What should the public know?
The U.S. Food and Drug Administration measures mercury in seafood, but its advisories are informative rather than actionable, according to Reinfelder. In other words, the agency isn’t banning food from being marketed – that means it’s up to the public to research and understand the guidelines.
The Environmental Protection Agency and the World Health Organization have guidelines on mercury, as does every US state. Reviews in New Jersey and Pennsylvania are lengthy and detail how often residents can safely consume specific fish species from each waterway in the state — whether it’s once a week, once a month, or never.
“It’s a bit of a quilt,” Reinfelder said.
The situation is more opaque when it comes to the global market, he explains, because fish caught in one area are transferred to another part of the world. More than 90% of the bluefin tuna he and his colleagues sampled between 2017 and 2019 exceeded the FDA and WHO limit for mercury in a top predatory fish. These are fish that have gone to market, he said.
“Individual fish do not carry a mercury content marker,” he said. “If information about age and location of capture were somehow tied to every fish in the market, regulators, commercial buyers and the public could assess the level of mercury in every fish. fish and make more informed decisions about human consumption.”
Pregnant women and parents of young children should be careful what’s on their plate, experts say, because mercury is a developmental neurotoxin that inhibits central nervous system development.
However, consuming more than the recommended amount of fish per week, month or year is not healthy for anyone.
Levels can vary – salmon is a low mercury choice, while bluefin tuna contains some of the highest levels of mercury. Canned tuna falls somewhere in the middle.
Changes need to be made globally to reduce mercury pollution, Reinfelder and Li said. Burning fossil fuels accounts for a significant amount of global mercury emissions.
“Most of the mercury in the environment right now is anthropogenic. [human-caused]. So if climate change is responsible for this increase in the future, that means we need to mitigate or reduce CO2 and other greenhouse gas emissions to combat the CO2 level,” Li said. “If we can’t achieve this and want to maintain seafood safety, we need to have a stricter policy on mercury emissions.”
Scientists hope that the 2017 Minamata Convention, which aims to control mercury supply and trade and reduce mercury emissions, will lead to positive environmental trends within the next decade.