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FORENSIC TOXICOLOGY. ETHYL ALCOHOL. TOXICOLOGY. The study of poisons. TOXICOLOGISTS. Detect and identify drugs and poisons in body fluids, tissues, and organs. ENVIRONMENTAL TOXICOLOGISTS. OCCUPATIONALTOXICOLOGISTS. FORENSIC TOXICOLOGISTS- duties limited to legal issues.
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FORENSIC TOXICOLOGY ETHYL ALCOHOL
TOXICOLOGY The study of poisons
TOXICOLOGISTS Detect and identify drugs and poisons in body fluids, tissues, and organs
FORENSIC TOXICOLOGISTS-duties limited to legal issues • Workplace drug testing - Postmortem drug testing Investigation of contraband materials
TOXICOLOGY OF ALCOHOL A CENTRAL NERVOUS SYSTEM DEPRESSANT
90 MILLION AMERICANS DRINK.. 10 MILLION HAVE A “DRINKING PROBLEM”
EFFECTS OF ETHYL ALCOHOLON THE HUMAN BODY PRINCIPAL EFFECT IS ON THE
FOREBRAIN IS AFFECTED FIRST • reasoning, planning, parts of speech, movement, • emotions, and problem solving
REAR PORTIONS ARE AFFECTED NEXT movement, orientation, recognition, perception of stimuli perception and recognition of auditory stimuli, memory, and speech
LOWERS INHIBITIONS In one study of unplanned pregnancies in 14-21 year olds, 1/3 of the girls who had gotten pregnant had been drinking when they had sex; 91% of them reported that the sex was unplanned. Half of all newly-reported AIDS cases are for young people ages 14-21…
IMPAIRS JUDGEMENT 40% OF TRAFFIC FATALITIES INVOLVE ALCOHOL
LONG-TERM EFFECTS CIRRHOTIC LIVER HEALTHY LIVER JAUNDICEDKIDNEYS
ABSORPTION INTO THE BLOODSTREAM 20% OF ALCOHOL IS ABSORBED INTO THE BLOODSTREAM ACROSS THE WALLS OF THE STOMACH 80% IS ABSORBED ACROSS THE WALLS OF THE SMALL INTESTINE
FACTORS THAT AFFECTHOW FASTALCOHOLIS ABSORBED INTO THE BLOODSTREAM
TYPE OF ALCOHOL ABSORBED SLOWLY ABSORBED FASTER
Maximum blood-alcohol concentrations in the blood may not be reached until after time of consumption TO 90 MIN IS AVERAGE
Under NORMAL SOCIAL DRINKING conditions It takes anywhere from30 – 90 minutes from the time of the final drink until absorption is complete
Since alcohol is distributed through the watery portions of the body Other organs may be tested for alcohol
ELIMINATION OF “BURN-OFF” RATE 0.015% - 0.020% w/v per hour (0.015% is .015 g alcohol per 100 ml blood) 1 – 1½ DRINKS PER HOUR
OXIDATION AROUND 95% OF ALCOHOL THAT ENTERS THE BODY IS OXIDIZED IN THE LIVER Alcohol → acetaldehyde → acetic acid→ CO2 + H2O
EXCRETION Is the elimination of alcohol in UNCHANGED STATE 5%
Measuring Breath for BAC Amount of Alcohol EXHALED is DIRECTLY PROPORTIONAL to the Concentration of alcohol in the BLOOD
Two ways to measure alcoholin the body: INDIRECT METHOD DIRECT METHOD:
ANATOMY ARTERIES VEINS CARRY BLOOD AWAY FROM THE HEART CARRY BLOOD TO THE HEART
Alcohol travels through the body: 20% of alcohol is Absorbed from walls of stomach To veins
(Small intestine) 80% passes from walls of small intestine to Veins to liver
In ALVEOLI oxygen enters the blood and CO2 leaves it
At 340 C The ratio of alcohol in the blood To alcohol in the alveoli is 2100:1
1 ml of blood contains the Same amount of alcohol as 2100 ml alveolar breath
DURING ABSORPTION: CONCENTRATION OF ALCOHOL IN ARTERIAL BLOOD WILL BE CONSIDERABLY HIGHER THAN VENOUS BLOOD (dark red color) During elimination, venous blood has higher BAC
THE BREATHALYZER Measures ALCOHOL CONTENTof ALVEOLAR BREATH
THEBREATHALYZER INDIRECTLY MEASURES THE AMOUNT OF ALCOHOL CONSUMED BY MEASURING THE ABSORPTION OF LIGHT USING A SPECTROPHOTOMETER
HOW IT WORKS: 16 H+(aq) + Cr2O72-(aq) + 3 C2H5OH(l) → (orange) (alcohol) 4 Cr3+(aq) + 3 CH3COOH(aq) + 11 H2O(l) (green) UNUSEDORANGEMIXES WITH GREEN PRODUCED TO MAKE A BLUE SOLUTION
In other words…. ORANGE + ALCOHOL→ GREEN (Cr2O72-(aq)) Little or no alcohol: ORANGE Some alcohol: BLUE (orange + green ) A lot of alcohol: GREEN or GREENISH BLUE The HIGHER the concentration of alcohol, the LOWER the concentration of potassium dichromate (K2Cr2O7)
FIELD SOBRIETY TESTS are performed to find the degree of impairment and whether an evidential test is justified