Death by arsenic: a comparative evaluation of exhumed body tissues in the presence of external contamination.

External contamination of hair or nails by inorganic arsenic compounds cannot effectively be removed with H2O or dilute HCl. The use of a modified Gutzeit apparatus allowed to establish or rule out external contamination. It was found that contaminated samples will generate large amounts of arsine gas when treated with Zn, Kl, SnCl2, and dilute HCl in a Gutzeit arsine generator. Arsenic present in the sample due to metabolic deposition resulted in significant arsine formation only after digestion. In one chronic arsenic death, digestion increased the liberated amount of arsine from nail by a factor of twenty. Direct examination of hair and nail from a female resulted in values near 100 micrograms As/g tissue even after washing with HCl and H2O. Deep thigh muscle and spinal cord released arsine only after digestion. Control hair soaked in a NaAsO2 solution, washed and dried, bound 775 micrograms of As/g.