Recent developments in analytical methods for the assessment of microplastic contamination in the groundwater

Abstract

Groundwater is the most important source of available freshwater used by more than 2 billion people around the world. Microplastics (MPs) is one of the emerging contaminants in the groundwater. There are several studies on the detection of MPs in the marine and freshwater environment and in the digestive tracts of several species, but only a few studies are conducted on the evaluation of MPs in the groundwater. In 2019, the World Health Organization (WHO) declared that MPs in drinking water do not appear to pose any health risk at the current levels. In 2015, the National Oceanic and Atmospheric Administration (NOAA) made an attempt to standardize the laboratory methods of MP. MP research is accompanied by many methodological challenges, which need to be overcome to assess the impact of MPs on aquatic systems. Therefore, the development of standardized operation protocols (SOPs) is a prerequisite for comparing the merit of different methods/analyses. In this chapter, the status of currently applied tools for the identification and quantification of MPs in groundwater is evaluated to provide a harmonized guideline for future SOPs. The analytical methods, including visual identification (naked-eye detection and optical microscope), dye staining, spectroscopy, and microscopy (Fourier transform infrared and Raman), thermal degradation by pyrolysis gas chromatography mass spectrometry (Py-GCMS) and thermal extraction desorption gas chromatography mass spectrometry (TED-GCMS) are discussed. The advantages and limitations of analytical methods are summarized. Additional techniques as well as combined application of analytical techniques are suggested for future research.