The perils of mercury-poisoning are laid bare by victims of the Niigata Minamata disease who recount lingering social stigma and the importance of protecting the environment in a new book by a Tokyo publisher.

“Memories of Aga, Voices from Aga,” compiled by students of Rikkyo University in Tokyo, tells the stories in Japanese of several patients suffering from Niigata Minamata disease, some of whom initially hesitated to come forward due to fears of bias. Other survivors stressed the need to preserve nature and to prevent future pollution-related tragedies.

During the two-year project, students conducted interviews with victims of the illness. Rumors of people feigning symptoms to claim compensation from the government made it more difficult for genuine sufferers to tell their stories.

“The students could learn about the social issue from those directly involved in it, while the patients could follow their footsteps anew by talking with the young interviewers,” said Reiko Seki, a Rikkyo professor who supervised the project.

Niigata Minamata disease, caused by tainted wastewater released into the Agano River from a Showa Denko K.K. chemical plant in Niigata Prefecture, was confirmed in 1965, nine years after the official recognition of the disease in Minamata in Kumamoto Prefecture.

The students began interviews with eight victims in 2014, prior to the 50th anniversary of the confirmation of the Niigata disease, known as “the second Minamata disease.”

While the Niigata Minamata disease has not drawn as much public attention as the initial outbreak of methylmercury poisoning in Kumamoto, “it has played important roles in forming a redress system for the victims,” said Seki, who studied the issue as a graduate student and has since taken it up repeatedly in her lectures and seminars.

The Niigata patients filed a suit for damages against Showa Denko in 1967, apparently prompting those in Kumamoto to file a lawsuit two years later. The Niigata plaintiffs won a court victory in 1971.

The two diseases were officially designated by the government as pollution-triggered illnesses in 1968. As of the end of 2016, 2,282 have officially been designated as Minamata disease patients in Kumamoto and neighboring Kagoshima prefectures, while 705 have received the designation in Niigata.

Among the Niigata patients who gave interviews was Yokio Chika, who actively spoke about his experience until his death in 2015 at the age 85.

Chika grew up in a village along the Agano River, which provided water for drinking, cooking and washing. He ate a lot of fish caught in the river, which were eventually found to be contaminated with mercury.

He admitted to missing the warning signs of contamination, such as the observed increase of weak or dead fish in the river. “We (incorrectly) judged by ourselves that we could eat the fish if we removed their entrails, as we did not have any information.”

Consequently, Chika suffered various symptoms, such as numbness in his extremities and buzzing in his ears. He stressed the necessity of speaking out, together with neighbors, when aberrations are noticed in the natural environment surrounding residential areas.

Pollution caused by humans can be terminated by humans, he says in the book.

Another interviewee, Yumiko Komachi, also ate river fish “as a precious protein source” in her childhood “without knowing they were contaminated.” In addition to numbness in her limbs and buzzing in the ears, she has difficulties reading.

But she was not aware that the symptoms were caused by mercury poisoning until she received a medical checkup at age 55.

There was also concern among victims that social discrimination may extend to later generations. The lingering fear that the disease may be hereditary or contagious would make it difficult for their children to marry, some patients said.

Komachi, a relatively young patient born in 1949, was told by older victims that they had been reluctant to step forward, citing discrimination that could result in them being fired from their jobs.

She said she decided to relay her story, in particular to future generations, in the hope that she could help promote understanding about the disease. “I hope children will tell their family members the true reality of Niigata Minamata disease after hearing what I say.”

Seki said she expected the students to gain awareness that the disease “destroyed the richness of people’s lives with nature as well as their close relationship in their communities.”

Akiho Fujikawa, who graduated from Rikkyo last spring, conducted the interview for the chapter on Komachi. Her thesis focused on Komachi and her brother, leader of a patients’ group.

“Hearing what they had to say, I understood that patients have their own peculiar symptoms and histories, as Ms. Komachi says, ‘There are 100 symptoms among 100 patients and 1,000 symptoms among 1,000 patients,’ ” she said. “We cannot know how they suffer by appearance alone as many of them outwardly seem to lead ordinary lives.”

“Above all, I was impressed since Ms. Komachi told me that my research has further encouraged her to continue telling her story,” Fujikawa said.