Contamination:
In the context of microplastic research, contamination is the unintentional introduction of microplastic particles from uncontrollable factors, or those that despite best efforts to control them may still impact the accuracy and reliability of the results. Substantial efforts are made to mitigate microplastic contamination of samples during sample collection and processing steps to enhance the precision and credibility of results (including the use of procedural controls).
Controls:
Deliberate measures implemented to minimise and account for potential sources of microplastic contamination.
Macroplastics:
Relatively large plastics, typically exceeding 2.5 cm in size, that can be visually identified as plastic products.
Mesoplastics:
Intermediate-sized plastic particles, ranging from greater than 0.5 cm to 2.5 cm. These are smaller than macroplastics but are generally discernible to the naked eye.
Microplastics:
Small plastic particles, typically less than 0.5 cm (i.e., < 5 mm) but greater than or equal to 1 μm in size, which are manufactured at a small scale (primary microplastic) or originate from the degradation of larger plastic items (secondary microplastic). Due to the small size of microplastics, these are mostly not discernible to the naked eye.
Nanoplastics:
Plastic particles that are smaller than microplastics with dimensions in the nanometer range. These are typically less than 1 μm (< 1000 nm). Nanoplastics can be intentionally manufactured at the nanoscale (primary nanoplastics) or result from the breakdown of larger plastic items (secondary nanoplastics). They pose unique challenges in terms of detection, characterisation, and understanding their environmental and biological impacts due to their nano-scale size.
Plastic morphology:
The description of the physical structure, form and characteristics (such as size, shape, texture, and colour) of plastic particles. The morphology of plastic artefacts influences factors such as the movement, distribution, transportation, ingestion capability, and environmental impacts of the plastic contaminant.
Polymer (or polymer type):
The core chemical composition (i.e., building blocks) of plastic materials. Polymers are large molecules composed of repeating monomers. Polymer composition, together with the presence of different molecular groups, define the main chemical properties of plastics. These include attributes and behaviours associated with chemical stability, toxicity, solubility, chemical resistance, degradation, and the presence and behaviour of additives.
Primary Plastic(s):
Plastics intentionally manufactured in a controlled size (macro, meso, micro, and nano) and shape for specific, predetermined purposes. These plastics are produced with a defined application, distinguishing them from secondary plastics. The intentional design and production of primary plastics allow for customisation to meet specific functional, aesthetic, or industrial requirements.
Secondary Plastic(s):
Plastics generated through the degradation or breakdown of pre-existing primary plastics (macro, meso, micro, and nano), resulting in the formation of new particles across macro, meso, micro, and nano sizes. These secondary plastics are distinct from primary plastics, as they originate from the recycling, weathering, or other processes acting upon primary and/or secondary plastic materials.
Spectroscopy:
A method for the identification of plastic polymers. Spectroscopy is an analytical technique that assesses the interaction of matter with electromagnetic radiation, resulting in a unique spectrum (specific for each matter) that is used for identifying the polymer(s) of the plastic.
Quality Assurance (QA):
Planned and systematic process that ensures the reliability, reproducibility, accuracy, and precision of data through the establishment and implementation of standardised procedures, protocols, and measures.
Quality Control (QC):
Mechanisms, measures and procedures taken to ensure the reliability and accuracy of sampling and analytical results.
Weathering:
The gradual alteration of plastic particles through physical, chemical or biological processes which alter the physical and chemical properties of plastic particles over time.