Unit 7: Toxicology
7.1 Classification of Toxic Substances
Forensic toxicology — the poisons-and-drugs science: the detection, the measurement, the interpretation. The classification’s faces:
- By the origin: the chemical (the pesticides, the metals), the plant (the alkaloids — the datura, strychnine, opium’s derivatives), the animal (the venoms), the gases (the carbon monoxide, the cyanide).
- By the action: the corrosives (the acids-and-alkalis), the irritants (the metals, the plant’s poisons), the neurotoxins (the opioids, the sedatives, the alcohols), the asphyxiants.
- By the use: the agricultural (the organophosphates — the pesticides’ epidemic: the suicides’-and-homicides’ common poison of South Asia), the pharmaceuticals, the drugs of abuse (U8), the household’s faces.
- By the case’s type: the acute (the single dose) vs the chronic (the repeated exposure).
7.2 Toxicity Value (Dose-Response Reaction)
The Paracelsus principle — the dose makes the poison (no substance absolutely safe-or-dangerous). The dose-response curve: the threshold’s concept (the no-effect level); the increasing response’s slope; the LD50 (the lethal dose’s 50% — the toxicity’s classic measure). The forensic’s application: the concentration’s interpretation (the therapeutic vs toxic vs lethal ranges); the individual’s variation (the age, weight, health, tolerance — the addiction’s tolerance); the synergies (the drug combinations — the alcohol-opioid potentiation).
7.3 Acute and Chronic Toxicity
The acute: the single-or-short exposure (the overdose, the homicidal dose, the accidental); the symptoms’ suddenness; the emergency’s medicine-and-autopsy faces. The chronic: the repeated exposure (the occupational — the metals; the domestic — the chronic arsenic; the drug dependence); the accumulation’s diseases; the forensic’s slow-poison lore (the historic homicides’ method — the modern detection’s answer). The Nepal faces: the pesticide suicides’ tragedy (the organophosphates’ access — the public-health-and-legal questions); the chronic exposures (the water’s arsenic-and-lead faces).
7.4 Types and Evidential Value of Forensic Toxicology Samples (Viscera, Blood and Other Body Fluids)
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