Pan-seared Walleye with a Dash of PCBs and Mercury | wisconsinacademy.org
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Pan-seared Walleye with a Dash of PCBs and Mercury

Tue, 09/15/2015 - 11:35am -- Jane Elder

What if there were a way to reduce toxic chemicals in our Great Lakes and inland waters, while reducing greenhouse gasses, and improving air quality? I think there is a way, and I’ve been working on it for a long time. Let’s start at the beginning.

I love Lake Superior. My mother grew up close to its shores, and I like to think that part of my DNA was formed in the embrace of water molecules from the cold, clear waters of the greatest of the Great Lakes—not a bad place to begin one’s journey in life.

Whether it was her childhood stories and nostalgia, or my own growing fascination, by the time I reached adulthood, the Great Lakes weren’t just in my DNA, but had become a passion. I also grew up in an era when their greatness was in peril. Life magazine declared Lake Erie “dead,” rivers from Indiana’s Calumet to Ohio’s Cuyahoga were catching fire, dead alewives were washing up in stinking heaps on Lake Michigan shores, eagles and other birds of prey were failing to hatch young, and sea lampreys were sucking the life out of lake trout.

In 1972, just two years after the first Earth Day, the U.S. Congress voted to override President Nixon’s veto and the modern Clean Water Act became law. That same year, after extensive negotiations, Nixon and Canada’s Prime Minister Pierre Trudeau signed the first Great Lakes Water Quality Agreement. This agreement, along with new domestic laws in each nation, formed the foundation of a new strategy to protect and restore the Great Lakes.

President Nixon and Canadian Prime Minister sign the historic Great Lakes Water Quality Agreement in 1972.

Part of the genius of the original Great Lakes Water Quality Agreement was its two advisory boards—one to support collaboration among the domestic federal, state, and provincial water quality agencies, and another to provide scientific advice. The Science Advisory Board (SAB) was unique, in that its primary constituents were the lakes and the International Joint Commission (IJC) overseeing the agreement, and not the domestic agencies or administrations of either nation. As such, it enjoyed a type of independence and freedom of inquiry rare in today’s domestic agencies. It became a driving force for finding answers to some of the most vexing problems in the lakes.

One of those problems was the rising presence of toxic pollution. In an era where dilution was considered a viable strategy for managing pollution, the lakes seemed too vast to be at risk. But the data was telling another story. While aggressive interventions to clean up sewage and farm runoff helped Lake Erie recover rapidly, it was the compounds we couldn’t see that were more insidious. 

On the Wind, In the Water, In Your Fish

By 1977, the SAB was raising concerns about the presence of Polychlorinated biphenyls (PCBs), banned pesticides (like DDT), heavy metals such as mercury, and other toxic chemicals accumulating in Great Lakes fish. The questions they asked and the research they drove led to startling findings over the next decade. We learned that the vast majority of toxic chemicals in the upper lakes (Superior, Michigan, and Huron) were coming from deposition from the atmosphere. While there was a growing uproar about acid rain, no one had bargained for toxic rain. Moreover, while some of the sources were local, many were regional or global. Scientists discovered the boll weevil pesticide Toxaphene in lake trout flesh in an inland lake on Isle Royale in Lake Superior—far from American cotton fields, along with “fresh” DDT—a substance banned in the United States in 1972. 

Dilution strategies don’t work in biological food webs when chemicals don’t dissolve and easily break down, and most on the list were these kinds of robust chemicals. These get passed up the food chain and around the food web and stored in the tissues of the predators that accumulate everything their prey have already stored—a process known as bioaccumulation.

The exponential concentration among the top predators boggles the mind. I remember one statistic in particular: a person would have to drink 40,000 glasses of water to get the same dose of PCBs as one lake trout or Great Lakes salmon fillet.

And humans weren’t the only consumers of these fish. Other fish, birds of prey from eagles to loons, colonial shore birds (such as gulls, terns, cormorants), and many other players in the rest of the food web were also eating and storing these contaminants.

Crossed bills and other birth defects in Great Lakes cormorants were correlated with PCB exposure in their habitats, as the cormorants are correlated, but their defects are.

In the 1980s, scientists found birth defects and hatching failures in cormorant colonies and mercury poisoning in loons. In one of the few human health studies, researchers found learning and behavioral deficits in children whose mothers ate large amounts of Great Lakes fish were correlated with PCB exposure.

And so I got involved, as did many others. Every Great Lakes state and province developed fish consumption advisories on what fish were safe to eat, for whom, and how often.  The scientists also helped us learn that the PCBs, dioxin and furan compounds, DDT and its metabolites, and other pesticides such as Aldrin, Dieldrin, and Lindane have chemical structures (benzene rings with attached chlorine or bromine atoms) that make them accumulate in fat. As a result, trimming out the dark flesh and skipping the skin on fish helps reduce exposure. Methyl mercury, however, binds strongly to chemical groups found in fish tissue, so you really can't reduce exposure by cleaning the fish.

Out of a much larger list, the IJC identified about a dozen very serious contaminants. Because many of these chemicals were already banned from use (although in some cases, not from manufacture or export) the solutions were complicated. Cleaning up contaminated harbor and river sediments was one strategy, additional bans another, and regulation of new emissions yet another. In my role as Sierra Club’s Great Lakes Program Director, I slaved to strengthen Section 112 of the 1990 Clean Air Act, by working to add language on research that could trigger regulation for the airborne troublemakers if they polluted the Great Lakes or other “great waters.” I was at home watching the House of Representatives debate the final version of the bill on the floor on C-Span, waiting for the big victory. But instead I watched a surprise play to exempt electrical utilities when it came to mercury. Even though the law passed with mercury still on the big list of toxic chemicals, the floor amendment was a preview of stalling tactics to come. There’s been aggressive foot-dragging ever since to delay or prevent regulations on mercury emissions from coal-burning power plants.

Later that summer, we were on a family trip to the Boundary Waters Canoe Area Wilderness with nephews from Florida. It was sad to see their excitement to fish with their dad tempered with the signs at the boat launch warning us about fish contamination. No child’s memories of fishing should be tainted with these unfortunate reminders about the condition of their environment.

My nephews were thrilled to be fishing in the apparently pristine waters of the Boundary Waters Canoe Area—and devastated when we had to tell them the fish were unsafe to eat.

I found this Fish Advisory statement from the US Forest Service at our launch point.

Mercury is Still a Growing Problem

We have made remarkable progress in reducing the levels of nearly all other most serious contaminants (although PCB levels seem to have reached a troublesome steady state after initial declines). But mercury is still a different story. A quarter of a century after that floor vote, mercury remains one of the most widespread and harmful contaminants in fish around the world, and also right at home. If you eat fish from the oceans or the Great Lakes, or your favorite pristine lake “up north,” you are sharing in the grim bounty of mercury pollution stored in the tissues of Earth’s food web. Your Wisconsin fishing license still notes that women of childbearing years and all children under 15 should limit their consumption of popular and delectable game fish like walleye to once a month, and to skip some fish entirely (See this guide to learn more).

If you are also eating ocean fish such as tuna or swordfish on a regular basis, you need to factor them into your monthly mercury math as well. It’s such a shame that such a great source of protein and nutrients has been compromised around the globe.

Current fish advisories in Wisconsin, from the Wisconsin Department Natural Resources.

Mercury is still on the advisory list, more than three decades after we knew it was a contaminant.  Mercury is still a big deal if you are a child, a pregnant or nursing mother, or a woman who wants to have children.

And so I take the 21-year lag between the Clean Air Act’s 1990 reauthorization, and the 2011 federal mercury rule personally, as well as the recent Supreme Court objection to it. It is mitigated somewhat by Wisconsin’s historic action to regulate mercury emissions at the state level which took effect in 2002 and was strengthened in 2007. Nearly all our largest power plants have already installed control equipment to achieve a 90% reduction. So in many ways, we’re ahead of the game, but we’re not in this alone. 

The largest source of mercury in the atmosphere is coal-burning power plants. Coal-burning power plants are also one of the largest sources of the gasses that cause global climate change. The vast majority of Wisconsin’s electricity—62%—is produced by coal-burning plants. Even with the progress we’ve made, we’re still part of the problem.

So if we can’t muster up the national courage to reduce emissions through rules on mercury directly, then let’s go for the wholesale approach, and reduce the overall emissions from these plants by shifting to cleaner sources. This will give us multiple benefits: cleaner air overall, less carbon emissions (greenhouse gasses), and less mercury in the atmosphere, and thus, less mercury in our fish, our bodies, and our offspring. The EPA’s Clean Power Plan might just be the trifecta strategy to get us all three. Are there costs? Sure. There are also plenty of costs—many of them hidden but directly affecting precious human health—associated with the status quo. If the Clean Power Plan or some similar bold strategy doesn’t move forward, I fear that 25 years from now, there will still be advisories for fish consumption, asthma rates will still be high, and our biggest opportunity to take meaningful action on climate change when it could have made a critical difference will have passed us by. We face important choices that can make great strides; let’s not let this one slip away.

In the meantime, bon appetit.

Contributors

Jane Elder is executive director of the Wisconsin Academy. She brings to the Wisconsin Academy a strong background in public policy leadership, nonprofit management, and involvement in Wisconsin arts. Her career has focused on environmental policy and communications, while personal interests include theater, modern dance and painting.

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