Poisons

● A poison is anything that when taken in sufficient quantities will cause a harmful or deadly reaction.

History Once considered coroner’s chemist Now must determine what and how much poisonous substance is present in human tissue samples They interpret these results using their understanding of the episode of intoxication

Acute v Chronic Toxicity Acute toxicity is an immediate response to high concentration of a contaminant. – Sickness or death occurs almost immediately Chronic toxicity is a delayed response to prolonged exposure to a contaminant – Exposure can go on for years – Can cause a variety of symptoms depending on the poison

When analyzing cases they must consider 1. Any possible symptoms 2. evidence found at the crime scene 3. Any relevant information related to the history of the case

Toxic Agents Can be in several forms: Gases Liquids Solids (biological toxins) Minerals Vegetable origins

Toxins can be……. Therapeutic or abused drugs Venoms House hold and industrial chemicals Environmental pollutants Naturally occurring substances

Routes of Exposure Inhalation Ingestion Injection Absorption thru the skin

What do toxicologists test for? The drug is quickly broken down by the body into metabolites Toxicologists must test for the toxin and metabolites

Toxicology Lab Toxicologists get body fluids, tissues, and organs that are removed at autopsy Drugs have to be separated and isolated from the tissues and potentially interfering substances Separated using acidic or basic extraction Followed by screening and confirmation test

Hair Analysis Can help toxicologists to determine if the drug has been being abused over a long period of time Drugs present in blood diffuse into capillary walls into the base of the hair and become permanently trapped in the hair’s protein structure As the hair grows the drug’s location on the hair becomes a historical marker for delineating drug intake. Average human head hair grows at a rate of 1 centimeter per month Analyzing segments of hair can create a timeline for drug use dating back over weeks, months, or even years depending on the length of the hair Timeline can be distorted by the environment or sweat

Types of Poisons: Arsenic Facts: Found in Earth’s crust Claimed more victims then any other poison No odor/no taste Absorbs through the lungs or stomach Combines with proteins to make them inactive Found in Insecticides Pesticides Herbicides Alloys Wood preservatives Animal feed Homeopathic medicine Paints and ceramics

Types of Poisons: Arsenic Symptoms Stomach pain Nausea Vomiting Diarrhea Anemia Abnormal heart rhythm Sore throat Irritated lungs Impaired nerve function Darkening of skin Mees lines develop after several weeks of exposure

Arsenic detection Detected in blood, urine, stomach, tissues Can be found in bone and hair after death

Types of Poisons: Cyanide Facts Rapid acting can kills in minutes Used in industrial processes Used in the gas chamber for capital crimes Can be found in salt form: sodium cyanide and potassium cyanide Salts are usually eaten and are the method most commonly used when someone is poisoned Smells like bitter almonds Cyanide stops cellular respiration and ATP production in the body causing cytotoxic or metabolic anoxia Cells can’t use oxygen (brain and heart)

Cyanide symptoms Headache Dizziness Nausea Vomiting Shortness of breath Mental deterioration Seizures, coma and cardiorespiratory collapse cause death

Types of Poisons: Strychnine Facts Colorless Obtained from the seeds of the strychnos nux-vomica tree Bitter taste Can only be hidden in bitter foods and drinks Used for killing rodents Can be absorbed through inhalation, oral or through absorption through the mucus membranes Symptoms Excruciatingly painful and violent spastic reactions Muscle cramps Muscle contractions Breathing is compromised and the person dies of asphyxiation

Types of Poisons: Carbon Monoxide Facts Colorless, odorless and tasteless gas Most commonly come from faulty heating systems, automobile exhaust, fires and cigarette smoke Binds to hemoglobin in red blood cells so oxygen cannot Symptoms Headaches Nausea Fatigue Visual disturbances Mental confusion Coma Death Prolonged exposure can lead to brain damage

Types of Poisons: Thallium Facts: Found in the Earth’s crust Used as rodent and ant poison Thallium sulfate is the form most commonly used for rat and ant poison It is odorless and tasteless Banned in the US for safety It can be eaten or inhaled Symptoms: Mimics potassium in the body Disrupts cellular function Causes cancer Pain in feet and hands Psychosis Delirium convulsions

Types of Poisons: Aconite Facts Known as wolf’s bane, women’s bane, monkshood and devil’s helmet Comes from the Aconitum napellus plant Used to poison the tips of arrows or an enemy’s water supply White powder Targets cells Symptoms Rapidly acting poison that takes effect within minutes Tingling and numbness at the point of contact Muscle weakness Visual and auditory disturbances Convulsions Then death by respiratory failure

Types of Poisons: Ricin Facts A protein extracted form the castor bean Comes from waste products of castor oil production Inhibits protein synthesis in the body First symptoms usually occur within 6 hours Death occurs within 36 to 72 hours If death has not occurred in 3-5 days the victim may recover Symptoms If inhaled: – Difficulty breathing, fever, cough, nausea, tightness in chest – Skin turns blue, low blood pressure and respiratory failure If ingested: – Vomiting – Dehydration and low blood pressure – Hallucinations, seizures and blood in the urine