1 Agree or Disagree? • "All substances are poisons; there are none which is not a poison. The right dose differentiates a poison and a remedy.“ – Paracelsus Swiss-German Physician (1493-1541) 2 Central Focus Students can explain how forensic toxicologists use components of chemistry, biology, and medicine to interpret and justify their toxicology results from bodily tissues/fluids. Students can explain the proper techniques used to identify toxins in the body and describe why toxins have different effects on different people. 3 Learning Standards Ga. SFS3. Students will analyze the use of toxicology in forensic investigations. a. Classify toxins and their effects on the body. c. Evaluate forensic techniques used to isolate toxins in the body 4 Day 1 Essential Questions • What is the difference between the type(s) of evidence that is analyzed by a forensic chemist versus a forensic toxicologist during a criminal investigation? • Why is toxicology important to criminal investigations? • How is lethality of a drug/poison determined? 5 Learning Targets. I can… • SFS1a – LK1: Match historical forensic scientists with their role in crime scene investigations • SFS3a – LK3: Describe how toxicology applies to criminal investigations. • SFS3a – LR6: Compare/contrast intoxicants, poisons, and toxins • SFS3a – LR7: Classify toxins and their effects on the body • SFS3a – LR8: Categorize toxin/poison exposure as intentional, deliberate, or accidental • SFS3a – LK4: Explain LD50 and how it applies to forensic toxicology 6 Toxicology • Mathieu Orfila – “Father of Toxicology” – “Traite des poisons” –first systematic approach to studying chemistry of poisons (arsenic) • Study of poisons or the detection of foreign substances in the body that can have a toxic effect such as: – alcohol, industrial chemicals, poisonous gas, illegal drugs, drug overdoses 7 Importance of Toxicology Toxicology can: – Be a cause of death – Contribute to death – Cause impairment – Explain behavior 8 Toxicologist Examples • Did a person die from a toxin or from natural causes? • Was the suspect’s behavior influenced by drugs in their system? • Was a suspect manufacturing illegal drugs? 60% of individuals arrested for most types of crimes test positive for illicit drugs at arrest. 9 Toxicologists • Toxicologists must understand chemistry, biology, and medicine. – Forensic toxicologists examine samples sent by forensic pathologist – BS or MS in related field; $35k-65k salary/year – Must be able to write up scientific report and serve as an expert witness – More experience necessary to be fully certified as a professional forensic toxicologist 10 Forensic Toxicology • application of toxicology to the law, including – workplace or forensic drug testing – postmortem toxicology – human performance testing (alcohol and driving) • Crime labs, medical examiners offices, hospital laboratories 11 Responsibilities of the Toxicologist 1. Know the chemical make-up, metabolites, and physiological actions 2. Understand drug metabolism 3. Understand chemical effects in healthy/unhealthy/addicted people. 4. Recognize signs/symptoms produced by the chemicals. Postmortem Forensic Toxicology • Must start analysis ASAP after death – Suspected drug intoxication – Homicides – Arson fire deaths – Motor vehicle fatalities – Deaths due to natural causes 13 Is it always on purpose…? People can be exposed to toxic substances: • intentionally— by treating illness or relieving pain • accidentally— by harmful combinations or overdoses • deliberately— by harming or killing others or by suicide 14 Lethal Dose 50 (LD50) • Measure of toxicity – mg of substance/kg body weight • Amount that kills 50% of the test population (usually rats/mice) within 4 hrs • Examples (in rats): – Sucrose 29,700 mg/kg (6 tsps/2.2 lbs) – Botulin toxin 0.000005 mg/kg -9 (1 x 10 tsp/2.2 lbs) 15 Factors Affecting Toxicity • Chemical or physical form of the substance • How it enters the body • Body weight and health of person • Age and sex • Length of exposure • Other chemicals present 16 Classifying Toxic Agents • Length of Exposure – acute Toxicity: brief exposure – chronic Toxicity: exposure for months or years • Route of Exposure – direct contact – ingestion – inhalation – injection 17 Classifying Toxic Agents • Other classifications –Deteriorated tissue or function –Mechanism of action –Chemical structure • Heavy metals 18 Quick Check • Which of the following does NOT affect toxicity? A.Whether the agent is inhaled or ingested B.Whether the exposed organism is male or female C.Whether the agent is synthetic or naturally occurring D.Whether the exposure is continuous or sporadic E.Whether the exposed organism is a child or an adult 19 What is Poison? • any substance that, when taken in sufficient quantities, causes a harmful or deadly reaction • The key: Sufficient Quantities • Example: arsenic, water intoxication, blood doping • What does “sufficient quantities” mean? https://www.youtube.com/watch?v=lvHCfm qy4JM 20 Intoxicants, Poisons, and Toxins • intoxicant: large amount needed to be lethal (ex. carbon monoxide or alcohol) • poison: a small amount is lethal (ex. cyanide) • toxin: poisonous substance from plant or animal; typically from microorganisms. Causes disease or death in small amounts. Note: Toxin can also be used generically to describe any chemical harmful to your body. 21 Day 2: Essential Questions • What is a poison? How are they classified? • What are the steps for metabolism of a poison or drug? • What is the difference between a forensic chemist and a forensic toxicologist? 22 Learning Standards Ga. SFS3. Students will analyze the use of toxicology in forensic investigations. a. Classify toxins and their effects on the bodybody. c. Evaluate forensic techniques used to isolate toxins in the body https://www.youtube.com/watch?v=GlpQK qf4LqI 23 Learning Targets. I can… • SFS3c – LR9: Compare/contrast forensic toxicology and forensic chemistry • SFS3c – LR10: Predict the presence of a toxin based on metabolites identified using chromatography and/or spectrophotometry • SFS3 – LK5: Describe how drugs are metabolized by the body. • SFS3 – LS1: Design an experiment to explain how solubility of drugs affects how they interact with the body. 24 Is poisoning common? • Poisoning causes less than ½ of 1% of all homicides • Forensic toxicologists believe number may be higher; mistaken for natural causes • Accidental drug overdoses are more common https://www.youtube.com/watch?v=HH3_cUnvIQU *Note: this video is for educational purposes only…don’t be getting any ideas. 25 Common Poisons • Strychnine – (rat poison) severe muscle spasms and eventually muscles give out and can’t breathe • Cyanide – can be difficult to detect. Similar to the effects of suffocation. Causes cherry red blood. • Botulinum Toxin – Produced by bacteria. Paralyzes muscles and causes irreversible damage to nerve endings. Extremely deadly in very small amounts. – Most poisonous biological substance • Tetanus (also called Lockjaw)- produced by bacteria; causes violent muscle spasms 26 Common Poisons • Carbon Monoxide (CO) – one of the most common poisons – Binds to hemoglobin – Percent saturation: amount in the blood • 50-60% is typically fatal • In presence of alcohol or other drugs, 35- 45% may be fatal – Questionable fire? Low CO = likely dead beforehand; high CO = likely alive 27 Bioterrorism Agents Ricin- A poisonous protein in the castor bean. • Lethal in extremely small amounts • Can enter the body by inhalation, ingestion or injection • Causes death within a few hours Anthrax - Bacillus anthracis • Spreads to humans from infected animals • Enters the human body through: – Inhalation; causing breathing problems that usually result in death – Ingestion; becoming fatal in 25% to 60% of cases – Absorption via the skin; leading to death in about 20% of untreated cases 28 Metals as Poisons • Metals – Arsenic – Iron – Mercury – Lead – Thallium – Antimony – Bismuth 29 Effects of Poisons • Odor (arsenic: garlic; cyanide: almonds) • Hair loss (thallium) • Convulsions (strychnine) • Paralysis (botulism) 30 Effects of Poisons • Skin color changes (carbon monoxide- cherry red; nitrates - blue) • Skin changes (arsenic: blisters) • Pupils (miosis, mydriasis) 31 Looking for toxins… • Challenging without supporting information – Nearby empty containers – Postmortem examination – Victim’s symptoms • Most toxins don’t change the body • Must look for other evidence in body fluids • Looking for small amounts; complicated by how body acts on the drug 32 Pharmacokinetics • Pharma = poison/drug • Kinetics = movement • Study of bodily absorption, distribution, metabolism, and excretion of drugs • How our body processes chemicals and drugs 33 Ingestion • How a drug/chemical enters the body • Can be with or without someone’s knowledge • Can depend on water solubility • Quick check: What is solubility? 34 Absorption • How the drug/chemical gets into the blood stream – digestive tract, skin, lungs, eye, sites of injection – Most drugs/chemicals must get into the blood stream to travel to their target for an effect – Dependent on physical and chemical properties of the drugs 35 Distribution • Drug/chemical getting to tissues throughout the body after absorption is complete – Circulates through blood – Dependent on solubility (fat vs. water) – Fat soluble will have higher volume of distribution and last longer Which mouse would store toxins longer? 36 Metabolism • Biotransformation (also called metabolism) – Body breaks down the drugs/chemicals and changes them to get