Tsinghua University announced on December 23 that Zhu Ling, an alumnus of the school's class of 1992, passed away in Beijing on December 22, 2023.
Zhu Ling, a 92-level student majoring in physical chemistry and instrumental analysis in the Department of Chemistry of Tsinghua University, was confirmed to have thallium salt poisoning on April 28, 1995.
The "Zhu Ling Incident" was a sensation, and Zhu Ling, a student of Tsinghua University, had bizarre symptoms of thallium poisoning while he was in school, which caused great harm to his health, and finally he was diagnosed and treated with the help of the Internet.
What is Thallium?
Thallium [ tā ] is an element naturally occurring in the earth's crust and is mainly found in the form of a monovalent element. In seawater, locally strongly oxidized freshwater and soil, trivalent oxides are mainly present.
Thallium generally exists in the soil, is easily soluble in water under acidic conditions, and is more stable in the dissolved state, while trivalent thallium can be precipitated from water in the form of oxides or hydroxides.
Thallium can be released into the living environment through the smelting of metal ores, mining, cement production, and the burning of minerals, mainly coal.
Sulphur arsenic-thallium-lead ore associated with calcite was found in Hexian County, Anhui Image source: mindat.org
Thallium is often coexisting with certain metals, and when smelted at high temperatures, the steam of thallium may cause poisoning.
Thallium can form many compounds, such as thallium carbonate, thallium sulfate, thallium nitrate, thallium iodide, etc., the first three salts have good water solubility, no peculiar smell, colorless, highly toxic, once used as rodenticide and depilatory, many countries have now restricted or banned the use, but some developing countries are still using. Thallium in this use can directly pollute the environment, and the human body can also be harmed by contact with thallium, and the latter compound has some special optical properties in industry, and there are opportunities for contact and use.
Can we come into contact with thallium in our lives?
There are four types of thallium poisoning on the mainland:
First, due to the collection and processing of thallium-containing ores (mercury ore), covering the soil on top of thallium-containing slag to grow vegetables, in drought years, groundwater is absorbed by cabbage-like vegetables with long roots through the slag layer, and people eat a large number of thallium-containing vegetables to cause thallium poisoning and cause localized endemic diseases (Guizhou case);
second, in the production environment of high-temperature processing of thallium salt, a large amount of thallium-containing vapor was inhaled without any protective equipment (Zhuzhou and Beijing cases);
the third is to mistakenly take thallium salt as table salt (Jiangxi case);
Fourth, as a means of possibly harming others.
How can you tell if thallium is poisoned?
The clinical manifestations of thallium poisoning are mainly gastrointestinal symptoms, peripheral nerve symptoms, central nervous system symptoms, psychiatric symptoms, motor weakness and heart, liver and kidney damage, all of which are non-specific manifestations.
How to prevent thallium poisoning?
Upon learning the news of Zhu Ling's death, netizens mourned: May the angels go all the way!
Editor: Liu Xinyu