Once a week.
Subscribe to our weekly newsletter.
How Scientists and the Media Magnify Mercury's Menace
Yet another analysis of the dangers of mercury feeds fears that aren't supported by solid evidence. Fanning false fears hurts people.
A thoughtful new analysis of the benefits of reducing public exposure to mercury adds to several studies suggesting that whatever it costs to make those cuts, either under the U.S. Mercury and Air Toxics Rule (MATS) or the international Minamata Convention, it's worth doing. But like that entire body of work, this new analysis is based on a controversial assumption about just how much harm mercury does in the first place. It turns out that this widely known and feared environmental bogeyman might not be as serious a danger as this new study suggests, which the environmental and science media are mostly failing to report.
The study, by Amanda Giang and Noelle Selin of MIT, (summarized for non-academic speakers here, in full here ) adds up all the health damage mercury is believed to do and assigns a dollar value to that harm. The study estimates that the cumulative value of the direct health benefits in the United States from the “Minamata" reductions total is a whopping: "$339 billion (2005 USD), with a range from $1.4 billion to $575 billion in our sensitivity scenarios."
It also estimates the value to the U.S. economy from reducing the productivity losses caused when mercury pollution makes workers sick: "Cumulative economy-wide benefits to the United States, realized by 2050, are $104 billion, with a range from $6 million to $171 billion."
And compared to achieving reductions the “Minamata" way, the study says the value of the U.S. mercury rule is 10 times greater.
That's a pretty persuasive case that mercury is really bad for us, and that reducing exposure, which comes mostly from seafood, would do us a lot of good. Unfortunately, that case rests on really shaky foundations. It makes a critical assumption that mercury causes cardiovascular problems, particularly heart attacks, even though that assumption is directly contradicted by several careful epidemiological studies. It is fair to say that there is a lot of disagreement and uncertainty in the epidemiological community about the connection between mercury and cardiovascular risk.
Giang and Selin make only a brief mention of that uncertainty in their main paper, and assume that the risk is real. Which doesn't seem honest, since the vast majority of their economic benefit from reduced mercury pollution comes from reduced cardiovascular risk.
If that risk doesn't exist, their whole thesis is shot. They do acknowledge the controversy, but buried in an Appendix, where they acknowledge: "[T]here is substantial uncertainty surrounding the cardiovascular effects of methylmercury." And: "The number of epidemiological studies addressing the cardiovascular impacts of mercury is relatively small." And: "[R]esults from these studies have been inconsistent, with some studies finding positive associations between methylmercury exposure and cardiovascular disease, and others finding no association."
That's an awful lot of doubt about a claim that is central to their findings. Giang and Selin mostly cite studies that support the belief that mercury raises cardiovascular risk. They fail to cite several that explicitly find there is no link between mercury and cardiovascular disease.
Mercury exposure and risk of cardiovascular disease in two U.S. cohorts found "no evidence of any clinically relevant adverse effects of mercury exposure on coronary heart disease, stroke, or total cardiovascular disease in U.S. adults at the exposure levels seen in this study."
Mercury and the risk of coronary heart disease in men reported: "Our findings do not support an association between total mercury exposure and the risk of coronary heart disease, but a weak relation cannot be ruled out."
So how do Giang and Selin justify their assumption of the link? They seem to rest their case on the fact that the EPA held a recent workshop to take the possibility of this risk seriously. But even the EPA says the link is speculative. When the agency did its own cost-benefit evaluation of its mercury rule, it did NOT calculate the benefits of cardiovascular risk reduction, because to the EPA, the evidence of the link just isn't solid enough.
The chart below illustrates what the EPA's own economic evaluation of its MATS rule found. Because it doesn't include the cardiovascular benefits, the reduction in mercury is a miniscule part of the overall benefit, which mostly comes from reducing other more harmful pollutants.
But what about the danger of mercury as a neurotoxin? Both the EPA and the Giang-Selin study also calculate the benefit of lowering mercury pollution and thus reducing the harm it does to the neural health of fetuses and infants. But both analyses find that this economic benefit is tiny, because all the research that identifies mercury as a neurotoxin has found that, at the levels the public is exposed to, mercury does very little harm to the fetus, less than one quarter of an IQ point and similar other minor cognitive deficits (measured when the children grow older). And that harm is counterbalanced by the benefits for healthy neural fetal development from pregnant moms eating the fish. (The fatty acids in the fish help create cells that insulate the wiring connecting neurons in the developing fetal brain.) The neurotoxic risks to the public of mercury in seafood are miniscule. Giang and Selin's numbers, and the EPA's numbers, agree.
Have you read anything about any of this? Probably not. Not about the low level of harm that even high doses of mercury — via seafood exposure — actually does. Not about the big doubts about whether mercury causes any cardiovascular risk at all. What you probably have heard is that mercury is a dangerous neurotoxin and associated with cardiovascular disease and heart attacks, without any of the critical qualifications that put the risk in perspective. That's in part because the news media is fed a constant diet of research findings supporting that more alarmist perspective, like the Giang and Selin study — a careful and thoughtful piece of work, but another academic shot in the Mercury War between those who play up the danger of mercury, and the public health researchers who take a more cautious view of the evidence. Research like the Giang-Selin study, that feeds the accepted wisdom about the danger of mercury, gets reported way more than findings that challenge that accepted wisdom and puts the known risks of mercury in perspective. Stories about scientific controversy don't attract too many readers. Stories about fear and danger do.
As a result, the public is under-informed, and more fearful of mercury than the evidence appears to justify. And that fear does actual harm, because lots of people who are scared of mercury don't eat as much seafood, and miss out on the benefits of that food. Ironically, these are lost cardiovascular benefits from the fatty acids in the fish, benefits that for nearly everyone outweigh mercury's risks.
It's hard enough for people to overcome all the inherent emotions and instincts that shape our perceptions of risk and make us more worried about some threats than we need to be, and less worried about some than we ought to be. It's a whole lot harder when academics are selective with the evidence, and when the journalists we rely on to keep us fairly and fully informed, don't.
image Getty Images; Creative RM, Karen Brinkema
What is human dignity? Here's a primer, told through 200 years of great essays, lectures, and novels.
- Human dignity means that each of our lives have an unimpeachable value simply because we are human, and therefore we are deserving of a baseline level of respect.
- That baseline requires more than the absence of violence, discrimination, and authoritarianism. It means giving individuals the freedom to pursue their own happiness and purpose.
- We look at incredible writings from the last 200 years that illustrate the push for human dignity in regards to slavery, equality, communism, free speech and education.
The inherent worth of all human beings<p>Human dignity is the inherent worth of each individual human being. Recognizing human dignity means respecting human beings' special value—value that sets us apart from other animals; value that is intrinsic and cannot be lost.</p> <p>Liberalism—the broad political philosophy that organizes society around liberty, justice, and equality—is rooted in the idea of human dignity. Liberalism assumes each of our lives, plans, and preferences have some unimpeachable value, not because of any objective evaluation or contribution to a greater good, but simply because they belong to a human being. We are human, and therefore deserving of a baseline level of respect. </p> <p>Because so many of us take human dignity for granted—just a fact of our humanness—it's usually only when someone's dignity is ignored or violated that we feel compelled to talk about it. </p> <p>But human dignity means more than the absence of violence, discrimination, and authoritarianism. It means giving individuals the freedom to pursue their own happiness and purpose—a freedom that can be hampered by restrictive social institutions or the tyranny of the majority. The liberal ideal of the good society is not just peaceful but also pluralistic: It is a society in which we respect others' right to think and live differently than we do.</p>
From the 19th century to today<p>With <a href="https://books.google.com/ngrams/graph?year_start=1800&year_end=2019&content=human+dignity&corpus=26&smoothing=3&direct_url=t1%3B%2Chuman%20dignity%3B%2Cc0" target="_blank" rel="noopener noreferrer">Google Books Ngram Viewer</a>, we can chart mentions of human dignity from 1800-2019.</p><img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDg0ODU0My9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTY1MTUwMzE4MX0.bu0D_0uQuyNLyJjfRESNhu7twkJ5nxu8pQtfa1w3hZs/img.png?width=980" id="7ef38" class="rm-shortcode" data-rm-shortcode-id="9974c7bef3812fcb36858f325889e3c6" data-rm-shortcode-name="rebelmouse-image" />
American novelist, writer, playwright, poet, essayist and civil rights activist James Baldwin at his home in Saint-Paul-de-Vence, southern France, on November 6, 1979.
Credit: Ralph Gatti/AFP via Getty Images
The future of dignity<p>Around the world, people are still working toward the full and equal recognition of human dignity. Every year, new speeches and writings help us understand what dignity is—not only what it looks like when dignity is violated but also what it looks like when dignity is honored. In his posthumous essay, Congressman Lewis wrote, "When historians pick up their pens to write the story of the 21st century, let them say that it was your generation who laid down the heavy burdens of hate at last and that peace finally triumphed over violence, aggression and war."</p> <p>The more we talk about human dignity, the better we understand it. And the sooner we can make progress toward a shared vision of peace, freedom, and mutual respect for all. </p>
Scientists find that bursts of gamma rays may exceed the speed of light and cause time-reversibility.
- Astrophysicists propose that gamma-ray bursts may exceed the speed of light.
- The superluminal jets may also be responsible for time-reversibility.
- The finding doesn't go against Einstein's theory because this effect happens in the jet medium not a vacuum.
Jet bursting out of a blazar. Black-hole-powered galaxies called blazars are the most common sources detected by NASA's Fermi Gamma-ray Space Telescope.
Cosmic death beams: Understanding gamma ray bursts<div class="rm-shortcode" data-media_id="cu2knVEk" data-player_id="FvQKszTI" data-rm-shortcode-id="c6cfd20fdf31c82cb206ade8ce21ba3f"> <div id="botr_cu2knVEk_FvQKszTI_div" class="jwplayer-media" data-jwplayer-video-src="https://content.jwplatform.com/players/cu2knVEk-FvQKszTI.js"> <img src="https://cdn.jwplayer.com/thumbs/cu2knVEk-1920.jpg" class="jwplayer-media-preview" /> </div> <script src="https://content.jwplatform.com/players/cu2knVEk-FvQKszTI.js"></script> </div>
Philosophers have been asking the question for hundreds of years. Now neuroscientists are joining the quest to find out.
- The debate over whether or not humans have free will is centuries old and ongoing. While studies have confirmed that our brains perform many tasks without conscious effort, there remains the question of how much we control and when it matters.
- According to Dr. Uri Maoz, it comes down to what your definition of free will is and to learning more about how we make decisions versus when it is ok for our brain to subconsciously control our actions and movements.
- "If we understand the interplay between conscious and unconscious," says Maoz, "it might help us realize what we can control and what we can't."
Puerto Rico's iconic telescope facilitated important scientific discoveries while inspiring young scientists and the public imagination.
- The Arecibo Observatory's main telescope collapsed on Tuesday morning.
- Although officials had been planning to demolish the telescope, the accident marked an unceremonious end to a beloved astronomical tool.
- The Arecibo radio telescope has facilitated many discoveries in astronomy, including the mapping of near-Earth asteroids and the detection of exoplanets.
Bradley Rivera via twitter.com<p>In 1963, the concave dish was built into a natural sinkhole on the northern coast of Puerto Rico. The location was <a href="https://www.space.com/20984-arecibo-observatory.html" target="_blank">picked because it was near the equator,</a> providing scientists a clear view of planets passing overhead, and also of the ionosphere, which is the uniquely reactive layer of Earth's upper atmosphere where the northern lights form.</p><p>Since its construction, scientists have used the Arecibo telescope to map near-Earth asteroids, detect gravitational waves, study pulsars, detect exoplanets and <a href="https://www.seti.org/goodbye-arecibo" target="_blank">search for alien civilizations</a>, among other projects. Here's a brief look at some of the discoveries and accomplishments made using the Arecibo telescope:</p><ul><li>1964: Astronomer <a href="https://en.wikipedia.org/wiki/Gordon_Pettengill" target="_blank" rel="noopener noreferrer">Gordon Pettengill</a> discovers that Mercury's rotation period is 59 days, significantly shorter than the previous prediction of 88 days.</li><li>1974: Physicists Russell Alan Hulse and Joseph Hooton Taylor Jr. discovers the first binary pulsar, for which they won a Nobel Prize in Physics.</li><li>1974: Scientists use the telescope to transmit the "Arecibo message" to <a href="https://en.wikipedia.org/wiki/Great_Globular_Cluster_in_Hercules" target="_blank" rel="noopener noreferrer">globular star cluster M13</a>. The message, when translated into image form, contains basic information about humanity and human knowledge: the numbers one to 10, a map of our solar system, an illustration of a human being, and the atomic numbers of certain elements.</li><li>1989: Scientists use the telescope to image an asteroid for the first time.</li><li>1992: Astronomers Alex Wolszczan and Dale Frail become the first to discover exoplanets.</li></ul>
The Google-owned company developed a system that can reliably predict the 3D shapes of proteins.