A federal study released today explains for the first time the link between global mercury emissions and the contamination of tuna and other marine life in the North Pacific Ocean.

The U.S. Geological Survey study [pdf] documents the formation in the North Pacific of methylmercury, a highly toxic form of mercury that rapidly accumulates in the food chain to levels that can cause serious health concerns for people who consume seafood. Scientists have known for some time that mercury deposited from the atmosphere can be transformed into methylmercury, but the study focuses on how that transformation occurs.

USGS showed that methylmercury is produced in mid-depth ocean waters by processes linked to "ocean rain." Algae, which are produced in sunlit waters near the surface, die quickly and "rain" downward to greater water depths. 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, the study shows.

The study unexpectedly reveals the significance of long-range movement of mercury within the ocean that originates in the western Pacific Ocean, off the coast of Asia, USGS scientist and co-author David Krabbenhoft said.

"Mercury researchers typically look skyward to find a mercury source from the atmosphere due to emissions from land-based combustion facilities," Krabbenhoft said in a statement.

"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."

The Obama administration said the study demonstrates the need to curb global mercury emissions.

"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," Interior Secretary Ken Salazar said in a statement.

Scientists have predicted an additional 50 percent increase in mercury in the Pacific Ocean by 2050 if mercury emission rates continue as projected. USGS water sampling shows mercury levels in 2006 were approximately 30 percent higher than those measured in the mid-1990s.

"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," EPA Administrator Lisa Jackson added. "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."

4 Comments

1. 1. fishman 11:09 PM 5/1/09

   Just another reason not to pass "cap and trade" and send more industry over to China and India. These countries do not use scrubbers of any kind. There is no argument except: we need to energy Tax the U.S. . Pushing industry over to countries that use poor cumbustion processes, will increase the amount of mercury raining into the western Pacific.
   Remember: logic, science, econ, skewed data are not to be considered when going ahead with creating a carbon fraud system.
   Food for thought: There are some people dumping tonns of ferris oxcide into the Atlantic O to create carbon credits by feeding plankton and have them trap CO2. The flaw is: the balance in the slow moving water may have a bad eco reaction but who cares, they are creating carbon credits.

   Reply | Report Abuse | Link to this

2. 2. Trent1492 in reply to fishman 10:17 AM 5/2/09

   "Just another reason not to pass "cap and trade" and send more industry over to China and India."
   
   I am not understanding why you think turning this country into another India or China is a good thing, What part of mercury contamination do you not understand?
   
   "These countries do not use scrubbers of any kind."
   
   So since other countries pollute and harm the environment then it OK for the U.S too? Have you ever heard of a tu quoque? Well, your making one.
   
   "Pushing industry over to countries that use poor cumbustion processes, will increase the amount of mercury raining into the western Pacific."
   
   How exactly are the power generating stations of California going to move to China and keep powering California?
   
   "Remember: logic, science, econ, skewed data are not to be considered when going ahead with creating a carbon fraud system."
   
   You did not read the article did you?
   
   "Food for thought: There are some people dumping tonns of ferris oxcide into the Atlantic O to create carbon credits by feeding plankton and have them trap CO2. The flaw is: the balance in the slow moving water may have a bad eco reaction but who cares, they are creating carbon credits."
   
   Here is some food for thought. Not once do you try to account for the staggering costs of what it will and does cost humanity to do nothing.
   
   
   
   

   Reply | Report Abuse | Link to this

3. 3. fishman 11:08 PM 5/4/09

   You are not getting it: people in China and India don't care what you think and stupid people do not understand the combustion process. So drones can't think but only one way, however seeing that we consume lots of shimp from this area, maybe you have your final ravenge aginst the carbon life forms.
   Just what we need, send more steel indust. to the p rim, that is what cap and trade will do. It is time to think to the next step. Cause, action and reaction, can you work this out?
   There is a price to: we don't do it here thinking- or should I say not thinking.
   P.S. good cut and paste job

   Reply | Report Abuse | Link to this

4. 4. galaxy_man in reply to Trent1492 02:56 PM 5/6/09

   I think he was saying that if cap and trade passes it will result in manufacturing industries relocating further to areas where they won't face restrictions. It makes sense, actually; after all, the number one lesson of capitalism is 'reduce overhead', and nothing reduces overhead like flagrantly ignoring safety measures. You are correct that our energy industry will remain, and the emissions they produce are significant. But even the worst one of ours can outperform the best of China's in terms of regulation.
   
   Overall I feel the concept of cap and trade is fundamentally flawed because the worst thing you can give to people you're trying to regulate is the means to create loopholes for themselves. Which is pretty much what cap and trade is doing for emissions. Outright taxation is probably the best way to go, but the companies will make sure only their customers feel that pinch. So what can we do?

   Reply | Report Abuse | Link to this