Methylmercury pollution is a problem – can Hollywood help?

January 29, 2021

The story of the world’s worst methylmercury poisoning disaster comes to the screen in February. The film, Minamata stars Johnny Depp as American photojournalist, W. Eugene Smith, whose work publicized the disaster in Minamata, Japan. Hopefully the film will renew public interest in mercury pollution, which remains a major threat to global public health.

(Warning – spoiler alert) The movie is set in Minamata in 1971, where Smith and his wife, Aileen, visited the small coastal fishing village for a journalistic expedition. The pair learn how Minamata and surrounding towns were ravaged by methylmercury water pollution from the chemical factory owned by Chisso Corporation. Smith captures the tragedy on his camera, which leads to an infamous eight-page spread in Life Magazine in 1972. Based on the trailer, centerpiece of the film is likely to be Smith creating this photospread.

The photos captured emotional scenes of the distorted, frail bodies of poisoning victims. To implicate Chisso, Smith sequentially arranged the photos: shots of factory wastewater followed by people fishing to explain the exposure, and lastly images of physically crippled victims in their daily life.

Left: Industrial waste from the Chisso Chemical company. Middle: Fishermen in Minamata Bay. Right: Tomoko Uemura is bathed by her mother. Photo credit: W. Eugene Smith.

Methylmercury is a potent neurotoxicant, a poisonous substance that causes brain damage. In the case of methylmercury, the damage is permanent. With high levels of exposure, such as those at Minamata, the brain damage results symptoms akin to cerebral palsy: erratic, uncoordinated movements and cognitive impairment.

A peculiar attribute of methylmercury is that it accumulates in fish tissue. Even small amounts in the environment can lead to extraordinarily high levels in fish. Thus, people who ate fish from the bay in Minamata were poisoned. Chisso stopped dumping wastewater in 1968, but hundreds of Japanese had already been crippled or killed by the poison. To date, approximately 3,000 victims been officially recognized, according to a recent report in the Japan Times.

Dr. John O’Donoghue, toxicologic neuropathologist based in Rochester, New York, first learned of Minamata after seeing Smith’s photo spread in Life Magazine many years ago. “One particular black and white photo has stayed in my mind ever since,” he said. “It was a picture of a woman who was bathing her crippled daughter with such care and tenderness – the child was precious to her.” In Smith’s photobook, Let Truth Be the Prejudice, the photo is called “Tomoko Uemura is bathed by her mother,” and is also pictured above.

Dr. Celia Chen, director of the Dartmouth Toxic Metals Superfund Research Program, was similarly struck by the same photo. “Seeing the degree of physical impact of a toxin through the environment was really sobering,” she said. “It was painful and inspiring as well – there are so many emotions with the photograph.”

The story of Minamata is powerful, but Dr. Chen stressed that the poisoning event was distinct from most mercury exposures. “Minamata was like a punch to the gut,” she said. Chen explained that the more subtle low-level exposures experienced most often today can still be dangerous. The most sensitive populations to methylmercury are unborn babies, who are exposed through contaminated seafood eaten by the mother. While all fish contain some level of mercury, the most concerning are large predatory species like swordfish, tuna, and shark; these are the ones clinicians advise pregnant mothers to avoid. Another way to protect the next generation is by reducing the amount of mercury in fish to begin with. For this reason, international limits on mercury emissions are crucial.

Indeed, the international Minamata Convention of Mercury was formed limit mercury emissions into the environment. According to Chen the Minamata Convention “is like the Treaty of Paris for carbon emissions.” Italy joined the Convention on January 5, 2021, bringing the total number of participating nations to 127.

Chen said that coal fire-power plants have the highest mercury emissions in the U.S. In order to regulate power plant mercury emissions, the U.S. Environmental Protection Agency (EPA) finalized the Mercury and Air Toxics Standards (MATS) in 2012. Chen explained that the MATS rule helps the U.S. meet commitments under the Minamata Convention.

The MATS rule has helped substantially reduce mercury emissions. According to EPA data, mercury emissions from the U.S. coal-fire power plants have declined by 85% from 92,000 pounds in 2006 to 14,000 pounds in 2016. Additionally, the estimated number of children born in the U.S. each year with pre-natal exposure to methylmercury levels exceeding the EPA reference dose has decreased by half.

Despite such progress, the EPA recently stepped back from its commitment to reduce mercury emissions.  On April 16, 2020, the Agency deemed that it is not, “appropriate and necessary” to regulate mercury and other hazardous pollutants from coal-fired power plants under section 112 of the Clean Air Act. According to legal scholars, this decision undermines the foundation of the MATS rule and invites challenges to mercury emissions standards.

While the Biden administration is likely to consider more stringent environmental regulations, it’s noteworthy that our new President neglected to include coal-fired power plants in his January 27th executive order limiting emissions (coal leasing) on federal lands.

Nevertheless, movies like Minamata can help people take notice of important environmental issues surrounding mercury. Public awareness and understanding of such issues can help protect the next generation from the health threats of methylmercury.

Researchers who study mercury today such as Chen, O’Donoghue, and myself are hopeful that the public reception of the film will be similar to that of prior historical dramas with an environmental interest. In the 1984 film, Silkwood, Meryl Streep brought a story of corporate negligence and plutonium radiation toxicity into the public eye. Mark Ruffalo did so more recently for perfluoroalkyl and polyfluoroalkyl substances (PFAS) in Dark Waters.

As Chen succinctly put it, These kinds of movies, whether on mercury or PFAS, are so important because the public will go see a movie and gain interest. Movies can be an on-ramp for people to care about important environmental issues.”