BIOL 1055: Topic 2 (Toxicology)

Toxicology definitions flashcards from BIOL 1055 study guide

Environmental toxicology

Study of the health effects of environmental contaminants on organisms and ecosystems

Toxic

Contains or is a poisonous material, especially when capable of causing death or serious debilitation in an organism

Toxin

A toxic substance that occurs naturally

Toxicant

A toxic substance developed by humans

Chemical

Any substance made of matter with its own unique and fixed composition

Acute effect

An effect that occurs rapidly after exposure to a large amount of a substance

Chronic effect

An effect resulting from exposure to small amounts of a substance over a long period of time

Lethal dose

A dosage amount of a substance that is lethal to humans

LD-50 (Lethal dose-50%)

A dose of a substance that is lethal to 50% of treated organisms

ED-50 (Effective dose-50%)

A dose of a substance that causes 50% of treated organisms to exhibit a significant response

Contaminant

A hazardous substance found in the environment in higher amounts than would occur naturally

Carcinogen

A substance that produces cancer either by itself or in conjunction with another substance

Developmental toxin / Teratogen

A substance that can cause developmental defects in an organism

Mutagen

A substance that mutates DNA; these mutations are often not heritable

Neurotoxicant / Neurotoxin

A substance that affects the function or development of nerve cells

Endocrine disruptor

A substance that interferes with the body's endocrine (hormonal) system, potentially causing developmental, reproductive, neurological, and immune effects

Allergen

A substance that causes allergic reactions

Arsenic

A naturally occurring element used in many operations worldwide. It is an endocrine disruptor and carcinogen that is highly persistent, potentially remaining for hundreds of years. Found in treated wood, rocks, and soil, potentially contaminating food and water

Mercury

A naturally occurring metal found in products and animals. Humans are exposed to elemental mercury and organic methylmercury. Commonly found in fish and batteries; exposure can cause neurological and teratogenic effects

Bisphenol A (BPA)

A synthetic chemical used to produce polycarbonate plastics and epoxy resins, often found in food and beverage packaging and can linings. It is a neurotoxin and endocrine disruptor

Phthalates

Synthetic chemicals used to soften plastics and vinyl. Found in cosmetics, personal care products, toys, wallpaper, curtains, and packaging. Exposure through inhalation or consumption can cause endocrine disruption and neurotoxicity

Lead

A naturally occurring metal found in rocks, soil, and fossil fuels. Has no taste or smell, making exposure difficult to identify. Used in batteries, pipes, roofing, electronics, and ceramic glazes. It is a known neurotoxin and endocrine disruptor, possible carcinogen and teratogen

Formaldehyde

A colorless, flammable gas or liquid with a pungent odor. Exposure can come from wood products, exhaust fumes, cigarettes, paint, carpets, and nail polish

Radiation

Energy emitted by atoms, including energy associated with X-rays and radioactive materials

Radon

A naturally occurring, odorless, colorless radioactive gas produced by the decay of uranium or thorium in soil. Its radioactive decay products can damage lung tissue and increase lung cancer risk

Forever chemicals (PFAS)

Man-made per- and polyfluoroalkyl substances with strong chemical bonds that resist breakdown by biological processes, water, heat, and sunlight

Toxoplasma gondii

A single-celled protozoan parasite that infects animal cells

Toxoplasmosis

An infection caused by the Toxoplasma gondii parasite in a host organism

Ozone

A molecule consisting of three bonded oxygen atoms

UV rays

Invisible electromagnetic energy commonly associated with the sun. UV-A causes cell and skin damage; UV-B is the most harmful type reaching Earth; UV-C is absorbed by the atmosphere and does not reach Earth's surface

Glyphosate

A widespread and effective pesticide used mainly for crop protection and weed control

DDT

Dichlorodiphenyltrichloroethane, a synthetic chemical compound known as a powerful insecticide

Critical window of development

Weeks 3–8 or 10 of embryonic development, when important features are forming and the embryo is particularly susceptible to harmful exposures

Bioaccumulation

The accumulation of chemicals and compounds inside the living tissues of an organism

Biomagnification

A process in which concentrations of toxic substances in living tissues increase, typically at higher levels of the food chain

Precautionary principle

The idea that cautious, preventative approaches should be taken toward potentially harmful chemicals and processes. Involves acting early when harm is suspected, seeking evidence, ensuring democratic control, and continually evaluating changes

Pesticide

Any substance intended to prevent, destroy, repel, or mitigate a pest (an organism in an area where it is unwanted)

Correlation vs. causation

Correlation describes how two things relate; causation means one event demonstrably produces an outcome. An observed health risk does not prove a substance caused it

US Clean Air Act

Legislation originally passed in 1963 to fund the study and cleanup of air pollution. Later amendments expanded regulation and enforcement of clean air practices

Environmental Protection Agency (EPA)

The agency that primarily implements and enforces Clean Air Act regulations by inspecting businesses and production facilities and ensuring compliance

Primary air pollutant

An air pollutant released directly from its source in a harmful form, such as carbon monoxide, organic compounds, and nitrogen oxides

Secondary air pollutant

An air pollutant formed through reactions between primary pollutants and atmospheric compounds, such as ground-level ozone

Smog

A mixture of air pollutants that often forms over urban areas as a result of fossil fuel combustion

Industrial smog

Smog produced by burning fossil fuels, releasing pollutants such as carbon dioxide, carbon monoxide, sulfur compounds, and particulates

Photochemical smog

Smog formed when sunlight drives chemical reactions between primary pollutants from automobiles and atmospheric compounds, often producing ground-level ozone

Acid rain

Precipitation with a pH below 5.6, commonly caused by sulfur dioxide and nitrogen oxides reacting in the atmosphere to form acids

Air particulate matter (PM)

Solid particles and liquid droplets suspended in air. Coarse particles are approximately 10 µm in diameter; fine particles range from 2.5–10 µm

Persistent organic pollutants (POPs)

Organic chemicals used as pesticides or industrial chemicals that threaten human health and ecosystems. They persist in the environment, bioaccumulate, and are toxic

Main types of toxins(5)

Carcinogens, Mutagens, Developmental toxins (Teratogens), Neurotoxins, Endocrine Disruptors

Chronic intake

Continuous intake of a substance over multiple days, weeks, months, etc

Cytotoxin

Substance that impairs cellular function

Air pollutants under U.S clean air act(6)

Particulate matter, Ground level ozone, Carbon monoxide, Sulfur oxides, Nitrogen oxides, Lead

Montreal protocol

An international 1987 protocol enacted by several nations to reduce CFC production. Lead to a decrease in CFCs by 95% (CFCs are used in freon coolers and aerosol cans which can react with UV light and ozone)

Chemical case studies from class(6)

Ozone (ground level), mercury, PFAS, toxoplasma gondii, glyphosate, DDT