FORENSIC TOXICOLOGY

6-2 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Introduction Toxicologists are responsible for detecting and identifying the presence of drugs and poisons in body fluids, tissues, and organs. crime laboratories and medical examiners’ offices hospital laboratories and health facilities to identify a drug overdose Lead poisoning in children Methadone maintenance programs

6-3 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Introduction Forensic Toxicologists are limited to matters pertaining to violations of criminal law. Toxicological services may be performed in a crime lab, medical examiner’s office or government health department lab Caseload reflects prevailing popularity of drugs abused in the community

6-4 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Introduction A major branch of forensic toxicology deals with the measurement of alcohol in the body for matters that pertain to violations of criminal law. Alcohol related: 40% of all traffic deaths (17,500 deaths) 2 million injuries requiring hospital treatment

6-5 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Toxicology of Alcohol The analysis of alcohol exemplifies the primary objective of forensic toxicology—the detection and isolation of drugs in the body for the purpose of determining their influence on human behavior. Alcohol, or ethyl alcohol, is a colorless liquid normally diluted with water and consumed as a beverage.

6-6 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Toxicology of Alcohol Like any depressant, alcohol principally effects the central nervous system, particularly the brain.

6-7 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Alcohol Levels All chemicals (including alcohol) are eventually broken down and transformed into other chemicals which are easier to eliminate – metabolism There are three steps for this process Absorption Distribution Elimination

6-8 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Absorption Alcohol appears in the blood within minutes after it has been taken by mouth and slowly increases in concentration while it is being absorbed from the stomach and the small intestine into the bloodstream.

6-9 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Absorption When all the alcohol has been absorbed, a maximum alcohol level is reached in the blood and the post- absorption period begins. Maximum blood alcohol concentration may not be reached for 2- 3 hours after consumption Under normal social drinking conditions, minutes after final drink Alcohol concentration will slowly decrease until a zero level is again reached.

6-10 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Alcohol Levels Factors affecting rate of alcohol absorption time taken to consume the drink the alcohol content the amount of alcohol consumed food present in the stomach

6-11 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Distribution Alcohol in the bloodstream is carried to all parts of the body and distributed throughout the water parts of the body. Fat, bones and hair are lower in water and contain little alcohol.

6-12 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Alcohol Levels Elimination of alcohol throughout the body is accomplished through oxidation and excretion % of alcohol is oxidized to either CO 2 or H 2 O by the enzyme dehydrogenase almost entirely in the liver Remaining alcohol is excreted unchanged in breath, urine and perspiration The amount of alcohol exhaled is in direct proportion to concentration of alcohol in the blood

6-13 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Alcohol Levels The extent to which an individual may be under the influence of alcohol is usually determined by either measuring the quantity of alcohol present in the blood system or by measuring the alcohol content in the breath.

6-14 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Alcohol Levels Experimental evidence has verified that the amount of alcohol exhaled in the breath is in direct proportion to the blood concentration.

6-15 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Alcohol & Circulatory System Humans have a closed circulatory system consisting of a heart, arteries, veins, and capillaries.

6-16 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Alcohol & Circulatory System Alcohol is absorbed from the stomach and small intestines into the blood stream. 20% of alcohol absorbed through stomach into the portal vein Remaining alcohol absorbed through walls of small intestines into bloodstream

6-17 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Alcohol & Circulatory System Alcohol is carried to the liver where the process of its destruction starts. Blood, carrying alcohol, moves to the heart and is pumped to the lungs.

6-18 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Alcohol & Circulatory System In the lungs, carbon dioxide and alcohol leave the blood and oxygen enters the blood in the air sacs known as alveoli. Then the carbon dioxide and alcohol are exhaled during breathing.

6-19 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Alcohol & Circulatory System During absorption, concentration of alcohol in arterial blood is higher than venous blood Typically 40% high about 30 minutes after the last drink Once absorption is complete, alcohol is evenly distributed throughout the body

6-20 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Testing for Intoxication Testing the blood of motorists suspected of being under the influence of alcohol is not a convenient method for monitoring drivers Transporting suspect to a medically qualified person to draw blood is time consuming and costly The most widespread method for rapidly determining alcohol intoxication is breath testing.

6-21 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Testing for Intoxication Breath-test results obtained during the absorption phase may be higher than results obtained from venous blood Breath test is more reflective of concentration of alcohol reaching the brain and therefore more accurately reflects the effects of alcohol on the subject Once absorption is complete, difference between blood test and a breath test should be minimal

6-22 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Breath Test Instruments Breathalyzer was the first instrument developed by an Indiana State Police Captain in ml of breath are collected 1 ml breath = 2100 ml of blood 52.5 ml of breath = 1/40 ml of blood Breath is added to a chamber with potassium dichromate.

6-23 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Breath Test Instruments The potassium dichromate is oxidized to acetic acid in the presence of alcohol Amount of potassium dichromate destroyed is proportionate to the amount of alcohol Breathalyzer is a spectrophotometer because it measures the absorption of light passing through the potassium dichromate

6-24 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Breath Test Instruments Modern breath testers are free of chemicals Breathalyzer was phased out in the 1970s Infrared light absorption devices Fuel cell detectors

6-25 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Infrared Light Absorption Devices The captured breath is exposed to infrared light. Wavelength of infrared light absorbed by alcohol is measured.

6-26 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Fuel Cell Detectors Fuel cells convert a fuel and an oxidant into an electrical current. Breath alcohol is the fuel and atmospheric oxygen is the oxidant Alcohol is converted into acetic acid that generates a current proportional to the amount of alcohol present in the breath

6-27 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Field Testing Law enforcement officers typically use field sobriety tests to estimate a motorist’s degree of physical impairment by alcohol and whether or not an evidential test for alcohol is justified. The horizontal gaze nystagmus test, walk and turn, and the one-leg stand are all considered reliable and effective psychophysical tests. Field Sobriety Test - Nystagmus Field Sobriety Test

6-28 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Field Testing A portable, handheld, roadside breath tester may be used to determine a preliminary breath-alcohol content. Roadside breath tester results are useful in determining whether someone needs medical assistance, but is not admissible into court as evidence.

6-29 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Gas Chromatography Testing Gas chromatography offers the toxicologist the most widely used approach for determining alcohol levels in blood.

6-30 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Chromatogram

6-31 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Gas Chromatography Testing Blood must always be drawn under medically accepted conditions by a qualified individual. It is important that a nonalcoholic disinfectant be applied before the suspect’s skin is penetrated with a sterile needle or lancet. Once blood is removed from an individual, its preservation is best ensured when it is sealed in an airtight container after an anticoagulant and a preservative have been added and stored in a refrigerator.

6-32 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Gas Chromatography Testing Stability in blood is affected by Storage temperature Presence of a preservative Time of storage No single blood specimen has shown an increase in alcohol level over time Decrease can be caused by lack of refrigeration of adding proper preservative Also, longer storage times can also reduce blood-alcohol levels

6-33 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Gas Chromatography Testing Collection of postmortem blood samples requires added precautions Ethyl alcohol may be generated in a deceased individual as a result of bacterial action. Collect a number of blood samples from different body sites Collect vitreous humor and urine samples, as well Do not suffer from significant postmortem ethyl alcohol production

6-34 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Alcohol and Law Constitutionally, every state in the United States must establish and administer statues regulating the operation of motor vehicles. The American Medical Association and the National Safety Council have been able to exert considerable influence in convincing the states to establish uniform and reasonable blood-alcohol standards.

6-35 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Alcohol and Law Between 1939 and 1964 a person having a blood-alcohol level in excess of 0.15 percent w/v (0.15 grams of alcohol per 100 ml blood) was to be considered under the influence In 1965, it was lowered to 0.10 percent In 1972 it was recommended to be lowered again to 0.08 percent w/v.

6-36 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Alcohol and Law All 50 states have adopted the 0.08 percent per se level. Commercial truck or bus driver is considered legally intoxicated at 0.04 percent. Australia, Finland, France, Germany, Ireland, Japan, the Netherlands and Norway have a 0.05 percent limit Sweden has lowered its blood-alcohol concentration limit to 0.02 percent.

6-37 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Alcohol and Law A person is about 4x more likely to become involved in an accident at 0.08 percent as a sober individual At.15 percent level, chances are 25x more likely

6-38 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Alcohol and Law What is ONE drink? 12 ounces of beer 4 ounces of wine 1 ounce of 80-proof alcohol If you had been drinking for the past two hours and had consumed five beers in that time, would you be legally intoxicated? Chart on page 228 Blood Alcohol Concentration (BAC)

6-39 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Alcohol and Law The US Constitution guarantees all citizens protection against self-incrimination Consent to take a breath test for alcohol could be considered self-incrimination Schmerber v. California went all the way to the Supreme Court Ruled that a suspect was protected from giving testimonial evidence by the 5 th amendment, but not physical evidence

6-40 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Alcohol and Law “Implied consent” law was adopted by all states by 1973, States that the operation of a motor vehicle on a public highway automatically carries with it the stipulation that a driver will submit for a test for alcohol intoxication if requested or be subject to loss of the license.

6-41 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Role of the Toxicologist Beyond the analysis of alcohol, the toxicologist is confronted with a maze of drugs and poisons. The toxicologist is originally presented with body fluids and/or organs and is normally requested to examine them for the presence of drugs and poisons.

6-42 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Role of the Toxicologist Rarely, supportive evidence may be provided victim’s symptoms, a postmortem pathological examination examination of the victim’s personal effects, Usually, the toxicologist is forced to use general screening procedures with the hope of narrowing thousands of possibilities to one.

6-43 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Challenges The toxicologist is not dealing with drugs at the concentration levels found in powders and pills, having been dissipated and distributed throughout the body. Drug analyst may have a gram or milligram Toxicologist works with nanogram or microgram

6-44 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Challenges Secondly, the body is an active chemistry laboratory as few substances enter and completely leave the body in the same chemical state. Heroin is almost immediately metabolized to morphine upon entering the bloodstream Only a small percentage of the morphine is excreted in urine unchanged Morphine becomes chemically bound to carbohydrates before it is eliminated in urine

6-45 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Role of the Toxicologist Lastly, when and if the toxicologist has surmounted all of these obstacles, he or she must be prepared to assess the toxicity of the drug or poison. Most drugs have published information about toxicity levels, but still need to know subject’s case history Anna Nicole Smith p. 233

6-46 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein The Analytical Scheme The forensic toxicologist must devise an analytical scheme that will successfully detect, isolate, and specifically identify toxic drug substances. 90% of cases involve alcohol, marijuana & cocaine Once the drug has been extracted from appropriate biological fluids, tissues, and organs, the forensic toxicologist can proceed to identify the drug substance present.

6-47 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein The Analytical Scheme Drug extraction is generally based on a large number of drugs being either acidic or basic. Acidity/basicity is expressed in a simple numerical value related to the concentration of hydrogen ions in a liquid medium – usually water Acid – donates a hydrogen ion to another compound Base – accepts the hydrogen ion from the acid

6-48 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein The Analytical Scheme pH scale

6-49 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein The Analytical Scheme Acid drugs are easily extracted from an acidic water solutions Barbiturates and aspirin Basic drugs are easily extracted from basic water solutions Phencyclidine, methadone, amphetamines, cocaine

6-50 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein The Analytical Scheme Two-step approach for identification Screening TLC, GC and immunoassay (IA) IA can detect small concentrations of drug in body fluids and organs (marijuana detection) Confirmation Gas chromatography-mass spectrometry The GC separates the sample into its components, while the MS represents a unique “fingerprint” pattern that can be used for identification.

6-51 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Detecting Drugs in Hair Tests are limited on a living person Bloodstream drugs remain up to 24 hours Urine specimen drugs remain up to 72 hours Head hair weeks, months or years depending on the length of the hair Only viable way to measure long-term abuse of a drug

6-52 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Detecting Non-Drug Poisons Heavy Metals Arsenic, bismuth, antimony, mercury and thallium Used to be encountered fairly commonly, but now environmental protection regulations make them hard to get Joann Curley: Caught by a Hair p.239

6-53 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Detecting Non-Drug Poisons Heavy Metals Reinsch Test Place body fluid/tissue in hydrochloric acid and insert copper strip A silvery or dark coating indicates presence of heavy metal Confirmed by emission spectroscopy or x-ray diffraction

6-54 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Detecting Non-Drug Poisons Carbon Monoxide One of the most common poisons encountered in forensic labs Absorbed by RBCs and combines with hemoglobin Prevents oxygen from combing with hemoglobin and causes asphyxiation

6-55 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Detecting Non-Drug Poisons Carbon Monoxide Two basic methods to measure concentration Spectrophotometric method Measures concentration of hemoglobin with carbon monxide and oxygen Gas chromatography Blood treated with reagent to free carbon monoxide Carbon monoxide concentration is measured

6-56 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Detecting Non-Drug Poisons Carbon Monoxide Saturation In a healthy middle-aged individual, carbon monoxide saturation greater than 50-60% is considered fatal Chain smokers have a constant 8-10% saturation level from CO in cigarettes Combined with alcohol or other depressants, fatal saturation levels are significantly lower 35-40% saturation may prove fatal with BAC of 0.20

6-57 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Detecting Non-Drug Poisons Carbon Monoxide Saturation Inhaling automobile fumes is a common way to commit suicide Level of CO in blood of a victim found at a fire can determine whether the victim was killed prior to fire

6-58 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Interpreting Toxicological Findings Once a drug is found and identified, toxicologist must make an assessment of how the drug influenced the behavior of the subject. Alcohol Many studies have determined how specific alcohol levels in the blood affect individuals Also legal guidelines

6-59 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Interpreting Toxicological Findings Other Drugs Toxicologist must judge how the drug affects an individual’s performance or physical state Observations of arresting officer Drug levels in various body organs and tissues provide information postmortem Age, physical condition and drug tolerance must also be considered

6-60 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Drug Recognition Expert (DRE) Police officers are routinely trained to recognize alcohol- impaired behavior 3-5 month specific training program to recognize other drug-impaired behavior Complete DRE Evaluation Form Not a substitute for toxicological screening

6-61 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Drug Recognition Expert (DRE) DRE Evaluation Form can suggest presence of 7 broad categories of drugs CNS depressants CNS stimulants Hallucinogens Dissociative anesthetics (PCP) Inhalants Narcotic analgesics Cannabis