Which of the following poison can be found even in skeletonized remains of the body?

Correct Answer: D. Arsenic

Arsenic is a heavy metal poison that binds irreversibly to sulfhydryl groups in proteins and persists indefinitely in skeletal tissues, particularly in bones and teeth. Unlike volatile or metabolizable poisons, arsenic undergoes minimal degradation even after complete soft tissue decomposition and skeletonization. In forensic pathology, arsenic can be detected in exhumed skeletal remains years or even decades after death through atomic absorption spectrophotometry or inductively coupled plasma mass spectrometry (ICP-MS). This persistence makes arsenic invaluable in forensic investigations of suspected chronic poisoning cases in India, where arsenic contamination in groundwater (particularly in West Bengal, Assam, and Bihar) is a public health concern. The metal accumulates in bones at concentrations proportional to exposure duration, allowing forensic experts to establish both the fact and timeline of poisoning even when soft tissue evidence is completely lost. This property has been crucial in several high-profile Indian medico-legal cases involving suspected homicide by arsenic administration.

Why the other options are wrong

A. Phosphorus — White phosphorus is volatile and highly reactive; it oxidizes rapidly in air and decomposes during putrefaction. It cannot persist in skeletal remains because it is consumed during the early stages of decomposition and does not bind stably to bone matrix. Phosphorus leaves no detectable residue in skeletonized remains. B. Carbon monoxide — Carbon monoxide is a volatile gas that binds reversibly to hemoglobin and dissociates rapidly after death. It cannot be detected in skeletal remains because it requires intact soft tissues (blood) for detection and is completely lost during decomposition and skeletonization. It is only detectable in fresh bodies. C. Hydrogen sulphide — Hydrogen sulphide is a volatile gas produced during putrefaction and is not a poison that accumulates in tissues. It is generated by bacterial action on proteins and escapes into the atmosphere during decomposition. It cannot be detected in skeletal remains as it is neither ingested nor stored in bone.

High-Yield Facts

Mnemonics

VAPE (Volatile And Persistent Elements) Volatile poisons (CO, H₂S, phosphorus) disappear with decomposition. Persistent heavy metals (Arsenic, Lead, Mercury) remain in bones forever. Use this when deciding which poison survives skeletonization. Heavy Metal Skeleton Rule Heavy metals = skeleton detectable. Volatile gases/reactive elements = skeleton undetectable. Arsenic is the classic heavy metal that forensic pathologists exhume and test.

NBE Trap

NBE pairs arsenic with other poisons to test whether students confuse persistence in tissue (arsenic) with presence at death (CO, H₂S). The trap is assuming any poison detectable in fresh bodies remains detectable in skeletal remains—only heavy metals do.

Clinical Pearl

In Indian medico-legal practice, exhumation and skeletal analysis for arsenic is a standard procedure in suspected chronic poisoning cases—particularly in endemic groundwater contamination zones. A single bone sample can confirm poisoning years after burial, making arsenic the forensic pathologist's most reliable witness in cold cases.

_Reference: Robbins Ch. 9 (Environmental and Nutritional Pathology); Parikh's Textbook of Medical Jurisprudence & Toxicology (Forensic Toxicology section)_