Mercury Air Pollution Reflected in Ocean Fish

Rising mercury levels in the air are likely to blame for increasing amounts of mercury in Hawaiian yellowfin tuna, researchers say.

Mercury concentrations in the fish are rising by 3.8% or more a year, they found after analyzing data from 1971, 1998 and 2008.

“The take-home message is that mercury in tuna appears to be increasing in lockstep with data and model predictions for mercury concentrations in water in the North Pacific,” said Paul Drevnick, an assistant research scientist at the University of Michigan School of Natural Resources and Environment.

“The study confirms that mercury levels in open ocean fish are responsive to mercury emissions,” Drevnick added in a university news release.

Yellowfin tuna, sold as ahi, is widely used in raw fish dishes – especially sashimi – and for grilling. This type of tuna is listed as a “high mercury” species by the U.S. Natural Resources Defense council.

Mercury is a potent toxin, and high concentrations in fish pose a health risk to people who eat them.
The main source of mercury in the open ocean is fallout from air pollution, especially from coal-fired power plants and artisanal gold mining, according to the authors of the study presented February 3rd in the journal Environmental Toxicology and Chemistry.

“Mercury levels are increasing globally in ocean water, and our study is the first to show a consequent increase in mercury in an open-water fish,” Drevnick said. “More stringent policies are needed to reduce releases of mercury into the atmosphere. If current deposition rates are maintained, North Pacific waters will double in mercury by 2050.”



My Take:
You have heard the argument for greater energy supplies in this country and less dependence on foreign oil. It is a good argument, but at what cost? If we pollute all the oceans of the world in the process we’d better have enough energy to escape from this planet and find another one. Coal-fired power plants are dirty business.

You can reduce your personal risk by limiting high mercury content fish consumption. In addition to tuna; swordfish, shark, tile fish, orange roughly, marlin, and king mackerel all contain very high levels of mercury. For the most part, these are big fish that roam the open ocean. Grouper, bluefish, Spanish mackerel, and Chilean sea bass all have high levels of mercury. Bass, dolphin, lobster, and canned tuna are rated as having moderate levels of mercury, along with more than a dozen other species. Salmon, shrimp, clams, and tilapia are on the list for the least amount of mercury. However, farm raised fish (like salmon and tilapia) often contain PCBs from land water run off. Please review my recent blog “Pesticides, Plastics Chemical Tied to Earlier Menopause in Women” posted on February 9, 2015 for information on PCBs.

Supplementing omega 3 fatty acids also offers some protection against mercury poisoning. I refer you to my blog “Could Nutrients in Fish Shield Fetus from Mercury’s Harms?” posted January 30, 2015.

The Bottom Line:
Take a stand against coal-fired power plants, limit high mercury fish, and take your omega 3s.

Source: February 3, 2015 National Institutes of Health