The blue cluster focuses mostly on the properties of these particles, specifically of microfibers, like surface structure, particle size, absorption, etc. There is also the appearance of a small lavender cluster that emphasizes the main location of this type of pollution (seawater, seawater pollution), the waste generated (waste polymeric materials), and water treatment (wastewater treatment). Lastly, there is a very small yellow cluster that shows other affected areas of MP pollution (soil, soil pollution), with connections to different types of bacteria. This reflects the effect of microplastics on bacteria and the accumulation of bacteria on the surface of microplastics. 51 The presence of microplastics is widespread; because of the facility of measurement, their occurrence in water has been more comprehensively studied than in solid matrixes, but their presence in soil and air is also substantiated. The oceans were estimated to contain 490,000 tons of plastic in 2010. In native sea water, 400 particles of microplastics were found per 1000 L of water, while the concentration in the North Pacific Subtropical Gyre (Garbage Patch) of microplastics is approximately 33 per 1000 L of water (or 250 mg microplastics/m 3 ). 15-31% of the microplastics in the oceans were estimated to be primary microplastics, with 35% of them being textile fibers, 28% tire wear particles, and 2% derived from cosmetics. The remaining 69-85% of the microplastics are thus secondary microplastics, derived from fragmentation of larger plastic pieces. In shallow ocean water, microplastics were predominantly polyethylene and polypropylene, while in deeper water microplastics containing polyesters and acrylates were the most prevalent. Drinking water obtained from faucets contained 5500 particles per 1000 L. Bottled water contained anywhere from 10-6300 particles/L, with water from glass and reusable plastic containing the most plastic and the number of particles found dependent on the size of particles interrogated. Surface water in Germany contained 7 particles per 1000 L, while the Los Angeles River contained 12,000 1-5 mm plastic particles per 1000 L. Solids, particularly soils, sediments, and sewage sludge, are another source of microplastic contamination. On a Brazilian beach, 50-300 particles were found per square meter. In sediments, 6-4300 particles/kg were found, including 81/kg in an Indian shipbreaking yard and 4300/kg in Tasmanian sediments. Sewage sludge from North America and Europe is estimated to contribute 700,000 tons of microplastic waste per year. Compost in Germany contained 900 particles/kg. Agricultural films are estimated to add 150,000 tons of plastic to soils in China per year. Shellfish and other water-borne organisms act both as sinks for microplastics and sources of microplastics for the environment and the humans and animals that may eat them. Mussels contained 0-4600 particles per kilogram of wet mass, with Chinese mussels containing larger counts of particles than European mussels. . 70-5800 microplastic particles per kilogram of wet mass were found in bivalves and 340-11,000 in clams. Lugworms contained 1200 particles per kilogram , and Scottish lobsters contained 280-680 g of microplastic per lobster. Salt, sea salt, and other foods contain microplastics; Mediterranean sea salt contained 37 g of microplastics per kilogram and sea salt contains 46-680 particles/kg (with the larger counts corresponding to smaller microplastic particles with diameters < 100 m). Finally, the air can transport microplastics as well. From samples of plastic debris from the oceans or marine sediments, the most prevalent polymers found were polyethylene (33%), polypropylene (27%), polystyrene (17%), polyesters (10%), poly(vinyl chloride) (2%), and poly(ethylene terephthalate) (1%). An important issue to note is that analytical methods for characterizing and counting microplastic particles are imprecise. Different methods are suitable for different types of polymers, and most cannot accommodate high-throughput methods, making determining their incidence in the environment onerous or impossible. In addition, nanometer-scale microplastic particles are harder yet to count and quantify, making the presence of microplastics in the environment and correlation of their presence to biological and health effects difficult if not impossible.