New research showing that that mercury levels are higher in some species of tuna could help consumers minimize their consumption of the silvery metal in their sushi and provide a powerful new tool for regulatory organizations.
The new research—combining DNA barcoding at that American Museum of Natural History with analysis of mercury content at Rutgers University—is published in Biology Letters early online edition and shows surprisingly that tuna sushi purchased in supermarkets might be healthier than that from restaurants. The sushi made for supermarkets tends to be yellowfin tuna.
"We found that mercury levels are linked to specific species," says Jacob Lowenstein, a graduate student affiliated with the Museum. "So far, the U.S. does not require restaurants and merchants to clarify what species they are selling or trading, but species names and clearer labeling would allow consumers to exercise greater control over the level of mercury they imbibe."
"People who eat fish frequently have a particular need to know which species may be high in contaminants," says Michael Gochfeld, professor at Robert Wood Johnson Medical School. "Some agencies have been afraid that any mention of contaminants will discourage people from eating any fish.Sushi samples for this research project were taken from 54 restaurants and 15 supermarkets in New York, New Jersey, and Colorado. The results are based on 100 samples, all of which were identified with DNA barcoding as either bigeye tuna (Thunnus obesus), yellowfin tuna (Thunnus albacares), or bluefin tuna species (Thunnus maccoyii, Thunnus orientalis, and Thunnus thynnus). All samples were tested for relative mercury content.
But there also seem to be other factors in play. Although yellowfin tuna is very lean, this species tends to have lower accumulation of mercury, likely because yellowfin are typically smaller than other tuna and are harvested at a younger age. Furthermore, yellowfin are tropical and do not thermoregulate like the warm-blooded bigeye tuna and bluefin tuna. Because bigeye and bluefin species eat three times more than yellowfin to maintain their energy level, they might bioaccumulate, or slowly increase the level of toxins over time.
"Although levels are highest in top-level predatory fish, some fish that are lower on the food chain have high levels," says Joanna Burger, professor at Rutgers University. "The levels of mercury in some tuna are sufficiently high to provide a health risk both to the fish themselves and to the predators that eat them, including humans, particularly those who eat fish frequently."
"We show how you can use DNA as a tool to uncover patterns of species-specific bioaccumulation," says Sergios-Orestis Kolokotronis, a geneticist at the Sackler Institute for Comparative Genomics at the Museum. "This is one of first applications of DNA barcodes in a non-academic setting—using this method in any human health context and not just for determining whether barcodes can quickly and accurately identify a species."
In addition to Kolokotronis, Gochfeld, Burger, and Lowenstein, authors include George Amato, director of the Sackler Institute for Comparative Genomics at the Museum, and Christian Jeitner of the Environmental and Occupational Health Sciences Institute at Rutgers University. This research was funded by the Alfred P. Sloan Foundation, the Richard Lounsbery Foundation, Columbia University, Rutgers University, and the National Institute for Environmental Health Sciences. The New York Times' food editor Marian Burros collected 20 of the samples for a story on mercury in sushi which were later barcoded and included in this analysis.
Kristin Elise Phillips | EurekAlert!
Individual Receptors Caught at Work
19.10.2017 | Julius-Maximilians-Universität Würzburg
Rapid environmental change makes species more vulnerable to extinction
19.10.2017 | Universität Zürich
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
19.10.2017 | Materials Sciences
19.10.2017 | Materials Sciences
19.10.2017 | Physics and Astronomy