FORENSIC SCIENCE Toxicology

1. FORENSIC SCIENCEToxicology

2. TOXICOLOGY DEFINITIONS: • Toxicology = study of the marriage of chemistry & physiology that deals with drugs, poisons, and other toxic substances, and how they alter living organisms. • Toxin = naturally occurring poison.

3. TOXICOLOGY DEFINITIONS: • Toxicity = the degree of toxicity of any substance depends on how much enters the body and over how long a period of time. • Drug = any substance causing physiologic or behavioral changes for medicinal purposes.

4. TOXICOLOGY DEFINITIONS: • Intoxicant = such as alcohol or carbon monoxide, typically requires that a large amount required to cause death • Poison = any substance that, when taken in sufficient quantities, causes a harmful or deadly reaction: smallamount required.

5. TOXICOLOGY Classes of Controlled Substances: • Stimulants-amphetamines & cocaine • Depressants-alcohol & barbiturates • Hallucinogens-marijuana & LSD & PCP • Narcotics-opiates………………………. • Anabolic Steroids-testosterone like

6. TOXICOLOGY Other Organic Toxins:are usually proteins made by one organism that will interfere with the metabolism of another organism. Venoms & Defenses : Bacterial Toxins : - Reptiles - Amphibians - Botulism - Insects - Mammals - Tetanus - Fish - Arachnids - Anthrax - Plants - Others ? - Salmonella - Corals - E. coli

7. TOXICOLOGY Heavy Metals:are also naturally occurring and are very poisonous. They have been used for suicides, homicides and accidental deaths. • Arsenic • Lead • Mercury

8. TOXICOLOGY Pesticides:some are naturally occurring and others are man-made. Both types are very poisonous. They have been used for suicides, homicides and accidental deaths. - Cyanide - DDT - Strychnine - Dioxin

9. TOXICOLOGY Forensic Toxicology Applications • Postmortem : medical examiner or coroner • Criminal : motor vehicle accidents (MVA), assault, etc. • Workplace drug testing • Sports : human and animal

10. TOXICOLOGY Why do Toxicology? Toxicology can: • Be a cause of death • Contribute to death • Cause impairment • Explain behavior

11. TOXICOLOGY Looking For Poisons - Most poisons don’t visibly change the body / tissues. - M.E. won’t notice poisoning in most cases…need to collect fluids and tissues to send to toxicology lab. - Biotransformation = conversion or transformation of one chemical into another by the body. This happens during metabolism. The new products are called metabolites. Ex. heroin morphine *Toxicologists most often test for metabolites.

12. TOXICOLOGY Best places of the body to collect samples… - Where chemical entered - Where chemical concentrates - Along body’s route of chemical’s elimination

13. TOXICOLOGY Best tissues to sample… • blood will show chemical and its metabolites blood levels correlate with effects on body • urine will show chemical at higher concentrations than in the blood because body is trying to return to homeostasis. • stomach contents: concentrations won’t correlate with blood levels so effect on body not known

14. TOXICOLOGY Best tissues to sample… • liver: many chemicals will concentrate in the liver even if none is found in the blood. it is the body’s detox factory. Ex opiates. • vitreous humor= eyeball fluid. Real slow to decay. Water soluble chemicals will be detectable here for a long time. There is a 2 hour delay for diffusion from blood.

15. TOXICOLOGY Best tissues to sample… • hair : chemicals take about 5 days to show up in core of hair shaft. All illicit drugs show up in hair. Certain heavy metals (arsenic and lead) concentrate here. Timelines can be established due to known growth rate ( ½ mm per day) • insects : are used in cases of severely decomposed bodies. Certain chemicals are concentrated in insect bodies due to bioaccumulation.

16. TOXICOLOGY Screening tests or presumptive tests….. Street Drugs • Vital signs • Injection sites • Basic Chemistry Analysis • Color Tests • Immunoassay • Chromatography (s)

17. TOXICOLOGY Basic Chemistry Analysis • Solubility • pH • Chemical reactivity

18. TOXICOLOGY Color tests Marquis--turns purple in the presence of opium derivatives and orange-brown with amphetamines Dillie-Koppanyi--turns violet-blue if barbiturates Duquenois-Levine--turns purple in the presence of marijuana VanUrk--turns a blue-purple in the presence of LSD Scotttest--turns blue in the presence of cocaine

19. TOXICOLOGY Immunoassay tests Antigen-antibody reactions will show the “family” that an unknown drug belongs to. Remember blood typing?

20. TOXICOLOGY Chromatography tests Paper, Thin layer, Gas….will show the “family” that an unknown drug belongs to. Remember Questioned Documents?

21. TOXICOLOGY Confirmatory tests Gas Chromatography-Mass Spectrometry (GCMS) The mixture is separated first in a gas chromatograph. The GC column is directly attached to the mass spectrometer where a beam of electrons is shot through the sample molecules. The electrons cause the molecules to lose electrons and become positively charged. These are unstable and decompose into many smaller fragments. These fragments pass through an electric or magnetic field and are separated according to their masses. NO TWO SUBSTANCES PRODUCE THE SAME FRAGMENTATION PATTERN.

22. TOXICOLOGY Example of GCMS unit

23. Toxicology of Alcohol The BIOLOGY of Alcohol… • Alcohol is a depressant which acts on the CNS • Extent of depression is proportional to the concentration of alcohol in nerve cells • Blood carries alcohol to all cells of the body • **blood alcohol conc. = brain alcohol conc. **Henry’s law • Alcohol is absorbed thru stomach and small intestine

24. Toxicology of Alcohol • Many factors determine rate of absorption • Consumption time • Alcohol content of beverage • Amount consumed • Amount of food in stomach • Type of food in stomach • Mixers used with alcohol • Time to peak effect varies 30 min to 3 hours • Elimination is accomplished thru 2 mechanisms • Oxidation into carbon dioxide & water in liver • Excretion via the breath, urine & perspiration

25. Toxicology of Alcohol • Excreted alcohol (unchanged) in breath is directly proportional to BAC • BAC can be measured via blood or breath • “Breathalyzer” since 1954 is a spectrophotometer • Other breath testers work on…. • -Infrared light absorption • -Fuel cell types measure oxidation ion • (most PBT’s)

26. Toxicology of Alcohol How much alcohol is “One Drink”?? • ½ ounce of pure ethyl alcohol • 10 oz. to 12 oz. of 4% to 5% BEER • 8 oz. to 12 oz. of 4% to 6% WINE COOLER • 4 oz. to 5 oz. of 9% to 12% TABLE WINE • 1.2 oz. of 40% (80 proof) ALCOHOL • 1 oz. of 50 % (100 proof) ALCOHOL ( PER HOUR )

27. TOXICOLOGY Screening tests or presumptive tests….. Alcohol-(ethanol=is the most abused drug) • Breath alcohol test • Interview with officer • Eye examination • Horizontal gaze nystagmus • Pupil dilatation • Divided attention psycho-physical tests • Walk and turn • One legged stand • Motor Skills • Finger to nose

28. TOXICOLOGY DETERMINING CAUSE AND MANNER OF DEATH Medical Examiner’s job, but needs toxicology report Natural ex. Heart attack. May be influenced by chemicals. Amphetamines or other drugs like cocaine in the body need to be weighed as to were they the cause of death or contributing to the death. Accidental -Most often happens at home and involves children putting things in their mouth. -When adult it is usually due to mislabel, miscalculation, or dangerous mixtures like ammonia & bleach or alcohol & sedatives.

29. TOXICOLOGY DETERMINING CAUSE AND MANNER OF DEATH Medical Examiner’s job, but needs toxicology report Suicidal This is the most common death by poison. #1 is carbon monoxide #2 is prescription overdose Homicidal More common further back in history. Why? We now know how to detect. It used to go unnoticed Technological advances in weapons…..GUNS