Light Meal, Heavy Metal: Spot checks find high levels of mercury in half of raw tuna samples

There it is, a delicious little potential mercury bomb. Photo illustration via WikiCommons/Pat Thaxton.
There it is, a delicious little potential mercury bomb. Photo illustration via WikiCommons/Pat Thaxton.

A recent round of spot checks by Hong Kong’s consumer watchdog found illegal levels of mercury in more than half of the raw tuna samples tested, and two samples — one tuna, one salmon — contained parasites, the organization announced today.

The Consumer Council tested 50 samples of sashimi and sushi, and found that all but one contained the mercury compound methylmercury. Ten of the 19 tuna samples taken, meanwhile, were found to contain levels of mercury that exceeded the legal limit — in one case by a multiple of three.

Some were so contaminated, the group said, if a pregnant mother were to eat just six pieces of the contaminated sushi in a week, “she will exceed the tolerable [mercury] intake limit suggested by” two UN bodies.

Pregnant women have long been cautioned to avoid consuming raw fish as mercury can impact the nervous system, “particularly the developing brain,” the council noted.

Meanwhile, one tuna sample and one salmon sample were found to contain ringworm, while the salmon sample also contained ringworm eggs. The parasites had been “chemically treated,” however, and the Consumer Council said it was unable to determine whether they were actually alive at the time of testing (if that’s any comfort to you).

Finally, as if to add insult to injury, one of the purported “salmon” samples actually came from its freshwater cousin, the rainbow trout.

In its report on the findings, the council drily noted: “The restaurant that sold the rainbow trout sample described it on the Chinese menu as ‘silver salmon’, a questionable description that does not correspond with the actual species.”

Questionable description, indeed, Consumer Council. You might even say it’s downright fishy (sorry, we’re contractually obligated to make a fish pun in all seafood-related stories).

If any of this gives you pause when it comes to ordering the tuna, keep in mind that some species, particularly bluefin, are extremely vulnerable thanks to years of overfishing. So yeah, maybe not the worst thing in the world if you go for something else.

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