Guest Post by Willis Eschenbach
There’s a new study out called Increase in mercury in Pacific yellowfin tuna by Paul E. Drevnick, Carl H. Lamborg, and Martin J. Horgan. It claims that:
By compiling and re-analyzing published reports on yellowfin tuna (Thunnus albacares) caught near Hawaii (USA) over the past half century, the authors found that the concentration of mercury in these fish currently is increasing at a rate of at least 3.8% per year.
That seemed a bit too neat for me, so I took a deeper look. To their credit, they posted the data as used along with the study. As usual, I started by taking a look at all of the data. There were three samples of tuna studied, which were caught in 1971, 1998, and 2008. Here is a boxplot of the raw data.
Figure 1. Boxplot of the tuna mercury data by year of collection. Width of the box is proportional to the number of data points. Boxes show where half of the data is located. Heavy black line is the median of the data. Notches are the error intervals on the median. Units are parts per million (ppm)
OK, so far, so good. Next, they removed both the big fish and the small fish. They also removed two outliers, which had mercury values of 1.32 and 0.015 ppm. Once those are removed, the result is shown in Figure 2.
Figure 2. As in Figure 1, but for the reduced dataset.
Note that because of the greatly reduced numbers in the 2008 data, the uncertainty notch has become much wider, and the width of the box is smaller.
Finally, they adjust the mercury content for the weight of the fish. This is important because as the fish gains weight, it bioaccumulates mercury. Figure 3 shows what happens to the reduced dataset once the mercury content has been adjusted (either upwards or downwards) depending on the weight of the individual fish.
Figure 3. As in Figure 2, but with the mercury levels adjusted for the weight of the individual fish.
This has made some obvious changes to the results. First, the outliers have been greatly reduced, as has the range of the data. This is because the outliers were heavy fish with lots of mercury, so when they were adjusted their mercury levels came down. And curiously, while there is not a lot of change in the median and spread of the 1971 and 1998 data, the 2008 data has risen significantly. Finally, while the adjustment process reduced the error of the median in 1971 and 1998 data, it actually increased the error of the median in the 2008 data.
Now, these are the results that they claim show that mercury in these tuna is “increasing at a rate of at least 3.8% per year.” I’m sorry, but I’m not seeing that. For starters, if anything the mercury levels fell during the period where we have good data, from 1971 to 1998. That means that the entirety of the purported increase occurred over 10 years, after being stable for nearly thirty years? I’m not buying that claim at all.
So why did the results in 2008 move up so much due to the adjustment by weight? The problem is in the weight distribution of the fish in the three groups. Figure 4 shows the same three groups, but this time it shows the weights of the fish instead of the mercury levels.
Figure 4. Boxplot of the weights of the fish involved in the tuna study.
As you can see, while the distribution of the weights of the fish caught in 1971 and 1998 are quite similar, the 2008 sample are predominantly small fish. In theory, then, the mercury levels in these fish should be increased to bring them in line with the larger fish.
However, there are a couple of problems with that. First, the mercury/weight relationship gets flat down at the lower end. As the authors say:
It was necessary to remove the fish of less than 22 kg from the analysis, because these fish did not adhere to the assumption of linearity. Mercury concentrations in young tuna tend to be low but highly variable [18]. A diet shift occurs in young tuna when a critical body mass is developed that enables endothermic capability to allow access to prey in deeper, colder water [19]. At a certain size (depending on species), likely because of this ontogenetic diet shift, the relationship of mercury concentration versus size conforms to expectations (i.e., a linear relationship).
But here’s the problem with that theory … ugly data. Figure 5 shows the scatterplot of mercury levels versus fish weight.
Figure 5. Scatterplot, fish weight versus raw (unadjusted) mercury levels. Colors indicate the years as in previous figures (red-1971, gold-1998, and blue-2008)
A couple of points stand out here. First, their 22 kg cutoff seems way too low. According to their own data, there is little difference between mercury levels in tuna up to about 40 kg. This means that there will be errors in the adjusted mercury for fish less than 40 kg or so. Second, most of the blue 2008 data is low-weight fish (blue dots) … and as a result, the adjusted mercury levels of the 2008 data will be overestimated. Finally, this preponderance of light weight fish in 2008 is also the reason that the mercury adjustment, rather than reducing the spread of the 2008 data, actually increased the spread of the data.
So to summarize. The 1971 mercury data is statistically indistinguishable from the 1998 data, and the fish have about the same weight distribution. Together, these two groups comprise 94% of the data. They show no change in mercury levels over that twenty-seven year period.
They’ve built their entire claim of an increase in mercury on a mere 14 fish, 6% of the data, which are significantly lighter in weight than the other 94% of the sample. And as Figure 5 shows, it is likely that their adjusted mercury content is overestimated. Fourteen small-fry fish are all they have to hold up their claims? Really? This is almost to the level of the One Yamal Tree farrago.
And in any case, the idea that there would be absolutely no increase in mercury levels for nearly thirty years and then the mercury would jump significantly over the next ten years doesn’t pass the laugh test.
Best to all,
w.
PS-if you disagree with someone, please QUOTE THEIR EXACT WORDS that you disagree with, so that we can all understand the exact nature of your objection.
ALSO-
Folks not familiar with them might be interested in my other posts on mercury, viz:
In the process of writing my piece about Lisa Jackson and the EPA, I got to reading about the EPA passing new mercury regulations. Their regulations are supposed to save the lives of some 11,000 people per year. So I figured I should learn something about mercury. It turned out…
I’ve been puzzling for a while about why the areas with the most power plants aren’t the areas with the worst levels of mercury pollution. Why aren’t the areas downwind from the power plants heavily polluted? I keep running across curious statements like “There was no obvious relationship between large-mouth bass or yellow perch fish…
The EPA’s mercury limits are the one major rule (MATS) that has brought down hundreds of coal-fired utility plants. The amount of mercury from all those plants? A few dozen tons, which is a small fraction of the total estimated releases from all sources.
The EPA found a trace element that could not be economically removed, and used it as a sledgehammer to shut down tens of thousands of otherwise cost-competitive megawatts. One promise that the Obama junta actually kept.
But he’s working hard to “fundamentally change” America.
… into Afghanistan, or a technologically equivalent 3rd world Stone Age h*llhole with a ruling elite living off the peasants. That’s the Progressive dream.
The history of the Mercury and Air Toxics Standards goes back (at least) to 2005, under Bush II. Some of the litigation over mercury emissions started under Bush I. During the years that Republicans controlled Congress, the White House or both, they never revised the Clean Air Act provisions that allow for extremely stringent standards. And if you want to assign blame, don’t forget that the Clean Air Act was signed by Nixon. The EPA itself originated through an Executive Order issued by Nixon.
Hydrargyrumphobia.
[Is that the fear of angry, spinning, multi-headed Washington bureaucrats who graduated from big government universities with Greek sororities? .mod]
Then there’s the term “quick silver” which I haven’t heard in years.
Hydrargyrumphobia is an irrational fear of mercury.
It’s first cousin is plumbumphobia, an irrational fear of lead.
Washington bureaucrats and their partners in the legacy press do not want to know that toxicity is in the dose; it could affect their employment. Tuna has mercury. Chickens have arsenic. It means nothing. 3.8% more of nothing is irrelevant.
Remarkable work Willis, no pidgeon-hole scientist art thou. I see another scientific discovery in the data that the author’s missed. It would seem that generalized knowledge of the subject was learned by fisherman and they kept only the little ones because of it by 2008 (assumes from the small sample numbers that these are sports fisherman catches. Or, alternatively, because of overfishing, the big ones have largely been overcaught in the past and, on average, fish are smaller.
I tried to recall and to research the UBC geology professor who in the 1960s was the first, I believe to detect mercury in fishe: trout livers in the Columbia River near the Cominco smelter (Now Teck Resources). His first name was “Harry” which is what everyone called him so I’ve not remembered his last name! I believe he pioneered the technique. He dried and ashed the livers and (presumably retorted it so that Hg didn’t disappear with heating). I don’t know how they do it today. Detection of ppm of anything was pretty new at the time and had been developed by Finnish geologists to detect anomalous metal levels in soils, river silt, and even water that might come from a mineral deposit . It was widely used in mineral exploration for the first time around that era. I guess we ate mercury without a thought back then.
This comment by Tom was likely the precise response the study was intended to produce.
“””””””Tom February 5, 2015 at 3:33 pm
Maybe it is real, though perhaps not statistically significant yet. I would suspect the recent rise in un-scrubbed coal fired power in China as a possible cause.”””””””””””””
After all if imaginary or meddled with science can point to rising mercury Tom and company will have another reason to cling to the belief in the fossil fuel boogeyman.
Willis, someone else may have already mentioned what I am about to say, but just in case they haven’t, I figure I should. Most journals have the option of other scientists publishing a formal Comment to an article in the same journal, if their argument is strong enough. If it is published, then the original authors also have the opportunity of publishing a Response to the Comment. I think you make a very good case here, and I would encourage you to see if the journal “Environmental Toxicology and Chemistry” accepts formal Comments. If so, I think you should submit this as a Comment to show the weaknesses of their analyses.
Thanks, Data. I’ve done that a couple of times, and there are problems with that approach. First, they generally don’t allow figures, and my work depends heavily on my graphics. Second, they allow the authors to respond, but you can’t reply to the authors’ response … so they get the last word.
Next, the authors will generally say something like “Mr. Eschenbach has failed to indicate why the results of the ANCOVA test ( (F2,223 = 1.17, p = 0.31) should not be considered as definitive proof of our thesis” or the like, and since I can’t respond, even if their claim is total nonsense it sails right on through …
Next, the people who review the Comment will likely be the same ones that foolishly gave a free pass to the shabby paper … do you think they will look on my comment favorably?
Next, the process is slow. By the time such a comment makes it through the process, the original paper has already made its mark and been accepted as true.
Finally, I have only a certain number of hours in my life to do this. In the time it takes to write such a response and argue it through the obviously partisan and uninformed reviewers, I could write three or six analyses such as the one above …
So I put my energy where I feel it can make the most difference. I want to affect the ongoing discussion.
Please don’t get me wrong. There is validity and value in the path you propose.
It’s just not the path for me.
However, if you want to take my findings and write and submit such a comment, I’m glad to sign on as a co-author. Let me know if you’re interested.
Best regards,
w.
Willis, you make great points. Your strongest point is “By the time such a comment makes it through the process, the original paper has already made its mark and been accepted as true.” Millions of people will read or hear this propaganda on the news, so I see your point how it is important to address this poor article on this very widely read website. A Comment, if accepted, on the other hand, will probably only be read by 100 scientists, a year after the original paper was published. The “news” will NEVER revisit this.
Thanks for providing your explanations! And thanks for the great science you regularly share here! What I like about your work is that you let it change your mind, if it doesn’t fit with your preconceptions. I wish all scientists were as open-minded as you.
The concern with mercury is, in reality, somewhere a lot farther up than the amount in the Tuna. I’ve had mercury based fillings in my teeth since about 1950 – they were gradually reduced in recent years, replaced by some plasticky compound that you have to have irradiated with ultraviolet (?). I guess in another decade, I will be reading the horror stories of what that stuff is all about. As a kid, we used to love to play with liquid mercury, coat pennies, roll it around in our hands – I’m sure a few kids swallowed some or licked their fingers after eating their fish and chips. Near Fort St John in northern British Columbia there is an old mercury mine – and there is mercury in virtually every lead-zinc-copper mine in the world. I’m sure a certain amount is good for you. At least at my age I can attest that it isn’t as bad for you as claimed in these small doses.
I remember having a beer with an old uncle of mine in the early 60s when an old friend of my uncle came into the beer parlour (fancy words like that in the old days) with a bag of groceries his wife had sent him out to get. Sticking out the top of his grocery bag was a wrapped smoked Winnipeg goldeye – one of two fish found only in Lake Winnipeg and some clean rivers connected (the other is tulibee – not the common one, the “short-jawed” one). These are superior to salmon when smoked. My uncle said aren’t these supposed to be filled with mercury? And the other old guy said yes, but what you do is hold your lighter under its tail for a few minutes and then quickly cut off its head.
Willis, about your 2012 post on the subject (EPA’s Mercurial Madness:”
Yes, EPA says that the mercury rule would save something like 10 K lives per year. But look a little closer.
None of those alleged lost lives are due to mercury exposure (put a different way, none of the lives allegedly saved are saved due to less mercury).
The “lives saved” are all due to “co-benefits.” EPA means by use of this term that the emissions controls that reduce mercury also reduce emissions of tiny particulate or their precursors. In this case, the emissions controls mean that there are less tiny sulfate particles in the air. EPA takes the position that any amount of tiny particles of any type will kill, and that each “statistically lost life” is valued at about $10.5 million, and that it doesn’t matter if the “statistical person” whose life is lost was a week away from mortality or a year or two (it is thought that “susceptible” people are most likely to be impacted by particles).
You will see by checking the tables in the Regulatory Impact Analysis (RIA) that about 99% of the monetized value of the mercury regulation comes from these “co-benefits.” These “co-benefits” total almost all of the monetized benefits calculated for the regulation in the RIA.
The only monetized benefits from reducing mercury itself are about $6 Million (about 1% of total benefits). Why are they so tiny? Because the only harm that EPA could find, and it is tiny, that would have a chance of being scientifically defended, had to do with reduction of mercury intake by pregnant women eating fresh caught fish in the US.
The benefit was to the IQ of the fetus: to the IQ of the child after it has been borne and raised. The total IQ loss across the entire US, from the 90% reduction in US mercury emissions from US power plants, was calculated to be 511 IQ points, spread across 240,000 children born each year. That is 2/1000 of an IQ point per child, The monetary value is calculated by the reduction in lifetime income from a total of fewer 512 IQ points in the population.
So note what has happened. EPA put out a mercury regulation, says it will save 11,000 or so people every year, leaving the implication that mercury is very deadly. None of the reporters say anything about the fact that none of the estimated deaths have to do with mercury, that the benefits of reducing mercury 90% are vanishingly small, or that the cost/benefit calculation for mercury itself is a cost of over $10 B for a $6 M benefit — in other words, costs are over 1000 times higher than mercury reduction benefits. Why do environmental reporters not to tell their readers that if you could wave a magic wand and reduce 90% of mercury emissions just like that, there would be virtually no benefits?
You might enjoy looking at the RIA (2011, I think), if you haven’t already. See last line in Table 4-7 for the total benefit of 511 IQ points from the mercury rule, 2/1000 of an IQ point per child:
http://www.epa.gov/ttnecas1/regdata/RIAs/matsriafinal.pdf
Co-benefits of up to $90 B are found in Table 5-1. Table ES-1 compares total costs and total calculated benefits.
We all know that mercury at very high doses is a poison: think of Minimata disease and Mad Hatters (who handled mercury daily for years on end). The question is whether mercury is poisonous at vanishingly small levels. The dose still makes the poison. Selenium is toxic in the environment at very high doses, yet it is also in multi-vitamins in tiny amounts, with legitimate purpose. Mercury, unlike selenium, doesn’t have any health benefits, but for both of them, tiny amounts appear unharmful or virtually so, based in mercury’s case on EPA published work (the RIA).
Many thanks, John. I was unaware of the fact that the “lives saved” weren’t from mercury. Let me strongly suggest that you write this up as a head post and submit it to Anthony, because the facts deserve much wider dissemination. Include graphics if possible, and link to the documents involved.
I look forward to reading it …
w.
Willis, you just read it. If I added more, it would just be expansion on the basic facts, which are above.
Thanks John — good info. The convolutions of logic needed to justify this nonsense are as bad as I imagined. Extrapolate these logic-gymnastics to a whole range of “pollutants” and you begin to sense the enormous scam being perpetrated.
There may be more problems with the study’s basic assumptions if yellowfins are anything like blue fins. A juvenile bluefin was found to have gone down more than a km, much deeper than the depth of max methyl mercury:
http://www.sciencedaily.com/releases/2009/09/090930102522.htm
http://toxics.usgs.gov/photo_gallery/photos/mercury/MeHg_O2_v_DepthGraph_xl.png
http://toxics.usgs.gov/highlights/pacific_mercury.html
–AGF
It could be that larger tuna move higher up on the Hg concentrating food chain by eating fish that smaller tuna can’t eat.
And the confounding factor is …: weight.
Give a man a fish, and he will eat for a day. Teach a man to fish, and he will sit in a boat and drink all your beer.
Thanks Willis. You have definitely uncovered something fishy about mercury.
Something else that smells fishy – the health advisories for canned tuna.
Methyl-mercury is known to lower IQ and shorten life-expectancy. However, the smallest (low mercury) fish are reserved for canning.
More, 81% of the world’s large, high mercury (‘fresh-caught’) tuna is consumed by the Japanese – and they enjoy the world’s highest IQ and life-expectancy.
Reblogged this on Daily Browse and commented:
It depends on what the meaning of ‘is’ is. Start with the same numbers and come up with different results. No malice is required to reach a faulty conclusion, just poor analysis.
Tony, if the original work is a pile of crap, yes, doing their work over for them, using the same data will give you different conclusions by definition. If you weren’t convinced from this analysis that there was at least something wrong, even if it was simply that there were only 11 fish, all small fry, out of ~250 fish and these 11 taken all in one year gave the trend that otherwise wasn’t there, then you are indeed a successful product of the education system designed by post normal progressives to obviate the need for questioning. You were undoubtedly top of your class. Is the ‘Daily Browse’ also a purveyor of ‘New Think’? Your IQ and mental health can be ruined by more things than just a bit of mercury in your tuna sandwich.
The poisoning of Minamata Japan
It started out quite simply, with the strangeness of cats “dancing” in the street–and sometimes collapsing and dying.
https://www1.umn.edu/ships/ethics/minamata.htm
Maybe the fish they caught spent the night with Venus. “One night with Venus, a lifetime with mercury.”
http://jmvh.org/article/syphilis-its-early-history-and-treatment-until-penicillin-and-the-debate-on-its-origins/
I live in the Baja Mex. I sometimes eat fish (mostly sea bass) twice a day. Most are from the Sea of Cortez (Gulf of California). Wonder how much mercury I am ingesting…
I’d be too embarassed to publish the ‘results’ of any study relying on just 14 fish out of millions – it would be a meaningless waste of my time and of the time of anybody and everybody who read it.
I look after some rare breed chickens for one of my sons – one group of 5 (all Silkies) will go into their house when I tell them – the other breeds won’t. Following the basis used in a number of ‘climate change’ studies perhaps I should now publish a ‘learned’ paper proving that Silkies are 97% more intelligent and obedient than other breeds of chicken…………
I recall a paper from the 70s where samples were taken from two record size lobsters hanging on the wall at the Boston Science Museum. The lobsters were caught in the 1800s and were significant for their size. The paper documented the specimens contained mercury levels consistent with large lobsters caught in modern times. The result was unexpected. I’ve had no luck finding this paper and I admit my memory is fading. I’m hoping a WUWT reader also recalls the paper. BTW the museum also had a good library and perhaps one of the older folks there could find the paper. I no longer live nearby.
Guy goes to the beach to goes swimming, parks his car. While he was gone a tidal wave hit his car. When he came back, he found tuna in his Mercury…
Sad that the 2008 fish were smaller than in previous years.
All juveniles or have larger fish been removed from the population ?
All right , there were only 14 of them but…..
Willis Eschenbach February 5, 2015 at 11:36 pm
RE: “My thanks to everyone for your comments.”
I was hoping that there’d be some science based comments/current data RE: don’t worry, eat ’em up.
I love the stuff, and (unfortunately) moderation has never been a major factor in my decisions . . . sigh.
I’m sure Willis is correct that there is something wrong (or missing) in the current data. But assuming the original study has some validity it appears that almost all the new accumulations of Mercury have occured between 1998 and 2008. What changed during that period? I would suggest it had something to do with the vast proliferation of florescent light bulbs that the environmentalists have forced us to buy.
Thanks, Jack. Unfortunately, we cannot conclude that there has been a large new accumulation of mercury in the ocean since 1998.
And in any case, I would say that the small number of fluorescent light bulbs that have escaped their proper resting places and gone into landfills and then leached out of the landfills into the ocean is far too tiny to affect the oceanic levels much … it’s a huge amount of water, after all, and there’s only 5 milligrams of mercury per bulb, and only a small part of that makes its way into the ocean.
Finally, at least according to NEMA, the increase in mercury from CFLs is offset by the decrease in mercury emitted during the power generation from coal-fired plants … not sure I buy that but it’s definitely a factor to be included.
w.