amino acids: Simple molecules that occur naturally in plant and animal tissues and that are the basic building blocks of proteins.
average: (in science) A term for the arithmetic mean, which is the sum of a group of numbers that is then divided by the size of the group.
behavior: The way something, often a person or other organism, acts towards others, or conducts itself.
cell: (in biology) The smallest structural and functional unit of an organism. Typically too small to see with the unaided eye, it consists of a watery fluid surrounded by a membrane or wall. Depending on their size, animals are made of anywhere from thousands to trillions of cells.
chemical: A substance formed from two or more atoms that unite (bond) in a fixed proportion and structure. For example, water is a chemical made when two hydrogen atoms bond to one oxygen atom. Its chemical formula is H2O. Chemical also can be an adjective to describe properties of materials that are the result of various reactions between different compounds.
chemistry: The field of science that deals with the composition, structure and properties of substances and how they interact. Scientists use this knowledge to study unfamiliar substances, to reproduce large quantities of useful substances or to design and create new and useful substances.
colon: (in biology) The majority of the large intestine, it runs between the cecum (a pouch below the small intestine) and the rectum. Foods are not digested in the colon, although this tissue lubricates wastes that will be excreted. Some liquids and salts, however, will be removed from materials stored in the colon before excretion.
concentration: (in chemistry) A measurement of how much of one substance has been dissolved into another.
contaminant: Pollutant; a chemical, biological or other substance that is unwanted or unnatural in an environment (such as water, soil, air, the body or food). Some contaminants may be harmful in the amounts at which they occur or if they are allowed to build up in the body or environment over time.
digestive tract: The tissues and organs through which foods enter and move through the body. In people, these organs include the esophagus, stomach, intestines, rectum and anus. Foods are digested — broken down — and absorbed along the way. Any materials not used will exit as wastes (feces and urine).
environment: The sum of all of the things that exist around some organism or the process and the condition those things create. Environment may refer to the weather and ecosystem in which some animal lives, or, perhaps, the temperature and humidity (or even the placement of things in the vicinity of an item of interest).
fluorescent: (v. fluoresce) Adjective for something that is capable of absorbing and reemitting light. That reemitted light is known as fluorescence.
gut: An informal term for the gastrointestinal tract, especially the intestines.
marine: Having to do with the ocean world or environment.
marker: (in biomedicine) The presence of some substance that usually can only be present because it signals some disease, pollutant or event (such as the attachment of some stain or molecular flag). As such, this substance will serve as a sign — or marker — of that related thing.
microbead: A small particle of plastic, usually between 0.05 millimeters and 5 millimeters in size. These particles can be found in exfoliating face wash, but can also take the form of fibers shed from clothing.
microplastic: A small piece of plastic, 5 millimeters (0.2 inch) or smaller in size. Microplastics may have been produced at that small size, or their size may be the result of the breakdown of water bottles, plastic bags or other things that started out larger.
model: A simulation of a real-world event (usually using a computer) that has been developed to predict one or more likely outcomes. Or an individual that is meant to display how something would work in or look on others.
plastic: Any of a series of materials that are easily deformable; or synthetic materials that have been made from polymers (long strings of some building-block molecule) that tend to be lightweight, inexpensive and resistant to degradation. (adj.) A material that is able to adapt by changing shape or possibly even changing its function.
policy: A plan, stated guidelines or agreed-upon rules of action to apply in certain specific circumstances. For instance, a school could have a policy on when to permit snow days or how many excused absences it would allow a student in a given year.
pollutant: A substance that taints something — such as the air, water, our bodies or products. Some pollutants are chemicals, such as pesticides. Others may be radiation, including excess heat or light. Even weeds and other invasive species can be considered a type of biological pollution.
polystyrene: A plastic made from chemicals that have been refined (produced from) crude oil and/or natural gas. Polystyrene is one of the most widely used plastics, and an ingredient used to make a widely used white, rigid foam (often sold under the name Styrofoam).
residue: A remnant or material that is left behind after something has been removed. For instance, residues of paint may remain behind after someone attempts to sand a piece of wood; or sticky residues of adhesive tape may remain on the skin after a bandage is removed; or residues of chemicals may remain in the blood after exposure to a pollutant.
risk: The chance or mathematical likelihood that some bad thing might happen. For instance, exposure to radiation poses a risk of cancer. Or the hazard — or peril — itself. (For instance: Among cancer risks that the people faced were radiation and drinking water tainted with arsenic.)
solution: A liquid in which one chemical has been dissolved into another.
toxic: Poisonous or able to harm or kill cells, tissues or whole organisms. The measure of risk posed by such a poison is its toxicity.
triclosan: A germ-killing chemical added to some common products such as hand soaps and sponges.
weathering: The process of breaking down rocks, soil and chemicals (such as crude oil). Weathering also can be chemical, such as by oxidation (rust), or mechanical, such as by water, ice or wind.
