Test 8: Toxicology, Arson and Explosions

Lethal Dose (LD₅₀)

the lethal dose where you kill of 50% of lab test animals

• Cyanide - 700 mg

• Nicotine - 140 mg

• Ethanol - 1,000 mg

• etc.

Acute Toxicity

adverse effects within short time of toxin exposure

• lots of poison at one time

Chronic Toxicity

condition caused by prolonged exposure to a toxin

• a little poison over a long time

Corrosive Poisons

substances that actually destroy tissue outright

• Acids/Bases (Alkali)

  • Sulfuric Acid

  • Hydrochloric Acid

  • Sodium Hydroxide

• Death can result from as little as 1 oz of sulfuric acid

  • Works by dehydrating tissues

  • Cells die fast because water is removed and proteins are destroyed by acid-catalyzed hydrolysis of peptide bonds

Metabolic Poisons

affect biochemical mechanisms (interfere with chemical reactions)

• Carbon Monoxide (gas) - colorless, odorless, toxic - suicide or homicide

  • Binds to iron in hemoglobin and only very slowly is released, displacing oxygen; Carboxyhemoglobin is 140 times more stable than oxyhemoglobin

  • Breathing 0.1% CO in air for 4 hours converts 60% of hemoglobin to carboxyhemoglobin

  • Not a cumulative poison (given time, the free hemoglobin is released)

• Cyanide (suicide or homicide - Tylenol murders)

  • Common industrial agent (plastics formation, electroplating, metal-ore processing)

  • NaCN reacts with acids to form HCN (gas) - weak odor of almonds

  • Naturally occurs in seeds (protects seeds until they germinate)

  • Very fast working (seconds)

  • Causes asphyxiation

    • Binds tightly with iron so that even though lots of oxygen gets to cells, they can’t use it to support life

  • Eventually, cyanide is removed by enzyme

  • Administer large amounts of thiocyanate can be effective - ANTIDOTE

Mad Hatter’s Disease

• “Mad as a hatter”

• Mercuric nitrate used to separate animal fur from skins was inhaled, poisoning them

Lead Poisoning

• heavy metal

• Romans - lead cooking vessels, cosmetics, and plumbing (downfall of Rome - Pb in Emperor’s wine and water led to mental illness)

  • See high Lead levels in bone evidence

  • “Plumbing” from Latin word for lead “plumbum”

• Modern - leaded gas, paint, water pipe joints

  • Plumbing - (joints) EPA allows max 15 ppb, many cities have 500 ppb

  • Paint - PbO (white paint) - children ingest (now use TiO₂ - nontoxic)

• Pb displaces physiological metals in chemical reactions

Narcotics

relief from pain and bring sleep; Analgesic - relieve pain by depressing nervous system

• gets rid of pain, brings about sleep

• Poppy plant (unripe pod) —> opium —> morphine —> codeine or heroin

• Oxycontin

  • For chronic pain

  • One of the most abused drugs in the US

  • Names: Oxy, O.C., killer, hillbilly heroin

  • Highly addictive with physical dependence

Methadone

• related to heroin

• eliminates the “high” if taking heroin

• helps break a heroin habit

Fentanyl

• Opiate - very addictive

• Dance Fever, Goodfellas, Apace

• 80 to 100 times stronger than morphine

• originally used for pain management

• mixed with street heroin - severe overdose risk

• breathing depressed, pupils constricted, vomiting, nausea, dizziness, death

Marijuana

• Pot, Grass, Wacky Baccy, Hash, Ganja, Hash Oil, Weed, Tree, Greens

• Wild weed: 5-15 ft

• Odd leaf number, serrated edge

• Crush leaves with flower, stem, and seed

• Plant Resin = Hashish

• THC active ingredient

• Can tentatively be identified by the Duquenois-Levine color test

• Symptoms

  • Lack of coordination - danger to drive

  • Reduced reaction time - danger to drive

  • Red eyes

  • Dilated pupils

  • Increased heart rate

  • Irrelevant giggling

Spice (Synthetic Marijuana)

• K2, Fake weed, Yucatan Fire, Skunk, Moon Rocks

• 5 active chemicals-cannabinoids

• Illegal, controlled drugs, Schedule 1 DEA

• Big use by high school age

• Rapid heart rate, vomiting, agitation, confusion, and hallucination - psychotic reactions

• Regular users may experience withdrawal and addiction symptoms

Physical Withdrawal - experience physical symptoms in the absence of a drug

LSD

• Hallucinogen

• Acid, boomers, yellow sunshines, Cid, Doses, and Trips

• Derived from Ergot Fungus (on grasses/grains)

• First described in 1943 after “accidental” lab ingestion (potent - 25 micrograms for long lasting effects)

• Causes hallucinations for 12hrs

• Mood swings, anxiety, tension

MDMA

hallucinogen - ecstasy, E, Adam, XTC, Fantasy, Date-Rape Drug

• Get abundant energy

• Increased color perception

• Dehydration

• Enhanced empathy

• Brain cell damage

• Anxiety

• Panic

• Insomnia

• Hallucinations

• Psychosis

• Memory loss

• Hypertension

Depressants

depress functions of the central nervous system, cause calm and bring about sleep (alcohol, barbituates, tranquilizers)

• Downers - relax, create feeling of well-being, produce sleep

• Act on CNS

• Usually taken orally

• Includes tranquilizers (librium and Valium) and “glue sniffing” (toluene, gasoline, freon, etc.) - all effect CNS

• Major Problems - chemical exposures cause permanent liver, kidney, heart, and brain damage

Alcohol

• Sedative

• Vasodilator = blood increased to extremities

• Diuretic

• Respiratory depression

• Gastric irritant

• Slurred speech

• Acute Toxicity: coma and death

• Chronic Toxicity: liver damage

Alcohol Specifics (Route)

• No. 1 abused drug with more related deaths per year than any other

• Alcohol in stomach (absorbed 20%) and intestine - first place of absorption

• Absorbed within minutes into bloodstream

• Timing affected by:

  • Time taken to consume drink

  • Alcohol content

  • Amount consumed

  • Stomach contents

Barbiturates

• Downers, Yellow Jackets, Blue Devils, Reds, Barbs

• Downers - suppress CNS

• Derived from Barbituric Acid

• Sedatives taken orally

• Physically addictive

• Ex: Amobarbital, Secobarbital, Phenobarbital, etc.

Ketamine

• Horse tranquilizer

• Special K, Kit Kat

Glue Sniffing, Sniff aerosol propellants and solvents

depressants

• Suppress CNS

• Euphoria

• Slurred speech

• Impaired judgment

• Double vision

• Risk liver, heart, brain damage, and death

Rohypnol

• date rape drug

• Felt in 30 mins, peak within 2 hrs, may persist for 8+ hrs

• Roofies, Rophies, Roche, Forget-me Pill, Circles, Mexican Valium, Rib, Roach-2, Roopies, Rope, Ropies, Ruffies, and Roaches

Date-Rape Drug Offenders

• the offender and victim are most likely classmates, friends, or significant others rather than acquaintances or strangers

Stimulants

increase alertness and activity

• Amphetamines - synthetic drugs that stimulate the CNS

• Methamphetamines

• Once stimulant wears off then severe depression usually sets in - requiring more stimulant (speed binge)

• Dilated pupils, insomnia, panic, confusion, increased heart rate, hypertension

Bath Salts

• One or more synthetic chemicals related to cathinone; amphetamine-like

• Euphoria, increased sociability, sex drive, paranoia, agitation, hallucinatory delirium; some even display psychotic and violent behavior, and deaths

• As soon as an ingredient is made illegal, chemists alter chemical’s structure

Cocaine

• Stimulant

• Interferes with dopamine, a chemical messenger associated with pleasure; continuous stimulation of “receiving” neurons, leads to euphoria

• The powdered, hydrochloride salt form of cocaine can be snorted or dissolved in water and injected

• Crack - comes in a rock crystal that can be heated and its vapors smoked; the term crack refers to the crackling sound heard when it is heated

• Acute cardiovascular or cerebrovascular emergencies, such as a heart attack or stroke

• Constricted blood vessels, dilated pupils, increased temperature, heart rate, nasal problems, headache, fatigue, high blood pressure

• Comes from the coca plant; ground to powder and chemicals are added

• 10lbs of leaves = 1 oz of cocaine

• Colombia - #1 manufacturer of cocaine

• People swallow baggies of cocaine to transport them

Steroids

• Anabolic Steroids (Roids)

• Synthetic (like testosterone)

• Enhanced muscle growth

• Risk liver growth

• Risk liver damage

• Reduced sex drive

• Reduced sperm production

• Severe acne

• Masculinization in females and infertility (pronounced jaw)

• Feminine characteristics in men (grow breasts)

• Teenage suspension of bone growth

• Mood swings and aggressive behavior

Drug Metabolism Issues — Analyte vs. Metabolite

Analyte - compound analyzing for

Metabolite - body can change chemical nature of drug (heroin to morphine)

Drug ID

• Immunoassay - radioactive/fluorescent tagged antibodies

• TLC

• GC

• HPLC

• GC/MS - find out exactly what the drug is

• LC/MS

• AA; ICP-MS

• Separation, detection, identification, and measurement of drugs in biological specimen

Motives for Arson

• Crime concealment

• Revenge or spite

• Monetary gain

• Malicious vandalism

• Mentally disturbed

Triangle of Fire

Fuel, Heat, Oxygen

Fuel

combustible material in any state of matter; solid, liquid, or gas

• Most solids and liquids become a vapor or gas before they will burn

Ignition Temperature

temperature a substance needs to reach before it begins to burn

• The heat from burning causes further oxidations which causes further burning

• Gasoline - 536 F

• Turpentine 488 F

• Kerosene 410 F

• Accelerant - any material used to start or sustain a fire

Full Development/Active Fire Stage

• Flashover begins

  • Simultaneous ignition of all combustibles

  • Occurs when items are rapidly heated to pyrolysis temperatures

  • “Raging” fire

• Backdraft near the end of this stage

  • Often explosive event

  • Sudden feed of Oxygen

    • Via window opening or roof collapse

  • Sudden flash combustion of remaining fuel

Spontaneous Combustion

• Burning resulting from natural heat-generating reactions

  • Ex. Hay and heat-producing bacteria

    • If no ventilation, heat builds to combustion

  • Ex. Oily rags

    • Slow accumulation of heat from oils oxidizing with air

Fire Origin

• V-pattern charring above point of origin

• Wind can distort the Vs

Evidence Collection

• 2 to 3 quarts of ash from origin

• Collect suspicious rug, floor, and cloth samples

• Collect control samples

• Package in airtight tin can containers, fill cans ⅔ full (top space for gas analysis)

• Don’t use plastic bags since they react with vapors

Damage from High Explosives

• Shock wave

• Heat

• Flying debris

USS Cole in Yemen

• 400 - 700 lbs of explosives

• Small ship loaded with explosives pulls up to the side of the ship and blew it up

• Killed some navy officials

EGIS

sucks in air samples to analyze for explosive residues

Evidence Storage

• metal cans

• avoid plastics since vapors can escape plastic bag