Mmm. Delicious. Forcing the Thallium Cycle in the Baltic Sea.

[NNadir]

In going through my notes, I realized I had not reviewed issue 19 of this year's volume, Volume 58, of Environmental Science and Technology. I'm catching up now, and came across an article about the element thallium, an element in the periodic table on which I seldom focus other than to note that it is the most toxic element therein.

I'm not going to spend much time talking about the paper I'll discuss, this one: Anthropogenic Forcing of the Baltic Sea Thallium Cycle Chadlin M. Ostrander, Yunchao Shu, Sune G. Nielsen, Olaf Dellwig, Jerzy Blusztajn, Heide N. Schulz-Vogt, Vera Hübner, and Colleen M. Hansel Environmental Science & Technology 2024 58 (19), 8510-8517, except to excerpt it to note its sources and the quantities released by those sources. (The article was published in May of this year.)

Thus the excerpt:

The Baltic Sea is the largest anthropogenically induced hypoxic area on Earth. Hypoxic settings, also referred to as Dead Zones, are defined by bottom water dissolved oxygen (O2) concentrations less than 2 mg L–1. (1,2) The hydrography of the Baltic Sea makes it susceptible to hypoxia; North Atlantic seawater must pass two shallow sills before entering the semi-isolated basin. (3,4) Baltic seawater is brackish as a result, and has a near-permanent salt-gradient, or halocline, that prevents efficient mixing of surface and deep waters. Human activities have compounded these hydrographic effects since at least ∼1950. (5) Warming surface waters in the Baltic Sea negatively impact water column mixing and O2 solubility. (6) And high nutrient loading drives eutrophication, in turn promoting large amounts of bottom water O2 consumption during microbial respiration. (7) Deep basins are the locus of hypoxia in the central Baltic, most prominently those near the Islands of Bornholm, Fårö, and Gotland, as well as the Landsort Deep. Conditions are so reducing in some of these “deeps” that bottom waters are anoxic and rich in hydrogen sulfide (H2S), conditions referred to as “euxinic”. (8)

Our focus in this investigation is the post-transition metal thallium (Tl). Thallium has a high toxicity: it is the most toxic metal for mammals, with an estimated minimal lethal dose for humans of 10 mg/kg. (9) The bioavailability of Tl in nature therefore has important implications for human health. (10) Some anthropogenic activities are strong point sources of Tl. An estimated ∼2000 tons of Tl are released annually as atmospheric emissions during coal combustion, cement production, and pyrite roasting. (11,12) Due to its low melting point, Tl is volatilized during these high-temperature processes and thereafter, upon cooling, condenses on the surface of ash particles. (13) Ash produced during these anthropogenic processes can be highly enriched in Tl, by up to a factor of 10 compared to the raw materials. (12,14) Thallium can accumulate to very high abundances in environments near anthropogenic point sources, greatly increasing the risk of Tl poisoning to neighboring communities. (15)

It's interesting to note how, in theory, although it is clearly diluted in most places, 2000 tons of thallium might kill. Assuming that the average human being is somewhere around 70 kg, it's enough to kill 2.9 million people roughly.

Again, it's probably diluted in most places, but I wouldn't be surprised to learn that in areas down wind from coal exhaust plants, or for that matter cement plants or iron smelting plants, real health effects related to thallium poisoning have been observed.

The main use for thallium is in electronics, low temperature thermometers. Historically it was used as a rat poison and insecticide, but this use has been discontinued.

Interesting, I think.

[erronis]

1. Just makes me think of another very toxic element, polonium.

Which has been used by a friend of Donald Idjiot Trump to kill opponents.

[NNadir]

2. Polonium is radiotoxic, and as a result of its radiotoxicity it is difficult to discern if it is also chemotoxic.

As tellurium and selenium are both toxic, although the latter is an essential element in small quantities, I would expect polonium to be chemotoxic, but it is difficult to imagine accumulating enough of the element to find this out.

Interestingly, in fish, polonium is the second largest source of radioactivity after potassium, ⁴⁰K, because it is in secular equilibrium with the nearly five billion tons of uranium found naturally in the ocean.

This was discussed in the context of the (largely failed) effort of the authors of the original "Fukushima Tuna Fish" paper to correct the media stupidity shit storm that grotesquely misinterpreted the original publication of their work, which was about tracking tuna fish migration patterns. Public stupidity led to the survival of many tuna fish that otherwise would have been killed for food, so it wasn't entirely a bad thing, for the fish.

I covered and linked the corrective paper here: Deluded Scientists Think They Can Reassure the Public on the Fukushima Tuna.

The Russian access to polonium is a function of their use of liquid lead bismuth eutectic (LBE) coolants in some of their fast reactors, including submarine reactors. Small amounts of polonium are generated by neutron capture in ²⁰⁹Bi, which leads through two beta decays to ²¹⁰Po. The main use for ²¹⁰Po is for thickness gauges and for the neutralization of static in certain sensitive manufacturing situations. Russia is or was the main supplier. It is "milked" from ²¹⁰Pb more conveniently that it can be isolated from uranium ores.

I'm personally rather fond of liquid lead coolants, although there are many other excellent options for fast reactors besides LBE or neat liquid lead (LL), besides LBE or LL, most of which are superior to the one of which I'm not all that fond, even if it's the most popular, liquid sodium.

[erronis]

3. It takes me a while to digest all of your very welcome information. You should be a high-paid consultant.

Even if much of your information is gleaned from other sources it takes someone with a lot of inherent knowledge to know where to look and how to digest and present it.

I spent many years working as a "subject matter expert" (SME) on various esoteric bits and pieces in the US defense communications world. It amazed me that people would pay me quite well to do research and prepare presentations as if I actually knew what I was talking about. Of course I always felt the need to be quite a bit ahead of the wave of new stuff that was coming down the pikes.

Kudos, and please keep this coming!