Asian Mercury Crossing the Ocean

NOAA

Let our journalists help you make sense of the noise: Subscribe to the Mother Jones Daily newsletter and get a recap of news that matters.


A fascinating new study documents for the first time how mercury gets from smokestacks in Asia to tuna on dinner tables in America. Scientists sampled Pacific Ocean water from 16 sites between Honolulu and Alaska, then constructed a computer model linking atmospheric emissions, transport and deposition of mercury, and ocean circulation.

Their findings published in Global Biogeochemical Cycles show how mercury originating from fossil-fuel-burning plants and waste-burning plants in Asia falls into the Pacific Ocean near the Asian coastline. The mercury-enriched waters are then carried by large ocean currents east towards North America.

The study documents for the first time something of the mysterious process by which mercury becomes methylmercury in the ocean. The simple version: Mercury rained down from the atmosphere is taken up by phytoplankton living in sunlit waters. When these plankton die they rain down into the depths where they’re decomposed by bacteria. The process of decomposition turns mercury into methylmercury.

Methylmercury is an environmental neurotoxicant that rapidly bioaccumulates in the foodweb, eventually concentrating in top-tier predators like tunas and humans. Some 40 percent of human exposure to mercury in the US comes from eating tuna hunted in the Pacific Ocean. Pregnant women who consume mercury-laden seafood can pass on life-long developmental effects to their children.

Since the Industrial Revolution anthropogenic mercury levels in the atmosphere have risen threefold, with corresponding increases in terrestrial and aquatic ecosystems. This study found mercury levels in water samples rose an alarming 30 percent between the mid 1990s and 2006. That’s hardly the end of it though. The authors predict another 50 percent increase in the Pacific by 2050 if emission rates continue as projected.

Yet another reason to we can’t tread water on fossil fuels. Too bad Australia’s Kevin Rudd just did a spineless jellyfish backflip on climate change. As if the economy is disconnected from the environment.
 

DOES IT FEEL LIKE POLITICS IS AT A BREAKING POINT?

Headshot of Editor in Chief of Mother Jones, Clara Jeffery

It sure feels that way to me, and here at Mother Jones, we’ve been thinking a lot about what journalism needs to do differently, and how we can have the biggest impact.

We kept coming back to one word: corruption. Democracy and the rule of law being undermined by those with wealth and power for their own gain. So we're launching an ambitious Mother Jones Corruption Project to do deep, time-intensive reporting on systemic corruption, and asking the MoJo community to help crowdfund it.

We aim to hire, build a team, and give them the time and space needed to understand how we got here and how we might get out. We want to dig into the forces and decisions that have allowed massive conflicts of interest, influence peddling, and win-at-all-costs politics to flourish.

It's unlike anything we've done, and we have seed funding to get started, but we're looking to raise $500,000 from readers by July when we'll be making key budgeting decisions—and the more resources we have by then, the deeper we can dig. If our plan sounds good to you, please help kickstart it with a tax-deductible donation today.

Thanks for reading—whether or not you can pitch in today, or ever, I'm glad you're with us.

Signed by Clara Jeffery

Clara Jeffery, Editor-in-Chief

payment methods

We Recommend

Latest