You may have heard recently about the Chemist in New Jersey who is being tried for her husbands’ murder. While most scientist believe her accused method of poisoning, Thallium, to be old fashioned, there are still reports of its use in poisoning today. While this chemical is no longer used in over the counter pesticides it is found in cigarettes.
What are the signs of Thallium poisoning?
In the first 48 hours after serious thallium exposure, the affected individual will usually experience nausea, vomiting, and diarrhea. Within a few days, symptoms of nervous system damage become apparent. These symptoms can include pain, loss of reflexes, convulsions, muscle wasting, headaches, numbness, dementia, psychosis, and even coma. After two to three weeks, characteristic changes are seen in the bases of hair shafts, and there is hair loss (alopecia). Finally, after around three weeks post-exposure, heart rhythm disturbances may occur.
Thallium poisoning can be treated. Effective treatment to prevent absorption of thallium is available if therapy is begun within six hours following ingestion. The antidote against thallium (known as potassium ferrihexacyanoferrate, or Prussian blue or Berlin blue) works by sequestering thallium molecules and preventing their absorption by the intestine. Other treatments that may be successful for victims of thallium poisoning include dialysis and medications to increase the kidneys’ excretion of thallium.
What is Thallium?
Thallium is a soft, malleable gray metal that was previously widely used in rat poisons and insecticides. Thallium itself and compounds containing the element are highly toxic. It is particularly dangerous because compounds containing thallium are colorless, odorless, and tasteless. Because of this high toxicity, the World Health Organization (WHO) recommends against the use of thallium in rodent and insect poisons. However, poisons containing thallium are still in use in some parts of the world.
Small amounts of thallium are normally found in the earth’s crust and atmosphere. It is also present in small amounts in cigarette smoke. Thallium has multiple industrial uses, and certain isotopes of thallium are used in medical imaging studies. Thallium can be absorbed from the skin as well as be ingested or inhaled. If a significant amount (significant poisoning is usually defined as ingesting over 1 gram of thallium, or over 8 milligrams per kilogram of body weight) of thallium enters the body, symptoms of thallium poisoning develop.
As even Wikipedia points out, thallium was “once an effective murder weapon”, but the emphasis is one “once”. That time is long past. Forensically, it’s not the first thing that you think of, certainly, but it got picked up at autopsy in this New Jersey case. And it’s not like there’s any other way a person could get a high level of the element in their tissues, nor, with modern analytical techniques, can it be mistaken for anything else. Honestly, anyone who believes that they have a good chance of getting away with a thallium murder is just not thinking the whole business through.
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