Knowra Microplastics Microplastics Microplastics are plastic particles smaller than 5 millimeters, either manufactured at small sizes or formed as larger plastic items fragment. They persist across environments and can be ingested by organisms.
Primary microplastics : Plastic particles manufactured at sizes below 5 millimeters, including industrial pellets and some product ingredients. These enter the environment already small, unlike fragments formed from larger debris.
Photodegradation : Chemical breakdown driven by light, especially ultraviolet radiation. Sunlight can embrittle exposed plastic and help it fragment into smaller particles.
Microplastic sampling : The collection of environmental samples to detect and quantify plastic particles. Sampling choices determine which particle sizes and environments are represented.
Marine plastic pollution : The accumulation of plastic debris in marine environments, from shorelines to the open ocean. Microplastics are a small-particle component of the wider marine plastic pollution problem.
Microplastic size definitions : The conventions used to set the upper and lower size limits for microplastics. The five-millimeter upper limit is widely used, but lower boundaries are not uniformly defined.
Secondary microplastics : Plastic particles produced when larger plastic objects fragment through weathering, abrasion, or other degradation. They arise from the breakdown of larger items across land and water.
Mechanical weathering : Physical breakdown caused by forces such as abrasion, impact, and repeated stress. Waves, wind, and contact with surfaces fracture larger plastic debris.
Microplastic identification : The classification of suspected plastic particles using visual and analytical methods. Reliable identification distinguishes plastics from natural particles and supports measurement.
Food chain : A sequence of organisms through which energy and nutrients pass as one organism consumes another. Ingested particles can move between organisms, though transfer and effects vary.
Analytical detection limits : The smallest amount or size of a substance that a measurement method can reliably detect. Different instruments miss different particle sizes, complicating comparisons among studies.
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