Thallium was an effective murder weapon before its effects became understood and an antidote (Prussian blue) discovered. It has been called the "poisoners poison" since it is colorless, odorless and tasteless; its slow-acting, painful and wide-ranging symptoms are often suggestive of a host of other illnesses and conditions. Cause
Bioconcentration
According to the United States Environmental Protection Agency (EPA), thallium release to the environment was reported in Texas and Ohio. This may indicate bioconcentration in aquatic ecosystems. Thallium compounds
The odorless and tasteless thallium sulfate was also used as rat poison and ant killer. Since 1975, this use in the United States and many other countries is prohibited due to safety concerns. Diagnosis
Thallium may be measured in blood or urine as a diagnostic tool in clinical poisoning situations or to aid in the medicolegal investigation of suspicious deaths. Normal background blood and urine concentrations in healthy persons are usually less than 1 μg/litre, but they are often in the 1–10 mg/litre range (1,000–10,000 times higher) in survivors of acute intoxication. Thallium is present in the blood for a very short time so urine testing is usually most appropriate. A quick way to assess possible thallium poisoning is to perform a microscopic analysis of a hair and its root. In thallium poisoning this analysis will show a tapered anagen hair with black pigmentation at the base (anagen effluvium). This is pathognomonic for thallium toxicity. Treatment
There are two main methods of removing both radioactive and stable isotopes of thallium from humans.
Guessing the substance his wife used, Flambeau gives Brown clues as to the antidote, Prussian Blue. In S6:E9 of Elementary, entitled "Nobody Lives Forever" (2018), a biology professor studying how to prolong life spans is poisoned with thallium. As he dies, he falls onto a shelf containing his lab rats, which escape and eventually eat part of his body. Some dead rats are found inside him, suggesting to the detectives that the cause of death was poisoning. References
External links

"Thallium, elemental". National Institutes of Health. NLM hazardous substances databank. U.S. Department of Health and Human Services. Curley, Robert. "Cyril Wecht, Thallium". crimelibrary.com. Archived from the original on 17 April 2008. "ToxFAQs". Centers for Disease Control. ATSDR. U.S. Department of Health and Human Services. "Two Iraqi children die from Thallium poisoning". The Guardian. reports. 9 February 2008.