sion-making on the best science we can find, because this is a scientific topic. And the science must be sifted, and put into perspective. Thank you very much.

[Prepared statement of Thomas H. Jukes follows:]

PREPARED STATEMENT OF THOMAS H. JUKES, PH.D., DEPARTMENT OF BIOPHYSICS, UNIVERSITY OF CALIFORNIA, BERKELEY, CA

Mr. Chairman ánď Committee Member's:

My name is Thomas Jukes. I am a professor of biophysics at the University of California, Berkeley, starting in 1963. I have a Ph.D. degree in biochemistry, and I also have worked in nutrition, vitamins and cancer chemotherapy.

I received the Bruce F. Cain Memorial Award, 1987

for Cancer Research for my participation in work on methotrexate, the first compound that was successfully used to treat leukemia in children. My work on this was at Lederle Laboratories, 1947 to 1952.

I support the proposal of the committee to investigate environmental toxins and children's health. This needs careful scientific analysis because there have been recent panics. The fear of pesticides in foods is widespread. Actually, most foods tested have no detectable pesticide residues.

It is quite easy to arouse fear by telling parents that their children may be poisoned by their food. In 1989, it was announced by FDA that Chilean grapes were contaminated with cyanide. As a result, tons of perfectly good fruit were dumped into the garbage and the Chilean fruit industry was severely damaged. An Oregon highway patrolman stopped a school bus by requests of a frantic mother to remove a child's lunch containing grapes. The contaminated grapes that started the panic were found by the FDA to contain 3

micrograms of cyanide in each of two grapes. The amount of cyanide normally present in lima beans is 100 micrograms per gram.

I dwell on these figures because the illustrate the basic principle of toxicity that the dose alone makes the poison. We cannot evaluate exposure to environmental toxins, including carcinogens, without adhering to this principle. In the case of the grapes, it had been known for years that cyanide is naturally present in many foods, published in the book Toxicants Occurring Naturally in Foods by National Academy of Sciences in 1973, and in another book edited by me. Cyanide in small doses is eliminated

harmlessly by the body in the form of thiocyanate. Big doses are intensely poisonous. A person would have had to

eat sixty pounds of the contaminated Chilean grapes to get a poisonous dose, and the person would have burst. So it is easy for the media to panic the public over non-existent risk.

The use of pesticides in food production must benefit

the consumer.

crops.

1. Pests are destroyed.

Pests consume and contaminate

Molds grow on food and produce cancer-causing toxins. Molds are killed by fungicides, which are pesticides.

2. The yields of fruits and vegetables are increased. Fruits and vegetables are recommended by all leading health authorities as valuable for the prevention of cancer. Any

program that deprives children of fruits and vegetables is removing nutritionally important foods that prevent cancer.

What are the risks? It is encouraging that during the years 1940 to 1983, in which synthetic pesticides came into use, life expectancy has risen from 63.6 years to 74.6 years. Of course, many public health matters improved. Pesticide residues are not present in most foods. The California Department of Food and Agriculture tested over 14,000 food samples in 1988 and again in 1989. No residues could be detected in more than 70% of the samples, both years. Residues were less than 50% of legal limits in another 20% of the samples. The legal limits provide about a 100-fold margin of safety. Only one-quarter of 1 per cent had residues above the limits. These figures tell us that to protect our children, we should be spending our time on something different from pesticide residues. There are many important problems: Lead poisoning is one. I would list also passive exposure to cigarette smoke, fetal alcohol syndrome and malnutrition.

Next, I shall try to put the carcinogen problem into perspective. It is generally concluded that the incidence of cancer could be substantially reduced by improving the diet. This conclusion comes from comparing diets in different countries with incidence of various types of cancer. High-fat diets may be a cause. More fiber in the diet and more fruit and vegetables are strongly advised.

These conclusions are based on incidence of cancer in human

beings.

Animal tests for carcinogens are of doubtful value,

first because mouse tests don't agree with rat tests, so that both rat and mouse tests are unlikely to be meaningful for humans. Second, rat and mouse tests are made with very high levels of the test substance, and these high levels are so toxic that the tissue damage may lead to cancer. This was where the evaluation of Alar went astray.

Professor

Bruce Ames estimates that 50% of all chemicals tested, either natural or synthetic, will produce cancer at high levels.

Then there is the fact that the levels of carcinogens naturally present in the diet are thousands of times greater than residues of synthetic pesticides. Scorched or burned foods contain highly potent carcinogens in animal tests,, as shown by Takashi Sugimura. Plants produce toxic substances, some of which are carcinogens, to protect themselves against insects. There are lots of carcinogens always in food, and we protect ourselves against their effects by means of natural anti-cancer substances such as antioxidants. of course, very large doses of carcinogens, such as cigarette smoke, alcohol or sunburn can overcome the natural means of protection.

The Mayo Clinic Nutrition Letter, June 1989, said:

America's food supply is abundant and generally

quite safe, more so than in the past

....

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