Sampling and identification of microplastics in groundwater

Microplastics pollution in groundwater remains significantly underreported within scientific literature. This paper presents a comprehensive protocol outlining the methodology for the sampling of groundwater from boreholes, as well as the steps of microplastics separation and analysis. It provides an extensive description of a filtration sampling system designed specifically for this purpose, along with the detailed sampling procedure. In addition, it presents the laboratory analysis of microplastic particles, including their characterization based on size, shape, color, transparency, and chemical structure using attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and micro-FTIR spectroscopy. Factors that can influence results are discussed, and special attention is paid to preventing contamination of samples. The methodology described also considers the requirements of the Annex of Commission Delegated Decision (EU) 2024/1441 of 11 March 2024, supplementing Directive (EU) 2020/2184 of the European Parliament and of the Council. This comprehensive written protocol, accompanied by video guidance, is intended to support the development of a synchronized methodology for monitoring microplastics in groundwater or drinking water. This resource will be of interest to researchers in the field of microplastics worldwide.