Plastic Pellets in the Aquatic Environment:
Sources and Recommendations

United States Environmental Protection Agency Office of Water (WH-556F) EPA 842/B-92/010 Dec92

6.0 Glossary

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Additive: Used to alter the physical characteristics of a polymer, such as the esthetic and physical properties and the ability to be further processed. 

Conveyor: A machine that transports materials from one place to another. 

Culvert: A sewer or drain crossing under a road. 

Effluent: Flow of waste water released from a facility. 

Epibiont: Organism that lives attached to another organism but without benefit or detriment to the host. 

Extrusion: Shaping plastic by forcing through a die. 

Gaylord: Large, 1000-lb capacity, cardboard box used for shipping pellets. 

Gizzard: A muscular enlargement of the digestive tract of a bird. 

Hopper: A receptacle in which materials are held in readiness for unloading or dispersing. 

Melt : A hot, very viscous liquid produced by the process of bulk polymerization. 

Monomer: A molecule that can be chemically bound as a unit of a polymer.

Neuston: Small- to medium-size organisms that live on or under the surface film of water bodies.

Pellet: Resins that are generally spherical, ovoid, or cylindrical in shape, and between 1 and 5 mm dia. 

Pelletizer: Equipment used to create pellets from polymers. The type of pelletizer used determines the size and shape of the pellets.

Packager: Sector of the plastics industry that breaks down bulk shipments of pellets into smaller containers such as bags and gaylords; also called contract packager.

Processor: Sector of the plastics industry that molds the pellets into fabricated user-products. 

Producer: Sector of the plastics industry that creates the polymers and extrudes the pellets.

Transporter: Sector of the plastics industry that moves or carries the pellets between the pellet producers, packagers, and processors.

Pinocytotic: Active ingestion of fluid by a cell, by invagination of the cell membrane to form vesicles. 

Pneumatic: Operated by compressed air. 

Polymer: A natural or synthetic compound consisting of smaller inter-linked molecules.

Polymerize: To make or combine into a polymer.

Railroad siding: A length of railroad track that is connected to the main track.

Resin: A polymer synthesized from petroleum or natural gas derivatives.

Skimmer: A motor-driven paddle device consisting of several rectangular paddles and a drive system. The paddles skim pellets from water surface into a containment system.

Thermoplastic Resins: Resins that can be melted or reprocessed without damaging or changing the chemical or physical properties of the polymer. Resins are highly malleable but become rigid when cooled. 

Thermoset Resins: Resins that tend to be rigid, infusible, and insoluble, and cannot be remelted and reformed. 

Weir: A mechanical device that controls the level and flow of water by using dams or similar mechanical devices. 

source: http://www.epa.gov/owowwtr1/OCPD/PLASTIC/sect6-.html 14apr03

[Table of contents | Executive Summary | Sections 1 · 2 · 3 · 4 · 5 · Glossary | Tables | References ]