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In a new study, researchers show widespread contamination of the Baltic Sea with a toxic metal. This can be fatal for humans and animals.
Rostock – Summer is approaching and preparations for the upcoming peak season are in full swing in many holiday resorts and tourist businesses. If you have already booked your summer holiday but want to avoid unpleasant surprises, it is recommended that you keep checking new laws or other innovations in the holiday country in question. Because in many European countries it will be 2024 again new laws that travelers have to adapt to.
Baltic Sea contaminated with toxic metal thallium
If you don’t want to spend your 2024 summer vacation abroad but in Germany, you might also consider a trip to the North Sea or Baltic Sea in addition to the foothills of the Alps or the Elbe Sandstone Mountains. While the North Sea attracts potential holiday destinations with its multitude of islands, a trip to the island of Helgoland is also a good idea when visiting the North Sea. where holidaymakers can benefit from tax advantages. The Baltic Sea, on the other hand, has many idyllic islands and offers bathers the advantage of being less affected by the ebb and flow of the tide. But vacationers also have a lot to consider when traveling to the Baltic Sea.
For example, what the state of the inland sea is like. New research from US scientists suggests that the concentration of thallium – the most toxic metal for mammals – could become problematic in the Baltic Sea in the future. And that the thallium contamination of the Baltic Sea can be traced back to many decades of human activity.
The Baltic Sea contamination with thallium is a man-made problem
As researchers at the Woods Hole Oceanographic Institution (WHOI) found, between 20 and 60 percent of the toxic thallium that has entered the Baltic Sea in the last 80 years can be traced back to human activities. They published their study results in the scientific journal Environmental Science & Technology.
According to the study, the amount of thallium in the Baltic Sea is currently still at a relatively low level. But according to the researchers, that could change soon. For example, if the sea continues to be exposed to the influences of human activity, as it has been up to now.
In this context, the researchers also warn of a re-enrichment of the Baltic Sea. This could cause their sulfide content to decrease, which in turn could increase the thallium concentration in the sea. Much of the thallium in the Baltic Sea, the largest man-made hypoxic area on earth, accumulates in its sediment thanks to the abundant sulfide minerals.
Researchers warn: If the human influence on the Baltic Sea does not decrease, there is a risk of “worrying things”
For the study, experts wanted to better understand how thallium and its two stable isotopes “203Tl” and “205Tl” are circulated in the Baltic Sea. To identify the modern thallium cycle, the researchers collected data on the concentration and ratios of various isotopes in seawater and in shallow sediment core samples.
In order to reconstruct the cycle of thallium occurring in the Baltic Sea further back, they supplemented their short cores with a longer sediment core that had previously been taken near one of the deepest parts of the sea. The researchers found that the seawater in the Baltic Sea was significantly more enriched with “205Tl” than predicted. According to the longer sediment core, this enrichment began around 1940 to 1947.
“Humans are introducing a lot of thallium into the Baltic Sea, and people should be made aware of that,” said Chadlin Ostrander, lead author of the paper, which he wrote as a postdoctoral researcher in the Department of Marine Chemistry and Geochemistry at WHOI. The assistant professor in the Department of Geology and Geophysics at the University of Utah explicitly appeals that the thallium concentration in the Baltic Sea will increase if human influences continue to affect it as usual in the future. Because of the toxicity of the metal, this would be “worrying,” warned Ostrander.
Thallium poisoning: these are the symptoms
If animals and people come into contact with the metal, there is a risk of acute poisoning through oral ingestion (through the mouth). This can be accompanied by the following symptoms and can also lead to death:
- Vomit
- Cardiac arrhythmias
- paralysis
- Source: pschyrembel.de
The Baltic Sea is the largest area in the world with such thallium contamination
It has long been known that the Baltic Sea has been heavily influenced by anthropogenic activities over decades. This became visible last but not least due to his ongoing loss of oxygen, which has led to ever greater losses for the fishing industry in recent decades. A more recent finding may be how widespread the contamination in the Baltic Sea already is.
“As far as I know, this is the largest geographical area where thallium contamination has ever been documented,” warned Sune Nielsen, a research associate in WHOI’s Division of Geology and Geophysics. She was involved in the study as a co-author. The fact that the thallium concentration can be traced back to humans to such a large extent raises the question of how to use it more responsibly.
In addition, some states bordering the Baltic Sea have been trying to counteract the loss of oxygen in the Baltic Sea for several years. So-called “dead zones”, i.e. areas with extremely low oxygen water, are to be renatured by external oxygen supply. The problem remains, however, that thallium ions dissolve from the sediment as a result of the oxygen supply and float freely in the sea. Not only are these thallium ions toxic when they come into contact with skin, but they also accumulate in fish.
Thallium contamination in the Baltic Sea is also a result of cement production in the Baltic Sea region
“While thallium pollution may not be the most immediate concern for the Baltic Sea ecosystem, I have no doubt that it increases the urgency of taking action to return the Baltic Sea to a state where people and marine life can thrive naturally “We can coexist in a way,” Nielsen appealed.
Like her research team, the geologist assumes that the pollution of the Baltic Sea with thallium is linked to cement production, which has long played an important role in the Baltic Sea region.
“As cement production continues to increase worldwide, this research could serve to alert manufacturers to the need to mitigate potential downstream impacts of cement kiln dust on surrounding aquatic and marine ecosystems,” the researcher emphasized. (fh)
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