whales.
Letters : Ridges aren't right
DBOWIE@doc.govt.nz
It’s pretty clear that Microsoft didn’t include in the documentation about
its kite the warning (old hat to kite experts) that the product would not be
stable in a windy-ridge environment
(Feedback, 6 September).
Seriously though (in case you have the opportunity for a pleasant experience
with a kite), rising slopes and gentle breezes are OK. Ridges or hill tops
generate downdrafts and turbulence and are no fun.