Thursday, January 12, 2017

Mystery Writer's Guide to Forensic Science - Arsenic


Arsenic is an irritant poison. It attacks the cells and in post mortem, you will find traces of arsenic in almost all parts of the body including the hair, bones, and fingernails. This method of killing has been used in many mysteries.

Symptoms of arsenic poisoning:
1) It will begin with irritation and burning in the throat, faintness, nausea and depression.
2) It will be followed by vomiting (food then mucus with blood)
3) Abdominal pain (like red-coals on the stomach)
4) Tongue covered in white fur and then constriction in the throat
5) After 12-18 hours, there will be diarrhoea and pain. Cramps will set in to the legs and the pulse will be weak and irregular.
6) Collapse and death soon occur.
7) Externally, the skin will appear blue due to lack of oxygen in the bloodstream (cyanosis)

Treatment:
Chemical and synthetic methods are now used to treat arsenic poisoning. Dimercaprol and dimercaptosuccinic acid are chelating agents which sequester the arsenic away from blood proteins and are used in treating acute arsenic poisoning.

Testings for arsenic:
There are tests available to diagnose poisoning by measuring arsenic in blood, urine, hair, and fingernails. The urine test is the most reliable test for arsenic exposure within the last few days. Urine testing needs to be done within 24–48 hours for an accurate analysis of an acute exposure. Tests on hair and fingernails can measure exposure to high levels of arsenic over the past 6–12 months. These tests can determine if one has been exposed to above-average levels of arsenic.

Marsh Test
The Marsh test is a highly sensitive method in the detection of arsenic, especially useful in the field of forensic toxicology when arsenic was used as a poison. It was developed by the chemist James Marsh and first published 1836.

Interesting facts about arsenic
1) Found in most human bodies
2) Smells like garlic when roasting the metallic ore

What are your favorite stories with arsenic poisoning?

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