You don't have to do this. Just imagine it. Take a glass bottle and drop it onto concrete from a height of 2 millimetres. Now take the same bottle and repeat from 2 metres. Note the difference.
What you have done, with childlike directness, is show the critical relationship between dose and response. Low dose, no worry. High dose, catastrophe. It is a perfect analogy for the way chemicals affect the human body. Most substances taken in small amounts are harmless. Almost anything taken in excess will cause worsening damage as the dose increases. One aspirin a day may prolong your life; 30 will end it. A pinch of salt will stimulate the taste buds; three teaspoons will kill a baby. A pint of water will satisfy your thirst; gulping six pints will finish you off. It is all a matter of thresholds. We understand this, and not many of us want to ban aspirin, salt or water.
But consider, say, ethoxylates of nonylphenol, polybrominated diphenyl ethers or tributyltin — the kind of stuff that drips, leaches or pours into our bodies every day through our nose, mouth and skin. The very sound of them is poisonous. Any amount of these things could be too much.
Compared with a quiet day at home, bungee jumping into a live volcano would be a good insurance risk. Night and day, there is no respite from toxic bombardment. Sheets and mattresses are laced with chemicals that can damage the immune system, cause birth defects and arrest brain development. Downstairs you may find the same stuff in your carpets, furniture, mobile phone, computer and television. Step onto a vinyl floor, and you risk long-term damage to liver, kidneys and testicles. Cosmetics, shampoo and shaving foam — even the bathroom shower curtain — threaten more of the same.
If you survive to reach the kitchen, then it will be to meet an onslaught of toxic cleaning fluids, detergents, nonstick cookware and dishwasher tablets. Even your trainers may be dripping with menace. So, too, are your children's pyjamas and their toys. On this evidence, any government seriously looking for weapons of mass destruction would target Tesco.
It is hard not to be sceptical. Chemicals in modern life have been ubiquitous for more than 50 years. Some 100,000 of them are registered for use in the EU, of which around 30,000 are made or imported annually in quantities of over one tonne. (A prodigious amount of a substance whose fatal dose might be measured in nanograms.) In most cases, our knowledge of their environmental and health effects hardly rises above zero. And yet the quickening flow of them into our lives has been accompanied not by an epidemic of withering disease but by steady improvements in health.
In 1961, the year before Rachel Carson published Silent Spring, the book that first highlighted the damage caused by pesticides and effectively launched the environment movement, life expectancy in the UK was 67.8 and 73.7 years for men and women respectively. By 2002 it had gone up to 76 and 81. This does not mean that our lives are free from danger, or that the precautionary principle (when in doubt, play safe) is redundant. The real risk is that, amid the forest of red flags, we may lose the ability to distinguish between justified concern and illogical fear.
Language is a large part of the problem. Science makes everything sound scary, and so we are scared. Even that neutral word "chemical" has been tainted by the company it keeps, as if it were somehow the antithesis of "natural". The truth is that all products, and all living things, contain chemicals, though no manufacturer or retailer is going to advertise the fact unless it's in a miracle cure for tooth decay or wrinkles.
Pesticides are the classic example. Among those you may have encountered recently are 1-hydroxyanthraquinone, methylformylhydrazone, monocrotaline, acetaldehyde, allyl isothiocyanate, crotonaldehyde, quercetin, symphytine... a small number of typical examples lifted at random from a very long list. All cause cancer in rats. You will have ingested them, or various of their toxic relatives, in apples, bananas, broccoli, cabbage, carrots, celery, coffee, garlic, grapefruit, grapes, honey, lemons, lettuce, mushrooms, onions, oranges, parsnips, peaches, pears, peas, potatoes, raspberries, tea, tomatoes... Coffee alone contains more than 1,000 different chemicals, of which some 27 have been assessed for carcinogenicity in rodents. Nineteen of these tested positive. Nobody knows about the rest.
You want to know which retailers are peddling such poisons? Which brands? The answer is short and shocking: all of them. Conventionally grown, organically grown, home-grown, it makes no difference. These toxins are all produced normally within the plants themselves as part of their evolved defence against fungi, insects, birds and animals. They are natural pesticides, whose only job in life is to be poisonous. Ninety-nine point nine per cent of the chemicals we consume are natural, and are found in fruit, vegetables and bread. They have existed throughout the entire evolutionary progress of vertebrate life, but still cause cancer in mice, rats and — well, who knows?
Literally thousands of such substances are in free circulation, of which only the tiniest fraction — a total at the last count of just 71 — has ever been tested. Thirty-seven of these proved carcinogenic to rodents, to the extent that they would not meet the regulatory criteria laid down for chemicals made by man. Day by day, the natural pesticides in our diet outweigh the synthetic ones by 20,000 to 1 — the approximate scale of difference between an elephant and a mouse. In terms of toxicity, so far as anyone can tell, there is little to choose between them. Two-thirds of synthetic chemicals are carcinogenic to rats and mice; so are two-thirds of the natural ones.
Scientists at the National Institute of Environmental Health at the University of California at Berkeley calculated that the known natural rodent carcinogens in one cup of coffee are about equal in weight to the synthetic pesticide residues in an average American's annual intake of fruit and vegetables. Every day, each of us consumes some 2,000mg of carcinogenic or mutagenic material — about a quarter of a teaspoonful — created by cooking. In the same time span, according to the US Food and Drug Administration, the average consumption of synthetic chemicals is just 0.09mg — about the weight of a single grain of refined salt.
What should we deduce from this? That we have been encouraged by environmental propagandists to become a generation of chemophobes with an irrational dread of science? That the statistics serve only to lay a smoke screen around the chemical industry, disguising the fact that our bodies, through long exposure, have developed a resistance to natural toxins that is no protection against the small but lethal minority of laboratory products? That there is everything to fear? Or nothing?
