Nav: Home

Identifying factors that influence mercury levels in tuna

January 23, 2019

Most consumers' exposure to toxic methylmercury occurs when they eat fish. But research just published in the ACS journal Environmental Science & Technology could help clarify why methylmercury concentrations in tuna vary geographically.

Inorganic mercury compounds are released into the atmosphere from natural sources, such as volcanoes, and human-based sources, such as fossil fuel combustion and gold mining. Some of these compounds settle onto oceans, where natural processes convert them into methylmercury. This substance is then naturally transferred to sea creatures, including tuna, which sometimes contain amounts exceeding food safety guidelines. David Point, Anne Lorrain, Valérie Allain and colleagues wanted to map regional variations in methylmercury levels in tuna and to investigate the biological, environmental and ecological factors that drive these variations.

The scientists studied bigeye, yellowfin and albacore tuna captured in a region known as the Western and Central Pacific Ocean (WCPO). The researchers found that methylmercury levels were below food safety guidelines for most of the samples. In addition, they confirmed earlier findings from other ocean regions that body size is the primary factor in determining contamination within a species, with bigger fish accumulating a higher concentration of methylmercury in their tissues than smaller fish. They found that sea-surface temperature and the depth of the ocean layer in which tuna feed also affect this concentration. The team developed a model that draws on these findings to predict methylmercury levels in tuna. The model worked well for WCPO, as well as for the North Central and Central Equatorial Pacific Oceans, though it underestimated levels in fish from the Eastern Equatorial Pacific Ocean. The researchers say that their results could help in evaluating the risks and benefits of eating tuna caught in a particular location, or tuna of different sizes.
-end-
The authors acknowledge funding from the Grand Observatoire du Pacifique Sud, the Pacific Fund VACOPA project, the Pacific Community, Government of New Caledonia, the Institut de Recherche pour le Développement and the French National Research Agency MERTOX project.

The paper's abstract will be available on Jan. 23 at 8 a.m. Eastern time here: http://pubs.acs.org/doi/abs/10.1021/acs.est.8b06058.

The American Chemical Society, the world's largest scientific society, is a not-for-profit organization chartered by the U.S. Congress. ACS is a global leader in providing access to chemistry-related information and research through its multiple databases, peer-reviewed journals and scientific conferences. ACS does not conduct research, but publishes and publicizes peer-reviewed scientific studies. Its main offices are in Washington, D.C., and Columbus, Ohio.

To automatically receive news releases from the American Chemical Society, contact newsroom@acs.org.

Follow us: Twitter | Facebook

American Chemical Society

Related Methylmercury Articles:

Newly identified microbial process could reduce toxic methylmercury levels
A team led by the Department of Energy's Oak Ridge National Laboratory has identified a novel microbial process that can break down toxic methylmercury in the environment, a fundamental scientific discovery that could potentially reduce mercury toxicity levels and support health and risk assessments.
Mystery of the missing mercury at the Great Salt Lake
Around 2010, the deep waters of Utah's Great Salt Lake contained high levels of toxic methylmercury.
'Super sponge' promises effective toxic clean-up of lakes and more
Mercury is very toxic and can cause long-term health damage, but removing it from water is challenging.
Fish and mercury: Detailed consumption advisories would better serve women across US
Among women of childbearing age in the US, fish consumption has increased in recent years while blood mercury concentrations have decreased, suggesting improved health for women and their babies, a new study shows.
Fluorescence method detects mercury contamination in fish
Researchers from the University of Burgos (Spain) have developed a fluorescent polymer that lights up in contact with mercury that may be present in fish.
New study identifies organic matter composition as a critical factor controlling mercury methylation
Swedish researchers at Uppsala and Umeå universities now show that the formation of methylmercury in sediment is controlled by the molecular composition of the organic matter.
Toxic mercury in aquatic life could spike with greater land runoff
A highly toxic form of mercury could jump by 300 to 600 percent in zooplankton -- tiny animals at the base of the marine food chain -- if land runoff increases by 15 to 30 percent, according to a new study.
Climate changes may lead to more poisonous mercury in plankton
Global warming is expected to increase runoff and input of organic matter to aquatic ecosystems in large regions of the Northern hemisphere including the Baltic Sea.
Bacteria control levels of dangerous pollutant in seabirds
Researchers have discovered that levels of mercury in seabirds off the coast of British Columbia have remained relatively stable over the past 50 years.
Quantifying the hidden environmental cost of hydroelectric dams
Hydroelectricity is a renewable energy, and the facilities that produce it give off less greenhouse gases than other power plants.

Related Methylmercury Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Changing The World
What does it take to change the world for the better? This hour, TED speakers explore ideas on activism—what motivates it, why it matters, and how each of us can make a difference. Guests include civil rights activist Ruby Sales, labor leader and civil rights activist Dolores Huerta, author Jeremy Heimans, "craftivist" Sarah Corbett, and designer and futurist Angela Oguntala.
Now Playing: Science for the People

#521 The Curious Life of Krill
Krill may be one of the most abundant forms of life on our planet... but it turns out we don't know that much about them. For a create that underpins a massive ocean ecosystem and lives in our oceans in massive numbers, they're surprisingly difficult to study. We sit down and shine some light on these underappreciated crustaceans with Stephen Nicol, Adjunct Professor at the University of Tasmania, Scientific Advisor to the Association of Responsible Krill Harvesting Companies, and author of the book "The Curious Life of Krill: A Conservation Story from the Bottom of the World".