On May 10, in a front-page lead story headlined "Taiji locals test high for mercury," The Japan Times reported the results of tests by the National Institute of Minamata Disease (NIMD) that found "extremely high methyl-mercury (MeHg) concentrations in the hair of some residents of Taiji, Wakayama Prefecture, where people have a tradition of eating whale and dolphin."

Specifically, the tests of 1,137 Taiji residents last year revealed that average MeHg levels were 11.00 parts per million (ppm) for men and 6.63 ppm for women — compared with an average of 2.47 ppm for men and 1,64 ppm for women at 14 other locations in Japan.

However, the May 10 report stated that "experts were at a loss to explain why none of Taiji's residents have mercury-related health problems" and that the NIMD would "continue to research" why no symptoms were observed, according to NMID Director General Koji Okamoto.

Such continuing research will perhaps intensify in light of further tests by Masaaki Nakamura, chief of the NIMD's Clinical Medicine Section, on 182 surveyed Taiji residents having the highest mercury levels. Dr. Nakamura's results found that 43 residents tested above 50 ppm of MeHg, with one showing a level of 139 ppm.

Nonetheless, all those tested were declared healthy at an NIMD-sponsored press conference in Taiji on May 9, at which the institute didn't give the 43 residents any dietary advice, with Okamoto noting, according to media reports, that, "It's important that they decide what they should eat."

Okamoto's comments have drawn scorn from respected medical authorities on three continents regarding those afflicted residents of the village of Taiji, where the 2010 Oscar-winning docudrama film "The Cove" was made about the annual slaughter of dolphins there. B efore the NIMD report on Taiji residents was issued, The Japan Times interviewed Okamoto. Asked his opinion whether mercury ingestion was dangerous, he said, "At this time we don't find people problematic (from consuming dolphin meat)."

Asked about the standard two-point "discrimination protocol" used in detecting neural damage, Okamoto said, "Neurology experts do not consider this (sensory) test routine in Japan."

Japan's Supreme Court in 2006, however, upheld that protocol as the standard for determining compensation to survivors of the world's worst mercury-pollution disaster, which occurred in Minamata, Kumamoto Prefecture, on the island of Kyushu in the 1950s. There, and in surrounding villages, a known 1,787 victims died from methyl-mercury poisoning after their consumption of contaminated seafood from Minamata Bay, and thousands more were affected by what became known as Minamata Disease.

That two-point "discriminatory protocol" test of sensory functions certified by Japan's top court is the clinical protocol that detects mercury-related brain damage. It is also the test applied by Shigeo Ekino in a joint study to diagnose the neurotoxic effect of MeHg on the cerebral cortex (brain) and neurons (the nervous system).

Ekino, a professor at the Graduate School of Medical Sciences at Kumamoto University, in Kumamoto, Kyushu is known for his studies of mercury- damaged brain specimens from Minamata victims. He has also published reports revealing how even low levels of MeHg can cause irreversible brain damage.

Ekino employs the two-point test to ascertain mental disability. This involves a subject lying on their back with their eyes closed while one or two compass points are applied to their thumb, forefinger or lip. If the subject feels only one compass point when two points are applied, that points to probable damage to the somatosensory cortex (where the sense of touch is located). Ekino is famous for his breakthrough studies of mercury- damaged brain specimens from Minamata victims, revealing how even low levels of MeHg can cause irreversible damage.

M eanwhile, commenting on Okamoto's advice for Taiji residents that it is "important that they decide what they should eat," Dr. Pal Wiehe, chief physician in the Department of Occupational Medicine, Public Health in the Danish-controlled Faroe Islands, said, "This is inappropriate advice . . . We have seen over a period of time that there were negative impacts at all levels in our neurological, physiological and psychological tests that were irreversible."

Wiehe said he conducted pediatric studies, starting in 1986 with newborns, then the same subjects at the ages of 7, 14 and, last year, at the age of 23. The tests involved a doctor specializing in occupational medicine and neurology, two psychologists and a pediatrician specializing in neuro-pediatrics.

Wiehe cited a wide range of symptoms emerging from this study, including attention-deficit problems, memory- retention disorders and other neurological symptoms that remained permanent at every age level. "We have also seen an impact on the cardiovascular system, such as heart-rate variations from MeHg, and also a negative impact on the immune system from ingesting whale blubber that contains significant levels of organochlorines such as PCBs and DDT, and other pollutants. . . . We have not seen . . . that selenium (Se) gives protection (against MeHg toxicity) . . . and claims by the NIMD that Se gives some protection . . . are questionable."

A joint study on prenatal exposure to MeHg, involving Japanese experts including Mineshi Sakamoto, an NIMD toxicologist, corraborates Wiehe's findings. The study, titled "Mercury and Heavy Metal Profiles of Maternal and Umbilical RBCs [Red Blood Cells] in the Japanese Population," revealed that Se had little effect as a protective barrier against placental transfer of MeHg to a fetus.

Regarding Ekino's study of the neurotoxic effects of mercury on the cerebral cortex, Wiehe said, "Absolutely, that's what we have been studying for years . . . and what we have seen in Minamata we have seen in the Faroes due to lower doses of MeHg."

Commenting on the high concentration of mercury in Taiji dolphin meat in 10 certified lab tests conducted on different dolphin species, which found the highest level, at 14.3 ppm, was almost 36 times over Japan's advisory level of 0.4 ppm, Wiehe said, " That to me, without any doubt, is dangerous to consumers' health . . . our average concentration (in pilot whales, which are oceanic dolphins) is 2 ppm."

He added, "We don't consider pilot whale meat proper human food." In fact, despite some harsh local opposition, on Dec. 1, 2008 Wiehe successfully recommended to the government of the Faroe Islands that residents discontinue the consumption of pilot whale meat.

But Wiehe is no ecoterrorist. Coming from the Faroes, where — as in Taiji — there is an ancient local culture of hunting and consuming cetaceans, in his youth he took part in the hunts, ate the meat of pilot whales and still says he respects that tradition. But he stresses, "Health issues are more important than tradition."

The NIMD report declaring Taiji residents free of mercury damage also drew flak from one of Japan's top medical researchers, who requested anonymity. He commented, "It is a miracle if no one has symptoms and, if true, it contradicts all scientific studies — or maybe Japanese people are supermen."

Just as the researcher said that fears of intimidation (and the withdrawal of research funding) prompted him to request his name be withheld, the Taiji dolphin-cull story and the toxic meat it produces is mostly ignored in Japan's vernacular media. Indeed, this writer has repeatedly been told by editors that the whole subject is "too sensitive" for them to cover.

W hatever the attempts in Japan to ignore questions surrounding the NIMD's approval for Japanese citizens to continue eating toxic dolphin, however, one of America's leading neurologists, Florida-based Dr. David Permutter — a recipient of the prestigious Linus Pauling Functional Medicine Award for his research into brain disease — was far less inhibited.

In a recent telephone interview, Permutter said, "To me, these (MeHg) levels found in dolphin meat are absolutely dangerous. A study was just published demonstrating that even low levels of mercury profoundly disrupt the blood- brain barrier and increase the presence of inflammatory reactivity in the brain . . . "

He continued: "These levels (of MeHg) are dramatically elevated. This practice of serving dolphin meat is tantamount to poisoning people; they may as well serve them arsenic, it would be no less harmful! What they're doing is wrong on every count; it's the wrong thing to do for the people and the wrong thing to do for the dolphins. No matter how you look at this, it's perverse — it's a tragedy and it should be condemned. If the role of government is to protect the people, then they're failing miserably in their role." M eanwhile, Japan's National Institute of Population and Social Security Research has cited mortality figures in Taiji, for 2007, at 67 deaths from a population of some 3,500 residents — putting the town's overall mortality rate more than 50 percent above many other villages nationwide of roughly the same population. However Kozagawa, west of Taiji, where dolphin meat is also consumed, showed an even higher rate — with 82 deaths from a population of 3,426 people in 2007.

Comparable villages of almost similar populations were Hiiezuson, Tottori Prefecture, which posted 31 deaths from a population of 3,110; Akamura, Fukishima, with 29 deaths among 3,387 people; Minamiyamashiromura in Kyoto with 37 deaths among 3,369 residents; Kitoshiobara in Fukishima Prefecture with 38 deaths among 3,307 residents, and Yomogitamura, Aomori Prefecture, with 35 deaths among 3,370 people.

Although age-related data and causes of death were not available from the research center, the spike in deaths in Taiji and Kozagawa — if nothing else — suggests something, whether mercury-tainted dolphin-meat consumption or otherwise, is happening there that ought to be cause for serious concern.

Chiho M. Jingu and Mark McBennett contributed vital research for this article. Stephen Hesse is taking a well-earned break, but his column, "Our Planet Earth," will return to the Nature page as normal next month.