Microplastic (MP) studies in freshwater environments are gaining attention due to the huge quantities of plastic particles reported from lakes and rivers and the potential for negative impacts in these environments. Different units have been used to report MP densities, which makes it difficult to compare data and can result in reports of extremely high concentrations that do not reflect the original sample size. We recommended that the density of MPs from bulk samples be reported as number L−1, while density from net samples should be reported as number m−3. If the density of MPs from net samples is expressed on an areal basis, values should be reported as number/1000 m2, and not as number km−2. Spectroscopy (ATR-μFT-IR and μRAMAN) and Pyrolysis-Gas Chromatography coupled to Mass Spectrometry are techniques that could be used for quantitative identification of the various types of polymers in MP particles.
TrAC Trends in Analytical Chemistry, Volume 113, April 2019, Pages 402-408.,