Navigation Links
Landmark USGS study
Date:5/1/2009

WASHINGTON, D.C. - A new landmark study published today documents for the first time the process in which increased mercury emissions from human sources across the globe, and in particular from Asia, make their way into the North Pacific Ocean and as a result contaminate tuna and other seafood. Because much of the mercury that enters the North Pacific comes from the atmosphere, scientists have predicted an additional 50 percent increase in mercury in the Pacific by 2050 if mercury emission rates continue as projected.

"This unprecedented USGS study is critically important to the health and safety of the American people and our wildlife because it helps us understand the relationship between atmospheric emissions of mercury and concentrations of mercury in marine fish," said Secretary of the Interior Ken Salazar. "We have always known that mercury can pose a risk, now we need to reduce the mercury emissions so that we can reduce the ocean mercury levels."

"This study gives us a better understanding of how dangerous levels of mercury move into our air, our water, and the food we eat, and shines new light on a major health threat to Americans and people all across the world," said EPA Administrator Lisa P. Jackson. "With this information in hand, plus our own mercury efforts, we have an even greater opportunity to continue working with our international partners to significantly cut mercury pollution in the years ahead and protect the health of millions of people."

Water sampling cited in the study shows that mercury levels in 2006 were approximately 30 percent higher than those measured in the mid-1990s. This study documents for the first time the formation of methylmercury in the North Pacific Ocean. It shows that methylmercury is produced in mid-depth ocean waters by processes linked to the "ocean rain." Algae, which are produced in sunlit waters near the surface, die quickly and "rain" downward to greater water depths. At depth, the settling algae are decomposed by bacteria and the interaction of this decomposition process in the presence of mercury results in the formation of methylmercury. Many steps up the food chain later, predators like tuna receive methylmercury from the fish they consume.

One unexpected finding from this study is the significance of long-range transport of mercury within the ocean that originates in the western Pacific Ocean, off the coast of Asia.

"Mercury researchers typically look skyward to find a mercury source from the atmosphere due to emissions from land-based combustion facilities. In this study, however, the pathway of the mercury was a little different. Instead, it appears the recent mercury enrichment of the sampled Pacific Ocean waters is caused by emissions originating from fallout near the Asian coasts. The mercury-enriched waters then enter a long-range eastward transport by large ocean circulation currents," said USGS scientist and coauthor David Krabbenhoft.

Scientists sampled Pacific Ocean water from 16 different sites between Honolulu, Hawaii and Kodiak, Alaska. In addition, the scientists constructed a computer simulation that links atmospheric emissions, transport and deposition of mercury, and an ocean circulation model.

In the United States, about 40 percent of all human exposure to mercury is from tuna harvested in the Pacific Ocean, according to Elsie Sunderland, a coauthor of the study. Methylmercury is a highly toxic form of mercury that rapidly accumulates in the food chain to levels that can cause serious health concerns for those who consume the seafood. Pregnant women who consume mercury can pass on life-long developmental effects to their children. That is why in 2004 EPA and FDA issued the landmark Joint Guidance on the Consumption of Fish specifically targeted towards pregnant women and nursing mothers. Previous studies show that 75 percent of human exposure worldwide to mercury is from the consumption of marine fish and shell fish.

Scientists have known for some time that mercury deposited from the atmosphere to freshwater ecosystems can be transformed (methylated) into methylmercury, but identifying the analogous cycles in marine systems has remained elusive. As a result of this study we now know more about how the process which leads to the transformation of mercury into methylmercury.


'/>"/>

Contact: Joan Moody
Joan_Moody@ios.doi.gov
202-208-6416
United States Geological Survey
Source:Eurekalert

Related medicine news :

1. Document Security Systems (Amex: DMC) Invites You to a Landmark Event
2. Less than one-third of women aware of landmark hormone therapy study, Stanford researcher finds
3. Pathway to cell death redefined in landmark study
4. Pathway to cell death redefined in landmark study
5. UCLA to lead local study center in landmark government study of child health
6. Landmark Report: Excess Body Fat Causes Cancer
7. In Landmark Phase III Head-to-Head Study, Prasugrel Statistically Superior to Clopidogrel in Reducing Risk of Heart Attack
8. Landmark trial to evaluate cardioprotective properties of insulin
9. Safeway Inc. and the Prostate Cancer Foundation to Fund Landmark Prostate Cancer Research Collaboration
10. Yale launches landmark VIRGO study of young women with heart disease
11. Hospital Launches Landmark Project in Emergency Medicine
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/27/2016)... California (PRWEB) , ... June 27, 2016 , ... "FCPX ... fully customizable inside of Final Cut Pro X," said Christina Austin - CEO of ... unique style. Final Cut Pro X users can now reveal the media ...
(Date:6/26/2016)... , ... June 27, 2016 , ... Quality metrics are ... in many ways they remain in the eye of the beholder, according to experts ... publication of The American Journal of Managed Care. For the full issue, click ...
(Date:6/26/2016)... Clarkston, Michigan (PRWEB) , ... June 26, 2016 ... ... respect to fertility once they have been diagnosed with endometriosis. These women need ... but they also require a comprehensive approach that can help for preservation of ...
(Date:6/25/2016)... ... 2016 , ... First Choice Emergency Room , the largest network of ... Medical Director of its new Mesquite-Samuell Farm facility. , “We are pleased to ... said Dr. James M. Muzzarelli, Executive Medical Director of First Choice Emergency Room. ...
(Date:6/24/2016)... Angeles, CA (PRWEB) , ... June 24, 2016 , ... ... surgery procedures that most people are unfamiliar with. The article goes on to state ... procedures, but also many of these less common operations such as calf and cheek ...
Breaking Medicine News(10 mins):
(Date:6/26/2016)... June 27, 2016 Jazz Pharmaceuticals plc (Nasdaq: ... under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as ... Celator Pharmaceuticals, Inc. ("Celator"; Nasdaq: CPXX ) ... Daylight Time). As previously announced on May ... definitive merger agreement under which Jazz Pharmaceuticals has commenced ...
(Date:6/24/2016)... June 24, 2016  Consumers have taken a ... have placed more emphasis on patient outcomes. ... programs in the pharmaceutical industry have evolved beyond ... pharmaceutical companies are focusing on becoming more patient-oriented ... products and services that improve health. ...
(Date:6/24/2016)... June 24, 2016   Bay Area Lyme ... Dean Center for Tick Borne Illness , ... Rehabilitation, MIT Hacking Medicine, University of California, Berkeley, ... announced the five finalists of Lyme Innovation ... More than 100 scientists, clinicians, researchers, entrepreneurs, and ...
Breaking Medicine Technology: