Quantcast
Science
Gates of the Arctic National Park, Alaska. Plants on the Arctic tundra absorb mercury from the air, then transfer it to soil when they die. Paxson Woelber / Flickr

Mercury From Industrialized Nations Is Polluting the Arctic—Here’s How It Gets There

By Daniel Obrist

Scientists have long understood that the Arctic is affected by mercury pollution, but know less about how it happens. Remote, cold and seemingly pristine, why is such an idyllic landscape so contaminated with this highly toxic metal?

I recently returned from a two-year research project in Alaska, where I led field research into this issue alongside fellow scientists from the University of Colorado; the University of Nevada's Desert Research Institute; the University of Toulouse and the Sorbonne University in France; and the Gas Technology Institute in Illinois.


Our work was the most comprehensive investigation to date of how mercury is deposited to the Arctic tundra, a vast northern ecosystem surrounding the Arctic Ocean. Our findings show that the gaseous form of mercury—emitted by coal-burning, mining and other industrial processes in the industrialized world—is being lofted into the region from thousands of miles away. In the Arctic, it is deposited onto tundra soils and ultimately runs off into ocean waters, threatening the region's wildlife and people.

Tracing Mercury's Pathways

Industrialized and developing nations emit about 2,000 tons of mercury into the atmosphere every year. Globally, the largest sources include emissions from small-scale and artisanal gold mining and coal-burning power plants.

Mercury emissions from the eight highest emitting industry sectors. Data for 2010 from the 2013 UNEP Global Mercury Assessment. Total estimated global anthropogenic mercury emissions are 1960 metric tons. USEPA

Mercury emissions from human activities take several forms that behave differently in the atmosphere Oxidized mercury, notated as Hg(II), generally settles or is rained out of the atmosphere close to emission sources. In contrast, gaseous elemental mercury or Hg(0), remains in the atmosphere for a long time and can travel around the globe.

In the Arctic, high levels of mercury are found in beluga whales, polar bears, seals, fish, eagles and other birds. This means that humans are also affected, particularly the Inuit, who rely on traditional hunting and fishing for food. Exposure to high levels of mercury over long periods can lead to neurological and cardiovascular problems. Scientists have been working for more than two decades to determine how mercury makes its way from industrialized countries to the Arctic.

From Atmosphere to Plants to Soil

From our observation site north of Alaska's Brooks Range, we determined that gaseous elemental mercury in the atmosphere is the dominant source of Arctic mercury. We calculated that it accounted for 70 percent of the mercury that finds its way into tundra soil. Previous studies focused mainly on deposition of airborne oxidized mercury. However, we estimate that oxidized mercury accounts for less than one-third of mercury deposition, and deposition by rain and snow for only 2 percent.

The next question is how gaseous mercury falls to the ground. We found that plants absorb it from the atmosphere in their leaves, much as they take up carbon dioxide. Then, when the plants shed leaves or die, the mercury they contain is deposited in soil.

This likely explains why runoff from tundra soil to the Arctic Ocean—which other researchers have estimated totals 50 to 85 tons per year—accounts for half to two-thirds of total mercury input into the Arctic Ocean. There, it can be converted to highly toxic organic methylmercury. As larger animals eat smaller animals, it biomagnifies through the aquatic food chain to harmful levels.

It could get worse. Our study did not examine the potential impact of global warming, but if climate change continues unchecked, warmer temperatures could destabilize mercury deposits in permafrost soils and allow even larger amounts to migrate into Arctic waters.

Cumulative atmospheric deposition of major mercury forms in the Arctic tundra. Obrist et al, Nature 547, 201–204 (July 13)

Fingerprinting Mercury Sources

We gathered our Arctic data year-round—a tall order in a place with long, dark winters when temperatures plunge to 40 degrees Fahrenheit below zero. Summers also pose challenges, especially with clouds of mosquitoes.

We used a lab set up on the tundra, which we visited regularly to calibrate and service our instruments and to collaborate with staff from Toolik Field Station, a research station operated by the University of Alaska at Fairbanks. Our instrumentation included measurements of all major forms of mercury in all environmental compartments, including the atmosphere, snow, rain, plants, lichen, mosses, and tundra soils and permafrost.

Many of our instruments allowed continuous measurements throughout the year via remote control. We needed to measure mercury levels year-round in order to develop annual mercury deposition mass balances—estimates of how much mercury was entering the Arctic from different sources and where it goes. In addition, my collaborators from France performed measurements of stable mercury isotopes—a novel and powerful technique that allowed us to fingerprint various sources of mercury in the environment.

Science to Support Global Action

Our research underscores the importance of the Minamata Convention on Mercury, the first global treaty designed to protect human health and the environment from this element's adverse effects. More than 120 countries, including the United States, have signed the convention, which took effect in August 2017.

The pact requires member nations to phase out or reduce mercury from products such as batteries, certain lightbulbs, cosmetics and pesticides. They also must control mercury air emissions from coal-fired power plants, waste incineration and related industrial processes, and reduce or eliminate mercury use in small-scale gold mining and chemical manufacturing.

Following on this study, I plan to continue investigating whether gaseous mercury is also a dominant source of pollution in other remote lands, and the mechanism of plant mercury uptake, which may be the main pathway for atmospheric mercury deposits to land. Scientists, regulators and policymakers need a better understanding of how the uptake of gaseous mercury in plants and soils is affecting the environment, including the world's forests. With the Minamata Convention as a framework, many nations will need this kind of scientific information to reduce toxic mercury hazards.

Reposted with permission from our media associate The Conversation.

Show Comments ()

EcoWatch Daily Newsletter

Sponsored
Popular
Kingborough Council

Tasmania Builds Road From Single-Use Plastics, Glass and Printer Toner

A local government in Tasmania found a clever way to recycle single-use plastics and other landfill-bound waste by building a new road.

The 500-meter (1,640-foot) stretch outside the city of Hobart is made of approximately 173,600 plastic bags and packaging, as well as 82,500 glass bottle equivalents diverted from landfill, the Kingborough council announced Tuesday.

Keep reading... Show less
Popular
Alchemy Goods / Bambaw / LuminAID

EcoWatch's Favorite Green Gifts for the Holidays

The holidays are coming and if you're stuck on what to give your eco-conscious friend or relative, we've got you covered. At EcoWatch, we're big fans of homemade presents, products that actually help the planet, and putting our dollars towards a good cause. This year, our staff has rounded up some of the best green gifts we've given and received, as well as the items on our wish list.

Keep reading... Show less
Politics
U.S. Department of Agriculture / Flickr / CC BY 2.0

Senate Approves Farm Bill

By Dan Nosowitz

The Farm Bill, which is supposed to be passed about every five years but which has for the past few been substantially delayed, finally saw the Senate floor Thursday, where it passed by a vote of 87 to 13.

Keep reading... Show less
Animals
Mtwrighter / CC BY-SA 4.0

Most Diverse Butterfly Center in the U.S. to be Bulldozed for Trump’s Border Wall

The National Butterfly Center in Mission, Texas is the most diverse butterfly sanctuary in the U.S. Some 200 species of butterflies find a home there each year, including the Mexican bluewing, the black swallowtail and the increasingly imperiled monarch. And, as soon as February, almost 70 percent of it could be lost to President Donald Trump's border wall, The Guardian reported Thursday.

Keep reading... Show less
Sponsored
Energy
McAfee Knob along the Appalachian Trail in Virginia. Appalachian Trail Conservancy / NPS

Court Tosses Controversial Pipeline Permits, Rules Forest Service Failed to ‘Speak for the Trees’

The Lorax would not approve of the Atlantic Coast Pipeline—the controversial pipeline intended to carry fracked natural gas through 600 miles in Virginia, West Virginia and North Carolina. That's the sentiment behind a ruling by a Virginia appeals court Thursday tossing out a U.S. Forest Service permit for the pipeline to cross 21 miles of national forest in Virginia, including a part of the Appalachian Trail, The News & Observer reported.

Keep reading... Show less
Business
The Overpass Light Brigade at Bascom Hall in Madison, Wisconsin on April 4, 2014. depthandtime / Flickr

Global Divestment Movement Celebrates Milestone: 1,000 Institutions With Nearly $8 Trillion in Assets Have Vowed to Ditch Fossil Fuels

By Jake Johnson

While the COP24 climate talks are at risk of ending without a concrete plan of action thanks in large part to the Trump administration's commitment to a dirty energy agenda, environmental groups on Thursday celebrated a major milestone in the global movement to take down the fossil fuel industry after the number of public and private institutions that have vowed to divest from oil, gas and coal companies surpassed 1,000.

Keep reading... Show less
Sponsored
Food

Slaughter-Free Lab Grown Steak Cast As Ethically Friendly Alternative

Lab-grown meat—also known as cultured meat or in vitro meat—is often cast as an environmentally and ethically friendly alternative to raising traditional livestock.

These slaughter-free products aren't available on the market yet, but the dream is so enticing that Bill Gates, Richard Branson and even Tyson Foods—one of the country's largest meat companies—have made big bets on it.

Keep reading... Show less
Energy
Northeast National Petroleum Reserve in Alaska. Bob Wick / BLM

Trump Administration's Alaska Oil and Gas Lease Sale a 'Major Flop'

Despite the Trump administration's unrelenting quest to drill the Arctic, Wednesday's oil and gas lease sale in the National Petroleum Reserve-Alaska (NPR-A) yielded a "disappointing" return of $1.5 million, E&E News reported.

Oil and gas giants ConocoPhillips, Emerald House and Nordaq Energy were the three companies that made uncontested bids on 16 tracts of land out of 254 tracts made available by the Bureau of Land Management's (BLM) annual sale in the western Arctic.

Keep reading... Show less
Sponsored

mail-copy

The best of EcoWatch, right in your inbox. Sign up for our email newsletter!