Toxicology - City University Of New York
FORENSICTOXICOLOGY
DWI
Introduction Toxicologists are charged with the responsibilityfor detecting and identifying the presence ofdrugs and poisons in body fluids, tissues, andorgans. Toxicologists not only work in crime laboratoriesand medical examiners’ offices, but may alsoreach into hospital laboratories and healthfacilities to identify a drug overdose or monitorthe intake of drugs. A major branch of forensic toxicology deals withthe measurement of alcohol in the body formatters that pertain to violations of criminal law.
Toxicology of Alcohol The analysis of alcohol exemplifies the primaryobjective of forensic toxicology—the detectionand isolation of drugs in the body for thepurpose of determining their influence on humanbehavior. Alcohol, or ethyl alcohol, is a colorless liquidnormally diluted with water and consumed as abeverage. Like any depressant, alcohol principally effectsthe central nervous system, particularly thebrain.
Alcohol Levels Alcohol appears in the blood within minutes afterit has been taken by mouth and slowly increasesin concentration while it is being absorbed fromthe stomach and the small intestine into thebloodstream. When all the alcohol has been absorbed, amaximum alcohol level is reached in the blood;and then the post-absorption period begins. Then the alcohol concentration slowly decreasesuntil a zero level is again reached.
Rate at which alcohol isabsorbed.Factors such as time taken to consume the drink, the alcohol content, the amount consumed, and food present in the stomachdetermine the rate at whichalcohol is absorbed.
Alcohol Levels – Contd. Elimination of alcohol throughout the body isaccomplished through oxidation and excretion. Oxidation takes place almost entirely in the liver, while alcohol is excreted unchanged in the breath,urine, and perspiration. The extent to which an individual may be under theinfluence of alcohol is usually determined by eithermeasuring the– quantity of alcohol present in the blood system or– by measuring the alcohol content in the breath. Experimental evidence has verified that the amount ofalcohol exhaled in the breath is in direct proportion to theblood concentration.
Alcohol and Circulatory System Humans have a closed circulatory system consisting of aheart, arteries, veins, and capillaries. Alcohol is absorbed from the stomach and small intestinesinto the blood stream. Alcohol is carried to the liver where the process of itsdestruction starts. Blood, carrying alcohol, moves to the heart and is pumped tothe lungs. In the lungs, carbon dioxide and alcohol leave the blood andoxygen enters the blood in the air sacs known as alveoli. Then the carbon dioxide and alcohol are exhaled duringbreathing.
Breath Testers Breath testers that operate on the principle of infraredlight absorption are becoming increasingly popular withinthe law enforcement community. Many types of breath testers are designed to capture aset volume of breath. The captured breath is exposed to infrared light. It’s the degree of the interaction of the light with alcoholin the captured breath sample that allows the instrumentto measure a blood alcohol concentration in breath.
Field Testing Law enforcement officers typically use fieldsobriety tests to estimate a motorist’s degree ofphysical impairment by alcohol and whether ornot an evidential test for alcohol is justified. The horizontal gaze nystagmus test, walkand turn, and the one-leg stand are allconsidered reliable and effectivepsychophysical tests. A portable, handheld, roadside breath testermay be used to determine a preliminary breathalcohol content.
Gas Chromatography Testing Gas chromatography offers the toxicologist the mostwidely used approach for determining alcohol levelsin blood. Blood must always be drawn under medically acceptedconditions by a qualified individual. It is important that a nonal
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. A portable, handheld, roadside breath tester may be used to determine a preliminary breath-alcohol content.
toxicology data would potentially be required. For example, as noted in the toxicology data requirements table, swimming pool, wood preservative, metalworking fluid, and aquatic areas uses require toxicology data in addition to the core toxicology data. Again, the use pattern and specific use site(s) should be examined to determine the data .
A Small Dose of Toxicology A book chapter of A Small Dose of Toxicology - The Health Effects of Common Chemicals By Steven G. Gilbert, PhD, DABT Institute of Neurotoxicology & Neurological Disorders (INND) Seattle, WA 98115 E-mail: sgilbert@innd.org Supporting web sites web: www.asmalldoseof.org - "A Small Dose of Toxicology"
forensic toxicology). SWGTOX will also establish a uniform Code of Ethics for forensic toxicologists, identify areas of research and development in the field of forensic toxicology, and promote public awareness of the field of forensic toxicology through outreach. What professional groups
4 Toxicology Toxicology Terminology Toxicology is the study of the adverse effects of chemicals or physical agents on living organisms. A toxicologist is a scientist that determines the harmful effects of agents and the cellular, biochemical, and molecular mechanisms responsible for the effects. Toxicant, toxin, and poison are often used interchangeably in the literature; however,
The classic connotation of toxicology was "the science of poisons." Since that time, the science has expanded to encompass several disciplines. Toxicology is the study of the interaction between chemical agents and biological systems. While the subject of toxicology is quite complex, it is necessary to understand the basic concepts in order to make
toxicology and carcinogenesis studies were conducted in F344/N rats by administering hexachloro- ethane (approximately 99%pure) in corn oil by gavage to groups of males and females for 16 days, 13 weeks, or 2 years. Genetic toxicology studies were conducted in Salmonella typhimurium and in Chi- nese hamster ovary (CHO) cells.
220-D200 Toxicology Training Manual Qualtrax ID: 2852 Issued by Toxicology Program Manager Qualtrax Revision 3 Issue Date: 14-August-2018 Page 6 of 63 1.3 Training Period The length of the training period is a highly variable matter and will be left to the determination of the Toxicology Program Manager.
Toxicology Tutors (Tox Tutors) In the Tox Tutors , created by the US Health and Human Services, you can learn about the history and explore an introduction to the basic principles of toxicology in the module entitled Introduction to Toxicology and Dose-Response.
