Home Water Treatment and the Sceptical Consumer

HOME WATER TREATMENT SYSTEMS are often promoted on the basis of the purported health (rather than aesthetic) benefits of using them. This is particularly in relation to urban drinking water given the full treatment — coagulation, sedimentation, filtration and disinfection — where such claims usually constitute misleading advertising. In this review I will focus on a number of misconceptions about the health benefits of water treatment, examining each assertion in its wider context. The ensuing discussion applies less to rural water supplies, where valid reasons often exist for use of treatments — eg removing nitrate or protecting against giardia.

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Skeptical Books

Guidelines For Testing Psychic Claimants by Richard Wiseman and Robert L. Morris, 1995, 72pp., University of Hertfordshire Press, Hatfield, UK, (pound)7.00.

Reviewed by Bernard Howard

When author Arthur Koestler and his wife died, they left money to found a university Chair in Parapsychology. Edinburgh University accepted this gift after some hesitation, and Robert L. Morris has occupied the Chair since 1985. In a university hundreds of kilometres to the south, and some hundreds of years younger, Dr Richard Wiseman has also turned a scholarly eye on the subject. This book is a result of their collaboration.

It starts, ominously, with “The Problem of Fraud”, and continues with chapters on initial meetings with claimants, research policies, pilot studies and formal research, and reporting, with an extra chapter on “Working with tricksters”. The book concludes with two reading lists (one of specific references, the other of books, articles and journals of general interest), names and addresses of relevant organisations (including the Magic Circle and the like), and even advice, with addresses, on how to make your experiments and results “secure”.

After reading all this detailed advice and the warnings about fraud, my feeling is that, if I saw a psychic claimant approaching me in the street, I should hastily cross to the other side.

Magic Minds Miraculous Moments by Harry Edwards. 231 pp., 1994. Harry Edwards Publications, 3 Nullaburra Road, Newport, NSW 2106, Australia. NZ$17.00.

Reviewed by Bernard Howard

The author is secretary of the Australian Skeptics; his book contains brief biographies in alphabetical order of just over 100 “psychics”, an average of two pages each. As well as background information on the lives of the subjects, he details the paranormal phenomena for which they were, or are, famous. Most entries finish with a “Comment” and a few references for further reading.

Many of the subjects are well known (Geller, The Fox sisters, Nostradamus, W.A. Mozart(!) for example), but most were unknown to me (who can name 100 psychics offhand?). This collection is a tribute to the author’s erudition and his thoroughness in searching the more obscure corners of the paranormal world.

Delightful browsing, and a very useful reference book.

Greenhouse — The Biggest Rort in Christendom by Peter Toynbee, published by Peter Toynbee Associates.

Reviewed by Owen McShane

Peter Toynbee is one of the few New Zealanders who has consistently stood up against the pseudo-science currently driving so much (not all) of New Zealand’s public policy on climate change and CO2 emissions.

Needless to say he has suffered from attacks on his personal integrity while his scientific arguments, like those of visiting Professor Lindzen of MIT, have been rebutted only by reference to the supposed consensus among those civil service scientists around the world who have found that a policy of promoting “scares and frights” is the best way to unlock the strings to Government funds.

Toynbee’s argument is simple. Man remains a trivial player in the planetary game. Nature rules on all but the local scale. He deserves support, if only because of his healthy scepticism, and his book contains a host of facts and reports with which to arm yourself against the next doomcaster you meet. And unlike so many recent publications, the book has an index. I cannot understand why so many books today have no index when word processing systems have made the task easier than ever before.

Even if you do not agree with Toynbee’s arguments or conclusions, the book is disturbing because, no matter which side of the argument prevails, governments have surely rushed to make a judgement on only one of the alternatives posed by the evidence of increased atmospheric CO2.

The costs of restraining fossil fuel consumption will be massive, especially for the third world, and there appears to have been no attempt to compare these costs against presumed benefits. Current studies indicate that the costs of adaptation to warming would be much lower, and of course would only need to be incurred if the warming actually eventuates. And the jury is definitely still out.

A Skeptical Miscellany

Picking Winners?

When the short list for the Booker prize was announced there was much chortling about the fact that Jill Paton Walsh had been unable to find a publisher in Britain for Knowledge of Angels. She had to publish it herself.

The Times Literary Supplement (9 Sep, 1994) points out that the English publishing houses could not justify their decision by claiming that they had a surplus of great and worthwhile books. Heinemann has just published what the TLS described as “a work of the purest bilge”. They refer to Nostradamus: his key to the centuries, prophecies of Britain and the world 1995-2010, by V.J. Hewitt.

This adventurous work is not Valerie Hewitt’s first appearance as a seer. In her earlier publication, Nostradamus: The end of the millenium, she predicted that George Bush would be re-elected in 1992, that the Prince of Wales would be crowned King Charles III on May 2 of the same year, and that California would be destroyed by an earthquake on 8 May 1993.

In spite of this unenviable track record, Valerie Hewitt seems to have no difficulty finding gullible publishers. Poetic justice could have won the day. Maybe they asked her, as Nostradamus’ UK agent, to pick the Booker Prize List as well.

An American Dilemma

In the September 16 issue of the Times Literary Supplement, Prof Claude Rawson made a nice point during his review of The Beginning of the Journey — the marriage of Diana and Lionel Trilling, by Diana Trilling. I’m sure the TLS won’t mind us quoting at length:

“[Diana] too persevered with analysis despite a series of discouraging experiences, including a date with her first psychiatrist, from which she had to be sent home by taxi in a drunken panic … Three of her analysts died on her, an occupational hazard in transactions not otherwise willingly terminated by either party. One was a drug addict who missed appointments and fell asleep during sessions … She was next treated by by Marianne Fris, wife of Ernst, who told her that Lionel was being mishandled by his analyst … At one point the Trillings shared the same analyst and became “sibling rivals, vying for the attention of the same father figure”

This (Stalinist) doctor turned out to be unqualified and had to be retrained. The next “analyst’s wife, herself a psychiatrist” maintained a courteous professional distance. When her husband fell under a car she demanded payment of bills already paid, maintaining professional behaviour to the end. Diana had seven analysts in all and still feels that she “was never properly analysed”.

You might think she was slow on the uptake, but the persistence with which busy and intelligent persons in the US lavish their time and money on analysis in the teeth of a continuous sense of the inefficacy of the whole thing is a cultural phenomenon that awaits explanation.

If you remain unconvinced, watch the wonderfully scary video called Whispers in the Dark. It’s hard to know who is the most terrifying — the psychiatrists or their patient/victims. (Not for children)

Science and the Citizen

On Tuesday 26 September, National Radio’s Morning Report carried an interview with a scientist discussing his research programme which I hope is better founded than it sounded — seeing that we are all paying for it.

Apparently some Danes have shown that males who eat organic food are more fertile than those who eat regular (inorganic?) food. Our local scientist plans to repeat the programme here because if they confirm the Danish findings, it will prove that — and wait for it — pesticides cause male infertility.

Where does one start being decently Skeptical?

Would it not be simpler and much more direct to dose people with pesticides — without greatly increasing the doses they are presumed to be absorbing from their normal fruit and veges — and then send them out into the world to multiply?

And surely any Skeptic can think of several reasons why organic food-eaters might be more fertile than the average member of the population. Do they wear organic ill-fitting underpants?

But there are even more interesting hypotheses to test. We know that we eat about 10,000 times as many natural pesticides as we do synthetic ones (J.D. Mann, New Zealand Skeptic 32). I buy organically grown potatoes because they taste so much better (even though they cost about twice as much), which suggests that they contain a greater and more concentrated range of compounds than the regular watery variety.

Maybe it’s these “special secret ingredients” in the organic fruit and vegetables which serve to boost fertility among Danish males, rather than any tendency for nasty chemicals to diminish the fertility off their less “green” brethren.

And what might these extra compounds be? I presume that the way to raise vegetables which are resistant to the normal range of pests and diseases is to grow them so robust and healthy that their natural defenses are good enough to provide adequate protection. (Any gardener knows that healthy plants are much less prone to disease than sickly ones.) So maybe the reason these Danish organophiles are more fertile is that they are taking in far more natural pesticides than the rest of their countrymen. (And yes they are men!)

Could be it be that our crafty bodies respond to this toxicologic challenge by producing extra sperm to improve the survival chances of our selfish genes?

Who approves funding this stuff — New Zealand On Earth?

New Zealand Skeptic will watch for the outcome with pitchfork drawn and at the ready.

Numero Uno?

I was driving my car when Kim Hill spent half an hour of public broadcasting time interviewing a woman who claimed to be a Pythagorean Numerologist. The woman claimed that she had not appreciated Pythagoras at school because the teachers focused on arithmetic and all that other dry stuff. But later she learned that Pythagorus was a genuine mystic at heart and was worthy of redemption.

Our numerologist explained to a somewhat sceptical — but not falling-about-the-floor laughing — Kim Hill that Pythagorean Numerology could identify all our personality traits by translating the letters of your born name into numbers and then combining these numbers with the numbers of your birthday.

Evidently we can then all be identified as five/sevens, tens/tens or whatever. As you would expect, a five person could be careful with money, but could be able to overcome this tendency by applying the determination which is also associated with five. These people would make wonderful economists — on the one hand this … but on the other hand that …

Kim Hill did raise the difficulty that Pythagoras used the Greek alphabet, but our numerologist explained that the system had been adjusted to fit the Roman alphabet.

Now if telepathy worked at all, Kim Hill would have heard my 10,000 watt telepathic messages saying “Ask her about the birthdays.” Even Pythagoras could not predict the assumed birthdate of Jesus Christ, so its difficult to imagine him building a numerology system based on his being born on the 30 September 582 BC or whenever. And I cannot conceive of any algorithm which would translate the calenders of Pythagorean times into the Gregorian calendar dates we use now.

Once again telepathy failed me, and we never heard how our numerologist dealt with this problem. However, we learned something about Pythagoras. Evidently he ran a University in which everyone would have been vegetarians, because vegetables, unlike meat, are such spiritual food. I suppose this explains the behaviour of that other famous vegetarian, Adolf Hitler. One of Kim Hill’s questions indicated that our numerologist’s extensive research seemed not to have revealed to her Pythagoras’s famous aversion to beans.

However, my frustration with all this nonsense was eased later on in the morning’s programme when Kim Hill read out a fax from an alert Skeptic who complained bitterly about the use of public radio to disseminate such garbage over the air waves. Well done.

Don’t these programmers realize that this sort of stuff makes it doubly hard to argue in favour of preserving public radio. The more National Radio sounds like No Idea On Air the harder it is for any of us to argue its case for survival.

Scary Headlines, Dodgy Science

The New Zealand Herald of 5 September carried the headline “Ozone gap to lift skin cancer 7 per cent”.

Then followed a report from Dr Richard McKenzie of the National Institute of Water and Atmospheric Research at Lauder. He said that ozone loss in the past 15 years had caused an increase of 8-10% in the amount of harmful ultraviolet rays reaching Otago and Southland, and that UV levels were expected to rise another 2-3%, reaching a peak in about five years.

So far so good. We have no reason to question the quality of the research and his findings that ozone depletion over the southern region has increased UV penetration over the South Island plains. But Dr McKenzie is then reported as saying that:

Cancers caused by past depletion were only now beginning to appear as the disease often developed some years after exposure to the rays.

And that:

Small changes in UV can have large effects on life. There will be extra skin cancers and earlier deaths will result.

Surely Dr McKenzie has moved beyond his field of expertise. The recent increase in skin cancer is almost entirely attributable to the craze for sun-bathing and sun-tans which began in the 1920s and reached a peak during the early ’70s. Any impact of increased ultraviolet penetration is insignificant when compared to this “life-style” choice which encouraged young children to play at the beach all day, fully exposed to the sun, and teenagers to bask in full summer sun for hours on end in their quest for the perfect tan.

Furthermore, changes in the level of ultraviolet light reaching the ground are much more dependent on cloud cover, general atmospheric pollution, and geographic latitude than on any recorded or predicted variations within the ozone layer. A move from the Arctic to the equator increases annual exposure to UV by 4,000%. If Aucklanders are worried about a 10% increase in UV penetration they should move 200 km south to, say, Taupo.

I am prepared to bet $1,000 to $1 that there will be no increase in skin cancers attributable to increased UV over the next few years. The increases which occur will be attributable to the sun-burned baby-boomers growing up and contracting melanoma. This will peak and decline as a new generation of parents encourage their children to wear hats and use sun-blocks.

If Dr McKenzie can set up an experiment using a control population which stays where it is, in an atmosphere which remains as clear as it is today, and in which no-one reduces their exposure to intense sunlight or increases their use of sun protection, then that population might record the increase he forecasts. But such an experiment would be totally unethical, so the predicted outcome cannot happen. Hence my confidence in the bet.

In an interview Dr McKenzie conceded he was no expert in public health. Maybe he should have stuck to his field and let someone else draw the public-health conclusions. People have to deal with daily predictions of doom from all directions. There is no need to add a fear of UV-induced melanoma epidemics to the list. His forecast sounds unavoidable — and it’s not.

Christchurch Pesticide Scare

The media were quick to cry “Wolf” when concerns were raised about the fungicide Benlate.

On 9 December, 1993, the people of Canterbury read an alarming headline in the Christchurch Press: “Herbicide scare after babies born with defects”. Three City Council staff “who worked with herbicides gave birth to babies with defects”. In this first report neither the nature of the defects nor a specific herbicide were mentioned.

Several comments by Council officials and others, intended to soothe public fears, were quoted in the report — “coincidence”, “a link between the defects and herbicides was unlikely”, “the substances … did not absorb well through the skin”. An occupational health expert had been asked to investigate and report urgently; a fourth parks employee of the Council, who had worked in the same area as the other mothers, had given birth to a healthy baby.

During 1993 the office of the Parliamentary Commissioner for the Environment, Helen Hughes, had been investigating the use and disposal of dangerous chemicals in New Zealand, and the report arising from these enquiries was published only a few days after the story in the Press. The Commissioner was quoted as saying that the controls recommended by her office would have been even stronger had she known of the Christchurch birth defects.

Despite the encouraging noises emerging from the Civic Offices and other official buildings, public anxiety increased almost to the level of hysteria.

Within a week the substance under suspicion had been identified as benomyl (a fungicide, not a herbicide), made by Du Pont and sold under the name “Benlate”. Sales plummeted, TV cameras were taken to garden centres to picture staff sweeping the stuff from the shelves, and only eight days after the first report, Du Pont’s New Zealand Manager was buying whole pages of advertising space in the newspapers to rebut the accusations made against his company’s product.

During the week journalists interviewed some of the people involved, and a few personal and medical details emerged. Two of the three babies were blind; the mother of one, born in 1990, was “in anguish” after slowly rebuilding her life; the parents of the other were in a more belligerent mood, threatening legal action against Du Pont. The Wellington bureaucracy was also quick to act; the Ministry for the Environment’s representative on the Pesticides Board announced she would press the Board to de-register benomyl, and recommend the Department of Health should ban its use.

Further comments intended to lessen public anxiety came from the City Council, including the announcement that Benlate was being withdrawn from use in the Parks Department. Then, less than ten days after the first report, the matter sank from public view while New Zealanders attended to the serious business of the Christmas-New Year summer holiday period. Behind the scenes, however, Dr John Alchin, Occupational Physician, was very busy. Before the issue became public, the City Council had asked him to investigate the birth defects. His report, 74 pages long, was submitted on 15 April, 1994, and reported in the Press the following day. The sub-editor’s summary of Alchin’s summary read, “Report on birth defects finds no pesticide link.”

Alchin’s investigation had been very thorough. He had examined the hospital obstetric and paediatric records, the medical and ante-natal records of the family doctors, and the notes of the obstetricians and paediatricians concerned. He had interviewed the parents at length and scrutinised City Council procedures. He instituted wide searches of two computerised medical databases, and talked to several New Zealand experts in epidemiology, environmental health, medical genetics and toxicology.

Concerning the two babies who were born blind, he noted: (1) one was born in 1990, the other in 1993; (2) their blindness resulted from two quite distinct congenital defects; (3) birth defects are not uncommon, there is roughly a 1 in 1000 chance of any two babies being born with major anomalies; (4) the two mothers had had minimal exposure to pesticides during pregnancy; and (5) other studies show no linkage of human birth defects to pesticide exposure. In view of the emphasis given to Benlate in the media reports, it is odd to note that Alchin could not confirm that either mother had been exposed to this material during pregnancy.

The third baby in the study was said in early reports to have “severe epilepsy”. Dr Alchin found he began having seizures at three or four days old, but from three months at least until nine months, had had none. His mother’s exposure, if any, had been to Roundup (glyphosate), not to Benlate. Alchin considers neonatal seizures to be common, and no evidence links their occurrence to pesticide exposure.

It seems that we have here another case of “chemophobia”, an irrational fear of exposure to chemicals, particularly synthetic, biologically active substances. What was presented initially as almost an epidemic of birth defects associated with horticultural sprays is seen on careful examination to be nothing of the kind.

Those of us who were born more or less whole, and have borne/sired healthy children, can hardly imagine the depth of pain suffered by the parents of these two blind babies, nor appreciate the handicap with which the infants start out in life. To seek some cause for such an affliction, any cause rather than no cause at all (chance), is perhaps natural. Nonetheless, to pin blame on something baselessly can in the long run only be harmful and an impediment to understanding.

Despite the thorough investigation, and Alchin’s exoneration of the pesticides, not everyone was convinced. A spokesman for the Toxins Action Group was quick (too quick even to have read the document) to label it a “whitewash”, and, at last report, the parents of one of the blind babies were continuing their legal action. Before the findings were announced, the Soil & Health Association had decided the eye defects were caused by Benlate, and was demanding its withdrawal.

The City Council emerges creditably from this affair. Its arrangements for proper handling of the wide range of horticultural materials used in our parks and gardens seem to be carefully designed with safety in mind, a thorough investigation was promptly set up as soon as an apparent problem appeared, and Council officials tried, though with little success, to counter the inappropriate public response.

As a Christchurch ratepayer, I feel my contribution to the costs of the enquiry was well worthwhile. It is good to know that this scare was unfounded; one can hope, but not with much optimism, that such scares may not occur again with so little cause.

Bruce Ames: Environmental Prophet or Apostate?

What is the link between chemicals and cancer?

Forty years ago, Bruce Ames was a young microbiologist working at NIH in the day and enjoying Scottish country dancing in the evening, when he had an inspiration: to use the rapid growth of bacteria as a method for determining whether a particular chemical was able to cause mutations. If the chemical was positive — i.e., was mutagenic — it might be considered as a possible cause of cancer. This method, soon called “the Ames test”, became widely used. It was cheap, fast, and sensitive. One of the first discoveries was that a dye commonly used in children’s pyjamas had mutagenic properties. Bruce Ames became a hero to the environmental movement when he led a successful campaign to ban such dyes.

Ames was more interested in reducing the death toll from cancer than he was in attacking new chemical technology. As more results from the Ames test accumulated, he realised that many naturally occurring chemicals were also giving positive results. Even more disturbing, the number of chemicals that seemed to be positive in high-dose tests on mice and rats was, he felt, excessive. In an extensive series of important reviews, published in prestigious journals such as Science and Proceedings of the National Academy of Sciences, he has attempted a quantitative estimate of the difference in human cancer. Because his figures show manmade chemicals in food and the environment to be quite insignificant compared to natural or self-inflicted factors, the name of Bruce Ames is now anathema to the same environmental movement that once applauded him. Nevertheless many professional scientists believe that Ames’ position is basically correct. If the inventor of the Ames test now says that most methods for detecting carcinogenicity are invalid, it is certainly not a case of sour grapes. This article is an attempt to summarise his beliefs. Those who are sufficiently interested should read some of the papers listed in the bibliography.

(1) What do we know about the incidence of cancer?

First, cancer risk increases according to the 5th power of age. That is, a 40-year-old is 100,000 times more likely to be cancerous than a 20-year-old. There are more cancer cases per 100,000 population simply because we are living longer and no longer dying of infectious diseases.

Second, the age-corrected mortality (death rate) from cancer has been declining since 1950 except in those over 84. Overall decline has been 13%. Naturally much of this decline is caused by improved detection and treatment. The only exceptions are lung and skin cancer, clearly caused by tobacco smoking and by increased exposure to sunlight. There are occasional claims that certain types of cancer are increasing slightly, but improved methods for detection are probably responsible.

Thirdly, some mostly unknown environmental factors have a major influence on the types of cancers that are likely. Japanese, for instance, have a high incidence of stomach cancer, yet Americans and Japanese-Americans have a low incidence. On the other hand, American men have much more likelihood of prostate cancer than do Japanese.

(2) What are the major known causal factors in cancer?

The single most important factor is smoking. This accounts for one-third of all US cancer deaths, not to mention one-fourth of heart disease. Each year, smoking causes 400,000 premature deaths in the US and 3 million deaths around the world.

Chronic infections contribute to about one-third of cancer on a world- wide basis. As mentioned below, any factor that causes body cells to divide increases the likelihood of cancer. Hepatitis B and C infect 500 million people, mainly in Asia and Africa. This liver infection is a major cause of “hepatocellular carcinoma”. Two different Schistosomiasis worms infect Chinese colons and Egyptian bladders, being associated with increased cancer risk in those two organs. Liver flukes cause chronic inflammation of the biliary tract, hence risk of cholangiocarcinoma. A bacterium, Helicobacter pylori, is adapted to living in the human stomach and is now believed to be a major cause of stomach cancer, ulcers and gastritis. (So much for the classical psychogenic explanation for ulcers!)

Overall about 70% of cancers might be caused by environmental factors, but pinpointing the exact causes is very difficult. There remains some 30% that cannot be ascribed to any factor other than age and bad luck.

(3) How does cancer develop?

The first requirement is that a dividing cell suffer some sort of damage to its DNA. (DNA is the basic material of our genes.) DNA damage occurs all the time, but our bodies have excellent repair mechanisms to detect and destroy damaged DNA. Based on the amount of DNA breakdown products in the urine, Ames and co-workers estimate about 10,000 “hits” on DNA every single day in an adult. These repair mechanisms are not 100% perfect, and some damaged DNA does escape.

DNA damage is mostly caused by oxidants. The oxidants in turn arise from both internal and external sources. Internal oxidants come from mitochondria, peroxisomes, cytochrome P450 enzymes, and phagocytic destruction of infected cells. The production of oxidants when infected cells are destroyed may be a factor in the connection between chronic infection and cancer. External sources of oxidants include the nitrogen oxides of tobacco smoke, iron and copper salts, and natural plant phenolics like chlorogenic and caffeic acid.

If oxidants are bad, then antioxidants should be good. They are: antioxidants protect against disease. Natural antioxidants include ascorbic acid (vitamin C) and tocopherol (vitamin E). Synthetic antioxidants are also good. One worker estimated about 5% reduction in cancer because of approved antioxidants added to our food.

The health benefits of antioxidants, provided mostly by fruits and vegetables, are statistically highly significant. The quarter of the US population with the lowest intake of fruits and vegetables has double the cancer rate of the quarter with the highest intake. This applied to “epithelial” cancers (lung, mouth, larynx, oesophagus, stomach, pancreas, cervix, bladder, and colorectal) plus ovarian cancer. Breast and prostate cancer, on the other hand, is less affected by fruit and vegetable diets. (Although there is at least a statistical link between fat/calorie intake and breast cancer.)

Persons taking daily tocopherol or ascorbate had one-third the risk of developing cataracts. In contrast, smoking and radiation (both well known oxidative stresses) are strong risk factors for cataracts. Smoking seems to destroy ascorbate: smokers need to take double or triple amounts of ascorbic acid to achieve the same blood levels as non-smokers. Incidentally, smoking by the father seems to affect sperm production and health; smoking fathers increase the risk of birth defects and childhood cancer in their offspring.

Excess food, at least in rats, is “the most striking rodent carcinogen ever discovered”. Even a 20% increase in calories over the optimal results in shorter life, with more endocrine and mammary tumours.

Excessive cell proliferation (cell division) is a very important factor in cancer production. This has been mentioned above in relation to chronic infection. Major dietary factors, such as salty pickles in the Japanese diet, have been hypothesised to be involved in the high rates of stomach cancer in this population. Even table salt, at high enough concentrations, can cause stomach cancer.

That cell proliferation predisposes to cancer is a major source of false positives in chemical screening as normally carried out. Test chemicals are repeatedly applied to animals at the “MTD” (maximum tolerated dosage). This is like chronic wounding, “which is known to be both a promoter of carcinogenesis in animals and a risk factor for cancer in humans”. Many chemicals that purportedly have caused cancer at high dose (MTD) levels, may therefore not be true carcinogens. The infamous saccharine tests are a case in point: only female mice dosed with nearly toxic levels of saccharine showed an increase in bladder tumours.

For these chemicals that “cause cancer” at high doses only by tissue irritation, a tenfold reduction of dose in a rat or mouse experiment would show much more than a tenfold reduction in risk. This seems to have been confirmed. One analysis of 52 tests showed that two-thirds of the purportedly positive results for carcinogenicity would not have been found if the dosage had been cut even by one-half! (I suspect that commercial cancer-screening laboratories get new contracts in direct relationship to how many “successes” they have had previously.)

(4) How do synthetic and natural chemicals line up as causes of cancer?

The conventional cancer-screening techniques are, as stated above, too sensitive. There are not merely a few chemicals that show up as carcinogenic. Instead, nearly one-half of all chemicals tested seem to be positive in these tests. The ratio is the same for both natural and manmade chemicals, even though very few natural chemicals have been tested. Thus we cannot generalise that natural chemicals are inherently safer or riskier than synthetic chemicals. We must look instead at the quantities of chemicals ingested.

Plants contain surprisingly large quantities of natural pesticides. One of Ames’ greatest achievements, in my opinion, has been to compile convincing evidence about how many natural chemicals have pesticidal functions. (In my youth, the question of the function of different “secondary” plant products was much debated. Some thought that products like alkaloids and lectins were mere accidents of metabolism, a plant process gone wild. I personally thought that the main role of these chemicals was to provide research material for young biochemists.) Ames pointed out that up to 5% of the fresh weight of vegetables can be natural pesticides.

The list is very long, and a sample limited just to non-toxic plants would include: the sharp flavours of mustard and other cabbage-family crops; piperine (10% of weight of black pepper); light-sensitising psoralens in parsnip and celery; chlorogenic and caffeic acid in coffee beans; nerve-poisoning alkaloids in potatoes, tomatoes and eggplants. The cat-attracting chemicals in catnip are actually very good insect repellents. The vast majority of plants are inedible by us. Even so we are at risk of poisoning if cattle or sheep graze on them. Abraham Lincoln’s mother died when she drank milk of cows that had grazed on snakeroot. A California infant was born deformed when fed milk from a goat that had been eating lupin. The concept that “natural is harmless” is simply false.

Ames has published numerous estimates of the amounts of natural pesticides that we eat every day. He calculates that we eat about 10,000 times more natural pesticides than synthetic pesticides. More usefully, he and his coworkers have attempted to estimate the relationship between the amounts of different chemicals we are exposed to, and their potency as carcinogens. After all, it is the dosage that makes the poison, to coin a phrase. Some of his calculations are shown in Table 1, rewritten from Ames et al., 1987. The last column (HERP%) is a relative risk. A 5% HERP doesn’t mean a 5% risk of cancer!

Material Carcinogen, dose to 70kg person Rodent Potency Risk (HERP%)
Tap Water Chloroform, 85 ug 90 0.001*
Contaminated Well water Trichloroethylene, 2800 ug 940 0.004
Home air Formaldehyde, 598 ug 1.5-44 0.6
PCB’s, daily PCB’s 0.2 ug (US average) 1.7-9.6 0.0002*
DDT/DDE, daily DDE, 2.2 ug (US average) 13 0.0003*
Bacon, cooked Nitrosamines, 0.4 ug 0.2 0.003-.006
Peanut butter Aflatoxin, 64 ng/sandwich 0.003 0.03
Brown mustard Allyl isothiocyanate, 5 mg 96 0.07
Mushroom, 1 raw Hydrazines 20-300 0.1
Beer, 350 ml Ethyl alcohol, 18 ml 9110 2.8*
Wine, 250 ml Ethyl alcohol, 30 ml 9110 4.7*
Comfrey-pepsin tablets, 9/day Comfrey root 626 6.2
Diet Cola, 350 ml Saccharin, 95 mg 2143 0.06*
Phenacetin pill Phenacetin, 300 mg 1246-2137 0.3**
Phenobarbital, 1 sleeping pill Phenobaribital, 60 mg 5.5 16***
Formaldehyde, industrial Formaldehyde, 6.1 mg 1.5-44 5.8
EDB, industrial exposure Ethylene dibromide, 150 mg 1.5-5.1 140

Table 1: Calculated risk factors for common chemicals.
* Material not believed to be gene-damaging; that is, acting as a carcinogen only by irritation or damage at high concentrations.
** Some evidence for increased kidney (renal) cancer after long-term use.
*** Apparently no cancer risk to people taking it for decades.

How then do these theoretical risks relate to the “real world”? A few links can be found. There have been perhaps dozens of cases of liver damage from comfrey-pepsin tablets, although this has been as “hepato-occlusive disease” rather than cancer. These comfrey-pepsin tablets have a risk factor (HERP%) of about six.

Although alcohol is a low-potency carcinogen, large quantities are consumed by some people. Alcoholics have significantly increased risk of cancer in the mouth and throat. Thus HERP’s around five seem to be genuine risks. On the other hand, the HERP value of 16 for one phenobarbital sleeping pill is apparently not connected with any risk of cancer. (Note that phenobarbital is one of the numerous so-called carcinogens that shows up as positive only at tissue-irritating concentrations.)

One interesting point is that TCDD (the dreaded “dioxin” of milk cartons and teabags) is known to cause most of its effects by reacting with an animal component called “Ah receptor”. There are chemicals in broccoli, mainly indole-carbinol, that also react with the Ah receptor. Both chemicals can protect against cancer if administered before challenge with a carcinogen. Both chemicals can promote cancer if administered after the carcinogen has already acted.

Taking potency into account, a 100 g portion of broccoli has 20,000 times more effect on the Ah receptor than a legally allowable TCDD intake of six femtograms/kg/day. (Perhaps it is not surprising, then, that experiments in which rats given a carcinogen were protected by including broccoli or cabbage in their diet. There is evidence that humans too are protected by these vegetables: People who are high-crucifer eaters are significantly less likely to wind up in cancer wards.)

(5) How pesticide regulations and chemical scares diminish public health.

Diet is one of the key routes to better health. Only 9% of the US population eats sufficient fruit and vegetables, higher consumption of these would decrease cancer as well as other diseases. There is plenty of margin to increase fruit and vegetable eating.

To discourage consumption of vegetables and fruits is to diminish public health. Excessively strict limits on harmless levels of synthetic pesticides act to increase vegetable and fruit prices, by reducing production and by increasing cost of production. Thus these regulatory restrictions may well be harming health rather than helping it.

Similar comments could be made about the attacks on Alar a few years ago, when apples disappeared from the lunchboxes of many children.

This then is one reason why Bruce Ames is hated by many “environmentalist” groups. He has shown that they are, in all likelihood, damaging public health under the guise of protecting it against non-existent or unimportant risks.


This review was inspired by an article by Dr Arthur B Robinson in Access to Energy, April 1994.


B.N. Ames. 1983. Dietary carcinogens and anticarcinogens. Science 221: 1256-1262.

B.N. Ames, R. Magaw, and L.S. Gold. 1987. Ranking possible carcinogenic hazards. Science 236: 271-280.

B.N. Ames and L.S. Gold. 1990. Environmental pollution and cancer: some misconceptions. In: Science and the Law (Ed. Peter Huber).

B.N. Ames and L.S. Gold. 1990. Too many rodent carcinogens: mitogenesis increases mutagenesis. PNAS 87: 7772-7776.

B.N. Ames, M. Profet and L.S. Gold. 1990. Dietary pesticides (99.99% all natural), mitogenesis, mutagenesis, and carcinogenesis. PNAS 87: 7777-7781.

B.N. Ames, M. Profet and L.S. Gold. 1990. Nature’s chemicals and synthetic chemicals: comparative toxicology. PNAS 87: 7782-7786.

B.N. Ames, M.K. Shigenaga and T.M. Hagen. 1993. Oxidants, antioxidants, and the degenerative diseases of aging. PNAS 90: 7915-7922.

B.N. Ames. n.d. Does current cancer risk assessment harm health? Published by The George C Marshall Institute, 1730 M Street, N. W., Suite 502, Washington, D. C. 20036-4505. ($US 5.00) [Not seen by me yet — JDM]


Hail Guns?

Several of my friends are orchardists, and two of them lost their crop last year due to a hailstorm.

The hot topic at present is “hail guns.” Do they work? How do they work?

There seems to be a dearth of real information on the topic. The manufacturers make extravagant claims but it comes to mind that not too long ago mankind was firing arrows and cannons at the clouds just as confidently.

Does anyone out there have the answers?

Phil Spencer, Westbank, Motueka

OOS and 6000

(1) It hurts me to write this, but as a sufferer from RSI (now called “Occupational Overuse Syndrome” or OOS) I was annoyed by Dr John Welch’s description of it (Skeptic 27) as “essentially a conversion disorder” and a “delusion.” I can assure him the pain is no delusion. In my case it arose after I began transcribing long interviews (fast, repetitive typing, unlike creative work), and that is precisely what you would expect from an analysis provided by the ACC in terms of the metabolism of oxygen by the muscles.

I am grateful for the publications on ergonomics, which have helped me; pity about the forests, but there are plenty of worse ways they are used (such as those that clog my letterbox every day).

Stress and boredom may well be factors, but in my case, disabling pain is likely to have an effect exactly the reverse of “helping [me] sort out [my] … financial problems.”

(2) All power to Phil Spencer and the celebration of the Hexamillennium, but has he taken into account the lack of a year zero (which is going to drive the world crazy at midnight on December 31, 1999, just one year too soon)? The change from the Julian to the Gregorian calendar? And the day that was lost when the sun stood still during the Battle of Jericho?

Congratulation to whoever typed out all those little slips saying “4004 BC”: I hope it didn’t give you RSI (OOS)

Hugh Young, Pukerua Bay

It was Bernard Howard who typed 300 little “4004 BC” slips and pasted them in every issue. We wish him well with the ACC. — Editor

Put a Pixie in Your Petrol

A Sprite in your Spirit, a Bogle in your Benzine, a Fury in your Fuel, a Greyhound in your Gasoline. With acknowledgement to the oil company which, many years ago, urged us to “Put a Tiger in your Tank.”

“It is far too easy for promoters of such products to make extravagant claims, and very difficult, time consuming and expensive to challenge such claims … there needs to be a system whereby advertisers can be required to prove such fulsome claims, rather than requiring disbelievers to disprove such claims.”

Yet another moan about homeopathic medicines from the pages of Skeptical Inquirer? Wrong! The quotation above is from the New Zealand Automobile Association’s Directions (September 1992), and refers to “Petrol Pills,” claimed by the distributors to improve your car’s fuel consumption by up to 17%, increase power by 8-12%, and to reduce harmful emissions. In careful tests, the AA could not confirm any of these claims.

The “Petrol Pills” promotion was backed by the usual “unsolicited testimonials” and by vague test reports of doubtful provenance. The subject of this next note has an apparently more respectable origin. It was observed by a contributor to Skeptiker, our German counterpart, at a well-respected technical exhibition, “Ceramitec,” in Munich.

Among the many well-attested marvels of modern ceramic technology was the stand of a Japanese firm, introducing “Mixrax” pellets — a “philosopher’s stone,” according to our German colleagues. A few pellets in your petrol tank will alter the molecular structure of the fuel (!), so that the specific heat of combustion is raised. This is claimed to allow fuel savings of 10-20%, power increases of 10-20%, the reduction of CO2 and hydrocarbon emissions by 30-40%, and a general cleaning of motor and exhaust systems. This material of paranormal power is made by sintering together over twenty common ceramic materials. One of these contains uranium, and the “Mirax” pellets contain much more radioactivity than is usually considered safe. Apart from the safety aspect, automotive engineers can see no way in which these pellets could work as claimed.

Our final “pixies” do not actually go into the tank; they are magnets which are fastened round the fuel intake to the carburetor. They are claimed to “excite” the fuel as it passes to the engine, making it burn more efficiently and less pollutingly. New Scientist has reported on a number of these devices recently. The British Advertising Standards Authority has ruled against the claims made for several, on the ground that no evidence was provided to substantiate them. More colourfully, a university engineer says a dead chicken wrapped around the pipe would be just as effective. American authorities, both state and federal, have used the courts to stop the sale of these devices until the claims are proved.

A joke from my boyhood was about a man who installed so many petrol- saving devices in his car that his fuel savings exceeded 100%, and he had to stop occasionally to empty his overflowing tank. Apparently the old chestnut has not lost its point.

Magic Medicine Turns Businessman into Sex Zombie

Magic potions made from natural ingredients are generally hailed as environmentally friendly. But is this necessarily true? Not if you’re a rhinocerous!

Rhino horn is highly valued for its alleged power as an aphrodisiac and can sell for up to three times the price of gold.

In 1968 there were 18,000 rhinos cantering playfully on the plains of Kenya; now there are 400. Organic horn harvesters have hunted the rhino to virtual extinction. But hey, there are culturally sensitive traditions to uphold… not to mention the oldest tradition of them all — wrangling money from the gullible.


Unconvinced Environmentalist

Your main article in the March issue (Skeptic, #23), “The Skeptical Environmentalist” by Vincent Gray, is perhaps the worst I have ever read. It consists almost entirely of bald assertions, all un- referenced and mostly false, vilifying unspecified “environmentalists”. I shall take room to correct only the worst of these assertions; my main complaint about the piece is more formal, namely that it is unrelated to the NZCSICOP’s aims, and on that ground alone should never have been printed in the magazine.

On the level of fact, Gray is almost completely astray. He admits “there are still people without enough to eat” but claims there’s lately been a “reduction in the likelihood of famine”. This is but one of a dozen major falsehoods in the article. More people are starving than ever, half a billion are severely malnourished, and the prospect is for yet worse famines. The “world glut of food” which Gray asserts is a cruel myth”.

Gray asserts “Green policies are unlikely to help solve these problems. Indeed they may exacerbate them.” No reasoning, or fact, is offered to support these contentions. The truth, by contrast, is that erosion of ecosystems’ productive capacities has already proceeded very far. I entreat readers to seek out the reputable sources which I have mentioned, and ascertain the facts on these crucial matters.

Gray’s main method is the well known “straw man” technique. He claims we have made exaggerated statements which he then knocks down, but many of the statements I have never seen before. Yet others that he mocks are not exaggerated, e.g., that human activities have “depleted resources”. Why would anyone want to mock that accurate statement?

He tries to make out that environmentalists have avoided the issue of population growth (while also accusing us of scaremongering with the term “population explosion”). I would concede that some sections of the environmental movement have indeed underplayed this issue, but as a generality, he’s wrong. It has been widely agreed that the four main categories of environmental problem are pollution, overpopulation, resource depletion and militarism. To the extent that population growth has been insufficiently curbed, the blame must be found largely elsewhere, not in failure of advocacy by environmentalists.

Gray suggestes that because weather forecasting is of limited reliability (though not totally unreliable as his unspecified “one study” claims) climate projections, e.g. nuclear winter, must be implausible. This is fallacious. A major global perturbation, such as a huge sooty cloud spreading over much of the planet or a 30% increase in the carbon dioxide concentration of the atmosphere, will cause results more confidently predictable than the very delicate quasi- random day-to-day changes of mere weather. Artificial climate change (a more accurate term than “global warming”) is accordingly predicted by almost all the relevant experts who have examined the issue. Gray does readers a severe disservice by trying to present a different picture.

Perhaps his gravest accusation is “lack of attention to human welfare when it conflicts with environmental dogma”. The leading environmentalists (such as Edward Goldsmith, editor of The Ecologist) have consistently maintained that it is only by taking care of Nature that humans can prosper. Trying to set up a phoney conflict “environment versus humanity” is an ignorant and mischievous distraction.

I cannot fathom why the editor of NZ Skeptic would contemplate such deceptive rubbish which furthermore is irrelevant to the purposes of NZCSICOP, to which I therefore do not renew my subscription.

Robert Mann, Editor, NZ Environment

CO2 and the Economy

While I agree with the points in Dr Gray’s article that some environmentalists use bad science and may appear to ignore population pressures on resources, I find the remainder of the article flawed.

The uncritical acceptance of the statement that a 20% reduction in CO2 will deepen New Zealand’s current recession, create more unemployment and inhibit exports is particularly disappointing.

Obviously a CO2 reduction strategy will produce growth and investment in some businesses, such as the large insulation manufacturer I work for and reduce the importance of othr businesses such as coal mining.

Overall, I see a net economic and social benefit to New Zealand from a considered strategy to reduce CO2 emissions. The research by many energy specialists both in New Zealand and overseas seems to support my understanding.

If global warming due to CO2 proceeds as predicted by a majority of the world’s climatologists, it will result in massive and costly environmental damge. After CFCs, acid rain and DDT, perhaps it is better to be cautious rather than careless.

I feel it was unfortunate that such a polarised view of environmentalists was published without a counter point.
Mark Stacey, Auckland

Scientific Reasoning

The views expressed by school teachers cited by M Carol Scott (Skeptic 23) exemplify a widespread shortcoming of science education at secondary and indeed tertiary level: its failure to inculcate scientific reasoning modes.

Science teaching appears to exhibit two main modes of transmission:

The “Gospel Truth” delivery style: “this is how things are,” usually employed when dealing with noncontroversial “hard facts,” such as acid/alkali reactions, Newton’s laws, or the digestive system of a rat.

  • The “Article of Faith” approach: “scientists believe that,” used when dealing with potentially controversial or non-deductively demonstrable models like stellar and biological evolution.

Laboratory work in educational institutions is usually only to illustrate what has been pre-taught; in my day “experiments” at school were “to prove that…” They were not at all experimental, and contained not a vestige of the epistemological processes which characterise “real” science in their design or execution. Since then, Discovery Learning methods have become more fashionable, but I would debate the assertion that they achieve little more than the Classical methods do in practice.

Do most degree holders in science really have a background in which scientific thinking was paid much formal attention to? To what extent do secondary science teacher training courses train aspirants to develop scientific reasoning processes in school pupils? In the case of my own first degree and teacher training, these questions are purely rhetorical. Now that I am on the other side of the lecturer’s bench, I am giving such matters a great deal of thought.

Science is not what scientists “believe” (that word describes the claims of both fundamentalists and palaeontologists!) and science is not an amorphous compendium of “facts.” It is an epistemological process which has evolved since the Renaissance. It is a way of thinking.

An introduction to science at first-year university level (compulsory for all BSC students) should feature a priming session of several weeks on the history and philosophy of science, and scienitific epistemology (The Scientific Method, as opposed to “scientific methods”). School science should similarly aim less for fact-cramming and more for cognitive development and the inculcation of scientific reasoning abilities.

Until we do just that, I believe that words like “evidence,” “theory,” and “chance” will remain forever incomprehensible to the general public, not to mention many of the teachers wbo produce that general public.

Barend Vlaardingerbroek, Goroka, PNG

If we are to teach epistemology in a basic science course, which epistemology is appropriate? In my experiance, Popperian falliblism is the most useful way to introduce philosophy of science to science students. Popper is hardly the last word (philosophical questions don’t have last words), but he does give students a useful structure for distinguishing legitimate science from religion and — most importantly — from pseudoscience. -DD

Light Hats

That photograph of the “light hat” (Skeptic 24) is a beauty! But as foolish as it seems, there may well be some reasonable scientific evidence to support its use.

There is a good body of scientific literature regarding seasonal affective disorder (SAD) and its treatment (including shining light on the patient and by taking a variety of medicines), despite the rather convenient-sounding acronym. There are four subtypes noted in DSM-III- R, the well-known psychiatry manual.

Research into the aetiology and treatment of SAD was sparse prior to the 1980s, but came of age rapidly in the middle of that decade, mainly under the impetus of Rosenthal and colleagues at the National Institute of Mental Health, Maryland, in the United States. Numerous well-designed clinical studies were published by this group.

The mechanism of the action of “phototherapy” (shining light on the patient, as in the photograph) remains controversial. Many researchers agree on the involvement of melatonin, suggesting that undiminished melatonin secretion during the months of shorter photoperiod may have a depressant effect. This is based on the observation that light exposure during phototherapy suppresses melatonin secretion; the first treatments with phototherapy were based on the original biological observation that seasonal rhythms in animals depended on photoperiod. The mismatch of melatonin and photoperiod in the human has been described as a “phase delay,” and as a “desynchronisation between solar and biological clocks.” Phototherapy aims to artificially extend the sufferer’s photoperiod. The first report of a portable unit was I think in 1990.

Drug therapy is not usually the first line of treatment for recognised SAD, but at least four groups of compounds have been used: beta- blockers, serotonin precursors and serotonin releasing compounds, benzodiazepines and monoamine-oxidase inhibitors.

There are obvious difficulties in carrying out conventional blind cross-over placebo-controlled trials in the assessment of the usefulness of phototherapy, but results thus far have prompted some to suggest that it would be wise to screen patients with major depression for a seasonal component.

A line in Morin’s 1990 paper states that SAD frequently improves with “travel toward the equator”. Suffering as we are now through a Christchurch winter, it’s easy to agree!

John Britten, Christchurch