Jingyi Li, Huihui Liu, J. Paul Chen,<\/p>\n
Microplastics in freshwater systems: A review on occurrence, environmental effects and methods
\nfor microplastics detection,<\/p>\n
Water Research,
\nVolume 137,
\n2018,
\nPages 362-374,
\nISSN 0043-1354,<\/p>\n
Abstract:<\/p>\n
The continuous increase in synthetic plastic production and
\npoor management in plastic waste have led to a tremendous increase in
\nthe dumping into our aqueous environment. Consequently, microplastics
\ncommonly defined as sizes less than 5\u202fmm are produced and stay in both
\nseawater and freshwater environment. The presence of microplastics as a
\nnew type of emerging contaminant has become a great issue of concerns
\nfrom public and government authorities. The sources of microplastics to
\nfreshwater systems are many with the largest portion from wastewater
\ntreatment plants. The abundance of microplastics varies with the
\nlocation, from above 1 million pieces per cubic meter to less than 1
\npiece in 100 cubic meters. Microplastics can cause several harmful
\nphysical effects on humans and living organisms through such mechanisms
\nas entanglement and ingestion. The microplastics can act as carriers of
\nvarious toxins such as additives from industrial production processes
\nand persistent contaminants by the sorption in waters. Those toxins may
\ncause great health problems to humans. A few studies on the fishes
\ndemonstrated that the microplastics and the associated toxins are
\nbio-accumulated and cause such problems as intestinal damage and change
\nin metabolic profiles. In studies of microplastics, fresh water is first
\nsampled by the nets with typical mesh size of 330\u202f\u03bcm for collection of
\nmicroplastics. After the volume reducing process, the samples will then
\ngo through the purification process including density separation by such
\ninorganic salts as sodium chloride and digestion process by oxidizing
\nagents or enzymes. The sequence of these two processes (namely
\npurification and digestion) is dependent on the sample type. The
\npurified samples can be studied by several analytical methods. The
\ncommonly used methods for the qualification studies are FTIR
\nspectroscopy, Raman spectroscopy, pyrolysis-GC\/MS, and liquid
\nchromatography. A tagging method can be used in the quantification
\nstudy. Our literature study finds that there is still no universal
\naccepted quantification and qualification tools of microplastics in
\nfresh waters. More work is anticipated so as to obtain accurate
\ninformation on microplastics in freshwater, which can then be used for
\nthe better assessment of the environmental risk.<\/p>\n