Tox 1 Flashcards
What is the definition of toxicology?
Toxicology is a science that deals with poisons.
What is a broader definition of toxicology?
The study of the detection, occurrence, properties, effects, and regulation of toxic substances.
How is toxicity of chemicals characterized?
Toxicity is dose-dependent.
What is the threshold dose?
The dose below which no effect or response is observed, also known as no observed effect level (NOEL).
What is an example of a chemical with varying toxicity at different doses?
Vinyl chloride, which is hepatotoxic at high doses and carcinogenic at low doses.
What is the relationship between dose and essential elements in diet?
Elements like iron, copper, and zinc are toxic at high doses.
What factors can affect toxicity among populations?
Genetic variations.
What is the role of exposure in toxicology?
Risk to toxicants results from exposure; without exposure, there is no hazard.
What are the four major routes of exposure to toxicants?
- Ingestion through gastrointestinal tract (GIT)
- Inhalation via the lungs
- Penetration through the skin
- Injection (IV, IP, IM, SC)
What is mechanistic toxicology?
The study of sequences of toxic events at the biochemical and molecular levels.
What does systemic toxicology focus on?
Carcinogenesis, teratogenesis, and mutagenesis.
What is the focus of clinical toxicology?
Diagnosis and treatment of human poisoning.
What are natural toxins?
Phytotoxins, mycotoxins, and minerals occurring in the environment.
What is toxicokinetics?
The study of how toxic substances are absorbed, distributed, metabolized, and eliminated by the body.
What is forensic toxicology?
The use of toxicology for legal purposes, assisting courts in determining the cause of death.
What is an expert witness?
An individual with specialized knowledge or experience in a subject beyond common knowledge.
What are the basic phases in investigating toxicant-related deaths?
- Collection of information and specimens
- Toxicological analysis
- Data interpretation
What types of samples are commonly analyzed in forensic toxicology?
- Blood
- Urine
- Tissues (e.g., brain, liver, kidney)
- Other fluids (e.g., tears, saliva)
What is the significance of vitreous humor in toxicology?
It is less susceptible to postmortem changes and can confirm blood values.
What is the importance of analytical toxicology in forensic toxicology?
It involves the qualitative and quantitative analysis of drugs or poisons in biological specimens.
What factors influence the choice of analytical methods in toxicological analysis?
- Amount of specimen available
- Nature of the toxicant
- Need to detect parent compound or metabolites
True or False: The highest concentrations of a poison are found at the site of administration.
True.
Fill in the blank: Toxic substances enter the body through the _______.
[gastrointestinal tract, lungs, skin]
What does a large quantity of drug in the GI tract and liver indicate?
Oral ingestion.
Why is blood and tissue analysis important in toxicology?
It helps determine concentrations of drug or toxicant in different tissues.
What may indicate inhalation of a toxicant?
Higher concentrations of drug or toxicant in the lungs compared to other tissues.
What is the primary organ for the excretion of most toxicants?
Kidney.
What is the first internal organ typically analyzed in toxicology?
Liver.
What types of tests are considered non-specific initial tests?
Colorimetric tests and immunoassays.
What is the purpose of confirmatory tests in toxicology?
To identify the particular drug within the class detected.
What does Thin-Layer Chromatography (TLC) detect?
Color changes or bands using UV light.
What analytical technique uses retention time for identification?
Gas Chromatography (GC).
What are the three steps in the toxicologic investigation of a poison death?
- Obtaining case history and specimens * Conducting toxicologic analyses * Interpreting analytic findings
What information is vital to collect in a toxicology case history?
- Age * Sex * Weight * Medical history * Occupation * Treatment administered before death * Gross autopsy findings * Drugs available to the deceased * Interval between onset of symptoms and death
What types of substances are typically analyzed in postmortem toxicology?
- Prescription drugs * Drugs of abuse * Commercial products * Gases
What specimen quantities are suggested for collection at autopsy?
- Brain: 100 g * Liver: 100 g * Kidney: 50 g * Heart blood: 25 g * Peripheral blood: 10 g * Vitreous humor: All available * Bile: All available * Urine: All available * Gastric contents: All available
What must be done before embalming to ensure toxicology analysis is effective?
Collect required specimens.
What analytic methods may be required for living victims of poisoning?
Sophisticated, highly sensitive GC/MS or HPLC/MS.
What is the primary focus of forensic urine drug testing (FUDT)?
Detection of controlled or illicit drugs.
What are the cutoff concentrations for marijuana metabolites in urine drug testing?
- Initial test: 50 ng/mL * Confirmatory test: 15 ng/mL
True or False: Positive urine drug tests prove impairment from drug abuse.
False.
What is the purpose of using cutoff values in urine drug testing?
To allow uniformity in drug testing and reporting of results.
What methods are used to detect urine adulterants?
- pH * Smell * Specific gravity * Creatinine * Color tests
What is a common application of human performance testing in forensic toxicology?
Determining driving under the influence of ethanol or drugs.
What is the statutory definition of DUI in the United States?
A BAC of either 0.08 or 0.10 g/dL.
What are the most commonly encountered drugs in emergency toxicology?
- Drugs of Abuse * Ethanol * Benzodiazepines * Acetaminophen * Tricyclic antidepressants * Ibuprofen * Dextropropoxyphene * Fluoxetine * Phenobarbital * Diphenhydramine
What is the role of legislation in regulatory toxicology?
To provide a framework for organized efforts to prevent toxicity.
What does the Toxic Substances Control Act (TSCA) regulate?
The introduction of chemicals into commerce and their hazards.
What is the main responsibility of the United States Environmental Protection Agency (USEPA)?
To protect and improve the nation’s air quality and the stratospheric ozone layer.
This includes administering the Clean Air Act.
What does the Clean Water Act aim to achieve?
The protection of surface water quality and the elimination of discharges of pollutants.
It applies to ‘waters of the United States’ including rivers and wetlands.
What two criteria are established under the Safe Drinking Water Act for contaminants in public water systems?
Maximum Contaminant Level Goal (MCLG) and Maximum Contaminant Level (MCL).
MCLG is the level with no known adverse health effects; MCL is the maximum permissible level.
What is the Delaney clause in the Federal Food, Drug, and Cosmetic Act?
Food additives that cause cancer in humans or animals at any level shall not be considered safe and are prohibited.
This clause emphasizes the strict regulation of carcinogenic substances.
What is the primary focus of the Occupational Safety and Health Act?
Health and safety in the workplace.
It created the Occupational Safety and Health Administration (OSHA).
What does the National Environmental Policy Act (NEPA) require from U.S. government agencies?
To prepare environmental impact statements for all federal actions affecting the quality of the human environment.
NEPA serves as an umbrella act for environmental considerations.
Fill in the blank: Almost 50% of all accidental poisoning death cases in the United States are among _______.
preschool children.
What safety measures should be taken regarding household chemicals?
Keep in original containers, locked storage if possible, and ensure adequate ventilation during use.
This helps prevent accidental poisoning, especially among children.
What does OSHA mandate regarding exposure levels of hazardous chemicals in the workplace?
Establishes exposure limit values.
These limits are based on studies by the National Institute for Occupational Safety and Health (NIOSH).
What are Threshold Limit Values (TLVs)?
Guidelines for permissible exposure limits for hazardous substances in the workplace.
TLVs are not legally binding but are adopted by OSHA as permissible exposure limits (PELs).
What is the ideal situation for chemical waste management?
Reduce chemical waste to an irreducible minimum and place the remainder in secure storage.
This is essential for environmental safety and pollution prevention.
What is environmental toxicology concerned with?
The likely harmful effects of chemicals as pollutants on living organisms.
It includes studying air pollution, soil, and water contaminants.
Define bioaccumulation.
The accumulation of a chemical within the tissues of an organism when its intake exceeds metabolism or excretion.
This can lead to higher concentrations of harmful substances in organisms.
What is biomagnification?
The increase in concentration of a contaminant as it moves up the food chain.
Even low concentrations in water can become highly concentrated in top predators.
List the five main toxicant substances contributing to air pollution.
- Carbon monoxide
- Sulfur oxides
- Hydrocarbons
- Nitrogen oxides
- Ozone.
What is a significant source of air pollution from agriculture?
Dust and various agricultural chemicals.
Industrial-scale farming contributes to air pollution significantly.
What is considered the greatest environmental threat?
Air pollution
Air pollution results from vapors, aerosols, smokes, particulates, and individual chemicals.
What are the five main toxicant substances constituting 98% of air pollution?
- Carbon monoxide (52%)
- Sulfur oxides (14%)
- Hydrocarbons (14%)
- Nitrogen oxides (14%)
- Ozone (4%)
These substances are significant contributors to air pollution.
What contributes a variety of air pollutants in agriculture?
- Dusts as particulates
- Pesticidal chemicals
- Hydrogen sulfide
Industrial-scale farming is particularly noted for these contributions.
What are some sources of air pollutants?
- Fossil fuel burning
- Transportation
- Manufacturing
- Industrial activities
- Electric power generation
- Space heating
- Refuse disposal
These activities release various pollutants into the atmosphere.
What has greatly reduced automobile-released air pollution?
Compulsory use of catalytic converters
This regulation has been implemented in many countries.
What was the impact of the ban on tetraethyl lead in gasoline?
It terminated a major source of lead contamination and childhood lead poisoning
This ban has significantly improved urban health outcomes.
What type of engines contribute to heavy ground-level air pollution in crowded cities in emerging economies?
Two-cycle engines
These engines are commonly used in transport and are linked to severe pollution issues.
What is the effect of ‘clean, low-sulfur’ diesel fuels?
They help reduce urban and highway pollutants such as sulfur oxides
This is part of efforts to improve air quality.
What adverse health effects are associated with sulfur dioxide and smoke from incomplete combustion of coal?
- Acute effects among children
- Adverse effects in the elderly
- Problems in individuals with preexisting diseases
These pollutants have been linked to various respiratory and cardiac issues.
What does EPA stand for?
Environmental Protection Agency
This agency sets standards for air pollutants.
What does OSHA stand for?
Occupational Safety and Health Administration
This agency sets standards for workplace exposure to pollutants.
What is the PEL for benzene?
1.0 ppm
This is the permissible exposure limit for benzene in the workplace.
What color and type of gas is sulfur dioxide?
Colorless irritant gas
It is primarily generated by the combustion of sulfur-containing fossil fuels.
What is nitrogen dioxide (NO2)?
A brownish irritant gas associated with fires and manufacturing
It is commonly produced by automobile and truck traffic emissions.
What is ozone (O3) at ground level considered?
An important pollutant
While beneficial in the ozone layer, it is harmful when present at ground level.
What are halogenated aliphatic hydrocarbons used for?
Manufacturing of industrial solvents, degreasing agents, and cleaning agents
Examples include carbon tetrachloride and chloroform.
What is toluene commonly associated with?
CNS depression and irritation of skin and eyes
It is not classified as a carcinogen.
What are organochlorine pesticides?
Synthetic chlorinated hydrocarbons classified into four categories
Includes DDT, benzene hexachlorides, cyclodienes, and toxaphenes.
How do organophosphorus pesticides function?
By inhibiting the acetylcholinesterase enzyme
This leads to neurological dysfunction and can cause death.
What are the effects of carbamate pesticides?
Inhibition of acetylcholinesterase with weak binding
Clinical effects are of shorter duration compared to organophosphates.
What is glyphosate used for?
As a herbicide in agriculture
It is the most widely used herbicide globally.
What is paraquat known for?
Causing lung edema and progressive fibrosis
It is a bipyridyl herbicide that forms free radical species.
