Newsletter -SAFETY OF OUR FOODS AND LIFE-
February,2000 , No.130
The International Symposium on Environmental Endocrine Disruptors was
held in Kobe, Japan, from December 9 to December 11, 1999. This symposium
was organized by the Environment Agency of Japan to discuss research
done by scientists from around the world. During the symposium, 64 scientists
gave speeches. One speaker, Dr. Gen Ohi, gave a presentation on the
dangers of failing to heed the Precautionary Principle. His speech is
The Precautionary Principle Saves lives
"In 1854, in London, John Snow observed that there was a high incidence of cholera cases in an area where water was supplied by a certain company. He reported it to the city council of London. In response to his report, the city council ordered the company to improve its water system. Thanks to this quick order, the incidence rate of cholera soon began to decrease.
Robert Koch established, beyond doubt, a bacteriological cause-result relationship when he discovered Biblio cholerae and defined Kocho's principle of causality at the turn of the century. Therefore, the action taken by the city of London can be regarded as an execution of the Precautionary Principle.
However, in Japan, when Minamata disease was initially noted along the coast of the Shiranui Sea in 1953, the Precautionary Principle was not applied. Minamata disease was identified as the outcome of consuming fish caught in Minamata Bay in 1956 where a chemical plant was discharging wastewater. Non-human fish eaters, such as cats and sea birds, also succumbed, prior to human victims, an illustrative example reflecting common knowledge of environmental toxicology. However, the official declaration from the Government acknowledging methylmercury as the causative agent of the disease was not made until 1968. The crucial reason for this delay was that the toxicological causal link between Minamata Disease and methylmercury was rejected until then.
If the epidemiological causal relationship had been accepted, and appropriate action based on the Precautionary Principle had been taken, the number of victims (about 500 deaths and more than several thousand people became this desease) would have been greatly reduced."
Give Information to Consumers
"Now, how should we deal with endocrine disruptors?
The primary difficulty of making estimations of health effects related to EDs is the uncertainty associated with identifying and counting these effects. In the cholera and Minamata Disease epidemics, there were readily identifiable clinical manifestations followed by deaths.
In the case of EDs, identifying both results (effects) and causes poses an enormous problem. First, infinitesimal amounts of EDs may exert an effect without demonstrating any observable threshold. Second, there are numerous endocrine disrupting chemicals in the environment. Third, they may disrupt endocrine signal transmissions during the fetal stage when gene-expression takes place and organ development is most active. Thus, the resulting effects can only be observed in the next generation.
What sort of countermeasures can social medicine provide to address this problem characterized by potentially devastating hazards without clear identification in each case? Since a determination of causality is not feasible in individual cases, it can only be done by operating a cohort study on groups with different degrees of ED exposure. Resorting to the Precautionary Principle may not be able to be justified before an epidemiological causality is demonstrated.
Thus, the remaining countermeasure appears to be based on the fact that the primary route of ED uptake is through diet: Information regarding the ED contamination of food must be disclosed without fail, so that consumers can make choices based on that information. The role of social medicine at this stage appears to be to provide consumers, especially reproductively active women, with knowledge related to ED, and to encourage them to behave wisely.
There were also about 240 posters presented at the symposium. The following posters are related to our daily lives.
Styrens may effect learning ability:
Poster title: "Behavioural change in pups produced by perinatal styrene exposure during their brain development stage," by Hiriyuki Aikawa, Takahiko Yoshida, Takaaki Kinoshita, Mitsugu Sakabe, and Fujio Kayama.
Bisphenol A leaching from dental sealant:
Poster title: "Analysis of bisphenol A in polycarbonate using as dental materials," by Kou Yajima, Miki Shimizu, Kayoko Kato, Hiroyuki Nakazawa et al.
Soybean may suppress cancer:
Poster title: "Suppressive effect of soy bean isoflavones on proliferation of breast cancer cells induced by nonylphenol," by Yukihiro Yoshida, Takanori Teramoto, Katsunori Ikeda, Yukio Iemori.
Pyrethroid agricultural chemicals are endocrine disruptors: Poster title:
"Evaluation of estrogenic activities of pyrethroid agricultural chemicals," by Naruhito Yamashita and Masahiro Kawanishi
"The Kobe symposium was a real scientific one. It was very successful since the low dose effects of endocrine disrupting chemicals were scientifically proved." Dr. Frederick Vom Saal, the winner of the dispute, said with a smile.
Last year in Kyoto, the issue of low doses of endocrine disruptors led to a heated discussion, when Dr. Frederick vom Saal reported that very low doses of bisphenol A could affect mice fetuses. Scientists representing the English chemical industry rejected these findings to protect their interests.
However, at the Kobe symposium, many people reported on very low dose effects of bisphenol A. Dr. Gupta, from the University of Pittsburgh, reported that 50 micrograms of bisphenol A per kilogram of body weight per day can enlarge the prostate of male fetuses in mice. Dr. Awao, of Kyushu University, reported that when rat fetuses are exposed to low doses of bisphenol A, the behavior of females and males becomes similar, so that there are no longer the normal differences between male behavior and female behavior. Dr. Osako from National Institute for Environmental Studies, Japan, reported that very low doses of bisphenol A can cause problems in spermatogenesis in the testes of adult rats.
When Dr. vom Saal gave his speech, all seats in the lecture hall were full. Many people who could not find seats stood, and others watched on a TV monitor in another room. The chair of the symposium introduced Dr. vom Saal as " today's main guest." Dr. vom Saal reported that both bisphenol A and birth control pills can cause problems in the development of the reproductive systems of fetuses. This time, nobody opposed his research.
Since it was proved that very low-dose chemicals can cause health problems, chemical industries must now begin to conduct safety evaluations of low-dose chemicals and reconsider the dangers of these chemicals.
"Pregnant women should avoid exposure to endocrine disruptors as much as they can. It is recommended not to use plastic food wrap in microwave ovens, pesticides, cigarette, and alcohol. When we feed bispehnol A to pregnant mice, bishenol A bioaccumulates in the fetus's body. It would be wise for pregnant women to avoid EDs."
"About 50 to 60 million women in the U.S. and Europe use oral contraceptives, and approximately 3 percent of these women annually become pregnant and unknowingly expose their fetuses to estrogenic chemicals. Among teenage girls in the U.S., the average number of pills missed per month is 3. Oral contraceptives are highly effective when taken properly (said to be 97 to 100% effective), but it is obvious that the rate of improper use is very high, particularly among teenage girls. The potential for problems is highlighted by research: Our findings with mice show that there was a permanent increase in prostate weight in male offspring at doses of ethinyl estradiol(per kilogram of maternal body weight) 250 times below the dose used in oral contraceptives.
Since mice and humans are different, we cannot apply our findings directly, but it is important for women to understand the potential dangerousness of the pill."
On June 16,1999, Japan's Ministry of Health and Welfare approved the Pill for use as a contraceptive. In the beginning of September, medical companies began to sell the Pill. Ethinyl estradiol is included in all pills sold in Japan. A good way to avoid fetal exposure is not to take birth control pills; however, if you decided to take the Pill, it is important to use them properly. If you miss a pill, it is important to use other means of birth control during the rest of that month.
Studies related to the low dose effects of EDs, such as birth control pills, have just begun, with Dr. Fred Vom Saal leading the study. Ministry of Health and Welfare officials that approved the Pill, and medical practitioners who prescribe the Pill do not know well about the low dose effects of EDCs. Medical companies and related individuals are assuming that they can get large profits from selling oral contraceptives. If 6 million Japanese women take the Pill, there will be 3 billion yen in sales for medical companies. Medical practitioners may also be able to make profits by prescribing pills, which may encourage a tendency to hide side effects and risks of the Pill. Therefore it is important for individuals to take all these risks into consideration, when choosing whether or not to use the Pill.
Children are crazy about "Pockemon" toys, based on the popular Japanese animation characters. But wait a minute, they are made of Poly Vinyl Chloride (PVCd). PVC monomer is a known as carciongen, and PVC often contains many chemical additives. So we asked the test center to analyze a variety of Pokemon toys, soaking them in 95 degree hot water for 30 minutes. The results found Bishpenol A leaching from "Pockemon toys" made of PVC.
3 dolls from left (made by Tommy ltd) 3.1 ug/ml the doll on the right (made by Bandai ltd) 0.56 ug/ml
In November, 1999, the European Commission recommended a ban on PVC teething toys, since phthalates, a PVC additive, may harm children. Not only phthalates, however, but also bisphenol A may leach from PVC toys. Small children tend to chew soft toys, and when they chew toys, harmful bishpenol A and phthalates will leach out.
SO don't choose PVC toys for your children!
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