Toxicology Final

Chapters 21, 22, 23, 24 part 1, 25 part 2

The process of assessing the effects of chemicals on living organisms to determine their potential hazards.

Toxicity Testing

Testing conducted using live animals to observe the effects of substances.

In vivo

Testing conducted using cell cultures or biological components outside of a living organism.

In vitro

The correlation between the dose of a substance and the magnitude of its effect on an organism.

Dose-effect relationship

No Observable Adverse Effect Limit; the highest dose at which there are no significant increases in adverse effects.

NOAEL

Lowest Observable Adverse Effect Limit; the lowest dose at which there are significant increases in adverse effects.

LOAEL

Lethal Dose for 50% of the test animals; a standard measure used to assess the toxicity of a substance.

LD50

Exposure to a chemical for less than 24 hours, often in a single or continuous dose.

Acute exposure

Repeated exposure to a chemical for more than 3 months.

Chronic exposure

The ratio used to compare the lethal dose of a substance at low levels with the effective dose at high levels, indicating safety.

Margin of Safety (MOS)

Issues related to the morality of using animals in testing, especially regarding harm to the animals.

Ethical concerns

The ability of a substance to produce a beneficial effect when properly administered.

Efficacy

Toxic Dose for 50% of the test population; the dose at which toxicity is observed.

TD50

Principles of Replace, Reduce, and Refine to improve ethical animal testing practices.

3R's of animal testing

Biological responses to chemical exposure that indicate toxicity levels.

Toxic endpoints

The routes through which a chemical may enter the body, such as ingestion, inhalation, or skin absorption.

Pathways of exposure

Alternative systems, like cell cultures, used in toxicity testing to reduce the need for live animals.

Surrogate animal models

Product labeling serves as the main method of communication between a manufacturer and the user, providing essential information about the product.

Purpose of Product Labeling

Numbers assigned to each chemical substance by the Chemical Abstracts Service to enable easy identification.

Chemical Abstracting Service (CAS) numbers

The ability of a substance to cause harmful effects shortly after exposure.

Acute Toxicity

A word on product labels that indicates the level of hazard associated with the product, such as 'Danger', 'Warning', or 'Caution'.

Signal Word

A law that regulates labeling and packaging of hazardous substances to ensure public safety.

Federal Hazardous Substance Act (FHSA)

Statements that must appear on pesticide product labels to ensure safe use and prevent adverse effects.

Mandatory Statements

Voluntary statements that offer additional guidance on the use of a product but do not conflict with mandatory statements.

Advisory Statements

A property of a substance indicating that it can easily ignite and catch fire.

Flammable

A document that contains detailed information about a product's hazards, handling, and safety precautions.

Safety Data Sheet (SDS)

Substances that can cause negative effects on health, particularly when ingested or absorbed.

Toxicants

Actions taken to remove a product from the market due to potential safety risks.

Recalls

The process by which the EPA assesses and approves pesticides for use, ensuring they meet safety standards.

Pesticide Registration

Substances in a pesticide formulation that are not active in controlling pests but are included for stability or usability.

Inert Ingredients

U.S. agency responsible for protecting the public from unreasonable risks of injury or death associated with consumer products.

Consumer Product Safety Commission

Clothing and equipment worn to minimize exposure to hazards.

Personal Protective Equipment (PPE)

U.S. agency that governs workplace health and safety regulations, including labeling requirements.

Occupational Safety and Health Administration (OSHA)

Medications that can be purchased without a prescription and are commonly used for self-treatment.

Over-the-Counter (OTC) Drugs

Potential negative effects on health resulting from exposure to hazardous substances.

Health Risks

Requirements for listing both active and inert ingredients in product formulations, especially for pesticides.

Ingredient Labeling

Accidental exposure to chemicals resulting in poisonings, accounting for approximately 84% of cases.

Unintentional Exposure

Deliberate ingestion or exposure to chemicals, accounting for less than 20% of reported poisonings, resulting in over 900 deaths.

Intentional Exposure

Medicines used to relieve pain, reported as the most involved substance class in human exposures (11.7%).

Analgesics

Process of reducing the absorption of a toxicant, often through washing with soap and water.

Decontamination

Procedure used to remove toxic agents from the stomach within 1-2 hours of ingestion, not used for corrosive substances.

Gastric Lavage

Substance used to limit further absorption of toxins if administered within one to two hours of ingestion.

Activated Charcoal

Clinical treatment to counteract the effects of poisons, developed based on understanding toxicokinetics and toxicodynamics.

Antidote

Management strategy that uses interactions with chemicals to reduce the effects of poisons.

Chemical Antagonism

A highly toxic gas that requires specific treatment such as the administration of oxygen.

Carbon Monoxide

Toxic substances like lead and iron that have specific antidotes such as DMSA or EDTA.

Heavy Metals

The ability of a chemical to produce an adverse response.

Hazard

The probability that the hazard will occur under defined conditions of exposure.

Risk

A quantitative process by which hazard, exposure, and risk are determined.

Risk assessment

The process of selection of the most appropriate actions based on the results of social, economic, and other concerns.

Risk management

A methodology focused on evaluating human health effects from exposure to chemicals.

Human risk assessment

Addresses species other than humans, such as wildlife and plant populations, and is more complicated due to diverse ecosystems.

Ecological risk assessment

Used to compensate for uncertainties of extrapolating from laboratory animals to human populations, set lower than observed laboratory thresholds.

Safety factors

Evaluates health problems associated with the chemical at different levels of exposure.

Dose-response assessment

Determines what toxicities are associated with exposures to the chemical(s).

Hazard identification

Assesses the excess risks in the exposed population.

Risk characterization

Identifies who is exposed to chemicals and the extent of exposure.

Exposure assessment

A quantification of the health problems associated with a chemical at different levels of exposure.

Dose-Response Assessment

The process of evaluating a chemical for its toxic potential, determining associated toxicities.

Hazard Identification

The summary of excess risks in the exposed population based on the assessments.

Risk Characterization

Identification of who is exposed to chemicals and the extent of their exposure.

Exposure Assessment

A level of exposure below which no adverse health effects are expected to occur for noncarcinogens.

Threshold Response

Substances that are considered to have risk at any dose, with no threshold dose established for cancer risk.

Carcinogens

Modifiers applied in risk assessment to account for variability and uncertainty in data.

Uncertainty Factors

The ratio of an exposure over time to the reference dose (RfD) for a substance; a value of 1 or more indicates a risk of adverse health effects.

Hazard Quotient

The accumulation of substances, such as pesticides, in an organism.

Bioconcentration

Estimation of the acceptable daily intake of noncarcinogenic chemicals to avoid adverse effects.

Noncancer Risk Assessment

When the combined toxicity of two chemicals is greater than the sum of their separate effects.

Synergistic Effects

When one chemical reduces the toxicity of another.

Antagonistic Effects

Occurs when chemicals produce effects through different physiological mechanisms.

Independent Effects

When a non-toxic chemical increases the toxicity of another chemical.

Potentiation Effects

A systematic approach used in hazard identification to evaluate the available information on toxicity.

Weight of Evidence