Putative Radiation Hazards of Chinese Coal.

[NNadir]

I came across this cute paper last night: Toward the Threshold of Radiation Hazards of U in Chinese Coal through the CART Algorithm (Na Xu, Yuchen Yang, Mengmeng Peng, Qing Li, Chuanpeng Xu, and Shifeng Dai, Environmental Science & Technology 2022 56 (3), 1864-1874)

Activated carbon is widely used in various forms to remove certain metals from solutions. It should therefore be unsurprising that coal, which is geologically compressed carbon is rich in metals, in particular heavy metals. Coal, despite what one hears from the anti-vax set referring to the discredited nonsense claim that thimerosal in vaccines causing autism, is the largest, by far, source of mercury pollution on the planet. The doses of mercury we all breathe (or drink or eat) are overwhelmingly from coal combustion and they dwarf the thimerosal doses in vaccines and even medical waste. I often speculate that the rising level of mass insanity on the planet is mass mad hatter's disease, a mild form of Minamata disease, driven by coal combustion.

Of course, air pollution associated with coal combustion is far more deadly than its mercury component.

I've taken to frequently citing a table from a publication on the estimated death toll from the thermal generation of electricity, to wit:

Anil Markandya, Paul Wilkinson, Electricity generation and health, The Lancet, Volume 370, Issue 9591, 2007, Pages 979-990.

Here's table 2:

Tonight, in Germany according to the Electricity Map (4:43 AM Berlin time 02/05/22, 10:44P EST US 02/04/22) Germany is producing 21.0 GW of electricity by burning coal. With a little digging it does seem to me that German coal combustion uses a lot of lignite. 21.0 GW of coal combustion (lignite) over a 24 hour period corresponds, using the Lancet table to 16 deaths per day, annualized to 6000 deaths per year were that figure constant; the case for hard coal would be 12 deaths per day, around 4500 per year.

Were the 21.0 GW produced by the nuclear plants Germany shut on the grounds they were "too dangerous," the average death toll would average 0.026 deaths per day, annualized to 9 deaths per year.

Thus the decision to close Germany's nuclear plants will surely kill people, since the Germans have replaced their nuclear plants with coal.

In "percent talk" the current German carbon intensity, 386 g CO2/kwh, is 654% higher than that of France, where the carbon intensity is, as of this writing, 59 g CO2/kwh.

The German nuclear phase out certainly has nothing to do with climate change. Indeed, its practice holds climate change in contempt.

That's insane. Mad hatter disease? Minamata disease? They do burn a lot of coal in Germany.

Radiophobia is a big deal in Germany, although I imagine one can get dental x-rays there, and so one wonders if the Germans are aware that coal often contains uranium, a topic the authors of the paper cited at the outset consider.

From the text:

Although other energy sources have developed rapidly in recent years, approximately 40% of total global energy is generated from coal, (1) and it still plays an important role in some developing countries, for example, China. Coal contains a wide range of elements including U and Th, two common radioactive elements. 238U and 232Th decay into a series of radioactive elements, notably including radium (226Ra and 228Ra), radon (222Rn and 220Rn), lead (210Pb), polonium (210Po), and potassium (40K), which are collectively termed as naturally occurring radioactive materials (NORMs). During the combustion of coal, the organic matter in coal is consumed so that the concentrations of several radionuclides are enriched in the coal combustion residues (CCRs). (2,3) Therefore, CCRs typically have significantly higher NORMs than their respective parent coals. (4,5) In China, the high volume of coal used for combustion leads to a large amount of CCRs produced every year. The utilization of a huge amount of CCRs has many benefits in both economic and environmental aspects. Over the years, CCRs have been used in the manufacturing of cement, bricks, and concrete; in the extraction of critical metals (e.g., U, Ge, Ga, Al, and rare-earth elements); and in the construction of roadbed and dams. (6?8) About 5% of the total ash produced in coal-fired power plants is currently used as the substituent for building materials in the construction of residence. (9) When CCRs with high NORMs are used in building materials, they may affect the human health by both external and internal irradiation. (2) If a 226Ra isotope enters the human body, about 80% of it is excreted, while the remaining 20% enters the bloodstream and bone tissues. Radium mainly accumulates in the bones, and it may cause bone cancer. (3) Since the high concentrations of radionuclides in CCRs can potentially affect the human health, (4,5,10) the threshold of U for the radiation hazard deserves to be well discussed.

To evaluate the radiation hazard of CCRs in coal, we start with the study by Lauer et al., (11) who suggested that the 226Ra activity in the CCRs is mainly controlled by the original 238U concentrations and ash yields of feed coals. Coals with high 238U concentrations would generate CCRs with high 226Ra activities following the linear relationships. Lauer et al. (12) employed the radium equivalent activity (Raeq) index to measure the potential radiation hazard of CCRs as the building materials from U-rich coals. The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) proposed the Ra eq standards and a Ra eq value of 370 Bq/kg in building materials, above which could result in potential health risks for the indoor inhabitants...

...Based on the study by Lauer et al., (12) 226Ra can be estimated by 238U due to the radioactive secular equilibrium. Thus, 226Ra is replaced by 238U in this study. In the CCRs, the U concentration of 1 mg/kg is approximately equal to 12.35 Bq/kg 238U, and the Th concentration of 1 mg/kg is approximately equal to 4.075 Bq/kg 232Th...

How these risk levels are calculated is subject to debate, often heated debate generating accusatory and/or personal approbation over the origins and validity of the so called "linear no threshold" LNT hypothesis for radiation risk. The LNT is a bête noire for U Mass Amherst Professor Edward J Calabrese, and Dr. Calabrese is a personal bête noire for Dr. Jan Beyea, who has some association with the Princeton University antinuclear campaigner Dr. Frank Von Hippel. Doctor Von Hippel - I've seen him speak and he's a very gracious man personally - writes papers about all the scary things that will happen if a major forest fire overtakes the Peach Bottom nuclear plant, but never writes, to my knowledge, about the number of people who will be killed by coal combustion in Pennsylvania (and New Jersey, which is downwind) tomorrow.

The publishing controversy engaged by Drs. Calabrese and Beyea often involves discussions of experiments conducted in the 1940's, 1950's and even earlier, which enters "angels on the head of a pin" territory. It kind of surprises me, since in the 2020's we possess very sophisticated molecular biology tools, NGS, advanced mass spectrometry, flow cytometers, what have you.

Actually, this sort of work is going on, for example: Seong-Jun Cho, Hana Kang, Eun-Hee Hong, Ji Young Kim & Seon Young Nam (2018) Transcriptome analysis of low-dose ionizing radiation-impacted genes in CD4+ T-cells undergoing activation and regulation of their expression of select cytokines, Journal of Immunotoxicology, 15:1, 137-146. There are actually a fair number of papers on the effects on the proteome and RNA expression in connection with radiation. They are a little more definitive than questions about research integrity in the 1940's.

(There has been some preliminary work on stimulating immune responses by exposure to low level radiation, with protein biomarker levels and RNA transcriptomes to track these effects.)

To be clear and honest, I am more in sympathy with Dr. Calabrese than Dr. Beyea:

In the Princeton academic energy community, if one grasps the tenor, we can just let climate change and millions of deaths per year from air pollution run happily along while we all wait for the so called "renewable energy" miracle that did not come, isn't here, and won't come, or until we have fusion plants in some future that has always remained 20 to 30 years away for nearly 3/4 of a century.

You know...Three Mile Island...Fukushima...and so on.

Minamata disease...mad hatting...

I do think Dr. Calabrese might make his point in better ways than discussing the motivations of dead scientists, and sometimes he seems to do so.

There is, irrespective of all the heads of pins on which people dance, a lower limit of radiation risk; a 70 kg human being will necessarily contain potassium or die from hypokalemia. The radioactive component of potassium, the naturally occurring radioisotope K-40 will result in a healthy 70 kg human being having between 4000 and 4500 Beq of radioactivity internally. If we try to "protect" people from 4000 Beq of high energy nuclear decays from potassium 40, we will kill them.

This said, molecular biology, in both qualitative and indeed quantitative manifestations, can and should be a key tool in exploring the effects of levels of radiation on living organisms, including human beings, but risk analysis is nonsense in the absence of comparison, i.e. risk must be relative, not absolute.

For reference, a gram of uranium 238 (isolated from its decay products like radium) has a specific activity of about 12,000 Beq/gram, equivalent to the radioactivity of between 2 and 3 human beings.

The question is not, actually, whether radiation is without risk at any level, as is postulated (but hardly proved) in the LNT, but rather a question of comparative risk, that is, asking ourselves "what is the risk of not allowing for the use of radioactive materials?" The official German fear of all things radioactive is killing people because they have declined to even consider that issue.

Anyway. Coal is radioactive, at least in China, probably in Germany as well. So is coal ash. But...If you're really, really scared of radioactivity, don't worry be happy: The chemotoxicity of uranium, a ubiquitous common element, is far more important than it's radiological risk. Avoid eating coal ash, even if it is impossible to avoid breathing it.

Anyway: Here's a figure from the Chinese paper:



It speaks for itself, but here's the caption:

Figure 2. Scatter plot of all data.

I hope you have a pleasant weekend.