A Survey of Microplastics Occurrence in Drinking Water Systems Globally

Topics in Drinking Water
Oral Presentation

Prepared by A. Eaton1, J. Skovly2, W. Lipps1, B. Cahoon1
1 - Eurofins Eaton Analytical LLC (EEA), 750 Royal Oaks Drive, #100, Monrovia, California, 91016, United States
2 - Eurofins Environment Testing Norway AS, Sandviksveien 110, Bergen, N-5035, Norway

Contact Information: andyeaton@eurofinsus.com; 626-386-1125


Microplastics have been a topic of increasing interest in the water industry over the last 5 years as a result of various studies showing their widespread occurrence in marine waters, wastewaters, and drinking water and even bottled water. One of the challenges of microplastics, as noted by EPA in a workshop in 2017, is that almost nothing is standardized, including sampling protocols, size ranges of interest, and analytical methods. In spite of this there have been regulations proposed by various entities (e.g. California 2018) for monitoring to establish an occurrence baseline. Of particular concern is that there is as yet no standard validated method available for microplastics and the methods employed continue to evolve. As an example, most of the work that has been done to date has either used dyes (Nile Red), FTIR, micro-FTIR, micro-Raman, and pyrolysis GC-MS. Most of these methods provide counts of particles, but pyrolysis GC-MS provides mass data in lieu of a particle count. The analytical method chosen is highly dependent on the matrix of interest, with FTIR and micro-Raman methods being used for smaller particles. To date most of the interest in water systems (wastewater, reuse water, and drinking water distribution systems) is generally in larger particles (5 um to 1500 um). The pyrolysis GC-MS method generally has a sensitivity of 0.1 to 1 ug/L and may be used for particles of as low as 1 um (if samples are filtered through 0.2 um filters) or larger, and also identify types of plastics.
As a result of Eurofins global presence, we elected to do a global survey of microplastics using the pyrolysis GC-MS method, which was validated in our lab in Bergen, Norway. Over 300 drinking water distribution samples from over 20 countries in 5 continents were analyzed using pyrolysis GC-MS. Samples were analyzed by filtering with Anodisc™ 0.2µm and the filter and particulates quantitatively pyrolysed and introduced directly into a calibrated GC-MS for the polymers: PE, PP, PS, PVC, PET, PMMA, PC, PA6 with a LOQ of 1-3µg/L depending on the polymer. This presentation will summarize the methods that have been proposed for microplastics testing and the results of the global study using pyrolysis GC-MS, and highlight any differences among regions. No individual water systems will be identified.