「鯨の街」の奇怪な検診　和歌山県太地町で

「鯨の街」の奇怪な検診　和歌山県太地町で公的「メチル水銀汚染調査」
Official “Methyl Mercury Contamination Testing” in Taiji, Wakayama

Bizarre Examinations Undertaken in “Whale Town”

日本語版がここにあります。

by Hiroshi Hasegawa
AERA magazine
October 26, 2009
Translation by Matthew Carmody

Taiji, Wakayama Prefecture, one of Japan’s most prominent whaling bases.

The high level’s of mercury detected upon examination of residents’ hair was reported in our June edition last year. And while general checkups have subsequently been undertaken by the government, the checkups themselves are questionable. Is there really no possibility of Minamata disease?

Upon visiting a community center and asking an elderly person whether they had had a health checkup, they lashed out in a big voice and stated: “I know everyone. There isn’t anyone around here with that sickness.”

Is Minamata disease (methyl mercury poising from seafood) occurring in one of Japan’s coastal whaling bases? While it wouldn’t be strange for the average person to make a similar claim to that at the start of this article, it would be impossible to overlook if specialized agencies began acting in a manner that even baffled researchers in the field.

This summer, the National Institute for Minamata Disease (NIMD) which was established in Minamata city, Kumamoto Prefecture in 1978 took hair samples from the local residents in Taiji, a small town of 3530 (as of August) in the Higashimuro district of Wakayama Prefecture to determine mercury levels after consulting with the Ministry for the Environment. As of mid-September when this was written more than 1000 hair samples had been taken to NIMD where they were      analyzed. Hair samples are still being collected. This, along with the health checkups to be mentioned later are the first time that NIMD has targeted a specific area outside of the Minamata region for such a large undertaking.

Highly Contaminated Toothed Whales

NIMD has refused to clearly state any figures regarding mercury levels as the hair sample testing is still in progress. However, according to an official in Taiji it would appear that there are a significant number of people with mercury levels exceeding 50ppm. Not only does this figure clearly surpass average mercury levels of 2.5pmm for Japanese males and 1.6ppm for Japanese females established during nationwide hair mercury level tests undertaken by NIMD between 1999 and 2003, but is also greatly exceeds levels warned to be dangerous by international institutes and researchers around the globe.

In response to this, NIMD lined up male results from the aforementioned nationwide test from high mercury levels down and took the figure representing 5% from the top, 7.2ppm as a rough indication before voluntary examination of around 150 Taiji residents who exceeded this level either at Taiji, or if possible they were taken to Minamata city for a 3 night stay. Those examined were “not found to have methyl mercury poisoning”, ruling out Minamata disease. However, through possible intentional error or plain negligence, the examination itself was outside standard neurologically based testing standards that take the brain deteriorating effects of methyl mercury poisoning into account.

Before verifying this, let’s first look at why it is that NIMD began such large-scale testing.

At present in Japan the coastal whaling of certain dolphins and other small toothed whales is undertaken in the 8 regions of Hokkaido, Aomori, Iwate, Miyagi, Chiba, Shizuoka, Wakayama, and Okinawa under the authorization of the Ministry of Agriculture and Forestry, or the Governor. As small whales are outside of the IWC’s jurisdiction, the Japanese government has accomplished this by finding loopholes in regulations set by the IWC who have banned the commercial whaling of baleen and other large whales. Such whaling is not related to deep sea “whaling surveys” of baleen and other whales for which Japan is heavily criticized by the international community.

However, while baleen whales feed on organisms such as plankton, fish-eating toothed whales are contaminated with notable amounts of harmful substances due to ingestion of methyl mercury that has built-up in sea fish.

As with the Minamata disease outbreaks of the 1950’s and 60’s along the Shiranui coast in Kumamoto Prefecture which resulted in the hospitalization and, in some cases, death of many, Nigata Minamata disease outbreaks downstream of the Agano river also occurred when residents ate seafood that had been contaminated by the methyl mercury contained in wastewater from a certain factory.

Due to such happenings, some residents in Tiaji expressed their concerns about the regular intake of toothed whales. With the help of such residents Aera took a small number of hair samples, from only 8 residents to be exact, along with meat from several species of toothed whales sold in the region to NIMD for methyl mercury level analysis in May last year.

The result, total mercury levels (90% of total mercury is methyl mercury) of the hair samples ranged from 3.60ppm to 86.30ppm, showing that all samples exceed average male and female mercury levels established by the aforementioned nationwide testing, in some cases extremely. Additionally, the total mercury level of toothed whale meat was a staggering 3.08 to 161.50 times the provisional regulation of “0.4ppm” set by the Ministry of Health and Welfare in 1973 regarding total mercury levels in seafood.

Diagnosis without Fundamental Testing

Upon publishing of these facts in the June 16^th edition of Aera last year, NIMD and the Taiji authorities engaged in a year long process of discussions and preparations, finally deciding to carry out hair sample tests on as many residents as possible, and to also carry out health checks on those who exceeded a certain level of mercury. 2 to 4 NIMD workers resided in Taiji and gathered hair samples by taking advantage of general health checks and other examinations.

Considering the international shame brought on Japan by the original political and governmental neglect of Minamata disease, the above measures taken by NIMD and the Taiji authorities were on the verge of being praised by medical specialists with an interest in Minamata disease. However, during this process the following bizarre happening occurred.

These facts came to light during a visit to NIMD.

It happened during a wide ranging Q&A session at NIMD at which Director General Koji Okamoto, Head of Basic Medical Sciences Masanori Sasaki, Chemical Lab Head Akira Yasutake, and Head of Clinical Medicine Masaaki Nakamura, who is a doctor and professor of clinical medicine at Kumamoto University and the sole overseer of the residents’ examinations, were all present.

Journalist “Did you undertake a two-point discrimination test?”

Nakamura “We don’t…undertake that kind of examination.”

Journalist “Did you test to see if patients could discriminate, for example, (3-dimentional) objects with a cross-section such as a triangle or hexagon by touching them?”

Nakamura “…No…”

All those seated appeared to become tense.

Dr. Nakamura continued on with following explanation,

“We examined all standard and fundamental neurological symptoms, including all items necessary for Minamata disease certification.”

However, there was no explanation given as to why the tests in question were not carried out.

The two-point discrimination test, where both ends of a 2 pointed compass-like instrument are pressed simultaneously against the fingertip and the distance narrowed to see how well the 2 points can be distinguished, and stereognosis testing, which involves closing your eyes and touching objects with a cross-section such as triangles and hexagons to see if they can be distinguished from one another, are both required tests when examining and diagnosing Minamata disease, as most pathology and clinical testing have established that methyl mercury related brain damage centered on the sensory cortex brings about a disturbance of sensation throughout the body. Indeed, such tests are considered by the international neurological science community to be standard medical procedure when diagnosing neurological disorders that are not related to Minamata disease.

Adamant Minamata Disease Designation Standards

For example, the widely used “Adams and Victor’s Principles of Neurology” which was originally published in 1977 by McGraw-Hill and is now available in its 9^th revision has a subsection “Two-Point Discrimination” on page 137 that shows how a blunt compass is used to carry out a painless two-point discrimination test, stating “Mistaking 2 points as 1 point is a characteristic of patients who have a damaged sensory cortex.”

Those with Minamata disease suffer a wide range of both light and severe ailments depending on the degree to which certain brain cells were damaged by methyl mercury poising, with patients sometimes unable to recognize their own symptoms.

However, initial Japanese research into Minamata disease was also influenced by a 1940 English paper in which rats were administered methyl mercury to determine peripheral nerve damage. Although the author of this paper later explained that no peripheral nerve damage is incurred by humans, something that both internal and external researchers supported, the standard for Minamata disease designation “Criteria for Differentiation of Acquired Minamata Disease” set by the Environment Agency in 1977 continued to be affected by the assumption of peripheral nerve damage, adamantly denying research results that state Minamata disease causes brain damage. Symptoms that suggest damage to the brain were therefore not designated as Minamata disease.

Concerns over “Fetal Minamata Disease”

And now, NIMD, an offshoot of the Ministry for the Environment, has not carried out two-point discrimination tests which would clearly determine damage to the cerebral cortex when examining residents of Taiji whose hair samples showed high levels of mercury. Professor Shigeo Ekino of the Faculty of Medical and Pharmaceutical Sciences at Kumamoto University, who has examined and researched Minamata disease patients on Goshoura Island in Amakusa city, Wakayama Prefecture for many years and published a paper in an influential foreign magazine stating that Minamata disease is the result of brain damage, states that “the situation in Taiji is an unparallel chance for Japan to contribute to the world by establishing what effect mercury pollution of deep sea dolphins and fish is having on the human body, so I want it to be scientifically investigated. This is an important research topic for Japanese who live on a diet of fish.”

Amongst these concerns, the most worrying development is the danger that fetal Minamata disease may occur if methyl mercury ingested by the mother is passed to the fetus through the placenta, and accumulated. NIMD appeals about this in its publication “Mercury & Health” in the following way.

“Methyl mercury poisoning in the womb causes brain paralyses and mental disorders.”

“Methyl mercury (abbreviated) easily passes through the placenta (abbreviated), a report made by WHO in 1990 states that there is a 5% chance the fetus will develop a disorder if the mother’s hair mercury level is 10 to 20ppm, while a 2003 gathering of international experts on food additives states that fetuses may be affected slightly at 14ppm (mother’s hair mercury level).”

Although it hasn’t been announced whether any of the Taiji residents with high hair mercury levels are pregnant, or may be suffering the above mentioned problem, shouldn’t people, especially pregnant woman, in the other 7 toothed whaling bases who face a potentially similar situation to Taiji be promptly alerted to the dangers and switched to a low mercury diet even if the hair testing is still being undertaken?

The Ministry for the Environment Cannot be Trusted

According to the same NIMD publication, WHO released a report in 1990 that sets 50ppm as the highest hair mercury level at which no neurological symptoms occurs. However, according to a joint paper published in 1998 by a 7 member research team led by Canadian Jean Lebel, central nervous system damage begins at hair mercury levels of around 15 to 25ppm.

And even if hair levels drop by not ingesting methyl mercury, it would appear that once the brain has been damaged by poisoning it will never return to its original state. This fact in itself points to the existence of a large number of potentially affected people.

Judging from the unscientific examinations that continue to be carried out, I am inclined to believe that the Ministry for the Environment should not be trusted to handle the mercury problem faced by coastal whaling bases such as Taiji. I don’t believe that anything will be solved until the central government confronts the problem head-on from an independent standpoint.

This manmade whale’s tale in a square near the arrival and departure wharf for sightseeing boats catches the eye.  A decommissioned whaling boat can be seen in the background.

Caption for photo on 2^nd page

There is even a “Whale Memorial Stone” in the whaling town of Taiji. Many people involved in fishing related and other jobs gather here for actual memorial services. Photo taken April 29^th 2009.

Map on 2^nd page

(Bottom right) Taiji, Wakayama Prefecture

(Middle) Pacific Ocean

(Left) Minamata city, Kumamoto Prefecture