Study of a stream in Argentina with a high concentration of microplastics: Preliminary analysis of the methodology

This study presents for the first time results about the microplastic concentration and their origin in a stream of the Pampas region in Argentina, receiving wastewater of an intermediate city. The most appropriate procedure to analyze and quantify the microplastics in the studied system is the use of an oxidative digestion process using a 30% H2O2 solution to eliminate the organic matter in the samples. A high quantity of MPs, on the order of millions of microplastics per m(3) of water, was estimated in the Langueyu stream. 56% of the microplastics correspond to fiberswith diameters between 10 and 15 mu m and lengths less than 500 mu m, while 44% are fragmentswith sizes of tens of micrometers. Raman microspectroscopy was used to identify the type of fibers. The characteristics of the microplastic fibers released in a wash load test are comparable with those observed in the Langueyu stream, in particular, the average sizes and the distribution of the diameters of the MPFs are similar. The processes in the sewage treatment plant, prior to their discharge in the stream, would affect the color of the fibers and their length. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

This study revealed high levels of microplastic pollution in the Langueyu stream, with a majority of fibers and some fragments. The use of oxidative digestion process was effective in analyzing and quantifying the microplastics in the system.