Toddler's Mercury Poisoning Puts China's 'Children's' Silver Cod on Notice

A two-year-old in Hangzhou is being treated for mercury poisoning that the child's mother traces to a premium baby food: silver cod, sold in "children's portions" and marketed to parents as an near-ideal first fish. Over eight months the family bought 21 boxes — 118 yuan, about 16 dollars, for 180 grams each — and served it two or three times a week. In late September, a blood test at Xinhua Hospital in Shanghai returned a mercury reading of 27.78 micrograms per liter. The child's doctor put the level a toddler should stay under at roughly 5.

The diagnosis came on September 23 from the hospital's pediatric kidney department, and the treatment is slow and invasive: three week-long courses of hospital care to chelate the mercury out. The child's liver and kidney function are holding, the mother told reporters, but whether the nervous system has been affected will only emerge in follow-up visits.

The case gripped Chinese social media because of what "silver cod" turned out to be. The name suggests a gentle white fish; the ingredient list on the box says otherwise. Yin xueyu, as it is sold in China, is not a cod at all but the Antarctic toothfish, a large predator high in the marine food chain in which methylmercury accumulates. "I thought it was one of the better varieties, so I kept giving it to my child," the mother said. "Then I came across a science post and learned its real name is Antarctic toothfish — a large ocean fish where methylmercury builds up. It simply isn't suitable for young children." The box she bought, reporters found, carried the words "children's portion," "contains omega-3 DHA" and "skinless, boneless, free of bones."

The manufacturer's answer is that the fish is legal. A third-party test it commissioned found methylmercury at 0.21 milligrams per kilogram, well inside China's national limit of 1.0. In a written reply, the company said "children's portion" describes the cut and the packaging — small, bone-free blocks convenient for preparing a child's meal — and was never meant to claim the product is made for infants, or to restrict who may eat it; wild deep-sea toothfish, it noted, naturally carries traces of mercury. The mother is not persuaded: mercury leaves the body slowly, she told Litchi News, and "plenty of merchants label this fish as very suitable for children, toddlers, babies as early food. I think the harm is enormous."

That gap — between a label parents read as an endorsement and a manufacturer that says it means only the packaging — is what the argument on Weibo has settled on. The product passed every test its maker can point to, and a two-year-old is in hospital anyway.