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1. Ch 10 ? Forensic Toxicology Alcohol in the bloodstream.
Human circulatory system.
Alcohol excretion in the breath.
Infrared breath-testing device.
Field sobriety tests.
Alcohol concentration in blood.
2. Blood alcohol in your state.
Significance of the implied consent law and the Schmerber v. California case to trafic enforcement.
Acids and bases.
Role of toxicologist in the criminal justice system.
Techniques of isolating and identifying drugs and poisons.
Finding a drug in human tissues and organs.
3. Collaboration between Drug Recignition Expert and Forensic Toxicologist in positive drug finding.
4. Absorption: passage of alcohol across the wall of the stomach and small intestine into the blood stream
?Oxidation: the combination of oxygen with other substances to produce new products
?Excretion: elimination of alcohol from the body in an unchanged state; alcohol is normally excreted in breath and urine
5. Artery: a blood vessel that carries blood away from the heart
Vein: a blood vessel that transports blood toward the heart
Capillary: a tiny blood vessel across whose walls exchange of materials between the blood and the tissue takes place; receives blood from arteries and carries it to veins
6. Alveoli: small sacs in the lungs through whose walls air and other between the breath the breath and the blood
Catalyst: a substance that acceleration the rate of a chemical reaction but is not itself permanently changed by the reaction
Fuel cell: a detector in which chemical reactions are used to produce electricit
7. Anticoagulant: a substance that prevents coagulation or clotting of the blood
Preservative: a substance that stops the growth of microorganisms in blood
Metabolize: transforming a chemical in the body to another chemical for the purpose of facilitating its elimination from the body
Acid: a compound capable of donating a hydrogen ion (H+) to another compound
8. Base: a compound capable of accepting a hydrogen ion (H+)
pH: a symbol used to express the basicity or acidity of a substance. A pH of 7 is neutral; lower values are acidic and higher values are basic
9. Ch. 10 - Forensic Toxicology Alcohol
10. What is Toxicology? Toxicological examinations involve the identification and often quantitation of drugs & toxic materials in the human body
The role of the forensic toxicologist is limited to matters pertaining to violations of criminal law
11. Paracelsus ?What is there that is not a poison?
All things are poison and nothing without poison. Solely the dose determines that a thing is not a poison.?
12. What is Forensic Toxicology? Toxicology: Study of drugs and poisons and their adverse affects on the human system. Subfields include:
pharmacokinetics (how the drug works on people)
pharmacodynamics (how people work on the drugs)
13. Toxic Substances LD50 Calculations:
Cyanide (for 150 lb human - ~ 70 Kg)
(70Kg)(10mg/Kg) = 700 mg (0.70g)
Nicotine (e.g.; from Cigarettes)
(70Kg)(2 mg/Kg) = 140 mg (0.14g)
(note 1 cig. = ~ 2 mg Nicotine)
(70Kg)(1000mg/Kg) = 70,000mg (70g)
Effect of Body Weight: Ethanol
150 lb Human = lethal dose = ~ 70 g
40 lb Dog = lethal dose = ~ 20 g
14. Forensic Toxicological Questions Intentional or Accidental Poisoning?
What type of Poison?
Corrosive Poisons - Substances that actually destroy tissue outright
Metabolic Poisons - Affect biochemical mechanisms.
Drug Use - what drug, how much and when?
Activity while under the influence of drugs?
15. Common Terms Analyte - the compound that you?re analyzing for.
Metabolite - Compound formed from the metabolism of a drug. Heroin quickly metabolizes to Morphine so Morphine is a metabolite of Heroin.
17. Specimen Collection Fluids: Organs:
Vitreous Humuor Hair and Fingernails
Oral Fluid Liver
Stomach Contents Bone
Bile Other (heart, brain?)
18. Sampling Blood - It matters where you sample in the body
Blood taken near the liver or other solid organ may contain drug that has diffused from the organ into the blood post-mortem to give very high drug levels. Take blood from femoral artery because it?s far from organs.
Urine - tends to concentrate compounds.
Can?t be sure of body concentration since it is unknown how long it has been accumulating in the body.
Liver - concentrates and stores drugs for long times.
good for detection but problematic for concentrations.
19. Sampling Bile - Useful for detection but not concentration.
Kidney - Similar to Bile.
Vitreous Humuor - Correlates well with femoral blood for most compounds.
Hair and Fingernails - Good for some compounds with timelines possible.
Oral Fluids - Can be easily disguised.
Others - May be good for certain analyses but not generally good sources for many compounds.
20. Additional Matrices Vomit Meconium
Earwax Amniotic Fluid
Semen Umbilical Cord Blood
21. Specimen Collection: Case Examples Deceased
Suspected drug related death
Road Traffic Death
Drug Facilitated Sexual Assault (DFSA)
Workplace drug testing
22. Roles of Forensic Toxicology Postmortem Forensic Toxicology
Human Performance Toxicology
Forensic Drug Testing
23. Postmortem Forensic Toxicology Death Investigation
Medical Examiners Office.
NYS - elected Coroners or appointed Medical Examiners depending upon county.
Forensic Pathologist responsible for performing autopsy.
Forensic Toxicologist responsible for analyzing biological samples for poisons.
24. Specimen Collection Essential to collect the appropriate specimens and that they are collected, packaged, transported, and stored correctly.
Pathologist is responsible for the collection of the human-derived specimens and may consult the toxicologist on unusual cases.
25. Specimen Collection MOST IMPORTANT STEP!!!!
Obtain a Representative Sample:
?A small portion of a material taken from a bulk specimen and selected in such a way that it possesses the essential characteristics of the bulk?.
[E.g., easily possible to pick out a few crystals from a sample that do not reflect the majority of the sample - maybe that?s why they crystallized]
26. Sample Handling Storage
Avoid - loss (due to volatility).
- contamination (e.g., insufficient seal).
Prevent - chemical interactions (e.g., Na and oil).
- Degradation (refrigerate biological samples).
27. Sample Preparation Homogenising - making the sample uniform:
grind (mortar and pestle)
dissolution (water, solvents, acids)
28. Postmortem Forensic Toxicology Blood Samples
Usually the most important specimen
Ideally 2 samples (25 mL each)
Femoral/jugular (peripheral site) - far as possible from solid organs
29. Postmortem Toxicology Vitreous humor samples - The clear, gel-like mass that fills the space between the lens and the retina.
Should be collected at all PM?s
Relatively stable matrix
Anatomically isolated area
Good correlation with blood
30. Postmortem Toxicology Urine samples:
All available sample should be collected.
Higher concentrations present than in other matrices, but not always.
Rapid tests available (both qualitative [what] and quantitative [how much] tests).
Not always available.
31. Postmorten Toxicology Digestive System
32. Postmortem Forensic Toxicology Bile samples
Alternative if urine unavailable
Accumulation of drugs
All available bile should be collected
Not an easy sample to analyze
33. Postmortem Forensic Toxicology Liver samples:
Drug metabolism occurs in the liver.
Drugs may be present in higher concentrations.
34. Postmortem Forensic Toxicology Other specimens:
Spleen (carbon monoxide) ? blood unavailable
Stomach Contents (drug overdose)
Hair ( drug use history)
35. Human Performance Toxicology The effects of drugs on skills, acquisition, learning, and performance.
Drugs may alter normal behavior by either enhancing or impairing performance.
Stimulant drugs can enhance performance ? short term but used regularly can impair performance.
36. Human Performance Toxicology Not only illicit drugs (e.g. heroin, cocaine, cannabis, etc?
Prescription medication can impair performance especially at the start of the treatment
E.g. antidepressants, muscle relaxants, etc.
38. Human Performance Toxicology Blood is the best specimen for determining impairment through drugs.
In contact with the central nervous system.
Hair/urine/sweat ? becoming popular but unlikely that a quantitative relationship will exist.
39. Human Performance Toxicology Alcohol and/or Drugs Involving Driving:
In addition to collecting the correct samples, additional information is essential:
Witness statements to the incident
Assessment of impairment at the scene
Field Sobriety tests
Drug Recognition Evaluation
40. Forensic Drug Testing - Where? Workplace Drug Testing
Private and public companies
International Olympic Committee
Drug Facilitated Sexual Assault (DFSA)
41. Toxicology of Alcohol The Fate of Alcohol in the Body
42. Properties of Alcohol Alcohol is a general term for a family of organic compounds
commonly encountered members include methanol, ethanol, isopropanol
The term alcohol will be taken to mean ethanol (ethyl alcohol)
43. Chemical Properties of Ethanol A clear volatile liquid
Slight, characteristic odor
Is very soluble in water
miscible in all proportions
44. Physiological Properties of Ethanol A central nervous system (CNS) depressant
CNS is the bodily system which is most severely affected by alcohol
The degree to which the CNS function is impaired is directly proportional to the concentration of alcohol in the blood
45. What Does the Body Do With Alcohol? When an alcoholic beverage is swallowed, it is diluted by stomach juices & quickly distributed throughout the body
Alcohol does not require digestion before its absorption into the bloodstream
some diffuses into bloodstream directly through the stomach wall
remainder passes into the small intestine
rapidly absorbed & circulated
46. Alcohol Absorption Alcohol is absorbed from all parts of the gastrointestinal tract largely by simple diffusion into the blood
small intestine is the most efficient region for absorption because of its large surface area
The rate of absorption varies according to the particular beverage & the state of the consumer?s stomach
47. Alcohol absorption Fasting individual
20-25% of a dose of alcohol is absorbed from the stomach
75-80% is absorbed from the small intestine
peak blood alcohol concentrations occur in 0.5-2.0 hrs
48. Alcohol Absorption Non-fasting individuals
presence of food in stomach (especially gatty foods) delays absorption
peak alcohol concentrations 1.0-6.0 hrs
Alcohol ingested with carbonated beverages
ordinarily absorbed more rapidly than straight alcohol
49. Alcohol Distribution Alcohol has a high affinity for water
Is diffused in the body in proportion to the water content of the various tissues & organs
greater concentration in blood & brain
lesser concentration in fat & muscle
50. Alcohol Distribution Absorbed alcohol is greatly diluted by the aqueous body fluids
1 oz. (29.57 mL) of 50% (100 proof) whiskey will be diluted in a man of average build, to a concentration ~2 parts per 10,000 in the blood (0.02%)
51. Blood Alcohol concentration BAC is the amount of alcohol in the bloodstream measured in percentages
BAC = 0.10%
means a person has 1 part alcohol per 1,000 parts of blood in the body
52. Elimination Liver eliminate ~95% of the alcohol through metabolism
oxidation via acetaldehyde & acetic acid to carbon dioxide & water
Remainder of eliminated through excretion in breath, urine, sweat, feces, milk & saliva
Rule of Thumb
0.5 oz (15 mL) alcohol eliminated per hr
53. Blood Alcohol Concentrations A set of probable average curves of BAC in an average-size man after rapid absorption of various amounts of alcohol
Shows rate of BAC decline over time as a result of metabolism & excretion
54. Elimination Absorbed alcohol is passed through the liver by circulating blood
ADH (alcohol dehydrogenase) converts the alcohol to acetaldehyde
acetaldehyde is a highly toxic substance
Aldehyde dehydrogenase converts acetaldehyde to acetate ion
Acetate enters blood stream & is ultimately oxidized to CO2
55. Elimination Both enzymatic reactions require a co-enzyme, NAD, which accepts a hydrogen from the molecule
The temporary depletion of NAD by the first step limits the rate at which alcohol can be metabolized
56. Curve a
drinking 2 oz alcohol each hr for 4 hours
BAC increase is cumulative because alcohol is consumed faster than it can be metabolized
drinking 8 oz all at once
58. BAC?s Affect Behavior
59. Some Alcohol Statistics ~half of traffic injuries involve alcohol
~1/3 of fatally injured passengers & pedestrians have elevated blood alcohol levels
~half of homicides involve alcohol
1/2 to 1/3 of suicides involve alcohol
CDC estimates ~30,000 unintentional injury deaths are directly attributable to alcohol
60. Alcohol & Driving
62. Respiratory System Volatile chemicals dissolved in the blood will be brought to equilibrium with the air in the lungs
fixed ratio between compound in breath & blood
63. Alcohol in Blood vs Breath The ratio of alcohol in blood to alcohol in alveoli air is 2100 to 1
1 mL of blood will contain about the same amount of alcohol as 2100 mL of breath
During the period of absorption, the alcohol concentration is higher in arterial blood than venous blood
breath test reflects alcohol conc. in the pulmonary artery (reflects what reaches the brain
64. The Breathalyzer Measures the alcohol content of alveolar breath
Subject blows into a mouthpiece until 52.5 mL of alveolar breath has been collected
measures alcohol concentration of 1/40 mL of blood
The alcohol in the blood is reacted with chromic acid
65. Breathalyzer Beers? Law
the concentration of Cr (VI) is directly proportional to the amount of 420 nm light light absorbed by the sample
Measures the concentration of the unknown solution to the concentration of a standard sample
66. Legal Alternatives How other countries handle drunken drivers
Australia ? the driver is jailed and the name is sent to the local paper and published under the heading ?He is drunk and in jail?
Malaysia ? the driver is jailed and, if married, his wife is also jailed
Turkey ? drunken drivers are taken 20 miles from town by the police and forced to walk back under escort
Norway ? three weeks in jail at hard labor, and one year loss of license (2nd offence w in five years and their license is revoked for life)
Finland and Sweden ? automatic jail for 1 year at hard labor
Costa Rica ? police remove plates from car
Soviet Union ? license revoked for life
England ? one year suspension, $250 fine, and jail for 1 year
France ? three years loss of license, one year in jail and $1000 fine
Poland ? Jail, fine, and mandatory political lectures
Bulgaria ? A second conviction results in execution
El Salvador ? your first offense is your last, execution by firing squad