Jingyi Li, Huihui Liu, J. Paul Chen,

Microplastics in freshwater systems: A review on occurrence, environmental effects and methods
for microplastics detection,

Water Research,
Volume 137,
2018,
Pages 362-374,
ISSN 0043-1354,

Abstract:

The continuous increase in synthetic plastic production and
poor management in plastic waste have led to a tremendous increase in
the dumping into our aqueous environment. Consequently, microplastics
commonly defined as sizes less than 5 mm are produced and stay in both
seawater and freshwater environment. The presence of microplastics as a
new type of emerging contaminant has become a great issue of concerns
from public and government authorities. The sources of microplastics to
freshwater systems are many with the largest portion from wastewater
treatment plants. The abundance of microplastics varies with the
location, from above 1 million pieces per cubic meter to less than 1
piece in 100 cubic meters. Microplastics can cause several harmful
physical effects on humans and living organisms through such mechanisms
as entanglement and ingestion. The microplastics can act as carriers of
various toxins such as additives from industrial production processes
and persistent contaminants by the sorption in waters. Those toxins may
cause great health problems to humans. A few studies on the fishes
demonstrated that the microplastics and the associated toxins are
bio-accumulated and cause such problems as intestinal damage and change
in metabolic profiles. In studies of microplastics, fresh water is first
sampled by the nets with typical mesh size of 330 μm for collection of
microplastics. After the volume reducing process, the samples will then
go through the purification process including density separation by such
inorganic salts as sodium chloride and digestion process by oxidizing
agents or enzymes. The sequence of these two processes (namely
purification and digestion) is dependent on the sample type. The
purified samples can be studied by several analytical methods. The
commonly used methods for the qualification studies are FTIR
spectroscopy, Raman spectroscopy, pyrolysis-GC/MS, and liquid
chromatography. A tagging method can be used in the quantification
study. Our literature study finds that there is still no universal
accepted quantification and qualification tools of microplastics in
fresh waters. More work is anticipated so as to obtain accurate
information on microplastics in freshwater, which can then be used for
the better assessment of the environmental risk.

https://drive.google.com/open?id=1j__KAjYyC0c42WZCTKNgoHAHud3KJhvE
https://doi.org/10.1016/j.watres.2017.12.056.(http://www.sciencedirect.com/science/article/pii/S0043135417310515)